Design Reference

- If you do manually change the system ID, take the necessary steps to ensure no duplication
exists in the network.
• Create two B-VLANs to allow load distribution over both B-VLANs. This configuration is
required if you use SMLT. Even if you do not use SMLT in the network, this is still good
practice as adding a second B-VLAN to an existing configuration allows SPBM to load balance
traffic across two equal-cost multipaths if the physical topology grants it.
• In a ring topology with OSPF and IS-IS configured in the core, a core link break causes slow
convergence that can lead to SPBM Layer 2 traffic loss. If the last member link of an OSPF
VLAN fails, it takes down the IP interface and OSPF reconverges. While OSPF reconverges,
SPBM does not have access to the CPU, which causes traffic loss.
SPBM
The following list identifies best practices for SPBM:
• Use a different, easily recognizable IS-IS nickname on each switch.
• If you enable IP shortcuts, you must configure an IS-IS IP source address on the switch.
Physical or MLT links between IS-IS switches
Virtual Services Platform supports only a single port or single MLT between a pair of IS-IS switches.
For example, if two individual ports exist between a pair of IS-IS switches, you can configure IS-IS
on both the ports, but an IS-IS adjacency only forms on one of the links.
If you configure a single MLT between a pair of IS-IS switches, all ports in the MLT are used. You
must configure the MLT before you enable IS-IS on the MLT.
CFM using manual mode configuration
Important:
Avaya recommends auto-configuration of CFM, which is simpler than the manual mode of
configuration.
For more information about these commands, see Commands Reference for Avaya Virtual
Services Platform 4000 Series, NN46251-104.
The following list identifies best practices for manual configuration of Connectivity Fault
Management (CFM):
• The CFM domain name must be the same on all switches in an IS-IS area.
• The maintenance association must be the same on all switches in an IS-IS area.
• To use CFM testing over both B-VLANs, create two maintenance associations, one for each B-
VLAN.
• You can configure the same maintenance domain intermediate points (MIP) on all switches in
an IS-IS area or uniquely defined per switch.
Important:
You must configure the MIP at the same level as the Maintenance Association Endpoints
(MEP) on all switches in the SPBM network.
Example of a configuration using best practices
spbm-id : 1
BVID #1 & BVID #2 : 4040, 4041 (ignore warning message when configuring)
SPBM design guidelines
100 Network Design Reference for Avaya VSP 4000 Series December 2014
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