Brocade 6910 Ethernet Access Switch Configuration Guide (Supporting R2.2.0.0) - Manual (Page 1149)

Brocade 6910 Ethernet Access Switch Configuration Guide 1093
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Layer 2 IGMP (Snooping and Query)
IGMP snooping will not function unless a multicast router port is enabled on the switch. This can
accomplished in one of two ways. A static router port can be manually configured (see
“Specifying
Static Interfaces for a Multicast Router” on page 1097). Using this method, the router port is never
timed out, and will continue to function until explicitly removed. The other method relies on the
switch to dynamically create multicast routing ports whenever multicast routing protocol packets or
IGMP query packets are detected on a port.
A maximum of up to 1023 multicast entries can be maintained for IGMP snooping. Once the table
is full, no new entries are learned. Any subsequent multicast traffic not found in the table is dropped
if unregistered-flooding is disabled (default behavior) and no router port is configured in the
attached VLAN, or flooded throughout the VLAN if unregistered-flooding is enabled (see
“Configuring
IGMP Snooping and Query Parameters” on page 1093).
Static IGMP Router Interface – If IGMP snooping cannot locate the IGMP querier, you can manually
designate a known IGMP querier (i.e., a multicast router/switch) connected over the network to an
interface on your switch (see
“Specifying Static Interfaces for a Multicast Router” on page 1097).
This interface will then join all the current multicast groups supported by the attached
router/switch to ensure that multicast traffic is passed to all appropriate interfaces within the
switch.
Static IGMP Host Interface – For multicast applications that you need to control more carefully, you
can manually assign a multicast service to specific interfaces on the switch (see
“Assigning
Interfaces to Multicast Services” on page 1099).
IGMP Snooping with Proxy Reporting – The switch supports last leave, and query suppression (as
defined in DSL Forum TR-101, April 2006):
• When proxy reporting is disabled, all IGMP reports received by the switch are forwarded
natively to the upstream multicast routers.
• Last Leave: Intercepts, absorbs and summarizes IGMP leaves coming from IGMP hosts. IGMP
leaves are relayed upstream only when necessary, that is, when the last user leaves a
multicast group.
• Query Suppression: Intercepts and processes IGMP queries in such a way that IGMP specific
queries are never sent to client ports.
The only deviation from TR-101 is that the marking of IGMP traffic initiated by the switch with
priority bits as defined in R-250 is not supported.
Configuring IGMP Snooping and Query Parameters
Use the Multicast > IGMP Snooping > General page to configure the switch to forward multicast
traffic intelligently. Based on the IGMP query and report messages, the switch forwards multicast
traffic only to the ports that request it. This prevents the switch from broadcasting the traffic to all
ports and possibly disrupting network performance.
CLI References
• “IGMP Snooping” on page 443