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Allied Telesis AR400 Using the other routermode options, Page 100 AlliedWare OS How To Note IGMP

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Using the other routermode options

Stopping snoopers from snooping non-IGMP messages > Controlling which addresses create All Groups entries

Using the other routermode options

As described earlier, routermode=multicastrouter is just a shortcut for the two IP addresses for DVMRP and PIM.

Manager Switch 2> set igmpsnooping routermode=multicastrouter

Info (1005282): IGMPSnooping Routermode successfully updated.

Manager Switch 2> show igmpsnooping routeraddress

IGMP Snooping Router Address

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IGMP Snooping Router Mode ......... multicastrouter

Router Address List

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224.0.0.4224.0.0.13

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The mode routermode=none stops any reserved multicast addresses from being identified as coming from routers.

Manager Switch 2> set igmpsnooping routerm=none

Info (1005282): IGMPSnooping Routermode successfully updated.

Manager Switch 2> show igmpsnooping routeraddress

IGMP Snooping Router Address

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IGMP Snooping Router Mode ......... none

Router Address List

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No reserved multicast addresses configured

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Conversely, the mode routermode=all means that all reserved multicast addresses (224.0.0.1 to 224.0.0.255) are identified as coming from routers.

Page 100 AlliedWare™ OS How To Note: IGMP

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Allied Telesis AR400 manual Using the other routermode options, Page 100 AlliedWare OS How To Note IGMP

Contents

Introduction ContentsAlliedWare OS Why convergence takes so long without query solicitation Enabling query solicitation on multiple switches in a looped topologyQuerier timer values Snooper timer valuesProducts and software versions this note applies to For most examples in this How To Note, we used z one AT-8948 switch, with Software Versionz two Rapier 24i switches, 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 SnooperPage 13 AlliedWare OS How To Note IGMP Next, look at the output of the command show ip igmp on the QuerierThis output now shows two entries, one for each of the following When a client leaves a group Page 14 AlliedWare OS How To Note IGMPPage 15 AlliedWare OS How To Note IGMP Multiple potential IGMP queriersExample 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 Page 21 AlliedWare OS How To Note IGMP IGMP proxyExample X Configure switch X Configure switchX Configure switch Switch 3 is an IGMP ProxyExplanation of IGMP proxy When there are no group membersWhen a client joins a group 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 worksInitial state TC and sendsQuery Solicit QS QS and sendsWhy convergence takes so long without query solicitation ExampleX Configure switch 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 topologyfrom switch Switch 2 sends QSto switch Switch 1 sends GQIGMP filtering controlling multicast distribution ExampleX Configure switch types commandX Configure switch X Configure switchPage 37 AlliedWare OS How To Note IGMP Explanation of IGMP filtering controlling multicast distribution ReceivedPassed DroppedPage 39 AlliedWare OS How To Note IGMP IGMP throttling limiting the number of streams for each subscriber ExampleX Configure switch X Configure switchPage 41 AlliedWare OS How To Note IGMP 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 Page 48 AlliedWare OS How To Note IGMP Static IGMPExample X Configure switch X Configure switchz enable IGMP z enable the interface as an IGMP interface 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 X Modify switch 3 Configuration port=5,26 counterPage 55 AlliedWare OS How To Note IGMP Page 56 AlliedWare OS How To Note IGMP MulticastPkts36350 MulticastPktsWhen a static entry’s port goes down Page 57 AlliedWare OS How To Note IGMPQuerier timer values How clients leave groups queries and timersOverview of leave process Snooper timer values Comparing the Querier and Snooper timers Consequences for high-loss and high-lag networksIGMP fast leave Exampleset igmpsnooping fastleave=onoff interface=vlanx 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 Configurable IGMP timers and counters Timer and counter relationshipsz Timer and counter relationships on page z Software versions on page 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 configurationLast Member Query Count and Last Member Query Interval Default valuesWhat these counters do Potential problems with changing these counters How to change these countersLast Member Query Interval 1/10secsPage 74 AlliedWare OS How To Note IGMP Last Member Query CountPotential problems with changing this counter How to change this counterRobustness Variable What this counter doesDefault Query Interval What this timer doesPotential problems with changing this timer How to change this timerQuery Response Interval What this timer doesPotential problems with changing this timer How to change this timerDefault Timeout Interval Synchronisation of timersWhat this timer does Potential problems with changing this timerIncrease Default Query Interval Defaults First, the following output shows the default settingsThe Default Timeout Interval = 2*125 + 100/10 = 260 seconds 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 IGMPDefault Timeout Interval = 2 * 200 + 10 = 410 seconds Default Timeout Interval =Page 82 AlliedWare OS How To Note IGMP Example of bad choices for timer values TimerDefault Timeout Interval set ip igmp timeout=126Problem 2 Query Response Interval short Problem 1 Last Member Query Interval too shortProblem 3 Default Timeout Interval too short For more information, see Synchronisation of timers on page not recommend thisExample Stopping snoopers from snooping non-IGMP messagesOSPF X Configure switch X Configure switchX Configure switch Page 87 AlliedWare OS How To Note IGMPX Configure the router Ports 25 Page 89 AlliedWare OS How To Note IGMPPorts Preventing an All Groups entry for a port Disabling All Groups entry for a port2. Check the group entry timeout values 3. Reset port 24’s packet countersEnabling All Groups entry again 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 IGMP8. Check the group entry timeout values again 6. Enable IGMP debuggingPage 93 AlliedWare OS How To Note IGMP z the ports internal timer hits zero and is refreshed Page 94 AlliedWare OS How To Note IGMPz the streams group entry times out and is refreshed, or It is most likely that the group entry will time out firstThis option Controlling which addresses create All Groups entriespackets from set igmpsnooping routermode=ip Configuring switchdelete igmpsnooping routeraddress=224.0.0.5 Page 97 AlliedWare OS How To Note IGMP Adding other router addresses Configuring switches 1 andPage 98 AlliedWare OS How To Note IGMP 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 IGMP2. Check the current IGMP snooping entries Statically specifying that a port is a router portExample 4. Stop port 6 from being a static router port 3. Statically add port 6 as a router port attached to VLANTo remove the static configuration, simply delete it X A client joins a group IGMP debuggingExample X A client leaves a group X Snooped ports change X A port entry times outPage 105 AlliedWare OS How To Note IGMP X A port in the All Groups list is unplugged X A report is filtered outPage 106 AlliedWare OS How To Note IGMP 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