CLI Reference Guide-R04

Chapter 27 | CFM Commands
Link Trace Operations
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ethernet cfm linktrace This command sends CFM link trace messages to the MAC address of a remote MEP.
Syntax
ethernet cfm linktrace {dest-mep destination-mpid | src-mep source-mpid
{dest-mep destination-mpid | mac-address} | mac-address} md domain-name
ma ma-name [priority level | ttl number]
destination-mpid – The identifier of a remote MEP that is the target of the
link trace message. (Range: 1-8191)
source-mpid – The identifier of a source MEP that will send the link trace
message. (Range: 1-8191)
mac-address – MAC address of a remote MEP that is the target of the link
trace message. This address can be entered in either of the following
formats: xx-xx-xx-xx-xx-xx or xxxxxxxxxxxx
domain-name – Domain name. (Range: 1-43 alphanumeric characters)
ma-name – Maintenance association name. (Range: 1-43 alphanumeric
characters)
number – The time to live of the linktrace message. (Range: 0-255 hops)
level - The priority level for sending the link trace messages. (Range: 0-7, 7
highest)
Default Setting
None
Command Mode
Privileged Exec
Command Usage
◆ Link trace messages can be targeted to MEPs, not MIPs. Before sending a link
trace message, be sure you have configured the target MEP for the specified
MA.
◆ If the MAC address of target MEP has not been learned by any local MEP, then
the linktrace may fail. Use the show ethernet cfm maintenance-points remote
crosscheck command to verify that a MAC address has been learned for the
target MEP.
◆ Link trace messages (LTMs) are sent as multicast CFM frames, and forwarded
from MIP to MIP, with each MIP generating a link trace reply, up to the point at
which the LTM reaches its destination or can no longer be forwarded.
◆ Link trace messages are used to isolate faults. However, this task can be difficult
in an Ethernet environment, since each node is connected through multipoint
links. Fault isolation is even more challenging since the MAC address of the
target node can age out in several minutes. This can cause the traced path to
vary over time, or connectivity lost if faults cause the target MEP to be isolated
from other MEPs in an MA.