Extreme Networks ExtremeWare 7.7, Command Reference Manual

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2052 ExtremeWare 7.7 Command Reference Guide
IP Multicast Commands
disable igmp snooping
disable igmp snooping {forward-mcrouter-only | hardware-flooding |
vlan <vlan name>}
Description
Disables IGMP snooping.
Syntax Description
Default
Enabled.
Usage Guidelines
If a VLAN is specified, IGMP snooping is disabled only on that VLAN, otherwise IGMP snooping is
disabled on all VLANs.
If the switch is in the
forward-mcrouter-only
mode, then the command
disable igmp snooping
forward-mcrouter-only
changes the mode so that all multicast traffic is forwarded to any IP router. If
not in the forward-mcrouter-mode, the command
disable igmp snooping forward-mcrouter-only
has no effect.
Without the
hardware-flooding
keyword, this command disables IGMP snooping only in software.
Multicast packets with unicast IP addresses are sent using slow path forwarding and are flooded using
slow path forwarding. This can load the CPU with heavy multicast traffic. To operate the switch in
Layer 2 mode and disable IGMP snooping, it is best to flood multicast IP traffic in hardware, using the
hardware-flooding
keyword.
When IGMP snooping is disabled with hardware-flooding, if you enable IGMP snooping for one or
more VLANs, the hardware-flooding option is automatically turned off, and IGMP snooping is
re-enabled.
To change the snooping mode you must disable IP multicast forwarding. Use the command:
disable ipmcforwarding
Example
The following command disables IGMP snooping on the VLAN accounting:
disable igmp snooping accounting
History
This command was first available in ExtremeWare 7.0.0.
forward-mcrouter-only Specifies that the switch forwards all multicast traffic to the multicast router only.
hardware-flooding Disables IGMP snooping in the hardware and allows multicast IP traffic to be flooded in
hardware.
vlan name Specifies a VLAN.