Igmp Overview; Group Membership Queries - Juniper JUNOSE 11.1.X MULTICAST ROUTING Configuration Manual

JUNOSe 11.1.x Multicast Routing Configuration Guide

IGMP Overview

The IPv4 address scheme assigns class D addresses for IP multicast. IGMP is the
protocol that uses these addresses, which can be in the range 224.0.0.0 to
239.255.255.255. The following addresses have specific functions or are unavailable:
This implementation of IGMP complies with IGMP versions 1, 2, and 3. IGMPv3
supports source-specific join and leave messages and is backward compatible with
IGMPv1 and IGMPv2.
IGMPv2 mode interfaces exchange the following types of messages between routers
and hosts:
IGMPv3 mode interfaces exchange the following types of messages with IGMPv3
hosts:

Group Membership Queries

A multicast router can be a querier or a nonquerier. Only one querier is on a network
at any time. Multicast routers monitor queries from other multicast routers to
determine the status of the querier. If the querier detects a query from a router with
a lower IP address, it relinquishes its role to that router.
IGMPv1 and IGMPv2 mode interfaces send two types of group membership queries
to hosts on the network:
IGMPv3 mode interfaces send the following types of queries to IGMPv3 hosts:
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IGMP Overview

224.0.0.0 is reserved you cannot assign it to a group.
224.0.0.1 is the all-hosts address a packet sent to this address reaches all hosts
on a subnet.
224.0.0.2 is the all-routers address a packet sent to this address reaches all
routers on a subnet.
Group membership queries
Group membership reports
Leave group membership messages
Group membership queries
IGMPv3 group membership reports
General queries to the all-hosts group address (224.0.0.1)
Specific queries to the appropriate multicast group address
General queries
Group-specific queries
Source-specific queries