User Guide

The report shows the following information.
Output of show ip igmp proxy stats TABLE 20
Field Description
Intf Interface
genQv1 RX IGMP v1 general query received on proxy interface.
genQv2 RX IGMP v2 general query received on proxy interface.
genQv3 RX IGMP v3 general query received on proxy interface.
GrpQ RX Group query received.
SrcQ RX Source query received.
Rprtv1 TX IGMP v1 report generated.
Rprtv2 TX IGMP 2 report generated.
Rprtv3 TX IGMP v3 report generated.
leave TX IGMP v2 leave generated.
IGMP V3
The Internet Group Management Protocol (IGMP) allows an IPV4 system to communicate IP Multicast
group membership information to its neighboring routers. The routers in turn limit the multicast of IP
packets with multicast destination addresses to only those interfaces on the router that are identified as
IP Multicast group members.
In IGMP V2, when a router sent a query to the interfaces, the clients on the interfaces respond with a
membership report of multicast groups to the router. The router can then send traffic to these groups,
regardless of the traffic source. When an interface no longer needs to receive traffic from a group, it
sends a leave message to the router which in turn sends a group-specific query to that interface to see
if any other clients on the same interface is still active.
In contrast, IGMP V3 provides selective filtering of traffic based on traffic source. A router running IGMP
V3 sends queries to every multicast enabled interface at the specified interval. These general queries
determine if any interface wants to receive traffic from the router. The following are the three variants of
the Query message:
• A "General Query" is sent by a multicast router to learn the complete multicast reception state of
the neighboring interfaces. In a General Query, both the Group Address field and the Number of
Sources (N) field are zero.
• A "Group-Specific Query" is sent by a multicast router to learn the reception state, with respect to a
*single* multicast address, of the neighboring interfaces. In a Group-Specific Query, the Group
IGMP V3
FastIron Ethernet Switch IP Multicast Configuration Guide 147
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