Chapter 39 Configuring Cisco IOS IP SLAs Operations

Chapter 39 Configuring Cisco IOS IP SLAs Operations
CH A P T E R
39
Configuring Cisco IOS IP SLAs Operations
This chapter describes how to use Cisco IOS IP Service Level Agreements (SLAs) on the Cisco ME 3400
Ethernet Access switch. Cisco IP SLAs is a part of Cisco IOS software that allows Cisco customers to
analyze IP service levels for IP applications and services by using active traffic monitoring—the
generation of traffic in a continuous, reliable, and predictable manner—for measuring network
performance. With Cisco IOS IP SLAs, service provider customers can measure and provide service
level agreements, and enterprise customers can verify service levels, verify outsourced service level
agreements, and understand network performance. Cisco IOS IP SLAs can perform network
assessments, verify quality of service (QoS), ease the deployment of new services, and assist with
network troubleshooting.
Note
Full Cisco IP SLAs functionality is supported only on switches that are running the metro IP access or
metro access image. Switches running the metro base image, such as the ME 2400, support only IP SLAs
responder functionality and must be configured with another device that supports full IP SLAs
functionality.
For more information about IP SLAs, see the Cisco IOS IP SLAs Configuration Guide, Release 12.4T
this URL:
http://www.cisco.com/en/US/docs/ios/ipsla/configuration/guide/12_4t/sla_12_4t_book.html
For command syntax information, see the command reference at this URL:
http://www.cisco.com/en/US/docs/ios/ipsla/command/reference/sla_book.html
This chapter consists of these sections:
•
Understanding Cisco IOS IP SLAs, page 39-1
Configuring IP SLAs Operations, page 39-6
Monitoring IP SLAs Operations, page 39-13
Understanding Cisco IOS IP SLAs
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Chapter 39
Configuring Cisco IOS IP SLAs Operations
Understanding Cisco IOS IP SLAs
Depending on the specific Cisco IOS IP SLAs operation, various network performance statistics are
monitored within the Cisco device and stored in both command-line interface (CLI) and Simple Network
Management Protocol (SNMP) MIBs. IP SLAs packets have configurable IP and application layer
options such as source and destination IP address, User Datagram Protocol (UDP)/TCP port numbers, a
type of service (ToS) byte (including Differentiated Services Code Point [DSCP] and IP Prefix bits),
Virtual Private Network (VPN) routing/forwarding instance (VRF), and URL web address.
Because Cisco IP SLAs is Layer 2 transport independent, you can configure end-to-end operations over
disparate networks to best reflect the metrics that an end user is likely to experience. IP SLAs collects a
unique subset of these performance metrics:
Delay (both round-trip and one-way)
Jitter (directional)
Packet loss (directional)
Packet sequencing (packet ordering)
Path (per hop)
Connectivity (directional)
Server or website download time
Because Cisco IOS IP SLAs is SNMP-accessible, it can also be used by performance-monitoring
applications like CiscoWorks Internetwork Performance Monitor (IPM) and other third-party Cisco
partner performance management products. You can find more details about network management
products that use Cisco IOS IP SLAs at this URL:
http://www.cisco.com/go/ipsla
Using IP SLAs can provide these benefits:
Service-level agreement monitoring, measurement, and verification.
Network performance monitoring
– Measures the jitter, latency, or packet loss in the network.
– Provides continuous, reliable, and predictable measurements.
IP service network health assessment to verify that the existing QoS is sufficient for new IP services.
Edge-to-edge network availability monitoring for proactive verification and connectivity testing of
network resources (for example, shows the network availability of an NFS server used to store
business critical data from a remote site).
Troubleshooting of network operation by providing consistent, reliable measurement that
immediately identifies problems and saves troubleshooting time.
Multiprotocol Label Switching (MPLS) performance monitoring and network verification (if the
switch supports MPLS)
This section includes this information about IP SLAs functionality:
Using Cisco IOS IP SLAs to Measure Network Performance, page 39-3
IP SLAs Responder and IP SLAs Control Protocol, page 39-4
Response Time Computation for IP SLAs, page 39-4
IP SLAs Operation Scheduling, page 39-5
IP SLAs Operation Threshold Monitoring, page 39-5
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Using Cisco IOS IP SLAs to Measure Network Performance
Cisco IOS IP SLAs Operation
Performance
management
application
Any IP device
IP SLA measurement
and IP SLA responder to
IP SLA Responder
IP SLA
SNMP
IP network
IP SLA responder
IP SLA
121381
Figure 39-1
IP SLA source
IP SLA measurement
and IP SLA responder to
IP SLA Responder
To implement IP SLAs network performance measurement, you need to perform these tasks:
1.
2.
3.
4.
5.
6.
Note
show ip sla application privileged EXEC command to verify that the operation type is supported on
your software image.
IP SLAs Responder and IP SLAs Control Protocol
Note
as Telnet or HTTP). You cannot configure the IP SLAs responder on non-Cisco devices and Cisco IOS
IP SLAs can send operational packets only to services native to those devices.
Response Time Computation for IP SLAs
39-4
Cisco IOS IP SLAs Responder Time Stamping
Source router
T2
T1
Target router
Responder
T3
T4
=T3-T2
RTT (Round-trip time) = T4 (Time stamp 4) - T1 (Time stamp 1) -
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Figure 39-2
IP SLAs Operation Scheduling
an IP SLAs operation, you must schedule the operation to begin capturing statistics
and collecting error information. You can schedule an operation to start immediately or to start at a
certain month, day, and hour. You can use the pending option to set the operation to start at a later time.
The pending option is an internal state of the operation that is visible through SNMP. The pending state
is also used when an operation is a reaction (threshold) operation waiting to be triggered. You can
schedule a single IP SLAs operation or a group of operations at one time.
You can schedule several IP SLAs operations by using a single command through the Cisco IOS CLI or
the CISCO RTTMON-MIB. Scheduling the operations to run at evenly distributed times allows you to
control the amount of IP SLAs monitoring traffic. This distribution of IP SLAs operations helps
minimize the CPU utilization and thus improves network scalability.
For more details about the IP SLAs multioperations scheduling functionality, see the “IP
SLAs—Multiple Operation Scheduling” chapter of the
URL:
at this
http://www.cisco.com/en/US/docs/ios/ipsla/configuration/guide/12_4t/sla_12_4t_book.html
To support successful service level agreement monitoring, you must have mechanisms that notify you
immediately of any possible violation. IP SLAs can send SNMP traps that are triggered by events such
as these:
Connection loss
Timeout
Round-trip time threshold
Average jitter threshold
One-way packet loss
One-way jitter
39-5
Configuration Guide at this URL:
http://www.cisco.com/en/US/docs/ios/ipsla/configuration/guide/12_4t/sla_12_4t_book.html
Configuring IP SLAs Operations
•
•
, page 39-7
•
•
Analyzing IP Service Levels by Using the UDP Jitter Operation, page 39-8
Analyzing IP Service Levels by Using the ICMP Echo Operation, page 39-11
Default Configuration
Configuration Guidelines
Cisco IOS IP SLAs Command Reference, Release
12.4T
Cisco IOS IP SLAs Configuration Guide,
Release 12.4T
39-6
Switch# show ip sla application
IP SLAs
Version: 2.2.0 Round Trip Time MIB, Infrastructure Engine-II
Time of last change in whole IP SLAs: 22:17:39.117 UTC Fri Jun
Estimated system max number of entries: 15801
Estimated
Number of
Number of
Number of
Number of
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
of
of
of
of
of
of
of
of
of
of
of
of
number of configurable operations: 15801
Entries configured : 0
active Entries
: 0
pending Entries
: 0
inactive Entries
: 0
Supported
Operation
Operation
Operation
Operation
Operation
Operation
Operation
Operation
Operation
Operation
Operation
Operation
Operation Types
to Perform: 802.1agEcho
to Perform: 802.1agJitter
to Perform: dhcp
to Perform: dns
to Perform: echo
to Perform: ftp
to Perform: http
to Perform: jitter
to Perform: pathEcho
to Perform: pathJitter
to Perform: tcpConnect
to Perform: udpEcho
IP SLAs low memory water mark: 21741224
Command
Step 1
Purpose
configure terminal
ip sla responder {tcp-connect |
}
ip-address
port-number
ip-address
port-number
39-7
copy running-config startup-config
Switch(config)# ip sla responder udp-echo 172.29.139.134 5000
Analyzing IP Service Levels by Using the UDP Jitter Operation
is 2 ms; if the packets arrive 8 ms apart, negative jitter is 2 ms. For delay-sensitive networks, positive
jitter values are undesirable, and a jitter value of 0 is ideal.
In addition to monitoring jitter, the IP SLAs UDP jitter operation can be used as a multipurpose data
gathering operation. The packets IP SLAs generates carry packet sending and receiving sequence
information and sending and receiving time stamps from the source and the operational target. Based on
these, UDP jitter operations measure this data:
•
Per-direction jitter (source to destination and destination to source)
•
Per-direction packet-loss
•
Per-direction delay (one-way delay)
•
Round-trip delay (average round-trip time)
Because the paths for the sending and receiving of data can be different (asymmetric), you can use the
per-direction data to more readily identify where congestion or other problems are occurring in the
network.
The UDP jitter operation generates synthetic (simulated) UDP traffic and sends a number of UDP
packets, each of a specified size, sent a specified number of milliseconds apart, from a source router to
a target router, at a given frequency. By default, ten packet-frames, each with a payload size of 10 bytes
are generated every 10 ms, and the operation is repeated every 60 seconds. You can configure each of
these parameters to best simulate the IP service you want to provide.
To provide accurate one-way delay (latency) measurements, time synchronization, such as that provided
by NTP, is required between the source and the target device. Time synchronization is not required for
the one-way jitter and packet loss measurements. If the time is not synchronized between the source and
target devices, one-way jitter and packet loss data is returned, but values of 0
39-8
configure terminal
ip sla
udp-jitter
destination-hostname
destination-port source-ip
ip-address hostname
source-port port-number
control enable disable
num-packets number-of-packets
interval interpacket-interval
destination-ip-address destination-hostname
destination-port
ip-address hostname —
port-number
number-of-packets
inter-packet-interval
frequency seconds
exit
Command
Purpose
operation-number
month day day month
hh:mm:ss
seconds
seconds
hh:mm:ss
seconds
Step 7
Step 8
Step 9
udp-jitter 172.29.139.134 5000
frequency 30
exit
ip sla schedule 5 start-time now life forever
end
show ip sla configuration 10
Target address/Source address: 1.1.1.1/0.0.0.0
Target port/Source port: 2/0
Request size (ARR data portion): 32
Operation timeout (milliseconds): 5000
Packet Interval (milliseconds)/Number of packets: 20/10
Type Of Service parameters: 0x0
Verify data: No
Vrf Name:
Control Packets: enabled
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Chapter 39
Configuring Cisco IOS IP SLAs Operations
Configuring IP SLAs Operations
Group Scheduled : FALSE
Randomly Scheduled : FALSE
Life (seconds): 3600
Entry Ageout (seconds): never
Recurring (Starting Everyday): FALSE
Status of entry (SNMP RowStatus): notInService
Threshold (milliseconds): 5000
Distribution Statistics:
Number of statistic hours kept: 2
Number of statistic distribution buckets kept: 1
Statistic distribution interval (milliseconds): 20
Enhanced History:
Analyzing IP Service Levels by Using the ICMP Echo Operation
Note
Command
Purpose
Step 1
Step 2
Step 3
•
•
•
Step 4
Step 5
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Chapter 39
Configuring Cisco IOS IP SLAs Operations
Configuring IP SLAs Operations
Command
Purpose
Step 6
•
•
•
•
•
Step 7
Step 8
Step 9
Switch(config)#
Switch(config-ip-sla)#
Switch(config-ip-sla-echo)#
Switch(config-ip-sla-echo)#
Switch(config)#
Switch(config)#
Switch#
IP SLAs, Infrastructure Engine-II.
Entry number: 12
Owner:
Tag:
Type of operation to perform: echo
Target address: 2.2.2.2
Source address: 0.0.0.0
Request size (ARR data portion): 28
Operation timeout (milliseconds): 5000
Type Of Service parameters: 0x0
Verify data: No
Vrf Name:
Schedule:
Operation frequency (seconds): 60
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Chapter 39
Configuring Cisco IOS IP SLAs Operations
Monitoring IP SLAs Operations
Next Scheduled Start Time: Pending trigger
Group Scheduled : FALSE
Randomly Scheduled : FALSE
Life (seconds): 3600
Entry Ageout (seconds): never
Recurring (Starting Everyday): FALSE
Status of entry (SNMP RowStatus): notInService
Threshold (milliseconds): 5000
Distribution Statistics:
Number of statistic hours kept: 2
Number of statistic distribution buckets kept: 1
Statistic distribution interval (milliseconds): 20
History Statistics:
Number of history Lives kept: 0
Number of history Buckets kept: 15
History Filter Type: None
Enhanced History:
Monitoring IP SLAs Operations
Table 39-1
Monitoring IP SLAs Operations
entry-number |
|
collection-statistics |
configuration ldp operational-state | scan-queue | summary
| neighbors
show ip sla reaction-configuration
show ip sla reaction-trigger
show ip sla responder
show ip sla statistics
aggregated details
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