Query Messages; Igmp Proxy - Huawei Quidway S3900 Series Operation Manual

Operation Manual – Multicast Protocol
Quidway S3900 Series Ethernet Switches-Release 1510
group G2, they will send IGMP host report packets about G2 to respond to the

query messages.

After the query/response process, the IGMP routers get to know that receivers
corresponding to the multicast group G1 exist in the network, and generate the (*,
G1) multicast forwarding entries, according to which the multicast information is
forwarded.
The data from the multicast source reaches the IGMP router through the multicast
routes. If there are receivers in the network connected to the IGMP router, the data
will be forwarded to this network segment and the receiver hosts receive the data.
IGMP leave packet is not defined in IGMPv1, so when a host leaves a multicast group,
only when a query message times out can the multicast router know that a host has left
the group.
When all the hosts in a network segment have left the multicast group, the branch
corresponding to the related network segment is pruned from the multicast tree.

6.1.4 IGMP Proxy

A lot of leaf networks (leaf 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 leaf networks.
To reduce the workload of configuration and management without affecting the
multicast connection of leaf networks, you can configure an IGMP Proxy in a Layer 3
switch in the leaf network (Switch B in the figure). The Layer 3 switch will then forward
IGMP join or IGMP leave messages sent by the connected hosts. After the
configuration of IGMP Proxy, the leaf switch is no longer a PIM neighbor but a host for
the external network. Only when the Layer 3 switch has directly connected members,
can it receive the multicast data of corresponding groups.
Figure 6-2 Diagram for IGMP Proxy
Switch A Switch A Switch A Switch A
33.33.33.1 33.33.33.1 33.33.33.1 33.33.33.1
VLAN-interface 1 VLAN-interface 1
General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information General group/ Group -Specific Query information
33.33.33.2 33.33.33.2 33.33.33.2 33.33.33.2
VLAN-interface 1 VLAN-interface 1
VLAN-interface 2 VLAN-interface 2
Switch B Switch B Switch B Switch B
IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP IGMP join/ IGMP
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Huawei Technologies Proprietary
6-4
Chapter 6 IGMP Configuration
General group/ Group-Specific Query message General group/ Group-Specific Query message General group/ Group-Specific Query message General group/ Group-Specific Query message
IGMP join / leave message IGMP join / leave message IGMP join / leave message IGMP join / leave message
Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network Exterior network
Leaf network Leaf network Leaf network Leaf network Leaf network Leaf network Leaf network
22.22.22.1 22.22.22.1 22.22.22.1 22.22.22.1
Host Host Host Host Host Host Host Host Host Host Host