Multimedia Traffic Control with IP Multicast (IGMP)
How IGMP Operates
IGMP Function Available With IP Addressing
Configured on the VLAN
Available
Without
IP
Addressing?
Operating Differences Without an IP Address
Configure IGMP traffic forwarding to normal or
Yes
None
high-priority forwarding.
Age-Out IGMP group addresses when the last
IGMP client on a port in the VLAN leaves the
group.
Support Fast-Leave IGMP and Forced Fast-
Leave IGMP (below).
Yes
Yes
Requires that another IGMP device in the VLAN has an IP
address and can operate as Querier. This can be a multi
cast router or another switch configured for IGMP oper
ation. (ProCurve recommends that the VLAN also include
a device operating as a backup Querier in case the device
operating as the primary Querier fails for any reason.
Support automatic Querier election.
No
Querier operation not available.
Operate as the Querier.
No
Querier operation not available.
Available as a backup Querier.
No
Querier operation not available.
Automatic Fast-Leave IGMP
Fast-Leave IGMP.
Depending on the switch model, Fast-Leave is enabled or
disabled in the default configuration.
Switch Model
Data-
IGMP Fast-
Default IGMP Behavior
or Series
Driven
Leave Setting
IGMP
Included?
Switch 8212zl
Yes
Always
Drops unjoined mulitcast traffic except for
Switch 6400cl
Enabled
always-fowarded traffic toward the Querier or
Switch 6200yl
multicast routers, and out of IGMP-forward
ports. Selectively forwards joined multicast
Switch 5400zl
traffic, except on IGMP-forward ports, which
Switch 5300xl
forward all multicast traffic.
Switch 4200vl
Switch 3500yl
Switch 3400cl
Switch 2910al
Switch 2500
Switch 2600
No
Disabled in
IGMP Fast-Leave disabled in the default
Switch 2600-
the Default
configuration. Floods unjoined multicast traffic
PWR
Configuration to all ports. Selectively forwards joined
Switch 4100gl
multicast traffic, except on IGMP-forward
ports, which forward all multicast traffic.
Switch 6108
On switches that do not support Data-Driven IGMP, unregistered multicast
groups are flooded to the VLAN rather than pruned. In this scenario, Fast-
Leave IGMP can actually increase the problem of multicast flooding by
2-14
