Multicast Notes - Part3

• IGMPv2 :

- Host Membership Query Functions:
   sent by Multicast Routers LAN interfaces to determine whether a multicast group member is on
   any interface.

- Host Membership Report Functions :
   there are two types which sent by host, (Solicited) which is response to query msg , and (unSolicited)
   when host join new group .

- Leave Group and Group-Specific Query Messages :
   In IGMPv2, when a host leaves a group, it sends an IGMPv2 Leave message. When an IGMPv2 router receives a Leave message, it immediately sends a Group-Specific Query for that group. The Group-Specific Query asks only whether any remaining hosts still want to receive packets for that single multicast group. As a result, the router quickly knows whether to continue to forward traffic for that multicast group.

•  IGMPv2 defines a querier election process that is used when multiple routers are connected to a subnet, The router with the lowest IP address on the subnet is elected as the IGMP querier .