Igmp Proxy - H3C S5600 Series Operation Manual

Operation Manual – Multicast
H3C S5600 Series Ethernet Switches
1) This host sends a Leave Group message (often referred to as leave message) to
all routers (the destination address is 224.0.0.2) on the local subnet.
2) Upon receiving the leave message, the querier sends a configurable number of
group-specific queries to the group being left. The destination address field and
group address field of message are both filled with the address of the multicast
group being queried.
3) One of the remaining members, if any on the subnet, of the group being queried
should send a membership report within the maximum response time set in the
query messages.
4) If the querier receives a membership report for the group within the maximum
response time, it will maintain the memberships of the group; otherwise, the
querier will assume that no hosts on the subnet are still interested in multicast
traffic to that group and will stop maintaining the memberships of the group.

3.1.4 IGMP Proxy

A lot of stub networks (stub domains) are involved in the application of a multicast
routing protocol (PIM-DM for example) over a large-scaled network. It is a hard work to
configure and manage these stub networks.
To reduce the workload of configuration and management without affecting the
multicast connection of leaf networks, you can configure an IGMP Proxy on a Layer 3
switch in the stub network (Switch B shown in
forward IGMP join or IGMP leave messages sent by the connected hosts. After IGMP
Proxy is configured, the stub switch is no longer a PIM neighbor but a host for the
exterior network. The Layer 3 switch receives the multicast data of corresponding
groups only when it has directly attached multicast members.
Figure 3-2 Diagram for IGMP proxy
Figure 3-2). The Layer 3 switch will then
3-4
Chapter 3 IGMP Configuration