Fabric Manager Users Guide, Version 6.1, Revision A - QLogic

2–Advanced Fabric Manager Capabilities
Fabric Multicast Routing
Figure 2-8. Example of a 3X3 Mesh with extra Channel Adapters on Perimeter
Switches
Fabric Multicast Routing
In addition to unicast, InfiniBand also supports multicast. Multicast allows a single
packet sent by an application to be delivered to many recipients. InfiniBand
Multicast is used for IPoIB broadcast for TCP/IP address resolution protocol
(ARP), IPoIB multicast for UDP/IP multicast applications, and can also be directly
used by other applications.
InfiniBand supports separate routes per Multicast Group. Each multicast group is
identified by a unique 128-bit Multicast GID. Within the fabric, the SM assigns
each active multicast group a 16-bit Multicast LID. The InfiniBand standard allows
for up to 16K unique Multicast LIDs in a fabric.
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