Allied Telesis AR400 User Manual
Page 45
Page 45 | AlliedWare™ OS How To Note: IGMP
IGMP throttling (limiting the number of streams for each subscriber) > Explanation of IGMP throttling (limiting the number of streams
When switch 2 drops groups by throttling, it does not send a Leave message, because IGMP
snooping cannot generate IGMP packets. Therefore, the Querier (switch 1) still believes that
switch 2 is interested in the throttled groups, as output from the command show ip igmp
on switch 1 shows.
This can cause the Querier to temporarily send more groups than necessary to a switch. The
older groups will eventually time out.
Note that the group list is sorted by refresh time, not group address.
The output above also shows that the IGMP Querier only records the IP address of the last
interested client—the Last Adv field shows the IP of the client who last sent an IGMP
Manager Switch 1> show ip igmp
IGMP Protocol
------------------------------------------------------------------------
Status ........................... Enabled
Default Query Interval ........... 125 secs
Default Timeout Interval ......... 260 secs
Last Member Query Interval ....... 10 (1/10secs)
Last Member Query Count .......... 2
Robustness Variable .............. 2
Query Response Interval .......... 100 (1/10secs)
Disabled All-groups ports ........ None
Interface Name .......... vlan100 (DR)
Group List ..............
Group. 224.12.13.13 Last Adv. 172.31.0.222 Refresh time 215 secs
Ports 49
Group. 224.12.13.14 Last Adv. 172.31.0.222 Refresh time 215 secs
Ports 49
Group. 224.12.13.15 Last Adv. 172.31.0.222 Refresh time 215 secs
Ports 49
Group. 224.12.13.16 Last Adv. 172.31.0.222 Refresh time 215 secs
Ports 49
Group. 224.12.13.17 Last Adv. 172.31.0.222 Refresh time 217 secs
Ports 49
Group. 224.12.13.18 Last Adv. 172.31.0.222 Refresh time 217 secs
Ports 49
Group. 224.12.13.19 Last Adv. 172.31.0.222 Refresh time 217 secs
Ports 49
Group. 224.12.13.11 Last Adv. 172.31.0.222 Refresh time 238 secs
Ports 49
Group. 224.12.13.12 Last Adv. 172.31.0.222 Refresh time 238 secs
Ports 49
------------------------------------------------------------------------