For each attached network, a multicast routing device can be either a querier or a
nonquerier. The querier routing device periodically sends general query messages to
solicit group membership information. Hosts on the network that are members of a
multicast group send report messages. When a host leaves a group, it sends a leave
group message.
IGMP version 3 (IGMPv3) supports inclusion and exclusion lists. Inclusion lists enable
you to specify which sources can send to a multicast group. This type of multicast group
is called a source-specific multicast (SSM) group, and its multicast address is 232/8.
IGMPv3 provides support for source filtering. For example, a routing device can specify
particular routing devices from which it accepts or rejects traffic. With IGMPv3, a multicast
routing device can learn which sources are of interest to neighboring routing devices.
Exclusion mode works the opposite of an inclusion list. It allows any source but the ones
listed to send to the SSM group.
IGMPv3 interoperates with versions 1 and 2 of the protocol. However, to remain compatible
with older IGMP hosts and routing devices, IGMPv3 routing devices must also implement
versions 1 and 2 of the protocol. IGMPv3 supports the following membership-report record
types: mode is allowed, allow new sources, and block old sources.
Release History Table DescriptionRelease
Starting in Junos OS Release 15.2, PIMv1 is not supported.15.2
Related
Documentation
Supported IP Multicast Protocol Standards•
• Enabling IGMP on page 447
• Disabling IGMP on page 450
• Configuring IGMP
Enabling IGMP
The Internet Group Management Protocol (IGMP) manages multicast groups by
establishing, maintaining, and removing groups on a subnet. Multicast routing devices
use IGMP to learn which groups have members on each of their attached physical
networks. IGMP must be enabled for the router to receive IPv4 multicast packets. IGMP
is only needed for IPv4 networks, because multicast is handled differently in IPv6 networks.
IGMP is automatically enabled on all IPv4 interfaces on which you configure PIM and on
all IPv4 broadcast interfaces when you configure DVMRP.
If IGMP is not running on an interface—either because PIM and DVMRP are not configured
on the interface or because IGMP is explicitly disabled on the interface—you can explicitly
enable IGMP.
447Copyright © 2017, Juniper Networks, Inc.
Chapter 14: Configuring Internet Group Management Protocol
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