Brocade Communications Systems Brocate Ethernet Access Switch 6910 - Manual (Page 510)

460 Brocade 6910 Ethernet Access Switch Configuration Guide
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IGMP Snooping
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Command Usage
IGMP Snooping uses a null IP address of 0.0.0.0 for the source of IGMP query messages which are
proxied to downstream hosts to indicate that it is not the elected querier, but is only proxying these
messages as defined in RFC 4541. The switch also uses a null address in IGMP reports sent to
upstream ports.
Many hosts do not implement RFC 4541, and therefore do not understand query messages with
the source address of 0.0.0.0. These hosts will therefore not reply to the queries, causing the
multicast router to stop sending traffic to them.
To resolve this problem, the source address in proxied IGMP query and report messages can be
replaced with any valid unicast address (other than the router's own address) using this command.
Rules Used for Proxy Reporting
When IGMP Proxy Reporting is disabled, the switch will use a null IP address for the source of IGMP
query and report messages unless a proxy query address has been set.
When IGMP Proxy Reporting is enabled, the source address is based on the following criteria:
• If a proxy query address is configured, the switch will use that address as the source IP
address in general and group-specific query messages sent to downstream hosts, and in
report and leave messages sent upstream from the multicast router port.
• If a proxy query address is not configured, the switch will use the VLAN’s IP address as the IP
source address in general and group-specific query messages sent downstream, and use the
source address of the last IGMP message received from a downstream host in report and
leave messages sent upstream from the multicast router port.
Example
The following example sets the source address for proxied IGMP query messages to 10.0.1.8.
Console(config)#ip igmp snooping vlan 1 proxy-address 10.0.1.8
Console(config)#
ip igmp snooping vlan query-interval
This command configures the interval between sending IGMP general queries. Use the no form to
restore the default.
Syntax
ip igmp snooping vlan vlan-id query-interval interval
no ip igmp snooping vlan vlan-id query-interval
vlan-id - VLAN ID (Range: 1-4093)
interval - The interval between sending IGMP general queries. (Range: 10-31744 seconds)
Default Setting
100 (10 seconds)
Command Mode
Global Configuration