Configuring Frame Relay

Configuring Frame Relay
Feature History
Release
Modification
Cisco IOS
For information about feature support in Cisco IOS
software, use Cisco Feature Navigator.
• Finding Feature Information, page 1
• Information About Frame Relay, page 1
• How to Configure Frame Relay, page 25
• Configuration Examples for Frame Relay, page 58
• Additional References, page 80
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and
feature information, see Bug Search Tool and the release notes for your platform and software release. To
find information about the features documented in this module, and to see a list of the releases in which each
feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Information About Frame Relay
Cisco Frame Relay MIB
The Cisco Frame Relay MIB adds extensions to the standard Frame Relay MIB (RFC 1315). It provides
additional link-level and virtual circuit (VC)-level information and statistics that are mostly specific to Cisco
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Frame Relay Hardware Configurations
Frame Relay implementation. This MIB provides SNMP network management access to most of the information
covered by the show frame-relaycommands such as, show frame-relay lmi, show frame-relay pvc, show
frame-relay map, and show frame-relay svc.
Frame Relay Hardware Configurations
You can create Frame Relay connections using one of the following hardware configurations:
• Routers and access servers connected directly to the Frame Relay switch
• Routers and access servers connected directly to a channel service unit/digital service unit (CSU/DSU),
which then connects to a remote Frame Relay switch
Note
Routers can connect to Frame Relay networks either by direct connection to a Frame Relay switch or
through CSU/DSUs. However, a single router interface configured for Frame Relay can be configured
for only one of these methods.
The CSU/DSU converts V.35 or RS-449 signals to the properly coded T1 transmission signal for successful
reception by the Frame Relay network. The figure below illustrates the connections among the components.
Figure 1: Typical Frame Relay Configuration
The Frame Relay interface actually consists of one physical connection between the network server and the
switch that provides the service. This single physical connection provides direct connectivity to each device
on a network.
Frame Relay Encapsulation
Frame Relay supports encapsulation of all supported protocols in conformance with RFC 1490, Multiprotocol
Interconnect over Frame Relay, allowing interoperability among multiple vendors. Use the IETF form of
Frame Relay encapsulation if your device or access server is connected to another vendor’s equipment across
a Frame Relay network. IETF encapsulation is supported either at the interface level or on a per-VC basis.
Shut down the interface prior to changing encapsulation types. Although shutting down the interface is not
required, it ensures that the interface is reset for the new encapsulation.
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Dynamic or Static Address Mapping
Dynamic or Static Address Mapping
Dynamic Address Mapping
Dynamic address mapping uses Frame Relay Inverse Address Resolution Protocol (ARP) to request the
next-hop protocol address for a specific connection, given its known Data link connection identifier (DLCI).
Responses to Inverse ARP requests are entered in an address-to-DLCI mapping table on the device or access
server. The DLCI mapping table is then used to supply the next-hop protocol address or the DLCI for outgoing
traffic.
Inverse ARP is enabled by default for all protocols it supports. However, it can be disabled for specific
protocol-DLCI pairs. As a result, you can use dynamic mapping for some protocols and static mapping for
other protocols on the same DLCI. You can explicitly disable Inverse ARP for a protocol-DLCI pair if you
know that the protocol is not supported on the other end of the connection. For more information, see the
Disabling or Reenabling Frame Relay Inverse ARP section.
Note
Because Inverse ARP is enabled by default, no additional command is required to configure dynamic
mapping on an interface and packets are not sent out for protocols that are not enabled on the interface.
Static Address Mapping
A static map links a specified next-hop protocol address to a specified Data link connection identifier (DLCI).
Static mapping removes the need for Inverse Address Resolution Protocol (ARP) requests; when you supply
a static map, Inverse ARP is automatically disabled for the specified protocol on the specified DLCI. You
must use static mapping in the any of the following scenarios:
• If the device at the other end does not support Inverse ARP at all
• If the device does not support Inverse ARP for a specific protocol that you want to use over Frame Relay.
You can simplify the configuration for the Open Shortest Path First (OSPF) protocol by adding the optional
broadcast keyword when doing this task. Refer to the frame-relay map command description in the Cisco
IOS Wide-Area Networking Command Reference and the examples at the end of this chapter for more
information about using the broadcast keyword.
LMI
The software supports Local Management Interface (LMI) autosense, which enables the interface to determine
the LMI type supported by the switch. Support for LMI autosense means that you are no longer required to
configure the LMI explicitly.
LMI autosense is active in the following situations:
• The router is powered up or the interface changes state to up.
• The line protocol is down but the line is up.
• The interface is a Frame Relay DTE.
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Frame Relay SVCs
• The LMI type is not explicitly configured.
Activating LMI Autosense
Status Request
When LMI autosense is active, it sends out a full status request, in all three LMI types, to the switch. The
order is ANSI, ITU, cisco, but it is done in rapid succession. software provides the ability to listen in on both
DLCI 1023 (cisco LMI) and DLCI 0 (ANSI and ITU) simultaneously.
Status Messages
One or more of the status requests will prompts a reply (status message) from the switch. The device decodes
the format of the reply and configures itself automatically. If more than one reply is received, the device
configures itself with the type of the last received reply. This is to accommodate intelligent switches that can
handle multiple formats simultaneously.
LMI Autosense
If Local Management Interface (LMI) autosense is unsuccessful, an intelligent retry scheme is built in. Every
N391 interval (default is 60 seconds, which is 6 keep exchanges at 10 seconds each), LMI autosense attempts
to ascertain the LMI type. For more information about N391, see the frame-relay lmi-n391dte command in
the chapter "Frame Relay Commands " in the Cisco IOS Wide-Area Networking Command Reference .
The only visible indication to the user that LMI autosense is in progress is that debug frame lmi is enabled.
At every N391 interval, the user sees 3 rapid status inquiries from the serial interface one in each of the
following LMI-type:
• ANSI
• ITU
• Cisco
Configuration Options
No configuration options are provided; LMI autosense is transparent to the user. You can turn off LMI
autosense by explicitly configuring an Local Management Interface (LMI) type. The LMI type must be written
into NVRAM so that next time the device powers up, LMI autosense will be inactive. At the end of autoinstall,
a frame-relay lmi-type xxx statement is included within the interface configuration. This configuration is not
automatically written to NVRAM; you must explicitly write the configuration to NVRAM by using the copy
system:running-config or copy nvram:startup-config command.
Frame Relay SVCs
Access to Frame Relay networks is made through private leased lines at speeds ranging from 56 kbps to 45
Mbps. Frame Relay is a connection-oriented packet-transfer mechanism that establishes VCs between endpoints.
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Frame Relay Traffic Shaping
Switched virtual circuits (SVCs) allow access through a Frame Relay network by setting up a path to the
destination endpoints only when the need arises and tearing down the path when it is no longer needed.
SVCs can coexist with PVCs in the same sites and routers. For example, routers at remote branch offices
might set up PVCs to the central headquarters for frequent communication, but set up SVCs with each other
as needed for intermittent communication. As a result, any-to-any communication can be set up without
any-to-any PVCs.
On SVCs, quality of service (QoS) elements can be specified on a call-by-call basis to request network
resources.
SVC support is offered in the Enterprise image on Cisco platforms that include a serial or HSSI interface.
You must have the following services before Frame Relay SVCs can operate:
• Frame Relay SVC support by the service provider--The service provider’s switch must be capable of
supporting SVC operation.
• Physical loop connection--A leased line or dedicated line must exist between the router (DTE) and the
local Frame Relay switch.
Operating SVCs
SVC operation requires that the Data Link layer (Layer 2) be set up, running ITU-T Q.922 Link Access
Procedures to Frame mode bearer services (LAPF), prior to signalling for an SVC. Layer 2 sets itself up as
soon as SVC support is enabled on the interface, if both the line and the line protocol are up. When the SVCs
are configured and demand for a path occurs, the Q.933 signalling sequence is initiated. Once the SVC is set
up, data transfer begins.
Q.922 provides a reliable link layer for Q.933 operation. All Q.933 call control information is transmitted
over DLCI 0; this DLCI is also used for the management protocols specified in ANSI T1.617 Annex D or
Q.933 Annex A.
You must enable SVC operation at the interface level. Once it is enabled at the interface level, it is enabled
on any subinterfaces on that interface. One signalling channel, DLCI 0, is set up for the interface, and all
SVCs are controlled from the physical interface.
Frame Relay Traffic Shaping
Traffic shaping applies to both PVCs and SVCs. Enabling Frame Relay traffic shaping on an interface enables
both traffic shaping and per-VC queueing on all the PVCs and SVCs on the interface. Traffic shaping enables
the router to control the circuit’s output rate and react to congestion notification information if also configured.
Note
Frame Relay traffic shaping is not effective for Layer 2 PVC switching using the frame-relay route
command.
Defining VCs for Different Types of Traffic
By defining separate VCs for different types of traffic and specifying queueing and an outbound traffic rate
for each VC, you can provide guaranteed bandwidth for each type of traffic. By specifying different traffic
rates for different VCs over the same line, you can perform virtual time division multiplexing. By throttling
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Frame Relay Traffic Shaping
outbound traffic from high-speed lines in central offices to lower-speed lines in remote locations, you can
ease congestion and data loss in the network; enhanced queueing also prevents congestion-caused data loss.
Frame Relay ForeSight
ForeSight is the network traffic control software used in some Cisco switches. The Cisco Frame Relay switch
can extend ForeSight messages over a User-to-Network Interface (UNI), passing the backward congestion
notification for VCs.
ForeSight allows Cisco Frame Relay routers to process and react to ForeSight messages and adjust VC level
traffic shaping in a timely manner.
ForeSight must be configured explicitly on both the Cisco router and the Cisco switch. ForeSight is enabled
on the Cisco router when Frame Relay traffic shaping is configured. However, the router’s response to ForeSight
is not applied to any VC until the frame-relay adaptive-shaping foresight command is added to the VCs
map-class. When ForeSight is enabled on the switch, the switch will periodically send out a ForeSight message
based on the time value configured. The time interval can range from 40 to 5000 milliseconds.
When a Cisco router receives a ForeSight message indicating that certain DLCIs are experiencing congestion,
the Cisco router reacts by activating its traffic-shaping function to slow down the output rate. The router reacts
as it would if it were to detect the congestion by receiving a packet with the backward explicit congestion
notification (BECN) bit set.
When ForeSight is enabled, Frame Relay traffic shaping will adapt to ForeSight messages and BECN messages.
Frame Relay ForeSight Prerequisites
For router ForeSight to work, the following conditions must exist on the Cisco router:
• Frame Relay traffic shaping must be enabled on the interface.
• The traffic shaping for a circuit is adapted to ForeSight.
The following additional condition must exist on the Cisco switch:
• The UNI connecting to the router is Consolidated Link Layer Management (CLLM) enabled, with the
proper time interval specified.
Frame Relay router ForeSight is enabled automatically when you use the frame-relay traffic-shaping
command. However, you must issue the map-class frame-relay command and the frame-relay
adaptive-shaping foresightcommand before the router will respond to ForeSight and apply the traffic-shaping
effect on a specific interface, subinterface, or VC.
Frame Relay Congestion Notification Methods
The difference between the BECN and ForeSight congestion notification methods is that BECN requires a
user packet to be sent in the direction of the congested DLCI to convey the signal. The sending of user packets
is not predictable and, therefore, not reliable as a notification mechanism. Rather than waiting for user packets
to provide the congestion notification, timed ForeSight messages guarantee that the router receives notification
before congestion becomes a problem. Traffic can be slowed down in the direction of the congested DLCI.
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Frame Relay Traffic Shaping
Enhanced Local Management Interface
Enhanced Local Management Interface (ELMI) allows the router to learn QoS parameters and connectivity
information from the Cisco switch and to use this information for traffic shaping, configuration, or management
purposes. ELMI simplifies the process of configuring traffic shaping on the router and reduces chances of
specifying inconsistent or incorrect values when configuring the router. ELMI works between Cisco routers
and Cisco switches (BPX and IGX platforms).
ELMI QoS Autosense
When used in conjunction with traffic shaping, ELMI enables the router to respond to changes in the network
dynamically. ELMI enables automated exchange of Frame Relay QoS parameter information between the
Cisco router and the Cisco switch. The figure below illustrates a Cisco switch and a Cisco router, both
configured with ELMI enabled. The switch sends QoS information to the router, which uses it for traffic rate
enforcement.
Routers can base congestion management and prioritization decisions on known QoS values, such as the
Committed Information Rate (CIR), Committed Burst Size (Bc), and Excess Burst Size (Be). The router senses
QoS values from the switch and can be configured to use those values in traffic shaping.
It is not necessary to configure traffic shaping on the interface to enable ELMI, but you may want to do so in
order to know the values being used by the switch. If you want the router to respond to the QoS information
received from the switch by adjusting the output rate, you must configure traffic shaping on the interface. To
configure traffic shaping, use the frame-relay traffic-shaping command in interface configuration mode.
ELMI Address Registration
ELMI address registration enables a network management system (NMS) to detect connectivity among Cisco
switches and routers in a network using the ELMI protocol. During ELMI version negotiation, neighboring
devices exchange their management IP addresses and ifIndex. The NMS polls the devices and uses the Cisco
Frame Relay MIB to collect this connectivity information. ELMI address registration allows for autodetection
of the complete network topology.
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The figure below shows a typical network in which ELMI address registration is in use.
Figure 3: Connectivity Detection Using ELMI Address Registration
ELMI address registration takes place on all interfaces on which ELMI is enabled, even if all the interfaces
are connected to the same router or switch. The router periodically sends a version inquiry message with
version information, the management IP address, and ifIndex to the switch. The switch sends its management
IP address and ifIndex using the version status message. When the management IP address of the switch
changes, an asynchronous ELMI version status message is immediately sent to the neighboring device.
Note
The ELMI address registration mechanism does not check for duplicate or illegal addresses.
When ELMI is enabled, the router automatically chooses the IP address of one of the interfaces to use for
ELMI address registration purposes. The router will choose the IP address of an Ethernet interface first, and
then serial and other interfaces. You have the option to use the IP address chosen by the router or to disable
the autoaddress mechanism and configure the management IP address yourself. You can also choose to disable
ELMI address registration on a specific interface or on all interfaces.
Traffic-Shaping Map Class for the Interface
If you specify a Frame Relay map class for a main interface, all the VCs on its subinterfaces inherit all the
traffic-shaping parameters defined for the class. You can override the default for a specific DLCI on a specific
subinterface by using the class VC configuration command to assign the DLCI explicitly to a different class.
See the section Configuring Frame Relay Subinterfaces, on page 45 for information about setting up
subinterfaces.
For an example of assigning subinterface DLCIs to the default class and assigning others explicitly to a
different class, see the section Example Frame Relay Traffic Shaping, on page 62.
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Frame Relay Switching
Specifying Map Class with Queueing and Traffic-Shaping Parameters
When defining a map class for Frame Relay, you can specify the average and peak rates (in bits per second)
allowed on virtual circuits (VCs) associated with the map class. You can also specify either a custom queue
list or a priority queue group to use on VCs associated with the map class.
Defining Access Lists
You can specify access lists and associate them with the custom queue list defined for any map class. The list
number specified in the access list and the custom queue list tie them together. See the appropriate protocol
chapters for information about defining access lists for the protocols you want to transmit on the Frame Relay
network.
Defining Priority Queue Lists for the Map Class
You can define a priority list for a protocol and you can also define a default priority list. The number used
for a specific priority list ties the list to the Frame Relay priority group defined for a specified map class. For
example, if you enter the frame relay priority-group 2 command for the map class "fast_vcs" and then you
enter the priority-list 2 protocol decnet high command, that priority list is used for the "fast_vcs" map class.
The average and peak traffic rates defined for the "fast_vcs" map class are used for DECnet traffic.
Defining Custom Queue Lists for the Map Class
You can define a queue list for a protocol and a default queue list. You can also specify the maximum number
of bytes to be transmitted in any cycle. The number used for a specific queue list ties the list to the Frame
Relay custom queue list defined for a specified map class.
For example, if you enter the frame relay custom-queue-list 1 command for the map class "slow_vcs" and
then you enter the queue-list 1 protocol ip list 100 command, that queue list is used for the "slow_vcs" map
class; access-list 100 definition is also used for that map class and queue. The average and peak traffic rates
defined for the "slow_vcs" map class are used for IP traffic that meets the access list 100 criteria.
Frame Relay Switching
Frame Relay switching is a means of switching packets based on the DLCI, which can be considered the
Frame Relay equivalent of a MAC address. You perform switching by configuring your Cisco router or access
server into a Frame Relay network. There are two parts to a Frame Relay network:
• Frame Relay DTE (the router or access server)
• Frame Relay DCE switch
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Frame Relay Switching
The figure below illustrates Frame Relay switched networks. Routers A, B, and C are Frame Relay DTEs
connected to each other via a Frame Relay network.
Figure 4: Frame Relay Switched Network
Frame Relay switching is supported on the following interface types:
• Serial interfaces
• ISDN interfaces
Note
Frame Relay switching is not supported on subinterfaces.
Frame Relay Switching over ISDN B Channels
Frame Relay switching over ISDN B channels enables you to transport Frame Relay data over ISDN. This
feature allows small offices to be hubbed out of larger offices rather than being connected directly to the core
network. The hub router acts as a Frame Relay switch, switching between ISDN and serial interfaces, as shown
in the figure below.
Figure 5: Router Used As a Frame Relay Switch over ISDN
Frame Relay switching over ISDN provides the following functionality:
• LMI is supported on ISDN Frame Relay DCE interfaces.
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Frame Relay Switching
• A single BRI/PRI interface can use a combination of switched PVCs and terminated Frame Relay PVCs.
• Frame Relay switching supports both leased-line ISDN, on which a B channel is permanently connected,
and switched ISDN, on which B channels may be dynamically set up and torn down.
Note the following restrictions for Frame Relay switching over ISDN:
• Frame Relay traffic shaping is not supported on ISDN interfaces.
• The router configured for Frame Relay switching over ISDN cannot initiate the ISDN call.
• PVC-level congestion management is not supported over ISDN. Interface-level congestion management
is supported.
When Frame Relay switching is performed by using a dialer profile, encapsulation of the underlying physical
(BRI) interface must be configured as high-level data link control (HDLC).
Frame Relay Traffic Shaping on Switched PVCs
Applying Frame Relay traffic shaping to switched PVCs enables a router to be used as a Frame Relay port
concentrator in front of a Frame Relay switch. The Frame Relay switch will shape the concentrated traffic
before sending it into the network. The figure below shows the network configuration.
Figure 6: Router Used As a Frame Relay Port Concentrator
When you configure traffic shaping, you will define the traffic-shaping parameters in a Frame Relay map
class and then attach the map class to the interface or a single switched PVC. All the traffic-shaping map-class
parameters are applicable to switched PVCs: namely, Bc, Be, CIR, minimum CIR, average rate, peak rate,
and adaptive shaping.
Frame Relay traffic shaping must be enabled on the interface before traffic-shaping map-class parameters
will be effective. Note that when you enable Frame Relay traffic shaping, all PVCs, switched and terminated,
will be shaped on that interface. Switched PVCs that are not associated with a map class will inherit shaping
parameters from the interface or use default values.
Traffic Policing
Traffic policing prevents congestion on incoming PVCs by discarding or setting the DE bit on packets that
exceed specified traffic parameters.
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Frame Relay Switching
You can associate the map class with the interface or individual switched PVCs. Switched PVCs that are not
associated with a map class will inherit policing parameters from the interface.
If you use a map class to configure both traffic policing and shaping, use the in keyword to specify incoming
traffic for policing and the out keyword to specify outgoing traffic for shaping. If you configure shaping on
one segment of a switched PVC and policing on the other, the shaping parameters will be derived from the
policing parameters unless you specifically define shaping parameters in the map class.
Congestion Management on Switched PVCs
Frame Relay congestion management can be used to manage outgoing traffic congestion on switched PVCs.
When Frame Relay congestion management is enabled, one way that the router manages congestion is by
setting backward explicit congestion notification (BECN) and forward explicit congestion notification (FECN)
bits on packets. When a switched PVC or interface is congested, packets experiencing congestion are marked
with the FECN bit, and packets traveling in the reverse direction are marked with the BECN bit. When these
bits reach a user device at the end of the network, the user device can react to the ECN bits and adjust the
flow of traffic.
When the output interface queue reaches or exceeds the ECN excess threshold, Frame Relay bit packets on
all PVCs crossing that interface will be marked with FECN or BECN, depending on their direction of travel.
When the queue reaches or exceeds the ECN committed threshold, all Frame Relay packets will be marked
with FECN or BECN.
A second way the router manages congestion is by discarding Frame Relay packets that are marked with the
discard eligible (DE) bit and that exceed a specified level of congestion.
When the queue reaches or exceeds the DE threshold, Frame Relay packets with the DE bit will be discarded
rather than queued.
You can define two levels of congestion. The first level applies to individual PVCs transmitting traffic in
excess of the committed information rate (CIR). The second level applies to all PVCs at an interface. This
scheme allows you to adjust the congestion on PVCs transmitting above the CIR before applying congestion
management measures to all PVCs.
Congestion management parameters can be configured on the output interface queue and on traffic-shaping
queues.
FRF.12 Fragmentation on Switched PVCs
The FRF.12 Implementation Agreement allows long data frames to be fragmented into smaller pieces. This
process allows real-time traffic and non-real-time traffic to be carried together on lower-speed links without
causing excessive delay to the real-time traffic. For further information about FRF.12 fragmentation, see the
section End-to-End FRF.12 Fragmentation, on page 20 later in this module.
Some Frame Relay access devices do not support the FRF.12 standard for end-to-end fragmentation. Large
packets sourced from these devices can cause significant serialization delay across low-speed trunks in switched
networks. Using FRF.12 fragmentation can help prevent this delay. An edge router that receives large packets
from a Frame Relay access device will fragment those packets before transmitting them across the switched
network. The edge router that receives the fragmented packets will reassemble those packets before sending
them to a Frame Relay access device that does not support FRF.12. If the receiving Frame Relay access device
does support FRF.12, the router will transmit the fragmented packets without reassembling them.
Note the following conditions and restrictions on FRF.12 fragmentation on switched PVCs:
• Frame Relay traffic shaping must be enabled.
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Frame Relay End-to-End Keepalives
• Interface queueing must be dual FIFO queueing or PVC interface priority queueing.
• Switched PVCs must be configured using the connect command.
• If the Frame Relay access device does not support FRF.12 fragmentation, the FRF.12 Support on Switched
Frame Relay PVCs feature will not benefit the interface between the Frame Relay access device and the
edge router. Fragmentation and reassembly occur on the interface between the edge router and the
switched Frame Relay network.
• If the Frame Relay access device is sending voice and unfragmented data on the same PVC, voice quality
will suffer. The edge router will not reorder packets on switched PVCs.
Frame Relay End-to-End Keepalives
Frame Relay end-to-end keepalives enable monitoring of PVC status for network monitoring or backup
applications and are configurable on a per-PVC basis with configurable timers. The Frame Relay switch within
the local PVC segment deduces the status of the remote PVC segment through a Network-to-Network Interface
(NNI) and reports the status to the local router. If LMI support within the switch is not end-to-end, end-to-end
keepalives are the only source of information about the remote router. End-to-end keepalives verify that data
is getting through to a remote device via end-to-end communication.
Each PVC connecting two end devices needs two separate keepalive systems, because the upstream path may
not be the same as the downstream path. One system sends out requests and handles responses to those
requests--the send side--while the other system handles and replies to requests from the device at the other
end of the PVC--the receive side. The send side on one device communicates with the receive side on the
other device, and vice versa.
The send side sends out a keepalive request and waits for a reply to its request. If a reply is received before
the timer expires, a send-side Frame Relay end-to-end keepalive is recorded. If no reply is received before
the timer expires, an error event is recorded. A number of the most recently recorded events are examined. If
enough error events are accumulated, the keepalive status of the VC is changed from up to down, or if enough
consecutive successful replies are received, the keepalive status of the VC is changed from down to up. The
number of events that will be examined is called the event window .
The receive side is similar to the send side. The receive side waits for requests and sends out replies to those
requests. If a request is received before the timer expires, a success event is recorded. If a request is not
received, an error event is recorded. If enough error events occur in the event window, the PVC state will be
changed from up to down. If enough consecutive success events occur, the state will be changed from down
to up.
End-to-end keepalives can be configured in one of four modes: bidirectional, request, reply, or passive-reply.
• In bidirectional mode, both the send side and the receive side are enabled. The send side of the device
sends out and waits for replies to keepalive requests from the receive side of the other PVC device. The
receive side of the device waits for and replies to keepalive requests from the send side of the other PVC
device.
• In request mode, only the send side is enabled, and the device sends out and waits for replies to its
keepalive requests.
• In reply mode, only the receive side is enabled, and the device waits for and replies to keepalive requests.
• In passive-reply mode, the device only responds to keepalive requests, but does not set any timers or
keep track of any events.
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PPP over Frame Relay
Because end-to-end keepalives allow traffic flow in both directions, they can be used to carry control and
configuration information from end to end. Consistency of information between end hosts is critical in
applications such as those relating to prioritized traffic and Voice over Frame Relay. Whereas SVCs can
convey such information within end-to-end signalling messages, PVCs will benefit from a bidirectional
communication mechanism.
End-to-end keepalives are derived from the Frame Relay LMI protocol and work between peer Cisco
communications devices. The key difference is that rather than running over the signalling channel, as is the
case with LMI, end-to-end keepalives run over individual data channels.
Encapsulation of keepalive packets is proprietary; therefore, the feature is available only on Cisco devices
running a software release that supports the Frame Relay End-to-End Keepalive feature.
You must configure both ends of a VC to send keepalives. If one end is configured as bidirectional, the other
end must also be configured as bidirectional. If one end is configured as request, the other end must be
configured as reply or passive-reply. If one end is configured as reply or passive-reply, the other end must be
configured as request
PPP over Frame Relay
Point-to-point protocol (PPP) over Frame Relay allows a router to establish end-to-end PPP sessions over
Frame Relay. This is done over a PVC, which is the only circuit currently supported. The PPP session does
not occur unless the associated Frame Relay PVC is in an "active" state. The Frame Relay PVC can coexist
with other circuits using different Frame Relay encapsulation methods, such as RFC 1490 and the Cisco
proprietary method, over the same Frame Relay link. There can be multiple PPP over Frame Relay circuits
on one Frame Relay link.
One PPP connection resides on one virtual access interface. This is internally created from a virtual template
interface, which contains all necessary PPP and network protocol information and is shared by multiple virtual
access interfaces. The virtual access interface is coexistent with the creation of the Frame Relay circuit when
the corresponding DLCI is configured. Hardware compression and fancy queueing algorithms, such as weighted
fair queueing, custom queueing, and priority queueing, are not applied to virtual access interfaces.
PPP over Frame Relay is only supported on IP. IP datagrams are transported over the PPP link using RFC
1973 compliant Frame Relay framing. The frame format is shown in the figure below.
Figure 7: PPP over Frame Relay Frame Format
The table below lists the Frame Relay frame format components illustrated in the figure above.
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Configuring Frame Relay
PPP over Frame Relay
Table 1: PPP Frame Relay Frame Format Descriptions
Field
Description
Flag
A single byte that indicates the beginning or end of
a frame.
Address
A two-byte field that indicates the logical connection
that maps to the physical channel; the DLCI.
Control
A single byte that calls for transmission of user data.
PPP over Frame Relay uses a value of 0X03, which
indicates that the frame is an unnumbered information
(UI) frame.
NLPID
Network layer protocol ID--a single byte that uniquely
identifies a PPP packet to Frame Relay.
PPP protocol
PPP packet type.
The figure below shows remote users running PPP to access their Frame Relay corporate networks.
Figure 8: PPP over Frame Relay Scenario
Before PPP over Frame Relay is configured, Frame Relay must be enabled on the router using the encapsulation
frame-relaycommand. The only task required in order to implement PPP over Frame Relay is to configure
the interface with the locally terminated PVC and the associated virtual template for PPP and IP, as described
in the following section.
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Configuring Frame Relay
Understanding Frame Relay Subinterfaces
After configuring Frame Relay encapsulation on the Cisco router or access server, you must configure the
physical interface with the PVC and apply a virtual template with PPP encapsulation to the DLCI.
Understanding Frame Relay Subinterfaces
Frame Relay subinterfaces provide a mechanism for supporting partially meshed Frame Relay networks. Most
protocols assume transitivity on a logical network; that is, if station A can talk to station B, and station B can
talk to station C, then station A should be able to talk to station C directly. Transitivity is true on LANs, but
not on Frame Relay networks unless A is directly connected to C.
Additionally, certain protocols such as AppleTalk and transparent bridging cannot be supported on partially
meshed networks because they require split horizon . Split horizon is a routing technique in which a packet
received on an interface cannot be sent from the same interface even if received and transmitted on different
VCs.
Configuring Frame Relay subinterfaces ensures that a single physical interface is treated as multiple virtual
interfaces. This treatment allows you to overcome split horizon rules. Packets received on one virtual interface
can be forwarded to another virtual interface even if they are configured on the same physical interface.
Subinterfaces address the limitations of Frame Relay networks by providing a way to subdivide a partially
meshed Frame Relay network into a number of smaller, fully meshed (or point-to-point) subnetworks. Each
subnetwork is assigned its own network number and appears to the protocols as if it were reachable through
a separate interface. (Note that point-to-point subinterfaces can be unnumbered for use with IP, reducing the
addressing burden that might otherwise result.)
The figure below shows a five-node Frame Relay network that is partially meshed (network A). If the entire
network is viewed as a single subnetwork (with a single network number assigned), most protocols assume
that node A can transmit a packet directly to node E, when in fact it must be relayed through nodes C and D.
This network can be made to work with certain protocols (for example, IP), but will not work at all with other
protocols (for example, AppleTalk) because nodes C and D will not relay the packet out the same interface
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Configuring Frame Relay
Understanding Frame Relay Subinterfaces
on which it was received. One way to make this network work fully is to create a fully meshed network
(network B), but doing so requires a large number of PVCs, which may not be economically feasible.
Figure 9: Using Subinterfaces to Provide Full Connectivity on a Partially Meshed Frame Relay Network
Using subinterfaces, you can subdivide the Frame Relay network into three smaller subnetworks (network
C) with separate network numbers. Nodes A, B, and C are connected to a fully meshed network, and nodes
C and D, as well as nodes D and E, are connected via point-to-point networks. In this configuration, nodes C
and D can access two subinterfaces and can therefore forward packets without violating split horizon rules.
If transparent bridging is being used, each subinterface is viewed as a separate bridge port.
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Configuring Frame Relay
Understanding Frame Relay Subinterfaces
Subinterface Addressing
Point-to-Point Subinterfaces
For point-to-point subinterfaces, the destination is presumed to be known and is identified or implied in the
frame-relay interface-dlci command. This command is used to enable routing protocols on main interfaces
that are configured to use Inverse ARP. This command is also helpful for assigning a specific class to a single
PVC on a multipoint subinterface.
If you define a subinterface for point-to-point communication, you cannot reassign the same subinterface
number to be used for multipoint communication without first rebooting the router or access server. Instead,
you can simply avoid using that subinterface number and use a different subinterface number.
Addressing on Multipoint Subinterfaces
• Accepting Inverse ARP for Dynamic Address Mapping on Multipoint Subinterfaces, on page 46
• Configuring a Map Group with E.164 or X.121 Addresses, on page 32
Accepting Inverse ARP for Dynamic Address Mapping on Multipoint Subinterfaces
Dynamic address mapping uses Frame Relay Inverse ARP to request the next-hop protocol address for a
specific connection, given a DLCI. Responses to Inverse ARP requests are entered in an address-to-DLCI
mapping table on the router or access server; the table is then used to supply the next-hop protocol address
or the DLCI for outgoing traffic.
Since the physical interface is now configured as multiple subinterfaces, you must provide information that
distinguishes a subinterface from the physical interface and associates a specific subinterface with a specific
DLCI.
Inverse ARP is enabled by default for all protocols it supports, but can be disabled for specific protocol-DLCI
pairs. As a result, you can use dynamic mapping for some protocols and static mapping for other protocols
on the same DLCI. You can explicitly disable Inverse ARP for a protocol-DLCI pair if you know the protocol
is not supported on the other end of the connection. See the section "Disabling or Reenabling Frame Relay
Inverse ARP, on page 49" later in this chapter for more information.
Because Inverse ARP is enabled by default for all protocols that it supports, no additional command is required
to configure dynamic address mapping on a subinterface.
Configuring Static Address Mapping on Multipoint Subinterfaces
A static map links a specified next-hop protocol address to a specified DLCI. Static mapping removes the
need for Inverse ARP requests; when you supply a static map, Inverse ARP is automatically disabled for the
specified protocol on the specified DLCI.
You must use static mapping if the router at the other end either does not support Inverse ARP at all or does
not support Inverse ARP for a specific protocol that you want to use over Frame Relay.
Backup Interface for a Subinterface
Both point-to-point and multipoint Frame Relay subinterfaces can be configured with a backup interface. This
approach allows individual permanent virtual circuit (PVCs) to be backed up in case of failure rather than
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Configuring Frame Relay
Disabling or Reenabling Frame Relay Inverse ARP
depending on the entire Frame Relay connection to fail before the backup takes over. You can configure a
subinterface for backup on failure only, not for backup based on loading of the line.
If the main interface has a backup interface, it has a precedence over the backup interface of the subinterface
in the case of complete loss of connectivity with the Frame Relay network. As a result, a subinterface backup
is activated only in the following cases:
• If the main interface is up
• If the interface is down and does not have a backup interface defined
If a subinterface fails while its backup interface is in use, and the main interface goes down, the backup
subinterface remains connected.
Disabling or Reenabling Frame Relay Inverse ARP
Frame Relay Inverse ARP is a method of building dynamic address mappings in Frame Relay networks
running AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, and XNS. Inverse ARP allows the router or
access server to discover the protocol address of a device associated with the VC.
Inverse ARP creates dynamic address mappings, as contrasted with the frame-relay map command, which
defines static mappings between a specific protocol address and a specific DLCI.
Inverse ARP is enabled by default but can be disabled explicitly for a given protocol and DLCI pair. Disable
or reenable Inverse ARP under the following conditions:
• Disable Inverse ARP for a selected protocol and DLCI pair when you know that the protocol is not
supported at the other end of the connection.
• Reenable Inverse ARP for a protocol and DLCI pair if conditions or equipment change and the protocol
is then supported at the other end of the connection.
Note
If you change from a point-to-point subinterface to a multipoint subinterface, change the subinterface
number. Frame Relay Inverse ARP will be on by default, and no further action is required.
You do not need to enable or disable Inverse ARP if you have a point-to-point interface, because there is only
a single destination and discovery is not required.
Broadcast Queue for an Interface
Very large Frame Relay networks may have performance problems when many DLCIs terminate in a single
router or access server that must replicate routing updates and service advertising updates on each DLCI. The
updates can consume access-link bandwidth and cause significant latency variations in user traffic; the updates
can also consume interface buffers and lead to higher packet rate loss for both user data and routing updates.
To avoid such problems, you can create a special broadcast queue for an interface. The broadcast queue is
managed independently of the normal interface queue, has its own buffers, and has a configurable size and
service rate.
A broadcast queue is given a maximum transmission rate (throughput) limit measured in both bytes per second
and packets per second. The queue is serviced to ensure that no more than this maximum is provided. The
broadcast queue has priority when transmitting at a rate below the configured maximum, and hence has a
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Configuring Frame Relay
Frame Relay Fragmentation
guaranteed minimum bandwidth allocation. The two transmission rate limits are intended to avoid flooding
the interface with broadcasts. The actual transmission rate limit in any second is the first of the two rate limits
that is reached.
Frame Relay Fragmentation
Cisco has developed three types of Frame Relay fragmentation, which are described in the following sections:
The following provides further information about Frame Relay fragmentation:
End-to-End FRF.12 Fragmentation
The purpose of end-to-end FRF.12 fragmentation is to support real-time and non-real-time data packets on
lower-speed links without causing excessive delay to the real-time data. FRF.12 fragmentation is defined by
the FRF.12 Implementation Agreement. This standard was developed to allow long data frames to be fragmented
into smaller pieces (fragments) and interleaved with real-time frames. In this way, real-time and non-real-time
data frames can be carried together on lower-speed links without causing excessive delay to the real-time
traffic.
End-to-end FRF.12 fragmentation is recommended for use on permanent virtual circuits (PVCs) that share
links with other PVCs that are transporting voice and on PVCs transporting Voice over IP (VoIP). Although
VoIP packets should not be fragmented, they can be interleaved with fragmented packets.
FRF.12 is configured on a per-PVC basis using a Frame Relay map class. The map class can be applied to
one or many PVCs. Frame Relay traffic shaping must be enabled on the interface in order for fragmentation
to work.
Note
When Frame Relay fragmentation is configured, WFQ or LLQ is mandatory. If a map class is configured
for Frame Relay fragmentation and the queueing type on that map class is not WFQ or LLQ, the configured
queueing type is automatically overridden by WFQ with the default values. To configure LLQ for Frame
Relay, refer to the Cisco IOS Quality of Service Solutions Configuration Guide , Release 12.2.
Setting the Fragment Size
Set the fragment size so that voice packets are not fragmented and do not experience a serialization delay
greater than 20 ms.
To set the fragment size, the link speed must be taken into account. The fragment size should be larger than
the voice packets, but small enough to minimize latency on the voice packets. Turn on fragmentation for low
speed links (less than 768 kbps).
Set the fragment size based on the lowest port speed between the routers. For example, if there is a hub and
spoke Frame Relay topology where the hub has a T1 speed and the remote routers have 64 kbps port speeds,
the fragment size needs to be set for the 64 kbps speed on both routers. Any other PVCs that share the same
physical interface need to configure the fragmentation to the size used by the voice PVC.
If the lowest link speed in the path is 64 kbps, the recommended fragment size (for 10 ms serialization delay)
is 80 bytes. If the lowest link speed is 128 kbps, the recommended fragment size is 160 bytes.
For more information, refer to the " Fragmentation (FRF.12)" section in the VoIP over Frame Relay with
Quality of Service (Fragmentation, Traffic Shaping, LLQ / IP RTP Priority) document.
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Configuring Frame Relay
Frame Relay Fragmentation
Frame Relay Fragmentation Using FRF.11 Annex C
When VoFR (FRF.11) and fragmentation are both configured on a PVC, the Frame Relay fragments are sent
in the FRF.11 Annex C format. This fragmentation is used when FRF.11 voice traffic is sent on the PVC, and
it uses the FRF.11 Annex C format for data.
With FRF.11, all data packets contain fragmentation headers, regardless of size. This form of fragmentation
is not recommended for use with Voice over IP (VoIP).
See the chapter "Configuring Voice over Frame Relay" in the Cisco IOS Voice, Video, and Fax Configuration
Guide for configuration tasks and examples for Frame Relay fragmentation using FRF.11 Annex C.
Cisco-Proprietary Fragmentation
Cisco-proprietary fragmentation is used on data packets on a PVC that is also used for voice traffic. When
the vofr cisco command is configured on a DLCI and fragmentation is enabled on a map class, the Cisco 2600
series, 3600 series, and 7200 series routers can interoperate as tandem nodes (but cannot perform call
termination) with Cisco MC3810 concentrators running Cisco IOS releases prior to 12.0(3)XG or 12.0(4)T.
To configure Cisco-proprietary voice encapsulation, use the vofr cisco command. You must then configure
a map class to enable voice traffic on the PVCs.
See the chapter "Configuring Voice over Frame Relay" in the Cisco IOS Voice, Video, and Fax Configuration
Guide for configuration tasks and examples for Cisco-proprietary fragmentation.
Frame Relay Fragmentation and Hardware Compression Interoperability
FRF.12, FRF.11 Annex C, and Cisco-proprietary fragmentation can be used with FRF.9 or data-stream
hardware compression on interfaces and virtual circuits (VCs) using Cisco-proprietary or Internet Engineering
Task Force (IETF) encapsulation types.
When payload compression and Frame Relay fragmentation are used at the same time, payload compression
is always performed before fragmentation.
Frame Relay fragmentation can be used with the following hardware compression modules:
• Cisco 2600 AIM-COMPR2
• Cisco 3620 and 3640 NM-COMPR
• Cisco 3660 AIM-COMPR4
• Cisco 7200 SA-COMPR
Voice over Frame Relay and Voice over IP packets will not be payload-compressed when Frame Relay
fragmentation is configured.
Note
On VCs using IETF encapsulation, FRF.9 hardware and software compression will work with Frame
Relay fragmentation but will not work with header compression.
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Configuring Frame Relay
Payload Compression
Frame Relay Fragmentation Conditions and Restrictions
When Frame Relay fragmentation is configured, the following conditions and restrictions apply:
• WFQ and LLQ at the PVC level are the only queueing strategies that can be used.
• Frame Relay traffic shaping (FRTS) must be configured to enable Frame Relay fragmentation (except
on the Cisco 7500 series routers on which Versatile Interface Processor-Based Distributed FRF.11 and
FRF.12 is enabled).
• VoFR frames are never fragmented, regardless of size.
• When end-to-end FRF.12 fragmentation is used, the VoIP packets will not include the FRF.12 header,
provided the size of the VoIP packet is smaller than the fragment size configured. However, when FRF.11
Annex C or Cisco-proprietary fragmentations are used, VoIP packets will include the fragmentation
header.
• If fragments arrive out of sequence, packets are dropped.
Note
Fragmentation is performed after frames are removed from the WFQ.
Payload Compression
Packet-by-Packet Payload Compression
You can configure payload compression on point-to-point or multipoint interfaces or subinterfaces. Payload
compression uses the Predictor method to predict what the next character in the frame will be. Because the
prediction is done packet by packet, the dictionary is not conserved across packet boundaries. Payload
compression on each VC consumes approximately 40 kilobytes for dictionary memory.
Standard-Based FRF.9 Compression
Frame Relay compression can now occur on the VIP board, on the Compression Service Adapter (CSA), or
on the main CPU of the router. FRF.9 is standard-based and therefore provides multivendor compatibility.
FRF.9 compression uses relatively higher compression ratios, allowing more data to be compressed for faster
transmission. FRF.9 compression provides the ability to maintain multiple decompression/compression
histories on a per-DLCI basis.
The CSA hardware has been in use on the Cisco 7200 series and Cisco 7500 series platforms, but it has had
no support for Frame Relay compression. The CSA can be used in the Cisco 7200 series or in the
second-generation Versatile Interface Processor (VIP2) in all Cisco 7500 series routers. The specific VIP2
model required for the CSA is VIP2-40, which has 2 MB of SRAM and 32 MB of DRAM.
Selecting FRF.9 Compression Method
The router enables compression in the following order:
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Configuring Frame Relay
TCP IP Header Compression
1 If the router contains a compression service adapter, compression is performed in the CSA hardware
(hardware compression).
2 If the CSA is not available, compression is performed in the software installed on the VIP2 card (distributed
compression).
3 If the VIP2 card is not available, compression is performed in the main processor of the router (software
compression).
Cisco-proprietary Data-Stream Compression
Data-stream compression is a proprietary hardware and software compression protocol that can be used on
the same VC or interface and IP header compression. Data-stream compression is functionally equivalent to
FRF.9 compression and must be used with Cisco-proprietary encapsulation. Frame Relay fragmentation can
also be used with data-stream compression.
TCP IP Header Compression
TCP/IP header compression, as described by RFC 1144, Compressing TCP/IP Headers for Low-Speed Serial
Links is designed to improve the efficiency of bandwidth utilization over low-speed serial links. A typical
TCP/IP packet includes a 40-byte datagram header. Once a connection is established, the header information
is redundant and need not be repeated in every packet that is sent. Reconstructing a smaller header that identifies
the connection, indicates the fields that have changed and the amount of change reduces the number of bytes
transmitted. The average compressed header is 10 bytes long.
For this algorithm to function, packets must arrive in order. If packets arrive out of order, the reconstruction
will appear to create regular TCP/IP packets but the packets will not match the original. Because priority
queueing changes the order in which packets are transmitted, enabling priority queueing on the interface is
not recommended.
Note
If you configure an interface with Cisco-proprietary encapsulation and TCP/IP header compression, Frame
Relay IP maps inherit the compression characteristics of the interface. However, if you configure the
interface with IETF encapsulation, the interface cannot be configured for compression. Frame Relay maps
will have to be configured individually to support TCP/IP header compression.
Specifying an Individual IP Map for TCP IP Header Compression
Note
An interface configured to support TCP/IP header compression does not also support priority queuing or
custom queuing.
TCP/IP header compression requires Cisco-proprietary encapsulation. If you need to have IETF encapsulation
on an interface as a whole, you can still configure a specific IP map to use Cisco-proprietary encapsulation
and TCP header compression. In addition, if you configure the interface to perform TCP/IP header compression,
you can still configure a specific IP map not to compress TCP/IP headers.
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Configuring Frame Relay
Real-Time Header Compression with Frame Relay Encapsulation
You can specify whether TCP/IP header compression is active or passive. Active compression subjects every
outgoing packet to TCP/IP header compression. Passive compression subjects an outgoing TCP/IP packet to
header compression only if a packet had a compressed TCP/IP header when it was received.
Specifying an Interface for TCP IP Header Compression
You can configure the interface with active or passive TCP/IP header compression. Active compression, the
default, subjects all outgoing TCP/IP packets to header compression. Passive compression subjects an outgoing
packet to header compression only if the packet had a compressed TCP/IP header when it was received on
that interface.
Note
If an interface configured with Cisco-proprietary encapsulation is later configured with IETF encapsulation,
all TCP/IP header compression characteristics are lost. To apply TCP/IP header compression over an
interface configured with IETF encapsulation, you must configure individual IP maps.
If you configure an interface with Cisco-proprietary encapsulation and TCP/IP header compression, Frame
Relay IP maps inherit the compression characteristics of the interface. However, if you configure the interface
with IETF encapsulation, the interface cannot be configured for compression. Frame Relay maps will have
to be configured individually to support TCP/IP header compression.
Real-Time Header Compression with Frame Relay Encapsulation
Real-time Transport Protocol (RTP) is a protocol used for carrying packetized audio and video traffic over
an IP network, providing end-to-end network transport functions intended for these real-time traffic applications
and multicast or unicast network services. RTP is described in RFC 1889. RTP is not intended for data traffic,
which uses TCP or UDP.
Discard Eligibility
Frame Relay packets can be set with low priority or low time sensitivity. These packets will be the first to be
dropped when a Frame Relay switch is congested. The mechanism that allows a Frame Relay switch to identify
such packets is the discard eligibility (DE) bit.
Discard eligibility requires the Frame Relay network to be able to interpret the DE bit. Some networks take
no action when the DE bit is set, and others use the DE bit to determine which packets to discard. The best
interpretation is to use the DE bit to determine which packets should be dropped first and also which packets
have lower time sensitivity.
You can create DE lists that identify the characteristics of packets to be eligible for discarding, and you can
also specify DE groups to identify the data link connection identifier (DLCI) that is affected.
You can create DE lists based on the protocol or the interface, and on characteristics such as fragmentation
of the packet, a specific TCP or UDP port, an access list number, or a packet size.
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Configuring Frame Relay
DLCI Priority Levels
DLCI Priority Levels
Data Link Connection Identifier (DLCI) priority levels allow you to separate different types of traffic and
provides a traffic management tool for congestion problems caused by the following:
• Mixing batch and interactive traffic over the same DLCI
• Queuing traffic from sites with high-speed access to destination sites with lower-speed access
Before you configure the DLCI priority levels, you must:
• Enable Frame Relay encapsulation.
• Define dynamic or static address mapping.
• Ensure that you define each of the DLCIs to which you intend to apply levels. You can associate
priority-level DLCIs with subinterfaces.
• Configure the LMI.
Note
DLCI priority levels provide a way to define multiple parallel DLCIs for different types of traffic. DLCI
priority levels do not assign priority queues within the device or access server. In fact, they are independent
of the priority queues of the device. However, if you enable queuing and use the same DLCIs for queuing,
then high-priority DLCIs can be put into high-priority queues.
How to Configure Frame Relay
Enabling Frame Relay Encapsulation on an Interface
Note
Frame Relay encapsulation is a prerequisite for any Frame Relay commands on an interface.
To enable Frame Relay encapsulation on the interface level, use the following commands beginning in global
configuration mode:
SUMMARY STEPS
1. enable
2. configure terminal
3. interface typenumber
4. encapsulation frame-relay[ietf]
5. end
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Configuring Frame Relay
Enabling Frame Relay Encapsulation on an Interface
DETAILED STEPS
Step 1
Command or Action
Purpose
enable
Enables privileged EXEC mode.
• Enter your password if prompted.
Example:
Device> enable
Step 2
configure terminal
Enters global configuration mode.
Example:
Device# configure terminal
Step 3
interface typenumber
Specifies the interface, and enters interface configuration
mode.
Example:
Device(config)# int ethernet 0/1
Step 4
encapsulation frame-relay[ietf]
Enables and specifies the Frame Relay encapsulation
method.
Example:
Device(config-if)# encapsulation frame-relay
ietf
Step 5
end
Returns to privileged EXEC mode.
Example:
Device(config-if)# end
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Configuring Frame Relay
Configuring Static Address Mapping
Configuring Static Address Mapping
To establish static mapping according to your network needs, use one of the following commands in interface
configuration mode:
Command
Router(config-if)#
protocol-address dlci
Purpose
frame-relay map protocol Maps between a next-hop protocol address and DLCI
[broadcast] [ietf] [cisco] destination address. The supported protocols and the
corresponding keywords to enable them are as
follows:
• IP--ip
• DECnet--decnet
• AppleTalk--appletalk
• XNS--xns
• Novell IPX--ipx
• VINES--vines
• ISO CLNS--clns
Router(config-if)#
[broadcast]
frame-relay map clns dlci
Router(config-if)# frame-relay
dlci [broadcast] [ietf]
map bridge
Defines a DLCI used to send ISO CLNS frames.
Defines a DLCI destination bridge.
Explicitly Configuring the LMI
Setting the LMI Type
If the device or access server is attached to a public data network (PDN), the LMI type must match the type
used on the public network. Otherwise, the LMI type can be set to suit the requirements of your private Frame
Relay network. You can set one of the following three types of LMIs on Cisco devices:
• ANSI T1.617 Annex D
• Cisco
• ITU-T Q.933 Annex A
To do so, use the following commands beginning in interface configuration mode:
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Configuring Frame Relay
Explicitly Configuring the LMI
SUMMARY STEPS
1. enable
2. configure terminal
3. interface typenumber
4. frame-relay lmi-type {ansi | cisco | q933a}
5. end
6. copy nvram:startup-config destination
DETAILED STEPS
Step 1
Command or Action
Purpose
enable
Enables privileged EXEC mode.
Example:
• Enter your password if prompted.
Device> enable
Step 2
configure terminal
Enters global configuration mode.
Example:
Device# configure terminal
Step 3
interface typenumber
Specifies the interface, and enters interface
configuration mode.
Example:
Device(config)# int ethernet 0/1
Step 4
frame-relay lmi-type {ansi | cisco | q933a}
Sets the LMI type.
Example:
Device(config-if)#
Step 5
end
Returns to privileged EXEC mode.
Example:
Device(config-if)# end
Step 6
copy nvram:startup-config destination
Example:
Device#
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Writes the LMI type to NVRAM.
Configuring Frame Relay
Enabling Frame Relay SVC Service
Setting the LMI Keepalive Interval
A keepalive interval must be set to configure the LMI. By default, this interval is 10 seconds and, according
to the LMI protocol, must be less than the corresponding interval on the switch. To set the keepalive interval,
use the following command in interface configuration mode:
Command
Router(config-if)#
Purpose
keepalive number
Sets the LMI keepalive interval.
Setting the LMI Polling and Timer Intervals
You can set various optional counters, intervals, and thresholds to fine-tune the operation of your Local
Management Interface data terminal equipment (LMI DTE) and data communications equipment (DCE)
devices. Set these attributes by using one or more of the following commands in interface configuration mode:
Command
Purpose
frame-relay lmi-n392dce threshold
Sets the DCE and Network-to-Network Interface
(NNI) error threshold.
frame-relay lmi-n393dce events
Sets the DCE and NNI monitored events count.
frame-relay lmi-t392dce seconds
Sets the polling verification timer on a DCE or NNI
interface.
frame-relay lmi-n391dte keep-exchanges
Sets a full status polling interval on a DTE or NNI
interface.
frame-relay lmi-n392dte threshold
Sets the DTE or NNI error threshold.
frame-relay lmi-n393dte events
Sets the DTE and NNI monitored events count.
Enabling Frame Relay SVC Service
Configuring SVCs on a Physical Interface
To enable SVC operation on a Frame Relay interface, use the following commands beginning in global
configuration mode:
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Enabling Frame Relay SVC Service
SUMMARY STEPS
1. Router(config)# interface type number
2. Router(config-if)# ip address ip-address mask
3. Router(config-if)# encapsulation frame-relay
4. Router(config-if)# map-group group-name
5. Router(config-if)# frame-relay svc
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number
Specifies the physical interface.
Step 2
Router(config-if)# ip address ip-address mask
Specifies the interface IP address, if needed.
Step 3
Router(config-if)# encapsulation frame-relay
Enables Frame Relay encapsulation on the interface.
Step 4
Router(config-if)# map-group group-name
Assigns a map group to the interface. Map group details are
specified with the map-list command.
Step 5
Router(config-if)# frame-relay svc
Enables Frame Relay SVC support on the interface.
Configuring SVCs on a Subinterface
Note
This task offers additional flexibility for SVC configuration and operation.
To configure Frame Relay SVCs on a subinterface, complete all the commands in the preceding section,
except assigning the map group. After the physical interface is configured, use the following commands
beginning in global configuration mode:
SUMMARY STEPS
1. Router(config)# interface type number . subinterface-number {multipoint | point-to-point}
2. Router(config-subif)# ip address ip-address mask
3. Router(config-subif)# map-group group-name
DETAILED STEPS
Command or Action
Step 1
Router(config)# interface type number . subinterface-number Specifies a subinterface configured for SVC
operation.
{multipoint | point-to-point}
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Purpose
Configuring Frame Relay
Enabling Frame Relay SVC Service
Command or Action
Purpose
Step 2
Router(config-subif)# ip address ip-address mask
Specifies the subinterface IP address, if needed.
Step 3
Router(config-subif)# map-group group-name
Assigns a map group to the subinterface.
Configuring a Map Class
Perform the following tasks to configure a map class:
• Specify the map class name. (Required)
• Specify a custom queue list for the map class. (Optional)
• Specify a priority queue list for the map class. (Optional)
• Enable BECN feedback to throttle the output rate on the SVC for the map class. (Optional)
• Set nondefault QoS values for the map class (no need to set the QoS values; default values are provided).
(Optional)
Note
You can define multiple map classes. A map class is associated with a static map, not with the interface
or subinterface. Because of the flexibility this association allows, you can define different map classes for
different destinations.
To configure a map class, use the following commands beginning in global configuration mode:
SUMMARY STEPS
1. Router(config)# map-class frame-relay map-class-name
2. Router(config-map-class)# frame-relay custom-queue-list list-number
3. Router(config-map-class)# frame-relay priority-group list-number
4. Router(config-map-class)# frame-relay adaptive-shaping[becn | foresight]1
5. Router(config-map-class)# frame-relay cir in bps
6. Router(config-map-class)# frame-relay cir out bps
7. Router(config-map-class)# frame-relay mincir in bps2
8. Router(config-map-class)# frame-relay mincir out bpsConfiguring a Map Class, on page 31
9. Router(config-map-class)# frame-relay bc in bitsConfiguring a Map Class, on page 31
10. Router(config-map-class)# frame-relay bc out bitsConfiguring a Map Class, on page 31
11. Router(config-map-class)# frame-relay be in bitsConfiguring a Map Class, on page 31
12. Router(config-map-class)# frame-relay be out bitsConfiguring a Map Class, on page 31
13. Router(config-map-class)# frame-relay idle-timer secondsConfiguring a Map Class, on page 31
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DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# map-class frame-relay map-class-name
Specifies Frame Relay map class name and enters
map class configuration mode.
Step 2
Router(config-map-class)# frame-relay custom-queue-list Specifies a custom queue list to be used for the map
class.
list-number
Step 3
Router(config-map-class)# frame-relay priority-group
list-number
Assigns a priority queue to VCs associated with the
map class.
Step 4
Router(config-map-class)# frame-relay
adaptive-shaping[becn | foresight]1
Enables the type of BECN feedback to throttle the
frame-transmission rate.
Step 5
Router(config-map-class)# frame-relay cir in bps
Specifies the inbound committed information rate
(CIR), in bits per second.
Step 6
Router(config-map-class)# frame-relay cir out bps
Specifies the outbound CIR, in bits per second.
Step 7
Router(config-map-class)# frame-relay mincir in bps2
Sets the minimum acceptable incoming CIR, in bits
per second.
Step 8
Router(config-map-class)# frame-relay mincir out
bpsConfiguring a Map Class, on page 31
Sets the minimum acceptable outgoing CIR, in bits
per second.
Step 9
Router(config-map-class)# frame-relay bc in
bitsConfiguring a Map Class, on page 31
Sets the incoming committed burst size (Bc), in bits.
Step 10
Router(config-map-class)# frame-relay bc out
bitsConfiguring a Map Class, on page 31
Sets the outgoing Bc, in bits.
Step 11
Router(config-map-class)# frame-relay be in
bitsConfiguring a Map Class, on page 31
Sets the incoming excess burst size (Be), in bits.
Step 12
Router(config-map-class)# frame-relay be out
bitsConfiguring a Map Class, on page 31
Sets the outgoing Be, in bits.
Step 13
Router(config-map-class)# frame-relay idle-timer
secondsConfiguring a Map Class, on page 31
Sets the idle timeout interval, in seconds.
1 This command replaces the frame-relay becn-response-enable command, which will be removed in a future Cisco IOS release. If you use the frame-relay
becn-response-enable command in scripts, you should replace it with the frame-relay adaptive-shaping becn command.
2 The in and out keywords are optional. Configuring the command without the in and out keywords will apply that value to both the incoming and the outgoing
traffic values for the SVC setup. For example, frame-relay cir 56000 applies 56000 to both incoming and outgoing traffic values for setting up the SVC.
Configuring a Map Group with E.164 or X.121 Addresses
After you have defined a map group for an interface, you can associate the map group with a specific source
and destination address to be used. You can specify E.164 addresses or X.121 addresses for the source and
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destination. To specify the map group to be associated with a specific interface, use the following command
in global configuration mode:
Command
Purpose
Router(config)# map-list map-group-name
source-addr {e164 | x121} source-address
dest-addr {e164 | x121} destination-address
Specifies the map group associated with specific
source and destination addresses for the SVC.
Associating the Map Class with Static Protocol Address Maps
To define the protocol addresses under a map-list command and associate each protocol address with a
specified map class, use the class command. Use this command for each protocol address to be associated
with a map class. To associate a map class with a protocol address, use the following command in map list
configuration mode:
Command
Purpose
Router(config-map-list)# protocol
protocol-address class class-name [ietf]
[broadcast [trigger]]
Specifies a destination protocol address and a Frame
Relay map class name from which to derive QoS
information.
• The ietf keyword specifies RFC 1490
encapsulation
• The broadcast keyword specifies that
broadcasts must be carried.
• The trigger keyword, which can be configured
only if broadcast is also configured, enables a
broadcast packet to trigger an SVC. If an SVC
already exists that uses this map class, the SVC
will carry the broadcast.
Configuring LAPF Parameters
Note
The LAPF tasks are not required and not recommended unless you understand thoroughly the impacts on
your network.
By default, the Frame Reject frame is sent at the LAPF Frame Reject procedure.
Frame Relay Link Access Procedure for Frame Relay (LAPF) commands are used to tune Layer 2 system
parameters to work well with the Frame Relay switch. Normally, you do not need to change the default settings.
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However, if the Frame Relay network indicates that it does not support the Frame Reject frame (FRMR) at
the LAPF Frame Reject procedure, use the following command in interface configuration mode:
Command
Router(config-if)#
Purpose
no frame-relay lapf frmr
Selects not to send FRMR frames at the LAPF Frame
Reject procedure.
Changing Layer 2 Parameters for Your Network
Note
Manipulation of Layer 2 parameters is not recommended if you do not know well the resulting functional
change. For more information, refer to the ITU-T Q.922 specification for LAPF.
If you must change Layer 2 parameters for your network environment and you understand the resulting
functional change, use the following commands as needed:
Command
Purpose
Router(config-if)#
frame-relay lapf k number
Router(config-if)#
frame-relay lapf n200
Sets the LAPF window size k.
Sets the LAPF maximum retransmission count N200.
retries
Router(config-if)#
Router(config-if)#
Sets maximum length of the Information field of the
frame-relay lapf n201 bytes LAPF I frame N201, in bytes.
frame-relay lapf t200
Sets the LAPF retransmission timer value T200, in
tenths of a second.
frame-relay lapf t203
Sets the LAPF link idle timer value T203 of DLCI 0,
in seconds.
tenths-of-a-second
Router(config-if)#
seconds
Configuring Frame Relay Traffic Shaping
Enabling Frame Relay Traffic Shaping on the Interface
To configure a map class with traffic-shaping and per-VC queueing parameters, see the sections Specifying
a Traffic-Shaping Map Class for the Interface and Defining a Map Class with Queueing and Traffic-Shaping
Parameters.
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Configuring Frame Relay Traffic Shaping
To enable Frame Relay traffic shaping on the specified interface, use the following command in interface
configuration mode:
Command
Router(config-if)#
Purpose
Enables Frame Relay traffic shaping and per-VC
frame-relay traffic-shaping queueing.
Note
The default committed information rate
(CIR) of 56K will apply in the following
situations: When traffic shaping is enabled
(by using the frame-relay traffic-shaping
command), but a map class is not assigned
to the VC and when traffic shaping is
enabled (by using the frame-relay
traffic-shapingcommand) and a map class
is assigned to the VC, but traffic-shaping
parameters have not been defined in the map
class.
Configuring Enhanced Local Management Interface
Enabling ELMI
To enable ELMI, use the following commands beginning in interface configuration mode:
SUMMARY STEPS
1. Router(config)# interface type number
2. Router(config-if)# encapsulation frame-relay[cisco | ietf]
3. Router(config-if)# frame-relay QoS-autosense
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number
Specifies the physical interface.
Step 2
Router(config-if)# encapsulation frame-relay[cisco | ietf] Enables Frame Relay encapsulation on the
interface.
Step 3
Router(config-if)# frame-relay QoS-autosense
Enables ELMI.
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Disabling Automatic IP Address Selection
Automatic IP address selection is enabled by default when ELMI is enabled. To disable the automatic selection
of the IP address to be used for ELMI address registration, use the following global configuration command:
Command
Purpose
no frame-relay address
registration auto-address
Router(config)#
Disables the automatic selection of the IP address to
be used for ELMI address registration.
Note
When automatic IP address selection is
disabled and an IP address has not been
configured using the frame-relay address
registration ip global configuration
command, the IP address for ELMI address
registration will be set to 0.0.0.0.
Configuring the IP Address to Be Used for ELMI Address Registration
To configure the IP address for ELMI address registration, use the following global configuration command:
Command
Purpose
frame-relay address
registration ip address
Router(config)#
Configures the IP address to be used for ELMI
address registration.
Note
Automatic IP address selection is disabled
when you configure the management IP
address using the frame-relay address
registration ip global configuration
command.
Enabling ELMI Address Registration on an Interface
To enable ELMI address registration on an interface, use the following interface configuration command:
Command
Router(config-if)#
enable
Purpose
frame-relay address-reg
Enables ELMI address registration on an interface.
To disable ELMI address registration on an interface,
use the no form of the command.
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Verifying ELMI Address Registration
To verify that ELMI address registration is configured correctly, use the following privileged EXEC
configuration command:
Command
Purpose
Router# show frame-relay
[interface interface]
qos-autosense
Displays the QoS values and ELMI address
registration information sensed from the switch.
Specifying a Traffic-Shaping Map Class for the Interface
To specify a map class for the specified interface, use the following command beginning in interface
configuration mode:
SUMMARY STEPS
1. Router(config-if)# frame-relay class map-class-name
DETAILED STEPS
Step 1
Command or Action
Purpose
Router(config-if)# frame-relay class map-class-name
Specifies a Frame Relay map class for the interface.
Defining a Map Class with Queueing and Traffic-Shaping Parameters
To define a map class, use the following commands beginning in global configuration mode:
SUMMARY STEPS
1. Router(config)# map-class frame-relay map-class-name
2. Router(config-map-class)# frame-relay traffic-rate average [peak]
3. Router(config-map-class)# frame-relay custom-queue-list list-number
4. Router(config-map-class)# frame-relay priority-group list-number
5. Router(config-map-class)# frame-relay adaptive-shaping{becn | foresight}
DETAILED STEPS
Step 1
Command or Action
Purpose
Router(config)# map-class frame-relay
map-class-name
Specifies a map class to define.
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Command or Action
Purpose
Step 2
Router(config-map-class)# frame-relay traffic-rate Defines the traffic rate for the map class.
average [peak]
Step 3
Router(config-map-class)# frame-relay
custom-queue-list list-number
Specifies a custom queue list.
Step 4
Router(config-map-class)# frame-relay
priority-group list-number
Specifies a priority queue list.
Step 5
Router(config-map-class)# frame-relay
adaptive-shaping{becn | foresight}
Selects BECN or ForeSight as congestion backward-notification
mechanism to which traffic shaping adapts.
Note
This command replaces the frame-relay
becn-response-enable command, which will be
removed in a future Cisco IOS release. If you use the
frame-relay becn-response-enable command in
scripts, you should replace it with the frame-relay
adaptive-shaping software command.
Configuring Frame Relay Switching
Enabling Frame Relay Switching
You must enable packet switching before you can configure it on a Frame Relay DTE or DCE, or with
Network-to-Network Interface (NNI) support. Do so by using the following command in global configuration
mode before configuring the switch type:
Command
Router(config)#
Purpose
frame-relay switching
Enables Frame Relay switching.
Configuring a Frame Relay DTE Device or DCE Switch or NNI Support
You can configure an interface as a DTE device or a DCE switch, or as a switch connected to a switch to
support NNI connections. (DTE is the default.) To do so, use the following command in interface configuration
mode:
Command
Router(config-if)#
| dte | nni]
Purpose
Configures a Frame Relay DTE device or DCE
frame-relay intf-type [dce switch.
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Creating Switched PVC over ISDN
To create a switched PVC over ISDN, or to create a switched PVC on which traffic shaping, traffic policing,
and congestion management can be configured, use the following command in global configuration mode:
Command
Purpose
connect connection-name
interface dlci interface dlci
Defines connections between Frame Relay PVCs.
Router(config)#
Creating a Switched PVC with Static Route
Note
Static routes cannot be configured over tunnel interfaces on the Cisco 800 series, 1600 series, and 1700
series platforms. Static routes can only be configured over tunnel interfaces on platforms that have the
Enterprise feature set.
To create a switched PVC with a static route, use the following command in interface configuration mode:
Command
Purpose
frame-relay route in-dlci
interface out-interface-type out-interface-number
out-dlci
Specifies a static route for PVC switching.
Router(config-if)#
Identifying a PVC As Switched
Before you can associate a map class with a switched PVC, you must identify the PVC as being switched. To
identify a PVC as switched, use the following command in interface configuration mode:
Command
Router(config-if)#
Purpose
frame-relay interface-dlci
Identifies a PVC as switched.
dlci switched
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Configuring Frame Relay Switching
Configuring Traffic Policing on UNI DCE Devices
Enabling Frame Relay Policing
To enable Frame Relay policing on a interface, use the following command in interface configuration mode:
Command
Router(config-if)#
Purpose
frame-relay policing
Enables Frame Relay policing on all switched PVCs
on the interface.
Configuring Frame Relay Policing Parameters
To configure policing parameters in a Frame Relay map class, use one or more of the following commands
in map-class configuration mode:
Command
Router(config-map-class)#
| out} bps
Router(config-map-class)#
| out} bits
Router(config-map-class)#
| out} bits
Router(config-map-class)#
Purpose
Sets the CIR for a Frame Relay PVC, in bits per
frame-relay cir {in second.
Sets the committed burst size for a Frame Relay PVC,
frame-relay bc {in in bits.
Sets the excess burst size for a Frame Relay PVC, in
frame-relay be {in bits.
frame-relay tc
milliseconds
Sets the measurement interval for policing incoming
traffic on a PVC when the CIR is zero, in
milliseconds.
Configuring Congestion Management on Switched PVCs
Configuring Frame Relay Congestion Management on the Interface
To configure Frame Relay congestion management on all switched PVCs on an interface, use the following
commands beginning in interface configuration mode:
SUMMARY STEPS
1. Router(config-if)# frame-relay congestion management
2. Router(config-fr-congest)# threshold de percentage
3. Router(config-fr-congest)# threshold ecn {bc | be} percentage
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DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config-if)# frame-relay congestion
management
Enables Frame Relay congestion management on all switched PVCs
on an interface and enters Frame Relay congestion management
configuration mode.
Step 2
Router(config-fr-congest)# threshold de
percentage
Configures the threshold at which DE-marked packets will be
discarded from switched PVCs on the output interface.
Step 3
Router(config-fr-congest)# threshold ecn {bc Configures the threshold at which ECN bits will be set on packets
in switched PVCs on the output interface.
| be} percentage
Configuring Frame Relay Congestion Management on Traffic-Shaping Queues
To configure Frame Relay congestion management on the traffic-shaping queues of switched PVCs, use one
or more of the following commands in map-class configuration mode:
Command
Purpose
Router(config-map-class)#
frame-relay
congestion threshold de percentage
Configures the threshold at which DE-marked packets
will be discarded from the traffic-shaping queue of a
switched PVC.
frame-relay
congestion threshold ecn percentage
Configures the threshold at which ECN bits will be
set on packets in the traffic-shaping queue of a
switched PVC.
Router(config-map-class)#
Router(config-map-class)#
frame-relay holdq
queue-size
Configures the maximum size of a traffic-shaping
queue on a switched PVC.
Configuring FRF.12 Fragmentation on Switched PVCs
To configure FRF.12 on switched PVCs, use the following map-class configuration command. The map class
can be associated with one or more switched PVCs.
Command
Purpose
frame-relay
fragment fragment_size switched
Router(config-map-class)#
Enables FRF.12 fragmentation on switched Frame
Relay PVCs for a Frame Relay map class.
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Verifying Frame Relay Switching
To verify the correct configuration of Frame Relay switching, use one or more of the following commands:
Command
show frame-relay fragment [interface
interface] [dlci]
Purpose
Displays statistics about Frame Relay fragmentation.
Router#
show frame-relay pvc [interface
interface] [dlci]
Router#
Router#
show interfaces [type number]
Displays statistics about Frame Relay PVCs including
detailed reasons for packet drops on switched PVCs
and complete status information for switched NNI
PVCs.
Displays information about the configuration and
queue at the interface.
Troubleshooting Frame Relay Switching
To diagnose problems in switched Frame Relay networks, use the following EXEC commands:
Command
Purpose
Displays debug messages for switched Frame Relay
debug frame-relay switching [interface PVCs. The interval keyword and seconds argument
interface] [dlci] [interval seconds]
sets the interval at which the debug messages will be
displayed.
Router#
show frame-relay pvc [interface
interface] [dlci]
Router#
Displays statistics about Frame Relay PVCs, including
detailed reasons for packet drops on switched PVCs
and complete status information for switched NNI
PVCs.
Customizing Frame Relay for Your Network
Configuring Frame Relay End-to-End Keepalives
Configuring End-to-End Keepalives
To configure Frame Relay end-to-end keepalives, use the following commands beginning in global configuration
mode:
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SUMMARY STEPS
1. Router(config)# map-class frame-relay map-class-name
2. Router(config-map-class)# frame-relay end-to-end keepalive mode {bidirectional | request | reply |
passive-reply}
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# map-class frame-relay
map-class-name
Specifies a map class for the VC.
Step 2
Router(config-map-class)# frame-relay
Specifies Frame Relay end-to-end keepalive mode.
end-to-end keepalive mode {bidirectional
• bidirectional --The device sends keepalive requests to the other end
| request | reply | passive-reply}
of the VC and responds to keepalive requests from the other end of
the VC.
• request --The device sends keepalive requests to the other end of the
VC.
• reply --The device responds to keepalive requests from the other end
of the VC.
• passive-reply --The device responds to keepalive requests from the
other end of the VC, but will not track errors or successes.
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Modifying the Default Parameters
You can modify the end-to-end keepalives default parameter values by using any of the following map-class
configuration commands:
Command
Purpose
frame-relay
end-to-end keepalive error-threshold {send
receive} count
Router(config-map-class)#
frame-relay
end-to-end keepalive event-window {send
receive} count
|
Router(config-map-class)#
frame-relay
end-to-end keepalive success-events {send
receive} count
|
Router(config-map-class)#
|
frame-relay
end-to-end keepalive timer {send | receive}
interval
Modifies the number of errors needed to change the
keepalive state from up to down.
Modifies the number of recent events to be checked
for errors.
Modifies the number of consecutive success events
required to change the keepalive state from down to
up.
Modifies the timer interval.
Router(config-map-class)#
Verifying Frame Relay End-to-End Keepalives
To monitor the status of Frame Relay end-to-end keepalives, use the following command in EXEC configuration
mode:
Command
Purpose
Shows the status of Frame Relay end-to-end
show frame-relay end-to-end keepalive keepalives.
interface
Router#
Enabling PPP over Frame Relay
To configure the physical interface that will carry the PPP session and link it to the appropriate virtual template
interface, perform the following task in interface configuration mode:
Command
Router(config-if)# frame-relay
dlci [ppp virtual-template-name]
Purpose
interface-dlci
Defines the PVC and maps it to the virtual template.
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For an example of configuring PPP over Frame Relay, see the section Example PPPoverFrameRelay, on page
75 or Example PPP over Frame Relay DCE, on page 75 later in this chapter.
Configuring Frame Relay Subinterfaces
Configuring Subinterfaces
Subinterfaces can be configured for multipoint or point-to-point communication. (There is no default.) To
configure subinterfaces on a Frame Relay network, use the following commands beginning in global
configuration mode:
SUMMARY STEPS
1. Router(config)# interface type number . subinterface-number {multipoint | point-to-point}
2. Router(config-subif)# encapsulation frame-relay
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number . subinterface-number Creates a point-to-point or multipoint subinterface.
{multipoint | point-to-point}
Step 2
Router(config-subif)# encapsulation frame-relay
Configures Frame Relay encapsulation on the serial
interface.
Defining Subinterface Addressing on Point-to-Point Subinterfaces
If you specified a point-to-point subinterface in the preceding procedure, use the following command in
subinterface configuration mode:
SUMMARY STEPS
1. Router(config-subif)# frame-relay interface-dlci dlci
DETAILED STEPS
Step 1
Command or Action
Purpose
Router(config-subif)# frame-relay interface-dlci dlci
Associates the selected point-to-point subinterface with
a DLCI.
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Accepting Inverse ARP for Dynamic Address Mapping on Multipoint Subinterfaces
To associate a specific multipoint subinterface with a specific DLCI, use the following command in interface
configuration mode:
Command
Router(config-if)#
Purpose
frame-relay interface-dlci
dlci
Associates a specified multipoint subinterface with a
DLCI.
Configuring Static Address Mapping on Multipoint Subinterfaces
To establish static mapping according to your network needs, use one of the following commands in interface
configuration mode:
Command
Purpose
Maps between a next-hop protocol address and DLCI
frame-relay map protocol destination address.
protocol-address dlci [broadcast] [ietf] [cisco]
The supported protocols and the corresponding
keywords to enable them are as follows:
Router(config-if)#
• IP--ip
• DECnet--decnet
• AppleTalk--appletalk
• XNS--xns
• Novell IPX--ipx
• VINES--vines
• ISO CLNS--clns
Router(config-if)#
[broadcast]
frame-relay map clns dlci
Router(config-if)# frame-relay
dlci [broadcast] [ietf]
map bridge
Defines a DLCI used to send ISO CLNS frames. The
broadcast keyword is required for routing protocols
such as OSI protocols and the Open Shortest Path
First (OSPF) protocol.
Defines a DLCI destination bridge.
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Configuring Transparent Bridging for Point-to-Point Subinterfaces
Note
All PVCs configured on a subinterface belong to the same bridge group.
To configure transparent bridging for point-to-point subinterfaces, use the following commands beginning in
global configuration mode:
SUMMARY STEPS
1. Router(config)# interface type number
2. Router(config-if)# encapsulation frame-relay
3. Router(config)# interface type number : subinterface-number point-to-point
4. Router(config-subif)# frame-relay interface-dlci dlci
5. Router(config-subif)# bridge-group bridge-group
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number
Specifies an interface.
Step 2
Router(config-if)# encapsulation frame-relay
Configures Frame Relay encapsulation on the
interface.
Step 3
Router(config)# interface type number :
subinterface-number point-to-point
Specifies a subinterface.
Step 4
Router(config-subif)# frame-relay interface-dlci dlci
Associates a DLCI with the subinterface.
Step 5
Router(config-subif)# bridge-group bridge-group
Associates the subinterface with a bridge group.
Configuring Transparent Bridging for Point-to-Multipoint Interfaces
Note
All PVCs configured on a subinterface belong to the same bridge group.
To configure transparent bridging for point-to-multipoint subinterfaces, use the following commands beginning
in global configuration mode:
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SUMMARY STEPS
1. Router(config)# interface type number
2. Router(config-if)# encapsulation frame-relay
3. Router(config)# interface typenumber:subinterface-number multipoint
4. Router(config-subif)# frame-relay map bridge dlci [broadcast] [ietf]
5. Router(config-subif)# bridge-group bridge-group
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number
Specifies an interface.
Step 2
Router(config-if)# encapsulation frame-relay
Configures Frame Relay encapsulation.
Step 3
Router(config)# interface typenumber:subinterface-number Specifies a subinterface.
multipoint
Step 4
Router(config-subif)# frame-relay map bridge dlci
[broadcast] [ietf]
Defines a DLCI destination bridge.
Step 5
Router(config-subif)# bridge-group bridge-group
Associates the subinterface with a bridge group.
Configuring a Backup Interface for a Subinterface
To configure a backup interface for a Frame Relay subinterface, use the following commands beginning in
global configuration mode:
SUMMARY STEPS
1. Router(config)# interface type number
2. Router(config-if)# encapsulation frame-relay
3. Router(config)# interface type number . subinterface-number point-to-point
4. Router(config-subif)# frame-relay interface-dlci dlci
5. Router(config-subif)# backup interface type number
6. Router(config-subif)# backup delay enable-delay disable-delay
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number
Specifies the interface.
Step 2
Router(config-if)# encapsulation frame-relay
Configures Frame Relay encapsulation.
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Command or Action
Purpose
Step 3
Router(config)# interface type number . subinterface-number Configures the subinterface.
point-to-point
Step 4
Router(config-subif)# frame-relay interface-dlci dlci
Specifies DLCI for the subinterface.
Step 5
Router(config-subif)# backup interface type number
Configures backup interface for the subinterface.
Step 6
Router(config-subif)# backup delay enable-delay
disable-delay
Specifies backup enable and disable delay.
Disabling or Reenabling Frame Relay Inverse ARP
To select or disable Inverse ARP, use one of the following commands in interface configuration mode:
Command
Purpose
frame-relay inverse-arp protocol dlci
Enables Frame Relay Inverse ARP for a specific
protocol and DLCI pair, only if it was previously
disabled.
no frame relay inverse-arp protocol dlci
Disables Frame Relay Inverse ARP for a specific
protocol and DLCI pair.
Creating a Broadcast Queue for an Interface
To create a broadcast queue, use the following command in interface configuration mode:
Command
Purpose
frame-relay broadcast-queue
size byte-rate packet-rate
Creates a broadcast queue for an interface.
Router(config-if)#
Configuring Frame Relay Fragmentation
Configuring End-to-End FRF.12 Fragmentation
To configure FRF.12 fragmentation in a Frame Relay map class, use the following commands beginning in
global configuration mode:
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SUMMARY STEPS
1. Router(config)# map-class frame-relay map-class-name
2. Router(config-map-class)# frame-relay fragment fragment_size
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# map-class frame-relay
map-class-name
Specifies a map class to define QoS values for a Frame Relay SVC or PVC.
The map class can be applied to one or many PVCs.
Step 2
Router(config-map-class)# frame-relay
fragment fragment_size
Configures Frame Relay fragmentation for the map class. The fragment_size
argument defines the payload size of a fragment; it excludes the Frame
Relay headers and any Frame Relay fragmentation header. The valid range
is from 16 to 1600 bytes, and the default is 53.
Verifying the Configuration of End-to-End FRF.12 Fragmentation
To verify FRF.12 fragmentation, use one or more of the following EXEC commands:
Command
Purpose
show frame-relay fragment [interface interface] Displays Frame Relay fragmentation information.
[dlci]
show frame-relay pvc [interface interface] [dlci] Displays statistics about PVCs for Frame Relay
interfaces.
Configuring Payload Compression
Configuring Payload Compression On a Multipoint Interface or Subinterface
To configure payload compression on a specified multipoint interface or subinterface, use the following
command in interface configuration mode:
Command
Purpose
Enables payload compression on a multipoint
frame-relay map protocol interface.
protocol-address dlci payload-compression
packet-by-packet
Router(config-if)#
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Configuring Payload Compression On a Point-to-Point Interface or Subinterface
To configure payload compression on a specified point-to-point interface or subinterface, use the following
command in interface configuration mode:
Command
Purpose
frame-relay
payload-compression packet-by-packet
Router(config-if)#
Enables payload compression on a point-to-point
interface.
Configuring FRF.9 Compression Using Map Statements
You can control where you want compression to occur by specifying an interface. To enable FRF.9 compression
on a specific CSA, VIP CPU, or host CPU, use the following commands beginning in global configuration
mode:
SUMMARY STEPS
1. Router(config)# interface type number
2. Router(config-if)# encapsulation frame-relay
3. Router(config-if)# frame-relay map payload-compression frf9 stac[hardware-options]
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number
Specifies the interface.
Step 2
Router(config-if)# encapsulation frame-relay
Specifies Frame Relay as encapsulation type.
Step 3
Router(config-if)# frame-relay map payload-compression
frf9 stac[hardware-options]
Enables FRF.9 compression.
Configuring FRF.9 Compression on the Subinterface
To configure FRF.9 compression on the subinterface, use the following commands beginning in global
configuration mode:
SUMMARY STEPS
1. Router(config)# interface type number
2. Router(config-subif)# encapsulation frame-relay
3. Router(config-subif)# frame-relay payload-compression frf9 stac[hardware-options]
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DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number
Specifies the subinterface type and number.
Step 2
Router(config-subif)# encapsulation frame-relay
Specifies Frame Relay as encapsulation type.
Step 3
Router(config-subif)# frame-relay payload-compression
frf9 stac[hardware-options]
Enables FRF.9 compression.
Configuring Data-Stream Hardware Compression and IP Header Compression on a Point-to-Point Subinterface
To configure data-stream hardware compression and TCP or Real-Time Transport Protocol (RTP) header
compression on a point-to-point subinterface, use the following commands beginning in global configuration
mode. Note that when you specify data-stream hardware compression, Cisco-proprietary encapsulation is
automatically enabled.
SUMMARY STEPS
1. Router(config)# interface type number point-to-point
2. Router(config-subif)# ip address address mask
3. Router(config-subif)# frame-relay interface-dlci dlci
4. Router(config-subif)# frame-relay payload-compression data-stream stac [hardware-options
5. Do one of the following:
• Router(config-subif)# frame-relay ip tcp header-compression [passive]
•
•
•
•
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number point-to-point
Configures a subinterface type and enters subinterface
configuration mode.
Step 2
Router(config-subif)# ip address address mask
Sets the IP address for an interface.
Step 3
Router(config-subif)# frame-relay interface-dlci dlci
Assigns a DLCI to a specified Frame Relay subinterface on
the router or access server.
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Command or Action
Purpose
Step 4
Router(config-subif)# frame-relay payload-compression Enables hardware compression on an interface or
subinterface that uses Cisco-proprietary encapsulation.
data-stream stac [hardware-options
Step 5
Do one of the following:
• Router(config-subif)# frame-relay ip tcp
header-compression [passive]
•
•
•
•
Configures an interface to ensure that the associated PVCs
carry outgoing TCP headers in compressed form.
Enables RTP header compression on the physical interface.
Example:
Router(config-subif)#
frame-relay ip rtp header-compression [passive]
Configuring Data-Stream Hardware Compression and IP Header Compression on a Multipoint Subinterface
To configure data-stream hardware compression and TCP or RTP header compression on a multipoint
subinterface, use the following commands beginning in global configuration mode. Note that when you specify
data-stream hardware compression, Cisco-proprietary encapsulation is automatically enabled.
SUMMARY STEPS
1. Router(config)# interface type number multipoint
2. Router(config-subif)# frame-relay interface-dlci dlci
3. Router(config-subif)# frame-relay map protocol protocol-address dlci [payload-compression data-stream
stac [hardware-options]]
4. Do one of the following:
• Router(config-subif)# frame-relay ip tcp header-compression [passive]
•
•
•
•
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DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config)# interface type number multipoint
Configures a subinterface type and enters subinterface
configuration mode.
Step 2
Router(config-subif)# frame-relay interface-dlci dlci Assigns a DLCI to a specified Frame Relay subinterface on
the router or access server.
Step 3
Router(config-subif)# frame-relay map protocol
protocol-address dlci [payload-compression
data-stream stac [hardware-options]]
Defines the mapping between a destination protocol address
and the DLCI used to connect to the destination address on
an interface that uses Cisco-proprietary encapsulation.
Step 4
Do one of the following:
Configures an interface to ensure that the associated PVCs
carry outgoing TCP headers in compressed form.
• Router(config-subif)# frame-relay ip tcp
header-compression [passive]
•
•
•
•
Enables RTP header compression on the physical interface.
Example:
Router(config-subif)#
frame-relay ip rtp header-compression [passive]
Verifying Payload Compression
To verify that payload compression is working correctly, use the following privileged EXEC commands:
Command
Purpose
Displays compression statistics.
Router#
show compress
Router#
show frame-relay pvc
Router#
show traffic-shape queue
dlci
Displays statistics about PVCs for Frame Relay
interfaces, including the number of packets in the
post-hardware-compression queue.
Displays information about the elements queued at a
particular time at the DLCI level, including the
number of packets in the post-hardware- compression
queue.
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Configuring TCP IP Header Compression
Configuring an Individual IP Map for TCP IP Header Compression
To configure an IP map to use Cisco-proprietary encapsulation and TCP/IP header compression, use the
following command in interface configuration mode:
Command
Purpose
frame-relay map ip ip-address dlci [broadcast] Configures an IP map to use TCP/IP header
tcp header-compression [active | passive]
compression. Cisco-proprietary encapsulation is
[connections number]
enabled by default.
Configuring an Interface for TCP IP Header Compression
To apply TCP/IP header compression to an interface, you must use the following commands in interface
configuration mode:
SUMMARY STEPS
1. Router(config-if)# encapsulation frame-relay
2. Router(config-if)# frame-relay ip tcp header-compression [passive]
DETAILED STEPS
Command or Action
Purpose
Step 1
Router(config-if)# encapsulation frame-relay
Configures Cisco-proprietary encapsulation on the
interface.
Step 2
Router(config-if)# frame-relay ip tcp header-compression Enables TCP/IP header compression.
[passive]
Disabling TCP IP Header Compression
You can disable TCP/IP header compression by using either of two commands that have different effects,
depending on whether Frame Relay IP maps have been explicitly configured for TCP/IP header compression
or have inherited their compression characteristics from the interface.
Frame Relay IP maps that have explicitly configured TCP/IP header compression must also have TCP/IP
header compression explicitly disabled.
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To disable TCP/IP header compression, use one of the following commands in interface configuration mode:
Command
Purpose
no frame-relay ip tcp header-compression
Disables TCP/IP header compression on all Frame
Relay IP maps that are not explicitly configured for
TCP header compression.
frame-relay map ip ip-address dlci nocompress Disables RTP and TCP/IP header compression on a
specified Frame Relay IP map.
Configuring Discard Eligibility
Defining a DE List
To define a DE list specifying the packets that can be dropped when the Frame Relay switch is congested,
use the following command in global configuration mode:
SUMMARY STEPS
1. Router(config)# frame-relay de-list list-number {protocol protocol | interface type number}
characteristic
DETAILED STEPS
Step 1
Command or Action
Purpose
Router(config)# frame-relay de-list list-number {protocol protocol |
interface type number} characteristic
Defines a DE list.
Defining a DE Group
To define a DE group specifying the DE list and DLCI affected, use the following command in interface
configuration mode:
Command
frame-relay de-group group-number
Purpose
dlci
Defines a DE group.
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Configuring DLCI Priority Levels
To configure DLCI priority levels, use the following command in interface configuration mode:
Command
Purpose
frame-relay priority-dlci-group group-number
high-dlci medium-dlci normal-dlci low-dlci
Enables multiple parallel DLCIs for different Frame
Relay traffic types; associates and sets level of
specified DLCIs with same group.
Note
If you do not explicitly specify a DLCI for
each of the priority levels, the last DLCI
specified in the command line is used as the
value of the remaining arguments. At a
minimum, you must configure the
high-priority and the medium-priority
DLCIs.
Monitoring and Maintaining the Frame Relay Connections
To monitor Frame Relay connections, use any of the following commands in EXEC mode:
Command
Purpose
clear frame-relay-inarp
Clears dynamically created Frame Relay maps, which
are created by the use of Inverse ARP.
show interfaces serial type number
Displays information about Frame Relay DLCIs and
the LMI.
show frame-relay lmi [type number]
Displays LMI statistics.
show frame-relay map
Displays the current Frame Relay map entries.
show frame-relay pvc [type number [dlci]]
Displays PVC statistics.
show frame-relay route
Displays configured static routes.
show frame-relay traffic
Displays Frame Relay traffic statistics.
show frame-relay lapf
Displays information about the status of LAPF.
show frame-relay svc maplist
Displays all the SVCs under a specified map list.
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Configuration Examples for Frame Relay
Configuration Examples for Frame Relay
Example IETF Encapsulation
Example IETF Encapsulation on the Interface
The following example sets IETF encapsulation at the interface level. The keyword ietf sets the default
encapsulation method for all maps to IETF.
encapsulation frame-relay ietf
frame-relay map ip 131.108.123.2 48 broadcast
frame-relay map ip 131.108.123.3 49 broadcast
Example IETF Encapsulation on a Per-DLCI Basis
The following example configures IETF encapsulation on a per-DLCI basis. This configuration has the same
result as the configuration in the first example.
encapsulation frame-relay
frame-relay map ip 131.108.123.2 48 broadcast ietf
frame-relay map ip 131.108.123.3 49 broadcast ietf
Example Static Address Mapping
Example Two Routers in Static Mode
The following example shows how to configure two routers for static mode:
Configuration for Router 1
interface serial0
ip address 131.108.64.2 255.255.255.0
encapsulation frame-relay
keepalive 10
frame-relay map ip 131.108.64.1 43
Configuration for Router 2
interface serial1
ip address 131.108.64.1 255.255.255.0
encapsulation frame-relay
keepalive 10
frame-relay map ip 131.108.64.2 43
Example AppleTalk Routing
The following example shows how to configure two routers to communicate with each other using AppleTalk
over a Frame Relay network. Each router has a Frame Relay static address map for the other router. The use
of the appletalk cable-range command indicates that this is extended AppleTalk (Phase II).
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Example Subinterface
Configuration for Router 1
interface serial0
ip address 172.21.59.24 255.255.255.0
encapsulation frame-relay
appletalk cable-range 10-20 18.47
appletalk zone eng
frame-relay map appletalk 18.225 100 broadcast
Configuration for Router 2
interface serial2/3
ip address 172.21.177.18 255.255.255.0
encapsulation frame-relay
appletalk cable-range 10-20 18.225
appletalk zone eng
clockrate 2000000
frame-relay map appletalk 18.47 100 broadcast
Example DECnet Routing
The following example sends all DECnet packets destined for address 56.4 out on DLCI 101. In addition, any
DECnet broadcasts for interface serial 1 will be sent on that DLCI.
decnet routing 32.6
!
interface serial 1
encapsulation frame-relay
frame-relay map decnet 56.4 101 broadcast
Example IPX Routing
The following example shows how to send packets destined for IPX address 200.0000.0c00.7b21 out on DLCI
102:
ipx routing 000.0c00.7b3b
!
interface ethernet 0
ipx network 2abc
!
interface serial 0
ipx network 200
encapsulation frame-relay
frame-relay map ipx 200.0000.0c00.7b21 102 broadcast
Example Subinterface
Example Basic Subinterface
In the following example, subinterface 1 is configured as a point-to-point subnet and subinterface 2 is configured
as a multipoint subnet.
interface serial 0
encapsulation frame-relay
interface serial 0.1 point-to-point
ip address 10.0.1.1 255.255.255.0
frame-relay interface-dlci 42
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Example Subinterface
!
interface serial 0.2 multipoint
ip address 10.0.2.1 255.255.255.0
frame-relay map ip 10.0.2.2 18
Example Frame Relay Multipoint Subinterface with Dynamic Addressing
The following example configures two multipoint subinterfaces for dynamic address resolution. Each
subinterface is provided with an individual protocol address and subnet mask, and the frame-relay
interface-dlci command associates the subinterface with a specified DLCI. Addresses of remote destinations
for each multipoint subinterface will be resolved dynamically.
interface serial0
no ip address
encapsulation frame-relay
frame-relay lmi-type ansi
!
interface serial0.103 multipoint
ip address 172.21.177.18 255.255.255.0
frame-relay interface-dlci 300
!
interface serial0.104 multipoint
ip address 172.21.178.18 255.255.255.0
frame-relay interface-dlci 400
Example IPX Routes over Frame Relay Subinterfaces
The following example configures a serial interface for Frame Relay encapsulation and sets up multiple IPX
virtual networks corresponding to Frame Relay subinterfaces:
ipx routing 0000.0c02.5f4f
!
interface serial 0
encapsulation frame-relay
interface serial 0.1 multipoint
ipx network 1
frame-relay map ipx 1.000.0c07.d530 200 broadcast
interface serial 0.2 multipoint
ipx network 2
frame-relay map ipx 2.000.0c07.d530 300 broadcast
For subinterface serial 0.1, the router at the other end might be configured as follows:
ipx routing
interface serial 2 multipoint
ipx network 1
frame-relay map ipx 1.000.0c02.5f4f 200 broadcast
Example Unnumbered IP over a Point-to-Point Subinterface
The following example sets up unnumbered IP over subinterfaces at both ends of a point-to-point connection.
In this example, router A functions as the DTE, and router B functions as the DCE. Routers A and B are both
attached to Token Ring networks.
Configuration for Router A
interface token-ring 0
ip address 131.108.177.1 255.255.255.0
!
interface serial 0
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Example SVC Configuration
no ip address
encapsulation frame-relay IETF
!
interface serial0.2 point-to-point
ip unnumbered TokenRing0
ip pim sparse-mode
frame-relay interface-dlci 20
Configuration for Router B
frame-relay switching
!
interface token-ring 0
ip address 131.108.178.1 255.255.255.0
!
interface serial 0
no ip address
encapsulation frame-relay IETF
bandwidth 384
clockrate 4000000
frame-relay intf-type dce
!
interface serial 0.2 point-to-point
ip unnumbered TokenRing1
ip pim sparse-mode
!
bandwidth 384
frame-relay interface-dlci 20
Example Transparent Bridging Using Subinterfaces
The following example shows Frame Relay DLCIs 42, 64, and 73 as separate point-to-point links with
transparent bridging running over them. The bridging spanning tree views each PVC as a separate bridge port,
and a frame arriving on the PVC can be relayed back out on a separate PVC.
interface serial 0
encapsulation frame-relay
interface serial 0.1 point-to-point
bridge-group 1
frame-relay interface-dlci 42
interface serial 0.2 point-to-point
bridge-group 1
frame-relay interface-dlci 64
interface serial 0.3 point-to-point
bridge-group 1
frame-relay interface-dlci 73
Example SVC Configuration
Example SVC Interface
The following example configures a physical interface, applies a map group to the physical interface, and
then defines the map group:
interface serial 0
ip address 172.10.8.6
encapsulation frame-relay
map-group bermuda
frame-relay lmi-type q933a
frame-relay svc
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Example Frame Relay Traffic Shaping
!
map-list bermuda source-addr E164 123456 dest-addr E164 654321
ip 131.108.177.100 class hawaii
appletalk 1000.2 class rainbow
!
map-class frame-relay rainbow
frame-relay idle-timer 60
!
map-class frame-relay hawaii
frame-relay cir in 64000
frame-relay cir out 64000
Example SVC Subinterface
The following example configures a point-to-point interface for SVC operation. It assumes that the main serial
0 interface has been configured for signalling and that SVC operation has been enabled on the main interface:
int s 0.1 point-point
! Define the map-group; details are specified under the map-list holiday command.
map-group holiday
!
! Associate the map-group with a specific source and destination.
map-list holiday local-addr X121 <X121-addr> dest-addr E164 <E164-addr>
! Specify destination protocol addresses for a map-class.
ip 131.108.177.100 class hawaii IETF
appletalk 1000.2 class rainbow IETF broadcast
!
! Define a map class and its QoS settings.
map-class hawaii
frame-relay cir in 2000000
frame-relay cir out 56000
frame-relay be 9000
!
! Define another map class and its QoS settings.
map-class rainbow
frame-relay cir in 64000
frame-relay idle-timer 2000
Example Frame Relay Traffic Shaping
Example Traffic Shaping with Three Point-to-Point Subinterfaces
In the following example, VCs on subinterfaces Serial0.1 and Serial0.2 inherit class parameters from the main
interface--namely, those defined in the map class "slow_vcs"--but the VC defined on subinterface Serial0.2
(DLCI 102) is specifically configured to use map class "fast_vcs".
Map class "slow_vcs" uses a peak rate of 9600 and average rate of 4800 bps. Because BECN feedback is
enabled, the output rate will be cut back to as low as 2400 bps in response to received BECNs. This map class
is configured to use custom queueing using queue-list 1. In this example, queue-list 1 has 3 queues, with the
first two being controlled by access lists 100 and 115.
Map class "fast_vcs" uses a peak rate of 64000 and average rate of 16000 bps. Because BECN feedback is
enabled, the output rate will be cut back to as low as 8000 bps in response to received BECNs. This map class
is configured to use priority-queueing using priority-group 2.
interface serial0
no ip address
encapsulation frame-relay
frame-relay lmi-type ansi
frame-relay traffic-shaping
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Example Frame Relay Traffic Shaping
frame-relay class slow_vcs
!
interface serial0.1 point-to-point
ip address 10.128.30.1 255.255.255.248
ip ospf cost 200
bandwidth 10
frame-relay interface-dlci 101
!
interface serial0.2 point-to-point
ip address 10.128.30.9 255.255.255.248
ip ospf cost 400
bandwidth 10
frame-relay interface-dlci 102
class fast_vcs
!
interface serial0.3 point-to-point
ip address 10.128.30.17 255.255.255.248
ip ospf cost 200
bandwidth 10
frame-relay interface-dlci 103
!
map-class frame-relay slow_vcs
frame-relay traffic-rate 4800 9600
frame-relay custom-queue-list 1
frame-relay adaptive-shaping becn
!
map-class frame-relay fast_vcs
frame-relay traffic-rate 16000 64000
frame-relay priority-group 2
frame-relay adaptive-shaping becn
!
access-list 100 permit tcp any any eq 2065
access-list 115 permit tcp any any eq 256
!
priority-list 2 protocol decnet high
priority-list 2 ip normal
priority-list 2 default medium
!
queue-list 1 protocol ip 1 list 100
queue-list 1 protocol ip 2 list 115
queue-list 1 default 3
queue-list 1 queue 1 byte-count 1600 limit 200
queue-list 1 queue 2 byte-count 600 limit 200
queue-list 1 queue 3 byte-count 500 limit 200
Example Traffic Shaping with ForeSight
The following example illustrates a router configuration with traffic shaping enabled. DLCIs 100 and 101 on
subinterfaces Serial 13.2 and Serial 13.3 inherit class parameters from the main interface. The traffic shaping
for these two VCs will be adaptive to the ForeSight notification.
For Serial 0, the output rate for DLCI 103 will not be affected by the router ForeSight function.
interface Serial0
no ip address
encapsulation frame-relay
frame-relay lmi-type ansi
frame-relay traffic-shaping
!
interface Serial0.2 point-to-point
ip address 10.128.30.17 255.255.255.248
frame-relay interface-dlci 102
class fast_vcs
!
interface Serial0.3 point-to-point
ip address 10.128.30.5 255.255.255.248
ip ospf cost 200
frame-relay interface-dlci 103
class slow_vcs
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Example Frame Relay Traffic Shaping
!
interface serial 3
no ip address
encapsulation frame-relay
frame-relay traffic-shaping
frame-relay class fast_vcs
!
interface Serial3.2 multipoint
ip address 100.120.20.13 255.255.255.248
frame-relay map ip 100.120.20.6 16 ietf broadcast
!
interface Serial3.3 point-to-point
ip address 100.120.10.13 255.255.255.248
frame-relay interface-dlci 101
!
map-class frame-relay slow_vcs
frame-relay adaptive-shaping becn
frame-relay traffic-rate 4800 9600
!
map-class frame-relay fast_vcs
frame-relay adaptive-shaping foresight
frame-relay traffic-rate 16000 64000
frame-relay cir 56000
frame-relay bc 64000
Example LMI Configuration
Example ELMI and Frame Relay Traffic Shaping
The following configuration shows a Frame Relay interface enabled with QoS autosense. The router receives
messages from the Cisco switch, which is also configured with QoS autosense enabled. When ELMI is
configured in conjunction with traffic shaping, the router will receive congestion information through BECN
or router ForeSight congestion signalling and reduce its output rate to the value specified in the traffic shaping
configuration.
interface serial0
no ip address
encapsulation frame-relay
frame-relay lmi-type ansi
frame-relay traffic-shaping
frame-relay QoS-autosense
!
interface serial0.1 point-to-point
no ip address
frame-relay interface-dlci 101
Example Configuring the IP Address for ELMI Address Registration
The following example shows how to configure the IP address to be used for ELMI address registration.
Automatic IP address selection is automatically disabled when the IP address is configured. ELMI is enabled
on serial interface 0.
interface Serial 0
no ip address
encapsulation frame-relay
frame-relay lmi-type ansi
frame-relay qos-autosense
!
frame-relay address registration ip address 139.85.242.195
!
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Configuring Frame Relay
Example Backward Compatibility
Example Disabling ELMI Address Registration on an Interface
In the following example, ELMI address registration is disabled on serial interface 0. This interface will share
an IP address of 0.0.0.0 and an ifIndex of 0. Automatic IP address selection is enabled by default when ELMI
is enabled, so the management IP address of other interfaces on this router will be chosen automatically.
interface Serial 0
no ip address
encapsulation frame-relay
frame-relay lmi-type ansi
frame-relay qos-autosense
no frame-relay address-reg-enable
!
Example Backward Compatibility
The following configuration provides backward compatibility and interoperability with versions not compliant
with RFC 1490. The ietf keyword is used to generate RFC 1490 traffic. This configuration is possible because
of the flexibility provided by separately defining each map entry.
encapsulation frame-relay
frame-relay map ip 131.108.123.2 48 broadcast ietf
! interoperability is provided by IETF encapsulation
frame-relay map ip 131.108.123.3 49 broadcast ietf
frame-relay map ip 131.108.123.7 58 broadcast
! this line allows the router to connect with a
! device running an older version of software
frame-relay map decnet 21.7 49 broadcast
Example Booting from a Network Server over Frame Relay
When booting from a TFTP server over Frame Relay, you cannot boot from a network server via a broadcast.
You must boot from a specific TFTP host. Also, a frame-relay map command must exist for the host from
which you will boot.
For example, if file "gs3-bfx" is to be booted from a host with IP address 131.108.126.2, the following
commands would need to be in the configuration:
boot system gs3-bfx 131.108.126.2
!
interface Serial 0
encapsulation frame-relay
frame-relay map IP 131.108.126.2 100 broadcast
The frame-relay map command is used to map an IP address into a DLCI address. To boot over Frame Relay,
you must explicitly give the address of the network server to boot from, and a frame-relay map entry must
exist for that site. For example, if file "gs3-bfx.83-2.0" is to be booted from a host with IP address
131.108.126.111, the following commands must be in the configuration:
boot system gs3-bfx.83-2.0 131.108.13.111
!
interface Serial 1
ip address 131.108.126.200 255.255.255.0
encapsulation frame-relay
frame-relay map ip 131.108.126.111 100 broadcast
In this case, 100 is the DLCI that can get to host 131.108.126.111.
The remote router must be configured with the following command:
frame-relay map ip 131.108.126.200 101 broadcast
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Configuring Frame Relay
Example Frame Relay Switching
This entry allows the remote router to return a boot image (from the network server) to the router booting
over Frame Relay. Here, 101 is a DLCI of the router being booted.
Example Frame Relay Switching
Example PVC Switching Configuration
You can configure your router as a dedicated, DCE-only Frame Relay switch. Switching is based on DLCIs.
The incoming DLCI is examined, and the outgoing interface and DLCI are determined. Switching takes place
when the incoming DLCI in the packet is replaced by the outgoing DLCI, and the packet is sent out the
outgoing interface.
In the figure below, the router switches two PVCs between serial interfaces 1 and 2. Frames with DLCI 100
received on serial 1 will be transmitted with DLCI 200 on serial 2.
Figure 10: PVC Switching Configuration
The following example shows one router with two interfaces configured as DCEs. The router switches frames
from the incoming interface to the outgoing interface on the basis of the DLCI alone.
Configuration for Router A
frame-relay switching
interface Serial1
no ip address
encapsulation frame-relay
keepalive 15
frame-relay lmi-type ansi
frame-relay intf-type dce
frame-relay route 100 interface
frame-relay route 101 interface
clockrate 2000000
!
interface Serial2
encapsulation frame-relay
keepalive 15
frame-relay intf-type dce
frame-relay route 200 interface
frame-relay route 201 interface
clockrate 64000
Serial2 200
Serial2 201
Serial1 100
Serial1 101
Example Pure Frame Relay DCE
Using the PVC switching feature, it is possible to build an entire Frame Relay network using routers. In the
figure below, router A and router C act as Frame Relay switches implementing a two-node network. The
standard Network-to-Network Interface (NNI) signalling protocol is used between router A and router C.
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Configuring Frame Relay
Example Frame Relay Switching
The following example shows a Frame Relay network with two routers functioning as switches and standard
NNI signalling used between them.
Figure 11: Frame Relay DCE Configuration
Configuration for Router A
frame-relay switching
!
interface serial 1
no ip address
encapsulation frame-relay
frame-relay intf-type dce
frame-relay lmi-type ansi
frame-relay route 100 interface serial 2 200
!
interface serial 2
no ip address
encapsulation frame-relay
frame-relay intf-type nni
frame-relay lmi-type q933a
frame-relay route 200 interface serial 1 100
clockrate 2048000
!
Configuration for Router C
frame-relay switching
!
interface serial 1
no ip address
encapsulation frame-relay
frame-relay intf-type dce
frame-relay route 300 interface serial 2 200
!
interface serial 2
no ip address
encapsulation frame-relay
frame-relay intf-type nni
frame-relay lmi-type q933a
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Configuring Frame Relay
Example Frame Relay Switching
frame-relay route 200 interface serial 1 300
!
Example Hybrid DTE DCE PVC Switching
Routers can be configured as hybrid DTE/DCE Frame Relay switches, as shown in the figure below.
Figure 12: Hybrid DTE/DCE PVC Switching
The following example shows one router configured with both DCE and DTE interfaces (router B acts as a
hybrid DTE/DCE Frame Relay switch). It can switch frames between two DCE ports and between a DCE
port and a DTE port. Traffic from the Frame Relay network can also be terminated locally. In the example,
three PVCs are defined as follows:
• Serial 1, DLCI 102, to serial 2, DLCI 201--DCE switching
• Serial 1, DLCI 103, to serial 3, DLCI 301--DCE/DTE switching
• Serial 2, DLCI 203, to serial 3, DLCI 302--DCE/DTE switching
DLCI 400 is also defined for locally terminated traffic.
Configuration for Router B
frame-relay switching
!
interface ethernet 0
ip address 131.108.123.231 255.255.255.0
!
interface ethernet 1
ip address 131.108.5.231 255.255.255.0
!
interface serial 0
no ip address
shutdown :Interfaces not in use may be shut down; shut down is not required.
!
interface serial 1
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Configuring Frame Relay
Example Frame Relay Switching
no ip address
encapsulation frame-relay
frame-relay intf-type dce
frame-relay route 102 interface serial 2 201
frame-relay route 103 interface serial 3 301
!
interface serial 2
no ip address
encapsulation frame-relay
frame-relay intf-type dce
frame-relay route 201 interface serial 1 102
frame-relay route 203 interface serial 3 302
!
interface serial 3
ip address 131.108.111.231
encapsulation frame-relay
frame-relay lmi-type ansi
frame-relay route 301 interface serial 1 103
frame-relay route 302 interface serial 1 203
frame-relay map ip 131.108.111.4 400 broadcast
Example Switching over an IP Tunnel
You can achieve switching over an IP tunnel by creating a point-to-point tunnel across the internetwork over
which PVC switching can take place, as shown in the figure below.
Note
Static routes cannot be configured over tunnel interfaces on the Cisco 800 series, 1600 series, and 1700
series platforms. Static routes can only be configured over tunnel interfaces on platforms that have the
Enterprise feature set.
Figure 13: Frame Relay Switch over IP Tunnel
The following example shows two routers configured to switch Frame Relay PVCs over a point-to-point IP
tunnel, which is the IP network configuration depicted in the figure above.
Configuration for Router A
frame-relay switching
!
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Configuring Frame Relay
Example Frame Relay Switching
interface ethernet0
ip address 108.131.123.231 255.255.255.0
!
interface ethernet1
ip address 131.108.5.231 255.255.255.0
!
interface serial0
no ip address
shutdown : Interfaces not in use may be shut down; shutdown is not required.
!
interface serial1
ip address 131.108.222.231 255.255.255.0
encapsulation frame-relay
frame-relay map ip 131.108.222.4 400 broadcast
frame-relay route 100 interface Tunnel1 200
!
interface tunnel1
tunnel source Ethernet0
tunnel destination 150.150.150.123
Configuration for Router D
frame-relay switching
!
interface ethernet0
ip address 131.108.231.123 255.255.255.0
!
interface ethernet1
ip address 131.108.6.123 255.255.255.0
!
interface serial0
ip address 150.150.150.123 255.255.255.0
encapsulation ppp
!
interface tunnel1
tunnel source Serial0
tunnel destination 108.131.123.231
!
interface serial1
ip address 131.108.7.123 255.255.255.0
encapsulation frame-relay
frame-relay intf-type dce
frame-relay route 300 interface Tunnel1 200
Example Frame Relay Switching over ISDN B Channels
The following example illustrates Frame Relay switching over an ISDN dialer interface:
frame-relay switching
!
interface BRI0
isdn switch-type basic-5ess
dialer pool-member 1
dialer pool-member 2
!
interface dialer1
encapsulation frame-relay
dialer pool 1
dialer-group 1
dialer caller 60038
dialer string 60038
frame-relay intf-type dce
!
interface dialer2
encapsulation frame-relay
dialer pool 2
dialer-group 1
dialer caller 60039
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Configuring Frame Relay
Example Frame Relay Switching
dialer string 60039
frame-relay intf-type dce
!
interface serial0
encapsulation frame-relay
frame-relay intf-type dce
!
connect one serial0 16 dialer1 100
connect two serial0 17 dialer2 100
dialer-list 1 protocol ip permit
Note
Note that when Frame Relay switching is performed by using a dialer profile, encapsulation of the
underlying physical (BRI) interface must be configured as high-level data link control (HDLC).
Example Traffic Shaping on Switched PVCs
In the example that follows, traffic on serial interface 0 is being shaped prior to entry to the Frame Relay
network. PVC 100/16 is shaped according to the "shape256K" class. PVC 200/17 is shaped using the
"shape64K" class inherited from the interface.
frame-relay switching
!
interface serial0
encapsulation frame-relay
frame-relay intf-type dce
frame-relay traffic-shaping
frame-relay class shape64K
frame-relay interface-dlci 16 switched
class shape256K
!
interface serial1
encapsulation frame-relay
frame-relay intf-type dce
!
connect one serial0 16 serial1 100
connect two serial0 17 serial1 200
!
map-class frame-relay shape256K
frame-relay traffic-rate 256000 512000
!
map-class frame-relay shape64K
frame-relay traffic-rate 64000 64000
Example Traffic Policing on a UNI DCE
In the following example, incoming traffic is being policed on serial interface 1. The interface uses policing
parameters configured in map class "police256K". PVC 100/16 inherits policing parameters from the interface.
PVC 200/17 uses policing parameters configured in "police64K".
frame-relay switching
!
interface serial0
encapsulation frame-relay
frame-relay intf-type dce
!
interface serial1
encapsulation frame-relay
frame-relay policing
frame-relay class police256K
frame-relay intf-type dce
frame-relay interface-dlci 200 switched
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Configuring Frame Relay
Example Frame Relay Switching
class police64K
!
connect one serial0 16 serial1 100
connect two serial0 17 serial1 200
!
map-class frame-relay police256K
frame-relay cir 256000
frame-relay bc 256000
frame-relay be 0
!
map-class frame-relay police64K
frame-relay cir 64000
frame-relay bc 64000
frame-relay be 64000
Example Congestion Management on Switched PVCs
The following example illustrates the configuration of congestion management and DE discard levels for all
switched PVCs on serial interface 1. Policing is configured on PVC 16.
frame-relay switching
!
interface serial0
encapsulation frame-relay
frame-relay intf-type dce
frame-relay policing
frame-relay interface-dlci 16 switched
class 256K
!
interface serial1
encapsulation frame-relay
frame-relay intf-type dce
frame-relay congestion-management
threshold ecn be 0
threshold ecn bc 20
threshold de 40
!
connect one serial1 100 serial0 16
!
map-class frame-relay 256K
frame-relay cir 256000
frame-relay bc 256000
frame-relay be 256000
Example Congestion Management on the Traffic-Shaping Queue of a Switched PVC
The following example illustrates the configuration of congestion management in a class called
"perpvc_congestion". The class is associated with the traffic-shaping queue of DLCI 200 on serial interface
3.
map-class frame-relay perpvc_congestion
frame-relay holdq 100
frame-relay congestion threshold ecn 50
interface Serial3
frame-relay traffic-shaping
frame-relay interface-dlci 200 switched
class perpvc_congestion
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Configuring Frame Relay
Example Frame Relay End-to-End Keepalive
Example FRF.12 Fragmentation on a Switched PVC Configuration
In the following example, FRF.12 fragmentation is configured in a map class called "data". The "data" map
class is assigned to switched pvc 20 on serial interface 3/3.
frame-relay switching
!
interface Serial3/2
encapsulation frame-relay
frame-relay intf-type dce
!
interface Serial3/3
encapsulation frame-relay
frame-relay traffic-shaping
frame-relay interface-dlci 20 switched
class data
frame-relay intf-type dce
!
map-class frame-relay data
frame-relay fragment 80 switched
frame-relay cir 64000
frame-relay bc 640
!
connect data Serial3/2 16 Serial3/3 20
Example Frame Relay End-to-End Keepalive
Example End-to-End Keepalive Bidirectional Mode with Default Configuration
In the following example, the devices at each end of a VC are configured so that a DLCI is assigned to a
Frame Relay serial interface, a map class is associated with the interface, and Frame Relay end-to-end keepalive
is configured in bidirectional mode using default values:
! router1
router1(config) interface serial 0/0.1 point-to-point
router1(config-if) ip address 10.1.1.1 255.255.255.0
router1(config-if) frame-relay interface-dlci 16
router1(config-if) frame-relay class vcgrp1
router1(config-if) exit
!
router1(config)# map-class frame-relay vcgrp1
router1(config-map-class)# frame-relay end-to-end keepalive mode bidirectional
! router2
router2(config) interface serial 1/1.1 point-to-point
router2(config-if) ip address 10.1.1.2 255.255.255.0
router2(config-if) frame-relay interface-dlci 16
router2(config-if) frame-relay class vceek
router1(config-if) exit
!
router2(config)# map-class frame-relay vceek
router2(config-map-class)# frame-relay end-to-end keepalive mode bidirectional
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Configuring Frame Relay
Example Frame Relay End-to-End Keepalive
Example End-to-End Keepalive Request Mode with Default Configuration
In the following example, the devices at each end of a VC are configured so that a DLCI is assigned to a
Frame Relay serial interface and a map class is associated with the interface. One device is configured in
request mode while the other end of the VC is configured in reply mode.
! router1
router1(config) interface serial 0/0.1 point-to-point
router1(config-if) ip address 10.1.1.1 255.255.255.0
router1(config-if) frame-relay interface-dlci 16
router1(config-if) frame-relay class eek
router1(config-if) exit
!
router1(config)# map-class frame-relay eek
router1(config-map-class)# frame-relay end-to-end keepalive mode request
! router2
router2(config) interface serial 1/1.1 point-to-point
router2(config-if) ip address 10.1.1.2 255.255.255.0
router2(config-if) frame-relay interface-dlci 16
router2(config-if) frame-relay class group_3
router1(config-if) exit
!
router2(config)# map-class frame-relay group_3
router2(config-map-class)# frame-relay end-to-end keepalive mode reply
Example End-to-End Keepalive Request Mode with Modified Configuration
In the following example, the devices at each end of a VC are configured so that a DLCI is assigned to a
Frame Relay serial interface and a map class is associated with the interface. One device is configured in
request mode while the other end of the VC is configured in reply mode. The event window, error threshold,
and success events values are changed so that the interface will change state less frequently:
! router1
router1(config) interface serial 0/0.1 point-to-point
router1(config-if) ip address 10.1.1.1 255.255.255.0
router1(config-if) frame-relay interface-dlci 16
router1(config-if) frame-relay class eek
router1(config-if) exit
!
router1(config)# map-class frame-relay eek
router1(config-map-class)# frame-relay end-to-end keepalive
router1(config-map-class)# frame-relay end-to-end keepalive
router1(config-map-class)# frame-relay end-to-end keepalive
router1(config-map-class)# frame-relay end-to-end keepalive
! router2
router2(config) interface serial 1/1.1 point-to-point
router2(config-if) ip address 10.1.1.2 255.255.255.0
router2(config-if) frame-relay interface-dlci 16
router2(config-if) frame-relay class group_3
router1(config-if) exit
!
router2(config)# map-class frame-relay group_3
router2(config-map-class)# frame-relay end-to-end keepalive
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mode request
event-window send 5
error-threshold send 3
success-events send 3
mode reply
Configuring Frame Relay
Example PPPoverFrameRelay
Example PPPoverFrameRelay
Example PPP over Frame Relay DTE
The following example configures a router as a DTE device for PPP over Frame Relay. Subinterface 2.1
contains the necessary DLCI and virtual template information. Interface Virtual-Template 1 contains the PPP
information that is applied to the PPP session associated with DLCI 32 on serial subinterface 2.1.
interface serial 2
no ip address
encapsulation frame-relay
frame-relay lmi-type ansi
!
interface serial 2.1 point-to-point
frame-relay interface-dlci 32 ppp virtual-template1
!
interface Virtual-Template1
ip unnumbered ethernet 0
ppp authentication chap pap
Note
By default, the encapsulation type for a virtual template interface is PPP encapsulation; therefore,
encapsulation pppwill not appear when you view the configuration of the router.
Example PPP over Frame Relay DCE
The following example configures a router to act as a DCE device. Typically, a router is configured as a DCE
if it is connecting directly to another router or if connected to a 90i D4 channel unit, which is connected to a
telco channel bank. The three commands required for this type of configuration are the frame-relay switching,
frame-relay intf-type dce, and frame-relay route commands:
frame-relay switching
!
interface Serial2/0:0
no ip address
encapsulation frame-relay IETF
frame-relay lmi-type ansi
frame-relay intf-type dce
frame-relay route 31 interface Serial1/2 100
frame-relay interface-dlci 32 ppp Virtual-Template1
!
interface Serial2/0:0.2 point-to-point
no ip address
frame-relay interface-dlci 40 ppp Virtual-Template2
!
interface Virtual-Template1
ip unnumbered Ethernet0/0
peer default ip address pool default
ppp authentication chap pap
!
interface Virtual-Template2
ip address 100.1.1.2 255.255.255.0
ppp authentication chap pap
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Configuring Frame Relay
Example Frame Relay Fragmentation Configuration
Note
By default, the encapsulation type for a virtual template interface is PPP encapsulation; therefore,
encapsulation pppwill not appear when you view the configuration of the router.
Example Frame Relay Fragmentation Configuration
Example FRF.12 Fragmentation
The following example shows the configuration of pure end-to-end FRF.12 fragmentation and weighted fair
queueing in the map class called "frag". The fragment payload size is set to 40 bytes. The "frag" map class is
associated with DLCI 100 on serial interface 1.
router(config)#
interface serial 1
router(config-if)# frame-relay interface-dlci 100
router(config-fr-dlci)# class frag
router(config-fr-dlci)# exit
router(config)# map-class frame-relay frag
router(config-map-class)# frame-relay fragment 40
Example Frame Relay Fragmentation with Hardware Compression
In the following example, FRF.12 fragmentation and FRF.9 hardware compression are configured on multipoint
interface 3/1 and point-to-point interface 3/1.1:
interface serial3/1
ip address 10.1.0.1 255.255.255.0
encapsulation frame-relay
frame-relay traffic-shaping
frame-relay class frag
frame-relay map ip 10.1.0.2 110 broadcast ietf payload-compression frf9 stac
!
interface serial3/1.1 point-to-point
ip address 10.2.0.1 255.255.255.0
frame-relay interface-dlci 120 ietf
frame-relay payload-compression frf9 stac
!
map-class frame-relay frag
frame-relay cir 64000
frame-relay bc 640
frame-relay fragment 100
Example Payload Compression Configuration
Note
Shut down the interface or subinterface prior to adding or changing compression techniques. Although
shutdown is not required, shutting down the interface ensures that it is reset for the new data structures.
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Example Payload Compression Configuration
Example FRF.9 Compression for Subinterfaces Using the frame-relaymap Command
The following example shows a subinterface being configured for FRF.9 compression using the frame-relay
map command:
interface serial2/0/1
ip address 172.16.1.4 255.255.255.0
no ip route-cache
encapsulation frame-relay IETF
no keepalive
frame-relay map ip 172.16.1.1 105 IETF payload-compression FRF9 stac
Example FRF.9 Compression for Subinterfaces
The following example shows a subinterface being configured for FRF.9 compression:
interface serial2/0/0
no ip address
no ip route-cache
encapsulation frame-relay
ip route-cache distributed
no keepalive
!
interface serial2/0/0.500 point-to-point
ip address 172.16.1.4 255.255.255.0
no cdp enable
frame-relay interface-dlci 500 IETF
frame-relay payload-compression FRF9 stac
Example Data-Stream Hardware Compression with TCP IP Header Compression on a
Point-to-Point Subinterface
The following example shows the configuration of data-stream hardware compression and TCP header
compression on point-to-point interface 1/0.1:
interface serial1/0
encapsulation frame-relay
frame-relay traffic-shaping
!
interface serial1/0.1 point-to-point
ip address 10.0.0.1 255.0.0.0
frame-relay interface-dlci 100
frame-relay payload-compression data-stream stac
frame-relay ip tcp header-compression
Example Data-Stream Hardware Compression with TCP IP Header Compression on a Multipoint
Subinterface
The following example shows the configuration of data-stream hardware compression and TCP header
compression on multipoint interface 3/1:
interface serial3/1
ip address 10.1.0.1 255.255.255.0
encapsulation frame-relay
frame-relay traffic-shaping
frame-relay map ip 10.1.0.2 110 broadcast cisco payload-compression data-stream stac
frame-relay ip tcp header-compression
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Example TCP IP Header Compression
Example Data-Stream Hardware Compression with RTP Header Compression and Frame Relay
Fragmentation
The following example shows the configuration of data-stream hardware compression, RTP header compression,
and FRF.12 fragmentation on point-to-point interface 1/0.1:
interface serial1/0
encapsulation frame-relay
frame-relay traffic-shaping
!
interface serial1/0.1 point-to-point
ip address 10.0.0.1 255.0.0.0
frame-relay interface-dlci 100
frame-relay class frag
frame-relay payload-compression data-stream stac
frame-relay ip rtp header-compression
!
map-class frame-relay frag
frame-relay cir 64000
frame-relay bc 640
frame-relay be 0
frame-relay fragment 100
frame-relay ip rtp priority 16000 16000 20
Example TCP IP Header Compression
Example IP Map with Inherited TCP IP Header Compression
Note
Shut down the interface or subinterface prior to adding or changing compression techniques. Although
shutdown is not required, shutting down the interface ensures that it is reset for the new data structures.
The following example shows an interface configured for TCP/IP header compression and an IP map that
inherits the compression characteristics. Note that the Frame Relay IP map is not explicitly configured for
header compression.
interface serial 1
encapsulation frame-relay
ip address 131.108.177.178 255.255.255.0
frame-relay map ip 131.108.177.177 177 broadcast
frame-relay ip tcp header-compression passive
Use of the show frame-relay map command will display the resulting compression and encapsulation
characteristics; the IP map has inherited passive TCP/IP header compression:
Router> show frame-relay map
Serial 1
(administratively down): ip 131.108.177.177
dlci 177 (0xB1,0x2C10), static,
broadcast,
CISCO
TCP/IP Header Compression (inherited), passive (inherited)
This example also applies to dynamic mappings achieved with the use of Inverse ARP on point-to-point
subinterfaces where no Frame Relay maps are configured.
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Example TCP IP Header Compression
Example Using an IP Map to Override TCP IP Header Compression
The following example shows the use of a Frame Relay IP map to override the compression set on the interface:
interface serial 1
encapsulation frame-relay
ip address 131.108.177.178 255.255.255.0
frame-relay map ip 131.108.177.177 177 broadcast nocompress
frame-relay ip tcp header-compression passive
Use of the show frame-relay map command will display the resulting compression and encapsulation
characteristics; the IP map has not inherited TCP header compression:
Router> show frame-relay map
Serial 1
(administratively down): ip 131.108.177.177
dlci 177 (0xB1,0x2C10), static,
broadcast,
CISCO
Example Disabling Inherited TCP IP Header Compression
In this example, following is the initial configuration:
interface serial 1
encapsulation frame-relay
ip address 131.108.177.179 255.255.255.0
frame-relay ip tcp header-compression passive
frame-relay map ip 131.108.177.177 177 broadcast
frame-relay map ip 131.108.177.178 178 broadcast tcp header-compression
Enter the following commands to enable inherited TCP/IP header compression:
serial interface 1
no frame-relay ip tcp header-compression
Use of the show frame-relay map command will display the resulting compression and encapsulation
characteristics:
Router> show frame-relay map
Serial 1
(administratively down): ip 131.108.177.177 177
dlci 177(0xB1, 0x2C10), static,
broadcast
CISCO
Serial 1
(administratively down): ip 131.108.177.178 178
dlci 178(0xB2,0x2C20), static
broadcast
CISCO
TCP/IP Header Compression (enabled)
As a result, header compression is disabled for the first map (with DLCI 177), which inherited its header
compression characteristics from the interface. However, header compression is not disabled for the second
map (DLCI 178), which is explicitly configured for header compression.
Example Disabling Explicit TCP IP Header Compression
In this example, the initial configuration is the same as in the preceding example, but you must enter the
following set of commands to enable explicit TCP/IP header compression:
serial interface 1
no frame-relay ip tcp header-compression
frame-relay map ip 131.108.177.178 178 nocompress
Use of the show frame-relay map command will display the resulting compression and encapsulation
characteristics:
Router> show frame-relay map
Serial 1
(administratively down): ip 131.108.177.177 177
dlci 177(0xB1,0x2C10), static,
broadcast
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Additional References
Serial 1
CISCO
(administratively down): ip 131.108.177.178 178
dlci 178(0xB2,0x2C20), static
broadcast
CISCO
The result of the commands is to disable header compression for the first map (with DLCI 177), which inherited
its header compression characteristics from the interface, and also explicitly to disable header compression
for the second map (with DLCI 178), which was explicitly configured for header compression.
Additional References
Related Documents
Related Topic
Document Title
Cisco IOS Wide-Area Networking configuration tasks Cisco IOS XE Wide-Area Networking Configuration
Guide
Wide-Area networking commands
Cisco IOS Wide-Area Networking Command
Reference
Sending DDR traffic over Frame Relay
• Configuring Legacy DDR Spokes
• Configuring Legacy DDR Hubs
Installing software on a new router or access server
by downloading from a central server over an
interface that supports Frame Relay
Loading and Maintaining System Images
Using AutoInstall over Frame Relay
Overview - Basic Configuration of a Cisco
Networking Device
Configuring transparent bridging between devices
over a Frame Relay network
Configuring Transparent Bridging
Configuring source-route bridging between SNA
devices over a Frame Relay network
Configuring Source-Route Bridging
Configuring serial tunnel (STUN) and block serial
tunnel encapsulation between devices over a Frame
Relay network
Configuring Serial Tunnel and Block Serial Tunnel
Configuring access between SNA devices over a
Frame Relay network
Configuring SNA Frame Relay Access Support
Configuring Voice over Frame Relay Using FRF.11
and FRF.12
Configuring Voice over Frame Relay
Wide-Area Networking Configuration Guide: Frame Relay, Cisco IOS Release 15S
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Configuring Frame Relay
Additional References
Related Topic
Document Title
Configuring low latency queueing, PVC interface
priority queueing, and link fragmentation and
interleaving using multilink PPP for Frame Relay
Cisco IOS Quality of Service Solutions Configuration
Guide
Standards
Standard
Title
None
--
MIBs
MIB
MIBs Link
None
To locate and download MIBs for selected platforms,
Cisco IOS XE software releases, and feature sets, use
Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
RFCs
RFC
Title
None
--
Technical Assistance
Description
Link
The Cisco Support website provides extensive online http://www.cisco.com/techsupport
resources, including documentation and tools for
troubleshooting and resolving technical issues with
Cisco products and technologies.
To receive security and technical information about
your products, you can subscribe to various services,
such as the Product Alert Tool (accessed from Field
Notices), the Cisco Technical Services Newsletter,
and Really Simple Syndication (RSS) Feeds.
Access to most tools on the Cisco Support website
requires a Cisco.com user ID and password.
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Additional References
Wide-Area Networking Configuration Guide: Frame Relay, Cisco IOS Release 15S
82
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