Allied Telesis AR400 - Manual (Page 90)

Page 90 | AlliedWare™ OS How To Note: IGMP
Stopping snoopers from snooping non-IGMP messages > Preventing an All Groups entry for a port
Preventing an All Groups entry for a port
This section stops port 24 from being in switch 2’s All Groups entry, then adds it back again.
Disabling All Groups entry for a port
You can avoid the All Groups entries shown above by simply disabling the All Groups entry
for the port that switch 2 uses to connect to the router.
Port 24 is now accompanied by a hash. This is because All Groups was disabled for the port
while the port was part of All Groups. The switch will keep sending port 24 traffic for the
group 224.12.13.14 until either port 24’s internal timer or the timer for the group
224.12.13.14 hits zero.
Note: The switch keeps an internal timer for each port in its All Groups list, which is
separate from the All Groups entry timeout displayed in output of the command
show igmpsnooping. There are no commands to view the internal timer, but every
time the switch receives a new IGMP (or in this case OSPF) message the timer
resets. This timer means that if the router stopped sending OSPF messages to the
port, the switches would eventually drop the relevant entries from their All Groups
lists.
Manager Switch 2> disable ip igmp allgroups=24
Info (1005003): Operation successful.
Manager Switch 2> show igmpsnooping
IGMP Snooping
------------------------------------------------------------------------
Status ........................... Enabled
Disabled All-groups ports ........ 24
Vlan Name (vlan id) ..... default (1)
Fast Leave .............. Off
Group List ..............
No group memberships.
Vlan Name (vlan id) ..... vlan100 (100)
Fast Leave .............. Off
Group List ..............
Group. 224.12.13.14 Entry timeout 164 secs
Ports None
All Groups Entry timeout 251 secs
Ports 24#,25
------------------------------------------------------------------------