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Allied Telesis AR400 manual Last Member Query Count, Page 74 AlliedWare OS How To Note IGMP

Models: AR400

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Last Member Query Count

Configurable IGMP timers and counters > Last Member Query Count and Last Member Query Interval

Similarly, if we change the LMQC from 2 to 3, the refresh time also changes.

Manager Switch 1> set ip igmp lmqc=3

Info (1005003): Operation successful.

Manager Switch 1> show ip igmp

IGMP Protocol

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

Status	Enabled
Default Query Interval	125	secs
Default Timeout Interval	385	secs
Last Member Query Interval	255	(1/10secs)
Last Member Query Count	3
Robustness Variable	3
Query Response Interval	100	(1/10secs)
Disabled All-groups ports	None

Interface Name	vlan100	(DR)
Group List
Group. 224.12.13.14	Last Adv. 172.31.0.222		Refresh time 74 secs
Ports 49

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

The refresh time in seconds is (LMQI/10) * LMQC = 255/10 * 3 = 76.5 seconds

Page 74 AlliedWare™ OS How To Note: IGMP

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Allied Telesis AR400 manual Last Member Query Count, Page 74 AlliedWare OS How To Note IGMP

Contents

AlliedWare OS ContentsIntroduction Querier timer values Why convergence takes so long without query solicitationEnabling query solicitation on multiple switches in a looped topology Snooper timer valuesProducts and software versions this note applies to z two Rapier 24i switches, with Software Version For most examples in this How To Note, we usedz one AT-8948 switch, with Software Version IGMP featureIGMP overview Queriers and SnoopersMessages Choosing group addresses Avoid x.0.0.y, x.0.1.y, x.128.0.y, and x.128.1.y Page 8 AlliedWare OS How To Note IGMPIGMP snooping ExampleX Configure switch X Configure switchX Configure switch Page 10 AlliedWare OS How To Note IGMPExplanation of IGMP snooping processUsing Show command output to investigate IGMP state igmpsnooping on the SnooperThis output now shows two entries, one for each of the following Next, look at the output of the command show ip igmp on the QuerierPage 13 AlliedWare OS How To Note IGMP When a client leaves a group Page 14 AlliedWare OS How To Note IGMPExample Multiple potential IGMP queriersPage 15 AlliedWare OS How To Note IGMP X Configure switch X Configure switchX Configure switch Page 16 AlliedWare OS How To Note IGMPWhen there are no group members Explanation of Multiple potential IGMP queriersWhen a client joins a group Page 18 AlliedWare OS How To Note IGMPPage 19 AlliedWare OS How To Note IGMP Refresh time 228 secsPage 20 AlliedWare OS How To Note IGMP Example IGMP proxyPage 21 AlliedWare OS How To Note IGMP X Configure switch X Configure switchX Configure switch Switch 3 is an IGMP ProxyWhen a client joins a group Explanation of IGMP proxyWhen there are no group members Page 23 AlliedWare OS How To Note IGMPPage 24 AlliedWare OS How To Note IGMP Refresh time 243 secsWhen a client leaves a group Page 25 AlliedWare OS How To Note IGMPQuery solicitation rapid recovery from topology changes How query solicitation worksQuery Solicit QS Initial stateTC and sends QS and sendsX Configure switch Why convergence takes so long without query solicitationExample X Configure switchExplanation from the perspective of switch 2, the snooper When link comes up again Page 30 AlliedWare OS How To Note IGMPExplanation from the perspective of switch 1, the querier shows this entryagain forwarding the multicast stream out the port Enabling query solicitation on multiple switches in a looped topology Speeding up IGMP convergence in a non-looped topologyto switch from switchSwitch 2 sends QS Switch 1 sends GQIGMP filtering controlling multicast distribution ExampleX Configure switch types commandPage 37 AlliedWare OS How To Note IGMP X Configure switchX Configure switch Passed Explanation of IGMP filtering controlling multicast distributionReceived DroppedPage 39 AlliedWare OS How To Note IGMP IGMP throttling limiting the number of streams for each subscriber ExamplePage 41 AlliedWare OS How To Note IGMP X Configure switchX Configure switch X Configure switch Page 42 AlliedWare OS How To Note IGMPConsider switch 2 after a client on port 2 has joined six groups from Page 44 AlliedWare OS How To Note IGMP Note that the group list is sorted by refresh time, not group address When we deny groups instead of replacing them X Modify switch 2 ConfigurationPage 47 AlliedWare OS How To Note IGMP Example Static IGMPPage 48 AlliedWare OS How To Note IGMP z enable IGMP z enable the interface as an IGMP interface X Configure switchX Configure switch Switch 2 is an IGMP SnooperX Configure switch Page 50 AlliedWare OS How To Note IGMPExplanation of Static IGMP Page 51 AlliedWare OS How To Note IGMPWhen we add a static entry on another switch X Modify switch 3 ConfigurationPage 53 AlliedWare OS How To Note IGMP Page 54 AlliedWare OS How To Note IGMP Page 55 AlliedWare OS How To Note IGMP port=5,26 counterX Modify switch 3 Configuration 36350 Page 56 AlliedWare OS How To Note IGMPMulticastPkts MulticastPktsWhen a static entry’s port goes down Page 57 AlliedWare OS How To Note IGMPOverview of leave process How clients leave groups queries and timersQuerier timer values Snooper timer values Comparing the Querier and Snooper timers Consequences for high-loss and high-lag networksset igmpsnooping fastleave=onoff interface=vlanx IGMP fast leaveExample set igmpsnooping vlan=vlanx fastleave=onoffX Configure switch X Configure switchX Configure switch Page 62 AlliedWare OS How To Note IGMPExplanation of IGMP fast leave Page 63 AlliedWare OS How To Note IGMPWhen fast leave is disabled Page 64 AlliedWare OS How To Note IGMPWhen you enable fast leave on switch It is safe to ignore the group entry on switchWhen you set fast leave on all interfaces Similarly, we can easily disable Fast Leave on all interfacesMultiple host mode for fast leave Page 68 AlliedWare OS How To Note IGMP z Timer and counter relationships on page z Software versions on page Configurable IGMP timers and countersTimer and counter relationships z Initial configuration on page z Default values on pageInitial configuration Software versionsX Configure switch X Configure switchX Configure switch Configurable IGMP timers and counters Initial configurationWhat these counters do Default valuesLast Member Query Count and Last Member Query Interval Last Member Query Interval Potential problems with changing these countersHow to change these counters 1/10secsPage 74 AlliedWare OS How To Note IGMP Last Member Query CountRobustness Variable Potential problems with changing this counterHow to change this counter What this counter doesPotential problems with changing this timer Default Query IntervalWhat this timer does How to change this timerPotential problems with changing this timer Query Response IntervalWhat this timer does How to change this timerWhat this timer does Default Timeout IntervalSynchronisation of timers Potential problems with changing this timerThe Default Timeout Interval = 2*125 + 100/10 = 260 seconds Increase Default Query IntervalDefaults First, the following output shows the default settings Next, change the Default Query Interval to 130 secondsIncrease Query Response Interval Page 80 AlliedWare OS How To Note IGMPOverride Default Timeout Interval Page 81 AlliedWare OS How To Note IGMPPage 82 AlliedWare OS How To Note IGMP Default Timeout Interval =Default Timeout Interval = 2 * 200 + 10 = 410 seconds Default Timeout Interval Example of bad choices for timer valuesTimer set ip igmp timeout=126Problem 3 Default Timeout Interval too short Problem 1 Last Member Query Interval too shortProblem 2 Query Response Interval short For more information, see Synchronisation of timers on page not recommend thisOSPF Stopping snoopers from snooping non-IGMP messagesExample X Configure switch X Configure switchX Configure switch Page 87 AlliedWare OS How To Note IGMPX Configure the router Ports Page 89 AlliedWare OS How To Note IGMPPorts 25 Preventing an All Groups entry for a port Disabling All Groups entry for a portEnabling All Groups entry again 2. Check the group entry timeout values3. Reset port 24’s packet counters 1. Permit port 24 to be an All Groups port again5. Check the group entry timeout values again Page 92 AlliedWare OS How To Note IGMPPage 93 AlliedWare OS How To Note IGMP 6. Enable IGMP debugging8. Check the group entry timeout values again z the streams group entry times out and is refreshed, or z the ports internal timer hits zero and is refreshedPage 94 AlliedWare OS How To Note IGMP It is most likely that the group entry will time out firstpackets from Controlling which addresses create All Groups entriesThis option delete igmpsnooping routeraddress=224.0.0.5 Configuring switchset igmpsnooping routermode=ip Page 97 AlliedWare OS How To Note IGMP Page 98 AlliedWare OS How To Note IGMP Configuring switches 1 andAdding other router addresses Returning to the default list To return to the default list, change the router mode to defaultUsing the other routermode options Page 100 AlliedWare OS How To Note IGMPExample Statically specifying that a port is a router port2. Check the current IGMP snooping entries To remove the static configuration, simply delete it 3. Statically add port 6 as a router port attached to VLAN4. Stop port 6 from being a static router port Example IGMP debuggingX A client joins a group X A client leaves a group Page 105 AlliedWare OS How To Note IGMP X A port entry times outX Snooped ports change Page 106 AlliedWare OS How To Note IGMP X A report is filtered outX A port in the All Groups list is unplugged X Output for show ip igmp changes Page 107 AlliedWare OS How To Note IGMPSwitch Appendix STP stateSwitch Page 109 AlliedWare OS How To Note IGMPSwitch USA Headquarters 19800 North Creek Parkway Suite 100 Bothell WA 98011 USA T +1 800 424 4284 F +1 425 481