Troubleshooting Guide

IS to get from one MEP to another, by showing all the hops between. Therefore, it can show where
connectivity is lost. It can also work for IP shortcuts.
Important:
To trace a route to a MAC address, the MAC address must be in the VLAN FDB table.
• For B-VLANs, you do not have to trigger an l2ping to learn the MAC address because IS-
IS populates the MAC addresses in the FDB table.
linktrace traces the path up to the closest device to that MAC address that supports CFM.
Before you begin
• You must have a MEP that is associated with a VLAN.
Procedure
Trigger a Layer 2 traceroute:
l2 traceroute {<vlan <1-4059> routernodename WORD<0–255> | <vlan <1-4059>
mac <0x00:0x00:0x00:0x00:0x00:0x00>} [priority <0–7>] [source-mode
<nodal|noVlanMac|smltVirtual>] [ttl <1–255>]
l2 traceroute {ip-address WORD<0–255>} [priority <0–7>] [source-mode
<nodal|noVlanMac|smltVirtual>] [ttl <1–255>] [vrf WORD <0–16>]
Example
VSP-4850GTS# l2 traceroute vlan 500 routernodename VSP-MONTIO
Please wait for l2traceroute to complete or press any key to abort
l2traceroute to VSP-MONTI0 (00:14:0d:a2:b3:df), vlan 500
0 VSP-PETER4 (00:15:9b:11:33:df)
1 VSP-MONTI0 (00:14:0d:a2:b3:df)
VSP-4850GTS# l2 traceroute ip-address 10.1.1.1
Please wait for l2trace to complete or press any key to abort
L2 Trace Statistics : IP 10.1.1.1, paths found 1
==================================================================
VSP-SHAMIM (00:1a:8f:08:53:df), vlan 500
0 VSP-PETER4 (00:15:9b:11:33:df)
1 VSP-MONTI0 (00:14:0d:a2:b3:df)
Variable definitions
Use the data in the following table to use the l2 traceroute command.
Variable
Value
{vlan <1-4059> routernodename
WORD<0–255>}
(vlan <1-4059> mac
<0x00:0x00:0x00:0x00:0x00:0x00>}
Specifies the destination for the L2 traceroute:
• <1-4059>
Specifies the VLAN ID in the range of 1 to 4059. VLAN IDs 1
to 4059 are configurable. The system reserves VLAN IDs
Table continues…
CFM configuration using ACLI
January 2017 Troubleshooting 173
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