Juniper Networks EX2500 - Manual (Page 87)

IGMP Snooping „ 73
Chapter 7
IGMP
Internet Group Management Protocol (IGMP) is used by IP Multicast routers to learn
about the existence of host group members on their directly attached subnet (see
RFC 2236). The IP Multicast routers get this information by broadcasting IGMP
Membership Queries and listening for IP hosts reporting their host group
memberships. This process is used to set up a client/server relationship between an
IP Multicast source that provides the data streams and the clients that want to
receive the data.
The EX2500 switch can perform IGMP Snooping, and connect to static multicast
routers (Mrouters).
The following topics are discussed in this chapter:
„ IGMP Snooping on page 73
„ FastLeave on page 74
„ IGMPv3 Snooping on page 75
„ IGMP Snooping Configuration Example on page 76
„ Static Multicast Router on page 76
„ IGMP Querier on page 77
IGMP Snooping
IGMP snooping allows the switch to forward multicast traffic to only those ports
that request it. IGMP Snooping prevents multicast traffic from being flooded to all
ports. The switch learns which server hosts are interested in receiving multicast
traffic, and forwards it only to ports connected to those servers.
IGMP snooping conserves bandwidth. With IGMP Snooping, the switch learns
which ports are interested in receiving multicast data, and forwards multicast data
to those ports only. In this way, other ports are not burdened with unwanted
multicast traffic.