Design Reference

Table Of Contents
Chapter 11: Layer 3 switch clustering and
multicast SMLT
Switch clustering is the logical aggregation of two nodes to form one logical entity known as the
switch cluster. The two peer nodes in a switch cluster connect using a virtual interswitch trunk
(vIST). The vIST exchanges forwarding and routing information between the two peer nodes in the
cluster. This section provides guidelines for switch clusters that use multicast and Split Multilink
Trunking (SMLT).
Related Links
General guidelines on page 62
Multicast triangle topology on page 64
Square and full-mesh topology multicast guidelines on page 66
SMLT and multicast traffic issues on page 69
General guidelines
The following list identifies general guidelines to follow if you use multicast and switch clustering:
Enable Protocol Independent Multicast - Sparse Mode (PIM-SM) on the vIST VLAN for fast
recovery of multicast. A unicast routing protocol is not required.
Enable Internet Group Management Protocol (IGMP) snooping and proxy on the edge
switches.
The following figure shows multicast behavior in an SMLT environment. The configuration in the
following figure provides fast failover if the switch or rendezvous point (RP) fails.
62 Network Design Reference for Avaya VSP 4000 Series June 2015
Comments on this document? infodev@avaya.com