Chapter 12 Multiprotocol Label Switching Checklist; Multiprotocol Label Switching Recommendations - Cisco CRS-1 - Carrier Routing System Router Troubleshooting Manual

Multiprotocol Label Switching Checklist
This chapter provides a checklist to troubleshoot the Multiprotocol Label Switching (MPLS) protocol.
You can collect information from the sample output on all routers for the following commands to
troubleshoot the problems in MPLS:
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For more detailed information about the show tech-support commands, see Cisco IOS XR Advanced
System Command Reference for the Cisco CRS-1 Router.

Multiprotocol Label Switching Recommendations

Follow these recommendations to troubleshoot Multiprotocol Label Switching (MPLS):
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show tech-support mpls rsvp
show tech-support mpls traffic-eng
show tech-support routing ospf
show tech-support routing isis
Verify the show commands for the MPLS control plane to ensure that there is no problem.
Ensure that the hardware is programmed correctly for Multiprotocol Label Switching (MPLS)
Traffic Engineering (TE) and Label Distribution Protocol (LDP).
Ensure that there are no communication problems in the MPLS infrastructure. If the control plane
has some problems, determine if they are due to the following reasons:
– Communication problems in the Resource Reservation Protocol (RSVP) infrastructure . In
certain instances, the tunnel is not up though the topology is correct and the RSVP messages are
lost.
Communication problems with the MPLS-TE infrastructure .
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Verify the sample output from the applicable show tech-support commands on all routers in the
entire network topology. Copy the output to the applicable TFTP location.
For MPLS-TE issues, verify the output from the show tech-support mpls traffic-eng, show
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tech-support mpls rsvp, show tech-support routing ospf, and show tech-support routing
isis commands.
For MPLS LDP issues, verify the output from the show tech-support mpls ldp command.
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Provide a topology diagram that indicates the applicable platform.
Specify the symptom of the problem. For example, for an MPLS-TE tunnel, the problem is detected
at the head, middle, or tail of a tunnel.
C H A P T E R
Cisco IOS XR Troubleshooting Guide for the Cisco CRS-1 Router
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