When a client leaves a group | Allied Telesis AR400 guide

IGMP snooping > Explanation of IGMP snooping

Finally, look at the output of the command show igmpsnooping on the Querier. Even though switch 1 is the Querier for this network instead of a Snooper, this command shows that a client for group 224.12.13.14 is reached out port 49.

Manager Switch 1> show igmpsnooping

IGMP Snooping

------------------------------------------------------------------------

Status			Enabled
Disabled All-groups		ports	........ None
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 247 secs
Ports 49

------------------------------------------------------------------------

When a client leaves a group

When a client wants to stop receiving a group’s multicast stream, it sends an IGMP Leave message with a destination address of the group. The Snooper forwards the Leave message out its All Groups port, so the message arrives at the IGMP Querier. At this point, the IGMP Querier sends a series of Specific Queries (2 by default) to see if anybody else is still listening to this group.

If the Snooper receives a response to the Specific Queries, it forwards the response to the Querier and continues to forward the multicast stream to the ports that want to receive it. If the Snooper does not receive a response to the Specific Queries, it stops forwarding the stream.

For a detailed description of how the leave process works, see "How clients leave groups: queries and timers" on page 58.

Page 14 AlliedWare™ OS How To Note: IGMP

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Allied Telesis AR400 When a client leaves a group, Group List Entry timeout 247 secs Ports, AlliedWare OS How To Note Igmp

Contents

Contents Introduction Configurable Igmp timers and counters Query solicitation rapid recovery from topology changesHow clients leave groups queries and timers Example of bad choices for timer values Products and software versions this note applies to Igmp feature Software versions Products 4 AlliedWare OS How To Note Igmp Queriers and Snoopers 5 AlliedWare OS How To Note IgmpIgmp overview 6 AlliedWare OS How To Note Igmp Messages IP address, binary 7 AlliedWare OS How To Note IgmpChoosing group addresses MAC address, hex 8 AlliedWare OS How To Note Igmp Avoid x.0.0.y, x.0.1.y, x.128.0.y, and x.128.1.y Example 9 AlliedWare OS How To Note IgmpIgmp snooping Configure switch 10 AlliedWare OS How To Note Igmp 11 AlliedWare OS How To Note Igmp Explanation of Igmp snooping Group List Entry timeout 257 Secs Ports All Groups 235 Using Show command output to investigate Igmp stateGroup List Entry timeout 136 secs Ports None 12 AlliedWare OS How To Note Igmp 13 AlliedWare OS How To Note Igmp Group Last Adv 14 AlliedWare OS How To Note Igmp When a client leaves a groupGroup List Entry timeout 247 secs Ports 15 AlliedWare OS How To Note Igmp Multiple potential Igmp queriers 16 AlliedWare OS How To Note Igmp 17 AlliedWare OS How To Note Igmp When there are no group membersOther Querier timeout .. secs All Groups Entry timeout Secs Ports When a client joins a groupGroup List Entry timeout 225 secs Ports 18 AlliedWare OS How To Note Igmp Group List Last Adv 19 AlliedWare OS How To Note IgmpGroup List 20 AlliedWare OS How To Note Igmp 21 AlliedWare OS How To Note Igmp Igmp proxy Switch 3 is an Igmp Proxy 22 AlliedWare OS How To Note Igmp 23 AlliedWare OS How To Note Igmp Group List Entry timeout 122 secs Ports NoneAll Groups Entry timeout 145 Secs Ports Explanation of Igmp proxy Group Entry timeout Secs Ports 24 AlliedWare OS How To Note Igmp Group Entry timeout 182 secs Ports 25 AlliedWare OS How To Note Igmp How query solicitation works Query solicitation rapid recovery from topology changes26 AlliedWare OS How To Note Igmp 27 AlliedWare OS How To Note Igmp Initial state Example Why convergence takes so long without query solicitation28 AlliedWare OS How To Note Igmp Explanation from the perspective of switch 2, the snooper 29 AlliedWare OS How To Note Igmp All Groups Entry timeout 236 secs Ports 30 AlliedWare OS How To Note Igmp 31 AlliedWare OS How To Note Igmp Explanation from the perspective of switch 1, the querierGroup Entry timeout 18 secs Ports Shows this entry Group Entry timeout 115 secs Ports 32 AlliedWare OS How To Note Igmp 33 AlliedWare OS How To Note Igmp Speeding up Igmp convergence in a non-looped topology 34 AlliedWare OS How To Note Igmp Switch 1 sends GQ 35 AlliedWare OS How To Note Igmp Igmp filtering controlling multicast distribution 36 AlliedWare OS How To Note Igmp Types commandSet switch port=1 igmpfilter=1 Switch 3 is also an Igmp Snooper 37 AlliedWare OS How To Note Igmp 38 AlliedWare OS How To Note Igmp Received Passed Dropped 39 AlliedWare OS How To Note Igmp No group memberships 40 AlliedWare OS How To Note Igmp 41 AlliedWare OS How To Note Igmp 42 AlliedWare OS How To Note Igmp 43 AlliedWare OS How To Note Igmp 44 AlliedWare OS How To Note Igmp 45 AlliedWare OS How To Note Igmp 46 AlliedWare OS How To Note Igmp When we deny groups instead of replacing themModify switch 2 Configuration Group 224.12.13.11 Entry timeout 255 secs Ports 224.12.13.12 47 AlliedWare OS How To Note Igmp 48 AlliedWare OS How To Note Igmp Static Igmp Switch 2 is an Igmp Snooper 49 AlliedWare OS How To Note Igmp 50 AlliedWare OS How To Note Igmp Explanation of Static Igmp Group Entry timeout Infinity Ports51 AlliedWare OS How To Note Igmp 52 AlliedWare OS How To Note Igmp When we add a static entry on another switchModify switch 3 Configuration MulticastPkts 675826 All Groups Entry timeout 247 secs Ports 53 AlliedWare OS How To Note Igmp 54 AlliedWare OS How To Note Igmp Group Entry timeout Infinity Ports 5,26 55 AlliedWare OS How To Note Igmp MulticastPkts 14756 56 AlliedWare OS How To Note IgmpMulticastPkts 36350 57 AlliedWare OS How To Note Igmp When a static entry’s port goes downGroup Entry timeout Infinity Ports None 58 AlliedWare OS How To Note Igmp How clients leave groups queries and timersQuerier timer values Overview of leave process Snooper timer values 59 AlliedWare OS How To Note Igmp Consequences for high-loss and high-lag networks Comparing the Querier and Snooper timers60 AlliedWare OS How To Note Igmp Describes the new behaviour 61 AlliedWare OS How To Note Igmp Igmp fast leave Switch 1 is an Igmp Querier 62 AlliedWare OS How To Note Igmp 63 AlliedWare OS How To Note Igmp Explanation of Igmp fast leave 64 AlliedWare OS How To Note Igmp When fast leave is disabledGroup Entry timeout 2 secs Ports Fast Leave Off Group Entry timeout Secs Ports None When you enable fast leave on switchIt is safe to ignore the group entry on switch 65 AlliedWare OS How To Note Igmp When you set fast leave on all interfaces 66 AlliedWare OS How To Note Igmp To specify single mode, use either of the commands Multiple host mode for fast leaveTo specify multiple mode, use the command 67 AlliedWare OS How To Note Igmp 68 AlliedWare OS How To Note Igmp 69 AlliedWare OS How To Note Igmp Configurable Igmp timers and countersTimer and counter relationships 70 AlliedWare OS How To Note Igmp Initial configurationEach example modifies the following base configuration Software versions 71 AlliedWare OS How To Note Igmp Last Member Query Count and Last Member Query Interval Default values72 AlliedWare OS How To Note Igmp What these counters do 73 AlliedWare OS How To Note Igmp Potential problems with changing these countersHow to change these counters Last Member Query Interval 255 10secs 74 AlliedWare OS How To Note Igmp Last Member Query Count Robustness Variable Potential problems with changing this counterHow to change this counter What this counter does Potential problems with changing this timer Default Query IntervalWhat this timer does How to change this timer Query Response Interval 100 10secs 77 AlliedWare OS How To Note IgmpQuery Response Interval 78 AlliedWare OS How To Note Igmp Default Timeout IntervalSynchronisation of timers Default Timeout Interval = 2*130 + 100/10 = 270 seconds 79 AlliedWare OS How To Note Igmp 80 AlliedWare OS How To Note Igmp Default Timeout Interval = 2*125 + 100/10 = 260 secondsDefault Timeout Interval 280 Secs Query Response Interval 200 10secs Default Timeout Interval 180 Secs 81 AlliedWare OS How To Note Igmp Default Query Interval 200 Secs Default Timeout Interval 410 82 AlliedWare OS How To Note Igmp Commands to configure these settings are Example of bad choices for timer valuesImagine the following changes to the configuration 83 AlliedWare OS How To Note Igmp Problem 3 Default Timeout Interval too short Problem 1 Last Member Query Interval too shortProblem 2 Query Response Interval short Last Member Query Interval was set to 5, using the command For more information, see Synchronisation of timers on 85 AlliedWare OS How To Note Igmp 86 AlliedWare OS How To Note Igmp Stopping snoopers from snooping non-IGMP messages 87 AlliedWare OS How To Note Igmp Router uses Ospf Configure the router88 AlliedWare OS How To Note Igmp Ports 24 89 AlliedWare OS How To Note Igmp Ports 25 Preventing an All Groups entry for a port Disabled All-groups Ports90 AlliedWare OS How To Note Igmp Disabling All Groups entry for a port Entry timeout 216 Secs Check the group entry timeout valuesReset port 24’s packet counters Enabling All Groups entry again 92 AlliedWare OS How To Note Igmp Check the group entry timeout values againEntry timeout Secs MulticastPkts 93 AlliedWare OS How To Note Igmp Enable Igmp debuggingEntry timeout 259 Secs 94 AlliedWare OS How To Note Igmp MulticastPkts 914 95 AlliedWare OS How To Note Igmp Controlling which addresses create All Groups entries 224.0.0.5 Configuring switch96 AlliedWare OS How To Note Igmp 97 AlliedWare OS How To Note Igmp Adding other router addresses Configuring switches 198 AlliedWare OS How To Note Igmp 224.0.0.254 Returning to the default list99 AlliedWare OS How To Note Igmp Using the other routermode options 100 AlliedWare OS How To Note Igmp Check the current Igmp snooping entries 101 AlliedWare OS How To Note IgmpStatically specifying that a port is a router port Statically add port 6 as a router port attached to Vlan To remove the static configuration, simply delete it102 AlliedWare OS How To Note Igmp Stop port 6 from being a static router port Client joins a group 103 AlliedWare OS How To Note IgmpIgmp debugging Client leaves a group IgmpSnoopMembershipQuery setting timer at 2 secs for group104 AlliedWare OS How To Note Igmp Several minutes later the group entry times out Port entry times out Manager Switch 3 del vlan=100 port=5105 AlliedWare OS How To Note Igmp Snooped ports change Port in the All Groups list is unplugged 106 AlliedWare OS How To Note IgmpReport is filtered out 107 AlliedWare OS How To Note Igmp Output for show ip igmp changes Appendix STP state Switch108 AlliedWare OS How To Note Igmp State Forwarding 109 AlliedWare OS How To Note Igmp Manager Switch 3 show stp port=25-26