Juniper Networks EX2500 - Manual (Page 88)

EX2500 Ethernet Switch Configuration Guide
74 „ FastLeave
The switch can sense IGMP Membership Reports from attached clients and can act
as a proxy to set up a dedicated path between the requesting host and a local IP
Multicast router. After the pathway is established, the switch blocks the IP Multicast
stream from flowing through any port that does not connect to a host member,
thus conserving bandwidth.
The client-server path is set up as follows:
1. An IP Multicast router (Mrouter) sends Membership Queries to the switch, which
forwards them to all ports in a given VLAN.
2. Hosts that want to receive the multicast data stream send Membership Reports
to the switch, which sends a proxy Membership Report to the Mrouter.
3. The switch sets up a path between the Mrouter and the host, and blocks all
other ports from receiving the multicast.
4. Periodically, the Mrouter sends Membership Queries to ensure that the host
wants to continue receiving the multicast. If a host fails to respond with a
Membership Report, the Mrouter stops sending the multicast to that path.
5. The host can send a Leave Report to the switch, which sends a proxy Leave
Report to the Mrouter. The multicast path is terminated immediately.
The EX2500 switch supports the following IGMP capacities:
„ IGMP versions 1, 2, and 3
„ 1024 VLANs
„ 128 Mrouters
„ 1024 multicast groups
FastLeave
In normal IGMP operation, when the switch receives an IGMPv2 leave message, it
sends a Group-Specific Query to determine if any other devices in the same group
(and on the same port) are still interested in the specified multicast group traffic.
The switch removes the affiliated port from that particular group, if the following
conditions apply:
„ If the switch does not receive an IGMP Membership Report within the
query-response-interval.
„ If no multicast routers have been learned on that port.
NOTE: Unknown multicast traffic is sent to all ports if the flood option is disabled.
To enable or disable IGMP flood, use the following command:
ex2500(config)# [no] ip igmp flood