Configuration Guide User guide

1474 FastIron Configuration Guide
53-1002494-02
IGMP snooping configuration
Specify the <port> variable in one of the following formats:
• FSX 800 and FSX 1600 chassis devices – <slotnum/portnum>
• FESX compact switches – <portnum>
To specify a list of ports, enter each port as ethernet <port> followed by a space. For example,
ethernet 1/24 ethernet 6/24 ethernet 8/17
To specify a range of ports, enter the first port in the range as ethernet <port> followed by the last
port in the range. For example, ethernet 1/1 to 1/8.
You can combine lists and ranges in the same command. For example: enable ethernet 1/1 to 1/8
ethernet 1/24 ethernet 6/24 ethernet 8/17.
Turning off static group proxy
If a device has been configured for static groups, it acts as a proxy and sends membership reports
for the static groups when it receives general or group-specific queries. When a static group
configuration is removed, it is deleted from the active group table immediately. However, leave
messages are not sent to the querier, and the querier must age out the group. Proxy activity can be
turned off. The default is on. To turn proxy activity off for VLAN 20, enter the following commands.
Brocade(config)# vlan 20
Brocade(config-vlan-20)# multicast proxy-off
Syntax: [no] multicast proxy-off
Enabling IGMP V3 membership tracking and
fast leave for the VLAN
IGMP V3 gives clients membership tracking and fast leave capability. In IGMP V2, only one client on
an interface needs to respond to a router's queries. This can leave some clients invisible to the
router, making it impossible to track the membership of all clients in a group. When a client leaves
the group, the device sends group-specific queries to the interface to see if other clients on that
interface need the data stream of the client who is leaving. If no client responds, the device waits a
few seconds before it stops the traffic. You can configure the wait time using the ip multicast
leave-wait-time command.
IGMP V3 requires every client to respond to queries, allowing the device to track all clients. When
tracking is enabled, and an IGMP V3 client sends a leave message and there is no other client, the
device immediately stops forwarding traffic to the interface. This feature requires the entire VLAN
be configured for IGMP V3 with no IGMP V2 clients. If a client does not send a report during the
specified group membership time (the default is 260 seconds), that client is removed from the
tracking list.
Every group on a physical port keeps its own tracking record. However, it can only track group
membership; it cannot track by (source, group). For example, Client A and Client B belong to group1
but each receives traffic streams from different sources. Client A receives a stream from (source_1,
group1) and Client B receives a stream from (source_2, group1). The device still waits for the
configured leave-wait-time before it stops the traffic because these two clients are in the same
group. If the clients are in different groups, then the waiting period is not applied and traffic is
stopped immediately.