Design Reference

Table Of Contents
Figure 18: Multicast routing using PIM-SM
Client switches run IGMP Snoop or PIM-SM, and the aggregation switches run PIM-SM. This design
is simple and, for the rest of the network, PIM-SM performs IP multicast routing. The aggregation
switches are the query devices for IGMP, so an external query device is not required to activate
IGMP membership. These switches also act as redundant switches for IP multicast.
Multicast data flows through the vIST link when receivers are learned on the client switch and
senders are located on the aggregation switches, or when sourced data comes through the
aggregation switches. This data is destined for potential receivers attached to the other side of the
vIST. The data does not reach the client switches through the two aggregation switches because
only the originating switch forwards the data to the client switch receivers.
Note:
Always place multicast receivers and senders on the core switches on VLANs different from
those that span the vIST.
The following figure shows a switch clustering configuration with a single switch cluster core and
dual-connected edge devices. This topology represents different VLANs spanning from each edge
device and those VLANs routed at the switch cluster core. You can configure multiple VLANs on the
edge devices, 802.1Q tagged to the switch cluster core.
Multicast triangle topology
June 2015 Network Design Reference for Avaya VSP 4000 Series 65
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