Troubleshooting Guide

The Nodal MEP and MIP are expanded to respond to both the Nodal MAC address as well as the
Virtual SMLT MAC address if both MACs are being advertised on its B-VLAN. In addition a source
mode is added to the LTM and LBM command to use either the Nodal MAC or the SMLT virtual
MAC address as the source MAC in the packet.
Configuration considerations
When you configure CFM, be aware of the following configuration considerations.
General CFM
• A single switch has a limit of one MEP and one MIP on a C-VLAN or B-VLAN.
• The maintenance level for MEPs and MIPs on a given B-VID (in a network) must be configured
to the same level for them to respond to a given CFM command.
• You can configure global CFM at only one MD level for each switch for each VLAN type.
• All nodal MEPs and MIPs are restricted to SPBM B-VIDs.
• SMLT Virtual MAC for C-VLAN does not exist, so the switch does not support this option for the
l2 ping and l2 traceroute commands.
Autogenerated CFM
• Autogenerated MEPs are not unique across the entire network unless you configure the global
MEP ID on each switch to a different value. You must configure a unique MEP ID at a global
level, for CFM.
• A single switch can have only one autogenerated MEP or MIP for each B-VLAN or C-VLAN.
Explicit CFM
• Previous explicit CFM configurations of MDs, MAs and MEPs on SPBM B-VLANs continue to
be supported. However, if you want to enable autogenerated CFM you must first remove the
existing MEP and MIP on the SPBM B-VLAN.
• 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 by
following the appropriate procedure:
-
Assigning a MEP MIP level to an SPBM B-VLAN on page 163
- Assigning MEP MIP levels to SPBM B-VLANs globally on page 165
- Configuring CFM nodal MEP on page 190
C-VLAN versus SPBM B-VLAN considerations
Important:
Only VSP 4000 Series supports CFM configuration on C-VLANs.
CFM breaks the network into sections, called MEPs, so you can determine exactly where the
problem exists.
The MEPs and MIPs configured for SPBM VLANs do not respond to CFM messages sent from C-
MAC VLANs because the VLAN and packet encapsulation are different.
To forward customer traffic across the core network backbone, SPBM uses IEEE 802.1ah Provider
Backbone Bridging (PBB) MAC-in-MAC encapsulation, which hides the customer MAC (C-MAC)
CFM fundamentals
January 2017 Troubleshooting 153
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