Troubleshooting guide

8-24
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 8 Troubleshooting Tag and MPLS Switching Connections
Troubleshooting MPLS Connections
Pinging Neighbors
Follow these steps to verify the neighbor MPLS interface connections:
Step 1 Enter the ping command to verify that the connection is up between the provider-edge ATM switch
router and the customer-edge router.
8540-PE2# ping vrf Red 222.2.2.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 222.2.2.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
8540-PE2#
This ping command example provides verification of the connections shown in Figure 8-5.
Step 2 Enter the debug mpls packet command or the MPLS-aware traceroute vrf command to verify the
MPLS labels are set.
8540-PE2# traceroute vrf Red 222.2.2.1
Type escape sequence to abort.
Tracing the route to 222.2.2.1
1 111.0.1.17 4 msec 0 msec 4 msec
2 111.0.1.101 0 msec 0 msec 0 msec
3 111.0.1.102 4 msec * 0 msec
8540-PE2#
Verify that the interfaces that appear in the traceroute command output display are the correct
cross-connect addresses. This traceroute vrf command example shows verification of the connections,
shown in Figure 8-5.
Verifying Label Distribution
Follow these steps to verify the label distribution between MPLS interface connections:
Step 1 Enter the show mpls forwarding-table command to display the discovered neighbors.
8540-P# show mpls forwarding-table
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
16 Untagged 100.1.0.0/16 0 AT9/0/0 4.4.4.2
17 Untagged 11.0.0.0/8 0 AT9/0/0 4.4.4.2
18 Untagged 200.1.0.0/16 0 AT9/0/1 6.6.6.2
19 Pop tag 222.2.1.1/32 624 Fa11/0/0 111.0.1.1
20 Pop tag 222.2.1.2/32 0 Fa11/0/1 111.0.1.18
The Local tag field displays the label assigned by this switch router.