Default values, What these counters do | Allied Telesis AR400

Configurable IGMP timers and counters > Default values

Default values

Output of the command show ip igmp shows the values of the configurable IGMP settings. The following output shows the default values.

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)

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Note that units for Last Member Query Interval (LMQI) and Query Response Interval are 0.1 seconds. Therefore, the default LMQI is 1 second and the default Query Response Interval is 10 seconds.

Last Member Query Count and Last Member Query Interval

The Last Member Query Count (LMQC) is the number of Specific Queries the Querier sends after receiving a Leave message—1 to 5 messages.

The Last Member Query Interval (LMQI) is the time between the Specific Queries—1 to 255 in units of 0.1 seconds.

These counters determine how quickly a group times out when the last client leaves the group. You should read this section in conjunction with "How clients leave groups: queries and timers" on page 58, which has an outline of the leave process and a detailed discussion of the timers.

What these counters do

On the Querier and all Snoopers, IGMP keeps group membership timeout values on each port. During general multicasting, these timeouts are (by default) 260 seconds. When a client leaves a group, these timeouts are reduced to make multicasting stop quickly after the last client leaves. The LMQC and LMQI determine the value of the timeout during this leave process (2 seconds with the default LMQC and LMQI).

On the Querier, the timeout during the leave process = LMQC * LMQI

On Snoopers, the timeout during the leave process =

LMQI from Querier * LMQC from Snooper

From Software Version 291-08, the command show igmpsnooping vlan={<vid>all} detail displays the timers for each individual port.

Page 72 AlliedWare™ OS How To Note: IGMP

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Allied Telesis AR400 manual Default values, Last Member Query Count and Last Member Query Interval, What these counters do

Contents

Contents Introduction Query solicitation rapid recovery from topology changes How clients leave groups queries and timersConfigurable Igmp timers and counters 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 5 AlliedWare OS How To Note Igmp Igmp overviewQueriers and Snoopers 6 AlliedWare OS How To Note Igmp Messages 7 AlliedWare OS How To Note Igmp Choosing group addressesIP address, binary 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 9 AlliedWare OS How To Note Igmp Igmp snoopingExample Configure switch 10 AlliedWare OS How To Note Igmp 11 AlliedWare OS How To Note Igmp Explanation of Igmp snooping Using Show command output to investigate Igmp state Group List Entry timeout 136 secs Ports NoneGroup List Entry timeout 257 Secs Ports All Groups 235 12 AlliedWare OS How To Note Igmp 13 AlliedWare OS How To Note Igmp Group Last Adv When a client leaves a group Group List Entry timeout 247 secs Ports14 AlliedWare OS How To Note Igmp 15 AlliedWare OS How To Note Igmp Multiple potential Igmp queriers 16 AlliedWare OS How To Note Igmp When there are no group members Other Querier timeout .. secs17 AlliedWare OS How To Note Igmp When a client joins a group Group List Entry timeout 225 secs PortsAll Groups Entry timeout Secs Ports 18 AlliedWare OS How To Note Igmp 19 AlliedWare OS How To Note Igmp Group ListGroup List Last Adv 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 Group List Entry timeout 122 secs Ports None All Groups Entry timeout 145 Secs Ports23 AlliedWare OS How To Note Igmp 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 Query solicitation rapid recovery from topology changes 26 AlliedWare OS How To Note IgmpHow query solicitation works 27 AlliedWare OS How To Note Igmp Initial state Why convergence takes so long without query solicitation 28 AlliedWare OS How To Note IgmpExample 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 Explanation from the perspective of switch 1, the querier Group Entry timeout 18 secs Ports31 AlliedWare OS How To Note Igmp 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 Types command Set switch port=1 igmpfilter=136 AlliedWare OS How To Note Igmp 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 When we deny groups instead of replacing them Modify switch 2 Configuration46 AlliedWare OS How To Note Igmp 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 Group Entry timeout Infinity Ports 51 AlliedWare OS How To Note IgmpExplanation of Static Igmp When we add a static entry on another switch Modify switch 3 Configuration52 AlliedWare OS How To Note Igmp 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 56 AlliedWare OS How To Note Igmp MulticastPkts 36350MulticastPkts 14756 When a static entry’s port goes down Group Entry timeout Infinity Ports None57 AlliedWare OS How To Note Igmp How clients leave groups queries and timers Querier timer values58 AlliedWare OS How To Note Igmp Overview of leave process Snooper timer values 59 AlliedWare OS How To Note Igmp Comparing the Querier and Snooper timers 60 AlliedWare OS How To Note IgmpConsequences for high-loss and high-lag networks 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 When fast leave is disabled Group Entry timeout 2 secs Ports64 AlliedWare OS How To Note Igmp Fast Leave Off When you enable fast leave on switch It is safe to ignore the group entry on switchGroup Entry timeout Secs Ports None 65 AlliedWare OS How To Note Igmp When you set fast leave on all interfaces 66 AlliedWare OS How To Note Igmp Multiple host mode for fast leave To specify multiple mode, use the commandTo specify single mode, use either of the commands 67 AlliedWare OS How To Note Igmp 68 AlliedWare OS How To Note Igmp Configurable Igmp timers and counters Timer and counter relationships69 AlliedWare OS How To Note Igmp Initial configuration Each example modifies the following base configuration70 AlliedWare OS How To Note Igmp Software versions 71 AlliedWare OS How To Note Igmp Default values 72 AlliedWare OS How To Note IgmpLast Member Query Count and Last Member Query Interval What these counters do Potential problems with changing these counters How to change these counters73 AlliedWare OS How To Note Igmp Last Member Query Interval 255 10secs 74 AlliedWare OS How To Note Igmp Last Member Query Count Potential problems with changing this counter How to change this counterRobustness Variable What this counter does Default Query Interval What this timer doesPotential problems with changing this timer How to change this timer 77 AlliedWare OS How To Note Igmp Query Response IntervalQuery Response Interval 100 10secs Default Timeout Interval Synchronisation of timers78 AlliedWare OS How To Note Igmp Default Timeout Interval = 2*130 + 100/10 = 270 seconds 79 AlliedWare OS How To Note Igmp Default Timeout Interval = 2*125 + 100/10 = 260 seconds Default Timeout Interval 280 Secs80 AlliedWare OS How To Note Igmp 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 Example of bad choices for timer values Imagine the following changes to the configurationCommands to configure these settings are 83 AlliedWare OS How To Note Igmp Problem 1 Last Member Query Interval too short Problem 2 Query Response Interval shortProblem 3 Default Timeout Interval too 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 Configure the router 88 AlliedWare OS How To Note IgmpRouter uses Ospf Ports 24 89 AlliedWare OS How To Note Igmp Ports 25 Disabled All-groups Ports 90 AlliedWare OS How To Note IgmpPreventing an All Groups entry for a port Disabling All Groups entry for a port Check the group entry timeout values Reset port 24’s packet countersEntry timeout 216 Secs Enabling All Groups entry again Check the group entry timeout values again Entry timeout Secs92 AlliedWare OS How To Note Igmp MulticastPkts Enable Igmp debugging Entry timeout 259 Secs93 AlliedWare OS How To Note Igmp 94 AlliedWare OS How To Note Igmp MulticastPkts 914 95 AlliedWare OS How To Note Igmp Controlling which addresses create All Groups entries Configuring switch 96 AlliedWare OS How To Note Igmp224.0.0.5 97 AlliedWare OS How To Note Igmp Configuring switches 1 98 AlliedWare OS How To Note IgmpAdding other router addresses Returning to the default list 99 AlliedWare OS How To Note Igmp224.0.0.254 Using the other routermode options 100 AlliedWare OS How To Note Igmp 101 AlliedWare OS How To Note Igmp Statically specifying that a port is a router portCheck the current Igmp snooping entries To remove the static configuration, simply delete it 102 AlliedWare OS How To Note IgmpStatically add port 6 as a router port attached to Vlan Stop port 6 from being a static router port 103 AlliedWare OS How To Note Igmp Igmp debuggingClient joins a group IgmpSnoopMembershipQuery setting timer at 2 secs for group 104 AlliedWare OS How To Note IgmpClient leaves a group Several minutes later the group entry times out Manager Switch 3 del vlan=100 port=5 105 AlliedWare OS How To Note IgmpPort entry times out Snooped ports change 106 AlliedWare OS How To Note Igmp Report is filtered outPort in the All Groups list is unplugged 107 AlliedWare OS How To Note Igmp Output for show ip igmp changes Switch 108 AlliedWare OS How To Note IgmpAppendix STP state State Forwarding 109 AlliedWare OS How To Note Igmp Manager Switch 3 show stp port=25-26