•IGMP Version 2
•multicast router with
lowest IP address is elected querier
•IGMPv1 was mcast
protocol specific and potentially conflicted.
•Group-Specific Query
message is defined. Enables router to transmit query to specific multicast address rather than to the
"all-hosts" address of 224.0.0.1
•Leave Group message is
defined. Last host in group wishes to leave, it sends Leave Group message to the "all-routers"
address of 224.0.0.2. Router then
transmits Group-Specific query and if no reports come in, then the router removes that group from the list of group
memberships for that interface
•IGMP Version 3
•Group-Source Report
message is defined. Enables hosts to specify which senders it can receive or not receive data from.
•Group-Source Leave
message is defined. Enables host to specify the specific IP addresses of a (source,group) that it wishes
to leave.
•