Ethernet OAM (Operations, Administration, and Maintenance)
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OmniAccess 5740 Unified Services Gateway CLI Configuration Guide
Alcatel-Lucent
T
O ENABLE/DISABLE CCM (CONTINUITY CHECK MESSAGE) ON MEP
CCM (Continuity Check Messages) are heart beat messages issued periodically
by MEP’s towards other MEP’s. They allow MEP’s to detect loss of service
connectivity among themselves. They allow MEP’s to discover other MEP’s within
a domain and allow MIP’s to discover MEP’s.
All MEPs belonging to a MD will receive it but will not respond to it. MEPs must be
configured with an expected set of remote MEPs, that will be compared to the
received CCM(s). The receiving MEPs will build a MEP database that has entities
of the format [MEP remote MEP, Port]. MEPs receiving this CCM message will
catalog it, and know that the maintenance entity (ME) is functional, including all
intermediate MIPs.
CCM is used for fault detection purposes. Specifically, a connectivity failure is
defined as:
• the inability of any MEP in an MA to receive three consecutive CCM(s) from
anyone of the other MEPs in its MA (Loss of CCM);
• the reception by a MEP of a CCM with an incorrect MAID (Maintenance
Association ID = MD Name + MA Name) or a lower MA level (MAID mismatch /
MA level mismatch).
CCM may operate for each Service Instance (VLAN tagged/untagged frame). The
definition of a MA for each instance, provides the chance to detect 100% of
connectivity failures within that Service Instance.
E
XAMPLE
ALU(config-oam-domain-assoc-mep)# ccm enable
ALU(config-oam-domain-assoc-mep)# ccm disable
Command (in OAM-DA MEP CM) Description
ccm {disable|enable} This command is used to enable/disable
CCM messages on a MEP.
By default, the CCM will be disabled.
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