Users Guide

Sending Loopback Messages and Responses

Loopback message and response (LBM, LBR), also called Layer 2 Ping, is an administrative echo transmitted by MEPs to verify

reachability to another MEP or MIP within the maintenance domain. LBM and LBR are unicast frames.

• Send a Loopback message

EXEC Privilege mode

ping ethernet domain name ma-name ma-name remote {mep-id | mac-addr mac-address}source {mep-

id | port interface}

Sending Linktrace Messages and Responses

Linktrace message and response (LTM, LTR), also called Layer 2 Traceroute, is an administratively sent multicast frames transmitted by

MEPs to track, hop-by-hop, the path to another MEP or MIP within the maintenance domain.

All MEPs and MIPs in the same domain respond to an LTM with a unicast LTR. Intermediate MIPs forward the LTM toward the target

MEP.

Figure 6. MPLS Core

Link trace messages carry a unicast target address (the MAC address of an MIP or MEP) inside a multicast frame. The destination group

address is based on the MD level of the transmitting MEP (01:80:C2:00:00:3[8 to F]). The MPs on the path to the target MAC address

reply to the LTM with an LTR, and relays the LTM towards the target MAC until the target MAC is reached or TTL equals 0.

• Send a Linktrace message. There is no need to specify a destination, as the LTM is a Multicast message sent to the entire ME.

EXEC Privilege

traceroute ethernet domain

Caching Link Trace

After you execute a Link Trace command, the trace information can be cached so that you can view it later without retracing.

To enable, set, display, and delete link trace caching, use the following commands.

• Enable Link Trace caching.

CONFIGURATION mode

traceroute cache

• Set the amount of time a trace result is cached.

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