Using Segment Routing OAM. Cisco Network Convergence System 5500 Series
विज्ञापन
विज्ञापन
C H A P T E R
17
Using Segment Routing OAM
Segment Routing Operations, Administration, and Maintenance (OAM) helps service providers to monitor label-switched paths (LSPs) and quickly isolate forwarding problems to assist with fault detection and troubleshooting in the network. The Segment Routing OAM feature provides support for BGP prefix SIDs,
IGP prefix and Flexible Algorithm SIDs, and Nil-FEC (forwarding equivalence classes) LSP Ping and
Traceroute functionality.
•
MPLS Ping and Traceroute for BGP and IGP Prefix-SID, on page 461
•
Examples: MPLS Ping, Traceroute, and Tree Trace for Prefix-SID, on page 462
•
MPLS LSP Ping and Traceroute Nil FEC Target, on page 464
•
Examples: LSP Ping and Traceroute for Nil_FEC Target , on page 465
•
Segment Routing Ping and Traceroute, on page 466
•
Segment Routing Ping and Traceroute for Flexible Algorithm, on page 474
•
Segment Routing over IPv6 OAM, on page 476
MPLS Ping and Traceroute for BGP and IGP Prefix-SID
Table 73: Feature History Table
Feature Name
MPLS Ping and Traceroute for
BGP and IGP Prefix-SID
Release
Release 7.6.1
Description
This feature is supported on Cisco
Network Convergence System 5700
Series routers and routers with the
Cisco NC57 line cards operating in native mode.
The MPLS LSP Ping feature is used to check the connectivity between ingress Label Switch Routers
(LSRs) and egress LSRs along an
LSP.
MPLS Ping and Traceroute operations for Prefix SID are supported for various BGP and IGP scenarios, for example:
• Within an IS-IS level or OSPF area
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Examples: MPLS Ping, Traceroute, and Tree Trace for Prefix-SID
• Across IS-IS levels or OSPF areas
• Route redistribution from IS-IS to OSPF and from OSPF to IS-IS
• Anycast Prefix SID
• Combinations of BGP and LDP signaled LSPs
The MPLS LSP Ping feature is used to check the connectivity between ingress Label Switch Routers (LSRs) and egress LSRs along an LSP. MPLS LSP ping uses MPLS echo request and reply messages, similar to
Internet Control Message Protocol (ICMP) echo request and reply messages, to validate an LSP. The destination
IP address of the MPLS echo request packet is different from the address used to select the label stack. The destination IP address is defined as a 127.x.y.z/8 address and it prevents the IP packet from being IP switched to its destination, if the LSP is broken.
The MPLS LSP Traceroute feature is used to isolate the failure point of an LSP. It is used for hop-by-hop fault localization and path tracing. The MPLS LSP Traceroute feature relies on the expiration of the Time to
Live (TTL) value of the packet that carries the echo request. When the MPLS echo request message hits a transit node, it checks the TTL value and if it is expired, the packet is passed to the control plane, else the message is forwarded. If the echo message is passed to the control plane, a reply message is generated based on the contents of the request message.
The MPLS LSP Tree Trace (traceroute multipath) operation is also supported for BGP and IGP Prefix SID.
MPLS LSP Tree Trace provides the means to discover all possible equal-cost multipath (ECMP) routing paths of an LSP to reach a destination Prefix SID. It uses multipath data encoded in echo request packets to query for the load-balancing information that may allow the originator to exercise each ECMP. When the packet
TTL expires at the responding node, the node returns the list of downstream paths, as well as the multipath information that can lead the operator to exercise each path in the MPLS echo reply. This operation is performed repeatedly for each hop of each path with increasing TTL values until all ECMP are discovered and validated.
MPLS echo request packets carry Target FEC Stack sub-TLVs. The Target FEC sub-TLVs are used by the responder for FEC validation. The BGP and IGP IPv4 prefix sub-TLV has been added to the Target FEC
Stack sub-TLV. The IGP IPv4 prefix sub-TLV contains the prefix SID, the prefix length, and the protocol
(IS-IS or OSPF). The BGP IPv4 prefix sub-TLV contains the prefix SID and the prefix length.
Examples: MPLS Ping, Traceroute, and Tree Trace for Prefix-SID
These examples use the following topology:
MPLS Ping for Prefix-SID
RP/0/RP0/CPU0:router-arizona# ping mpls ipv4 1.1.1.4/32
Thu Dec 17 01:01:42.301 PST
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Using Segment Routing OAM
Examples: MPLS Ping, Traceroute, and Tree Trace for Prefix-SID
Sending 5, 100-byte MPLS Echos to 1.1.1.4, timeout is 2 seconds, send interval is 0 msec:
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 2/2/3 ms
MPLS Traceroute for Prefix-SID
RP/0/RP0/CPU0:router-arizona# traceroute mpls ipv4 1.1.1.4/32
Thu Dec 17 14:45:05.563 PST
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
0 12.12.12.1 MRU 4470 [Labels: 16004 Exp: 0]
L 1 12.12.12.2 MRU 4470 [Labels: 16004 Exp: 0] 3 ms
L 2 23.23.23.3 MRU 4470 [Labels: implicit-null Exp: 0] 3 ms
! 3 34.34.34.4 11 ms
MPLS Tree Trace for Prefix-SID
RP/0/RP0/CPU0:router-arizona# traceroute mpls multipath ipv4 1.1.1.4/32
Thu Dec 17 14:55:46.549 PST
Starting LSP Path Discovery for 1.1.1.4/32
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
LL!
Path 0 found, output interface TenGigE0/0/0/0 nexthop 12.12.12.2
source 12.12.12.1 destination 127.0.0.0
L!
Path 1 found,
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MPLS LSP Ping and Traceroute Nil FEC Target output interface TenGigE0/0/0/0 nexthop 12.12.12.2
source 12.12.12.1 destination 127.0.0.2
LL!
Path 2 found, output interface TenGigE0/0/0/1 nexthop 15.15.15.5
source 15.15.15.1 destination 127.0.0.1
L!
Path 3 found, output interface TenGigE0/0/0/1 nexthop 15.15.15.5
source 15.15.15.1 destination 127.0.0.0
Paths (found/broken/unexplored) (4/0/0)
Echo Request (sent/fail) (10/0)
Echo Reply (received/timeout) (10/0)
Total Time Elapsed 53 ms
MPLS LSP Ping and Traceroute Nil FEC Target
Table 74: Feature History Table
Feature Name
MPLS LSP Ping and Traceroute
Nil FEC Target
Release
Release 7.6.1
Description
This feature is supported on Cisco
Network Convergence System 5700
Series routers and routers with the
Cisco NC57 line cards operating in native mode.
This feature allows operators to provide the ability to freely test any label stack by allowing them to specify the following:
• label stack
• outgoing interface
• nexthop address
The Nil-FEC LSP ping and traceroute operations are extensions of regular MPLS ping and traceroute.
Nil-FEC LSP Ping/Traceroute functionality supports segment routing and MPLS Static. It also acts as an additional diagnostic tool for all other LSP types. This feature allows operators to provide the ability to freely test any label stack by allowing them to specify the following:
• label stack
• outgoing interface
• nexthop address
In the case of segment routing, each segment nodal label and adjacency label along the routing path is put into the label stack of an echo request message from the initiator Label Switch Router (LSR); MPLS data plane forwards this packet to the label stack target, and the label stack target sends the echo message back.
The following table shows the syntax for the ping and traceroute commands.
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Examples: LSP Ping and Traceroute for Nil_FEC Target
Table 75: LSP Ping and Traceroute Nil FEC Commands
Command Syntax ping mpls nil-fec labels { label [ ,label ]} [ output { interface tx-interface } [ nexthop nexthop-ip-addr ]] traceroute mpls nil-fec labels { label [ ,label ]} [ output { interface tx-interface } [ nexthop nexthop-ip-addr ]]
Examples: LSP Ping and Traceroute for Nil_FEC Target
These examples use the following topology:
Node loopback IP address: 172.18.1.3
172.18.1.4
172.18.1.5
172.18.1.7
Node label: 16004 16005 16007
Nodes: Arizona ---- Utah ------- Wyoming ---- Texas
Interface:
Interface IP address:
GigabitEthernet0/2/0/1 GigabitEthernet0/2/0/1
10.1.1.3
10.1.1.4
RP/0/RP0/CPU0:router-utah# show mpls forwarding
Tue Jul 5 13:44:31.999 EDT
Local Outgoing Prefix Outgoing Next Hop Bytes
Label Label or ID Interface Switched
------ ----------- ------------------ ------------ --------------- ------------
16004 Pop
Pop
16005 16005
16005
16007 16007
No ID
No ID
No ID
No ID
No ID
Gi0/2/0/1
Gi0/2/0/2
Gi0/2/0/0
Gi0/2/0/1
Gi0/2/0/0
10.1.1.4
10.1.2.2
10.1.1.4
10.1.2.2
10.1.1.4
1392
0
0
0
4752
16007
24000 Pop
24001 Pop
24002 Pop
24003 Pop
24004 Pop
24005 Pop
24006 Pop
24007 Pop
24008 Pop
No ID
SR Adj (idx 0)
SR Adj (idx 2)
SR Adj (idx 0)
SR Adj (idx 2)
No ID
No ID
No ID
No ID
No ID
Gi0/2/0/1
Gi0/2/0/0
Gi0/2/0/0
Gi0/2/0/1
Gi0/2/0/1 tt10 tt11 tt12 tt13 tt30
10.1.2.2
10.1.1.4
10.1.1.4
10.1.2.2
10.1.2.2
point2point point2point point2point point2point point2point
0
0
0
0
0
0
0
0
0
0
Ping Nil FEC Target
RP/0/RP0/CPU0:router-arizona# ping mpls nil-fec labels 16005,16007 output interface
GigabitEthernet 0/2/0/1 nexthop 10.1.1.4 repeat 1
Sending 1, 72-byte MPLS Echos with Nil FEC labels 16005,16007, timeout is 2 seconds, send interval is 0 msec:
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no label entry,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'd' - see DDMAP for return code,
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Segment Routing Ping and Traceroute
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
!
Success rate is 100 percent (1/1), round-trip min/avg/max = 1/1/1 ms
Total Time Elapsed 0 ms
Traceroute Nil FEC Target
RP/0/RP0/CPU0:router-arizona# traceroute mpls nil-fec labels 16005,16007 output interface
GigabitEthernet 0/2/0/1 nexthop 10.1.1.4
Tracing MPLS Label Switched Path with Nil FEC labels 16005,16007, timeout is 2 seconds
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no label entry,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'd' - see DDMAP for return code,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
0 10.1.1.3 MRU 1500 [Labels: 16005/16007/explicit-null Exp: 0/0/0]
L 1 10.1.1.4 MRU 1500 [Labels: implicit-null/16007/explicit-null Exp: 0/0/0] 1 ms
L 2 10.1.1.5 MRU 1500 [Labels: implicit-null/explicit-null Exp: 0/0] 1 ms
! 3 10.1.1.7 1 ms
Segment Routing Ping and Traceroute
Table 76: Feature History Table
Feature Name Release
Information
Feature Description
Segment Routing Ping and Traceroute
Release
7.6.1
This feature is supported on Cisco Network Convergence System
5700 Series routers and routers with the Cisco NC57 line cards operating in native mode.
Segment routing ping and traceroute features extendsthe MPLS LSP ping and traceroute functionality to perform the connectivity verification on the segment routing control plane.
SR OAM for SR Policy
(Policy Name / Binding
SID / Custom label stack)
Release
7.3.1
This feature extends SR OAM ping and traceroute function for an SR policy (or binding SID)-LSP end-point combination.
This addresses the limitations of the Nil-FEC LSP Ping and Traceroute function which cannot perform a ping operation to a segment list that is not associated with an installed SR policy. Also, it cannot validate egress device-specific SR policies.
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Segment Routing Ping
Segment Routing Ping
The MPLS LSP ping feature is used to check the connectivity between ingress and egress of LSP. MPLS LSP ping uses MPLS echo request and reply messages, similar to Internet Control Message Protocol (ICMP) echo request and reply messages, to validate an LSP. Segment routing ping is an extension of the MPLS LSP ping to perform the connectivity verification on the segment routing control plane.
Note Segment routing ping can only be used when the originating device is running segment routing.
You can initiate the segment routing ping operation only when Segment Routing control plane is available at the originator, even if it is not preferred. This allows you to validate the SR path before directing traffic over the path. Segment Routing ping can use either generic FEC type or SR control-plane FEC type (SR-OSPF,
SR-ISIS). In mixed networks, where some devices are running MPLS control plane (for example, LDP) or do not understand SR FEC, generic FEC type allows the device to successfully process and respond to the echo request. By default, generic FEC type is used in the target FEC stack of segment routing ping echo request. Generic FEC is not coupled to a particular control plane; it allows path verification when the advertising protocol is unknown or might change during the path of the echo request. If you need to specify the target
FEC, you can select the FEC type as OSPF, IS-IS, or BGP. This ensures that only devices that are running segment routing control plane, and can therefore understand the segment routing IGP FEC, respond to the echo request.
Configuration Examples
These examples show how to use segment routing ping to test the connectivity of a segment routing control plane. In the first example, FEC type is not specified. You can also specify the FEC type as shown in the other examples.
RP/0/RP0/CPU0:router# ping sr-mpls 10.1.1.2/32
Sending 5, 100-byte MPLS Echos to 10.1.1.2/32, timeout is 2 seconds, send interval is 0 msec:
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/5 ms
RP/0/RP0/CPU0:router# ping sr-mpls 10.1.1.2/32 fec-type generic
Sending 5, 100-byte MPLS Echos to 10.1.1.2/32, timeout is 2 seconds, send interval is 0 msec:
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
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Segment Routing Ping
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
RP/0/RP0/CPU0:router# ping sr-mpls 10.1.1.2/32 fec-type igp ospf
Sending 5, 100-byte MPLS Echos to 10.1.1.2/32, timeout is 2 seconds, send interval is 0 msec:
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
RP/0/RP0/CPU0:router# ping sr-mpls 10.1.1.2/32 fec-type igp isis
Sending 5, 100-byte MPLS Echos to 10.1.1.2/32, timeout is 2 seconds, send interval is 0 msec:
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
RP/0/RP0/CPU0:router# ping sr-mpls 10.1.1.2/32 fec-type bgp
Sending 5, 100-byte MPLS Echos to 10.1.1.2/32, timeout is 2 seconds, send interval is 0 msec:
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
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Segment Routing Traceroute
Ping for SR Policy
You can perform the ping operation for an SR policy (or binding SID), and LSP end-point combination. Use the ping command’s policy name lsp-end-point and policy binding-sid lsp-end-point options to perform this task. You can instantiate the policy through the CLI, Netconf, PCEP or BGP-TE process.
IPv6 policies are not supported for SR OAM function.
Note As a prerequisite, you must enable the MPLS OAM function.
Router(config)# mpls oam
Router(config)# commit
Router# ping sr-mpls policy name srte_c_4_ep_10.0.0.1 lsp-end-point 209.165.201.1
Router# ping sr-mpls policy binding-sid 1000 lsp-end-point 209.165.201.1
Segment Routing Traceroute
The MPLS LSP traceroute is used to isolate the failure point of an LSP. It is used for hop-by-hop fault localization and path tracing. The MPLS LSP traceroute feature relies on the expiration of the Time to Live
(TTL) value of the packet that carries the echo request. When the MPLS echo request message hits a transit node, it checks the TTL value and if it is expired, the packet is passed to the control plane, else the message is forwarded. If the echo message is passed to the control plane, a reply message is generated based on the contents of the request message. Segment routing traceroute feature extends the MPLS LSP traceroute functionality to segment routing networks.
Similar to segment routing ping, you can initiate the segment routing traceroute operation only when Segment
Routing control plane is available at the originator, even if it is not preferred. Segment Routing traceroute can use either generic FEC type or SR control-plane FEC type (SR-OSPF, SR-ISIS). By default, generic FEC type is used in the target FEC stack of segment routing traceroute echo request. If you need to specify the target FEC, you can select the FEC type as OSPF, IS-IS, or BGP. This ensures that only devices that are running segment routing control plane, and can therefore understand the segment routing IGP FEC, respond to the echo request.
The existence of load balancing at routers in an MPLS network provides alternate paths for carrying MPLS traffic to a target router. The multipath segment routing traceroute feature provides a means to discover all possible paths of an LSP between the ingress and egress routers.
Configuration Examples
These examples show how to use segment routing traceroute to trace the LSP for a specified IPv4 prefix SID address. In the first example, FEC type is not specified. You can also specify the FEC type as shown in the other examples.
RP/0/RP0/CPU0:router# traceroute sr-mpls 10.1.1.2/32
Tracing MPLS Label Switched Path to 10.1.1.2/32, timeout is 2 seconds
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
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Segment Routing Traceroute
Type escape sequence to abort.
0 10.12.12.1 MRU 1500 [Labels: implicit-null Exp: 0]
! 1 10.12.12.2 3 ms
RP/0/RP0/CPU0:router# traceroute sr-mpls 10.1.1.2/32 fec-type generic
Tracing MPLS Label Switched Path to 10.1.1.2/32, timeout is 2 seconds
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
0 10.12.12.1 MRU 1500 [Labels: implicit-null Exp: 0]
! 1 10.12.12.2 2 ms
RP/0/RP0/CPU0:router# traceroute sr-mpls 10.1.1.2/32 fec-type igp ospf
Tracing MPLS Label Switched Path to 10.1.1.2/32, timeout is 2 seconds
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
0 10.12.12.1 MRU 1500 [Labels: implicit-null Exp: 0]
! 1 10.12.12.2 2 ms
RP/0/RP0/CPU0:router# traceroute sr-mpls 10.1.1.2/32 fec-type igp isis
Tracing MPLS Label Switched Path to 10.1.1.2/32, timeout is 2 seconds
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
0 10.12.12.1 MRU 1500 [Labels: implicit-null Exp: 0]
! 1 10.12.12.2 2 ms
RP/0/RP0/CPU0:router# traceroute sr-mpls 10.1.1.2/32 fec-type bgp
Tracing MPLS Label Switched Path to 10.1.1.2/32, timeout is 2 seconds
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Segment Routing Traceroute
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
0 10.12.12.1 MRU 1500 [Labels: implicit-null/implicit-null Exp: 0/0]
! 1 10.12.12.2 2 ms
This example shows how to use multipath traceroute to discover all the possible paths for a IPv4 prefix SID.
RP/0/RP0/CPU0:router# traceroute sr-mpls multipath 10.1.1.2/32
Starting LSP Path Discovery for 10.1.1.2/32
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
!
Path 0 found, output interface GigabitEthernet0/0/0/2 nexthop 10.13.13.2
source 10.13.13.1 destination 127.0.0.0
!
Path 1 found, output interface Bundle-Ether1 nexthop 10.12.12.2
source 10.12.12.1 destination 127.0.0.0
Paths (found/broken/unexplored) (2/0/0)
Echo Request (sent/fail) (2/0)
Echo Reply (received/timeout) (2/0)
Total Time Elapsed 14 ms
Traceroute for SR Policy
You can perform the traceroute operation for an SR policy (or binding SID), and LSP end-point combination.
Use the traceroute command’s policy name lsp-end-point and policy binding-sid lsp-end-point options to perform this task. You can instantiate the policy through the CLI, Netconf, PCEP or BGP-TE process.
IPv6 policies are not supported for SR OAM function.
Note As a prerequisite, you must enable the MPLS OAM function.
Router(config)# mpls oam
Router(config)# commit
Router# traceroute sr-mpls policy name srte_c_4_ep_10.0.0.1 lsp-end-point 209.165.201.1
Router# traceroute sr-mpls policy binding-sid 1000 lsp-end-point 209.165.201.1
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Segment Routing Treetrace Enhancements
Segment Routing Treetrace Enhancements
Table 77: Feature History Table
Feature Name
Segment Routing Treetrace
Enhancements
Release
Release 7.3.2
Description
The OAM Treetrace operation provides enhanced traceroute functionality to validate ECMP paths between two endpoints.
This feature augments the Treetrace operation to support SR policies,
SR NIL FEC, SR Flex Algo, or a custom list of labels.
The SR-OAM Treetrace (multipath traceroute) operation provides enhanced traceroute functionality to validate
ECMP paths between two endpoints.
The Segment Routing Treetrace enhancements augment the Treetrace operation to support SR policies, Flex
Algo labels, or a custom list of labels.
• Use the traceroute sr-mpls multipath policy EXEC command to specify the target SR policy.
• Use the traceroute sr-mpls multipath labels EXEC command to specify the target custom list of labels:
• The custom list can have 1 to 12 prefix-SID labels.
• A label can be Algo 0 or Flex Algo prefix-SID label.
• Use the traceroute sr-mpls multipath nil-fec EXEC command to specify the target custom list of labels and outgoing information or the target SR policy, to be verified using Nil FEC.
Note As a prerequisite, you must enable the MPLS OAM function.
Router(config)# mpls oam
Router(config-oam)# commit
Example 1: Treetrace Operation for an SR Policy
Router# traceroute sr-mpls multipath policy name srte_c_10_ep_192.168.0.3 lsp-endpoint
192.168.0.3
Starting LSP Path Discovery for SR Policy with name [srte_c_10_ep_192.168.0.3]
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
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L!
Path 0 found, output interface GigabitEthernet0/0/0/0 nexthop 10.10.10.2
source 10.10.10.1 destination 127.0.0.0
L!
Path 1 found, output interface GigabitEthernet0/0/0/1 nexthop 11.11.11.2
source 11.11.11.1 destination 127.0.0.0
Paths (found/broken/unexplored) (2/0/0)
Echo Request (sent/fail) (4/0)
Echo Reply (received/timeout) (4/0)
Total Time Elapsed 14 ms
Example 2: Treetrace Operation for an SR Policy with Nil FEC
Router# traceroute sr-mpls multipath nil-fec policy name srte_c_10_ep_192.168.0.3
Starting LSP Path Discovery for SR Policy with name [srte_c_10_ep_192.168.0.3]
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
L!
Path 0 found, output interface GigabitEthernet0/0/0/0 nexthop 10.10.10.2
source 10.10.10.1 destination 127.0.0.0
L!
Path 1 found, output interface GigabitEthernet0/0/0/1 nexthop 11.11.11.2
source 11.11.11.1 destination 127.0.0.0
Paths (found/broken/unexplored) (2/0/0)
Echo Request (sent/fail) (4/0)
Echo Reply (received/timeout) (4/0)
Total Time Elapsed 14 ms
Example 3: Treetrace Operation for a Custom List of Labels with SR Label FEC
Router# traceroute sr-mpls multipath labels 16128 lsp-end-point 1.1.1.5
Starting LSP Path Discovery for SR Label FEC with lsp end point 1.1.1.5, SID Label(s) [16128]
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
LL!
Path 0 found,
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Segment Routing Ping and Traceroute for Flexible Algorithm output interface GigabitEthernet0/0/0/0 nexthop 10.10.10.2
source 10.10.10.1 destination 127.0.0.0
LL!
Path 1 found, output interface GigabitEthernet0/0/0/1 nexthop 11.11.11.2
source 11.11.11.1 destination 127.0.0.0
Paths (found/broken/unexplored) (2/0/0)
Echo Request (sent/fail) (6/0)
Echo Reply (received/timeout) (6/0)
Total Time Elapsed 30 ms
Example 4: Treetrace Operation for a Custom List of Labels with Nil FEC
Router# traceroute sr-mpls multipath labels 16004,16005 output interface GigabitEthernet
0/0/0/2 nexthop 12.12.12.3
Starting LSP Path Discovery for Nil FEC with labels [16004,16005]
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
LL!
Path 0 found, output interface GigabitEthernet0/0/0/2 nexthop 12.12.12.3
source 12.12.12.1 destination 127.0.0.2
!
Path 1 found, output interface GigabitEthernet0/0/0/2 nexthop 12.12.12.3
source 12.12.12.1 destination 127.0.0.0
Paths (found/broken/unexplored) (2/0/0)
Echo Request (sent/fail) (4/0)
Echo Reply (received/timeout) (4/0)
Total Time Elapsed 30 ms
Segment Routing Ping and Traceroute for Flexible Algorithm
Table 78: Feature History Table
Feature Name Release
Information
Feature Description
Segment Routing Ping and Traceroute for
Flexible Algorithm
Release
7.6.1
This feature is supported on Cisco Network Convergence System
5700 Series routers and routers with the Cisco NC57 line cards operating in native mode.
Flexible Algorithm validation method is based on segment identifier
(SID) label and label switched path (LSP) destination, instead of being based on IP address.
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Flexible Algorithm validation method is based on segment identifier (SID) label and label switched path (LSP) destination, instead of being based on IP address. The assigner is validated against the topology prefix information provided by SR-PCE database. If the assigner is valid, then the label given is also validated against the SR-PCE database. On the egress side, the destination label is contained in a new SR Label sub-TLV. This label is verified against a SID list provided by SR-PCE.
Note Observe the following guidelines and restrictions:
• All routers within an area must share the same Flexible Algorithm definition for a Flexible Algorithm to be valid.
• All routers within the domain must be configured with the same SRGB range of values.
• BGP-LS must be enabled.
• Only prefix SIDs and Flexible Algorithm SIDs are supported.
• Only single label stack is supported.
Segment Routing Ping for Flexible Algorithm
Router# ping sr-mpls labels 16131 lsp-end-point 1.1.1.5
Fri Dec 13 19:26:29.517 IST
Sending 5, 100-byte MPLS Echos with SR Label FEC with lsp end point 1.1.1.5, SID Label(s)
[16131], timeout is 2 seconds, send interval is 0 msec:
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/6 ms
Segment Routing Traceroute for Flexible Algorithm
Router# traceroute sr-mpls labels 16130 lsp-end-point 1.1.1.5
Fri Dec 13 19:26:59.368 IST
Tracing MPLS Label Switched Path to SR Label FEC with lsp end point 1.1.1.5, SID Label(s)
[16130], timeout is 2 seconds
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
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Segment Routing over IPv6 OAM
'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
0 13.13.13.1 MRU 1500 [Labels: 16130 Exp: 0]
L 1 13.13.13.3 MRU 1500 [Labels: 16130 Exp: 0] 5 ms
L 2 16.16.16.4 MRU 1500 [Labels: implicit-null Exp: 0] 4 ms
! 3 18.18.18.5 4 ms
Segment Routing over IPv6 OAM
Segment Routing over IPv6 data plane (SRv6) implementation adds a new type of routing extension header.
Hence, the existing ICMPv6 mechanisms including ping and traceroute can be used in the SRv6 network.
There is no change in the way ping and traceroute operations work for IPv6- or SRv6-capable nodes in an
SRv6 network.
Restrictions and Usage Guidelines
The following restriction applies for SRv6 OAM:
• Ping to an SRv6 SID is not supported.
Examples: SRv6 OAM
The following example shows using ping in an SRv6 network.
RP/0/RP0/CPU0:Router# ping ipv6 2001::33:33:33:33
Mon Sep 17 20:04:10.068 UTC
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2001::33:33:33:33, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms
The following example shows using traceroute in an SRv6 network.
RP/0/RP0/CPU0:Router# traceroute ipv6 2001::33:33:33:33 probe 1 timeout 0 srv6
Fri Sep 14 15:59:25.170 UTC
Type escape sequence to abort.
Tracing the route to 2001::33:33:33:33
1 2001::22:22:22:22[IP tunnel: DA=cafe:0:0:a4:1:::: SRH =(2001::33:33:33:33 ,SL=1)] 2 msec
2 2001::2:2:2:2[IP tunnel: DA=cafe:0:0:a4:1:::: SRH =(2001::33:33:33:33 ,SL=1)] 2 msec
3 2001::44:44:44:44 2 msec
4 2001::33:33:33:33 3 msec
The following example shows using traceroute in an SRv6 network without an SRH.
RP/0/RSP1/CPU0:Router# traceroute ipv6 2001::44:44:44:44 srv6
Wed Jan 16 14:35:27.511 UTC
Type escape sequence to abort.
Tracing the route to 2001::44:44:44:44
1 2001::2:2:2:2 3 msec 2 msec 2 msec
2 2001::44:44:44:44 3 msec 3 msec 3 msec
The following example shows using ping for a specified IP address in the VRF.
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Segment Routing over IPv6 OAM
RP/0/RP0/CPU0:Router# ping 10.15.15.1 vrf red
Mon Sep 17 20:07:10.085 UTC
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.15.15.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
The following example shows using traceroute for a specified IP address in the VRF.
RP/0/RP0/CPU0:Router# traceroute 10.15.15.1 vrf red
Mon Sep 17 20:07:18.478 UTC
Type escape sequence to abort.
Tracing the route to 10.15.15.1
1 10.15.15.1 3 msec 2 msec 2 msec
The following example shows using traceroute for CE1 (4.4.4.5) to CE2 (5.5.5.5) in the VRF:
RP/0/RP0/CPU0:Router# traceroute 5.5.5.5 vrf a
Wed Jan 16 15:08:46.264 UTC
Type escape sequence to abort.
Tracing the route to 5.5.5.5
1 14.14.14.1 5 msec 1 msec 1 msec
2 15.15.15.1 3 msec 2 msec 2 msec
3 15.15.15.2 2 msec * 3 msec
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