Troubleshooting Guide

Chapter 19: Operations and Management
CFM fundamentals
The Shortest Path Bridging MAC (SPBM) network needs a mechanism to debug connectivity issues
and to isolate faults. This is performed at Layer 2, not Layer 3. Connectivity Fault Management
(CFM) operates at Layer 2 and provides an equivalent of ping and traceroute. To support
troubleshooting of the SPBM cloud, the Avaya Virtual Services Platform switch supports a subset of
CFM functionality. Configure CFM on all SPBM VLANs.
CFM is based on the IEEE 802.1ag standard.
IEEE 802.1ag Connectivity Fault Management (CFM) provides OAM tools for the service layer,
which allows you to monitor and troubleshoot an end-to-end Ethernet service instance. CFM is the
standard for Layer 2 ping, Layer 2 traceroute, and the end-to-end connectivity check of the Ethernet
network.
The 802.1ag feature divides or separates a network into administrative domains called Maintenance
Domains (MD). Each MD is further subdivided into logical groupings called Maintenance
Associations (MA). A single MD can contain several MAs.
Each MA is defined by a set of Maintenance Points (MP). An MP is a demarcation point on an
interface that participates in CFM within an MD. Two types of MP exist:
• Maintenance End Point (MEP)
• Maintenance Intermediate Point (MIP)
CFM supports three kinds of standard CFM messages: Continuity Check Message (CCM),
Loopback Message (LBM), and Linktrace Message (LTM). Messages are sent between
Maintenance Points (MP) in the system.
On the switch, CFM is implemented using the LBM and LTM features only to debug SPBM. CCM
messages are not required or supported in the current release.
You can assign maintenance levels for each CFM SPBM MEP and MIP to each SPBM B-VLAN
individually or you can assign maintenance levels and global MEPs for all SPBM VLANs.
January 2017 Troubleshooting 144
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