WAN-LAN PIM Multicast Routing and LAN IGMP Feature Overview and Configuration Guide
This guide describes WAN-LAN PIM Multicast Routing and IGMP on the LAN and how to configure WAN-LAN PIM multicast routing and LAN IGMP snooping.
The Allied Telesis Unified Threat Management (UTM) Firewalls can perform routing of IPv4 and IPv6 multicast, using PIM-SM and PIM-DM. Also, switching interfaces of the UTMs are IGMP aware, and will only forward multicast steams to these switch ports that have received reports.
IGMP snooping allows a device to only forward multicast streams to the links on which they have been requested.
PIM Sparse mode requires specific designated routers to receive notification of all streams destined to specific ranges of multicast addresses. When a router needs to get hold of a given group, it sends a request to the designated Rendezvous Point for that group. If there is a source in the network that is transmitting a stream to this group, then the Rendezvous Point will be receiving it, and will forward it to the requesting router.