EtherHaul Operation, Administration and Maintenance Manual
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13.1.8
Working with Linktrace Messages
Linktrace messages are multicast from an originating MEP to a target MAC (MIP or
MEP)/MEP ID, to verify the path between the two. Linktrace Reply messages (LTRs) are
unicast from the target (or MIPs on route) to the originating MEP. Receipt of an LTR
verifies the path.
Arriving LTRs are stored on a per-MEP basis in the LTR database.
LTRs are stored in ascending sequence number order and LTRs with the same sequence
number (i.e. replies to the same LTM) are grouped together.
Since storage is limited, arrival of a new message results in discarding older messages.
Entire groups that use the same sequence number are discarded.
Use the following command to display LTR database information:
show cfm ltr-db [{<md-idx-list> | all} [{<ma-idx-list> | all}
[{<mepid-list> | all} [{SN-list | all}]]]]
SN stands for the Sequence Number of the LTR message stored. This does not refer to
the real sequence number stored in the LTR header, but rather, to the relative SN which
is equal to Real SN modulo Maximum Allowed Number of SNs.
For example, if the maximum allowed number of stored LTRs (with different SNs) is 20,
then the Real SN = 807 is translated into the Relative SN = 7.
It is possible to specify more than one SN in the command by designating indexed
objects.
13.1.9
Sample CFM Configuration
This section provides a sample CFM configuration script.
Configuring the Local System
The first step in configuring CFM parameters is to enable the OAM license, which is part
of the L2 Networking license. Without an enabled OAM license, the necessary CFM
commands are not available.
set license oam status enable
The next step in this configuration is to configure an MD at level 0:
set cfm-md 1 name string Link level 0
The following command creates an MA:
set cfm-ma 1 1 name string Link interval 300hz
The following command creates a Component MA and assigns VLAN 200 as its Service
Selector:
set cfm-ma-comp c2 1 1 vlan 200
