Allied Telesis AR400 manual AlliedWare OS How To Note Igmp, Initial state

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Query solicitation (rapid recovery from topology changes) > How query solicitation works

The following figure shows how Query Solicitation works when a port goes down.

			Multicast
Initial state:	Switch 1: Querier	Switch 2: STP root	Switch 3	Switch 4
Port on Switch 3	Switch 1: Querier	Switch 2: STP root	Switch 3	Switch 4
Port on Switch 3
is blocking.	Multicast			Multicast
Multicasts flow	Multicast			Multicast
Multicasts flow
from server to
client via Switches
1 and 4

1.Link to Switch 4

goes down.	Switch 2: STP root	Switch 3
goes down.
Switch 3 stops		TC
blocking and		TC
blocking and
sends topology
change (TC)

2.Switch 2 receives

TC and sends	Switch 2: STP root
Query Solicit (QS)		QS
QS	QS	QS

3.Switch 1 receives

QS and sends	Switch 1: Querier
General Query (GQ)	GQ	GQ	GQ	GQ

4.Host receives GQ

and responds with Membership Report

Report

Final state:

Multicasts flow from server to client via Switches 1, 2, 3, and 4

Switch 1: Querier

Switch 2: STP root

Switch 3

Switch 4

Multicast

igmp-qs.eps

Page 27 AlliedWare™ OS How To Note: IGMP

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Contents Introduction ContentsExample of bad choices for timer values Query solicitation rapid recovery from topology changesHow clients leave groups queries and timers Configurable Igmp timers and countersProducts and software versions this note applies to 4 AlliedWare OS How To Note Igmp Igmp feature Software versions Products5 AlliedWare OS How To Note Igmp Igmp overviewQueriers and Snoopers Messages 6 AlliedWare OS How To Note IgmpMAC address, hex 7 AlliedWare OS How To Note IgmpChoosing group addresses IP address, binaryAvoid x.0.0.y, x.0.1.y, x.128.0.y, and x.128.1.y 8 AlliedWare OS How To Note Igmp9 AlliedWare OS How To Note Igmp Igmp snoopingExample 10 AlliedWare OS How To Note Igmp Configure switchExplanation of Igmp snooping 11 AlliedWare OS How To Note Igmp12 AlliedWare OS How To Note Igmp Using Show command output to investigate Igmp stateGroup List Entry timeout 136 secs Ports None Group List Entry timeout 257 Secs Ports All Groups 235Group Last Adv 13 AlliedWare OS How To Note IgmpWhen a client leaves a group Group List Entry timeout 247 secs Ports14 AlliedWare OS How To Note Igmp Multiple potential Igmp queriers 15 AlliedWare OS How To Note Igmp16 AlliedWare OS How To Note Igmp When there are no group members Other Querier timeout .. secs17 AlliedWare OS How To Note Igmp 18 AlliedWare OS How To Note Igmp When a client joins a groupGroup List Entry timeout 225 secs Ports All Groups Entry timeout Secs Ports19 AlliedWare OS How To Note Igmp Group ListGroup List Last Adv 20 AlliedWare OS How To Note Igmp Igmp proxy 21 AlliedWare OS How To Note Igmp22 AlliedWare OS How To Note Igmp Switch 3 is an Igmp ProxyExplanation of Igmp proxy Group List Entry timeout 122 secs Ports NoneAll Groups Entry timeout 145 Secs Ports 23 AlliedWare OS How To Note Igmp24 AlliedWare OS How To Note Igmp Group Entry timeout Secs Ports25 AlliedWare OS How To Note Igmp Group Entry timeout 182 secs PortsQuery solicitation rapid recovery from topology changes 26 AlliedWare OS How To Note IgmpHow query solicitation works Initial state 27 AlliedWare OS How To Note IgmpWhy convergence takes so long without query solicitation 28 AlliedWare OS How To Note IgmpExample 29 AlliedWare OS How To Note Igmp Explanation from the perspective of switch 2, the snooper30 AlliedWare OS How To Note Igmp All Groups Entry timeout 236 secs PortsShows this entry Explanation from the perspective of switch 1, the querierGroup Entry timeout 18 secs Ports 31 AlliedWare OS How To Note Igmp32 AlliedWare OS How To Note Igmp Group Entry timeout 115 secs PortsSpeeding up Igmp convergence in a non-looped topology 33 AlliedWare OS How To Note IgmpSwitch 1 sends GQ 34 AlliedWare OS How To Note IgmpIgmp filtering controlling multicast distribution 35 AlliedWare OS How To Note IgmpTypes command Set switch port=1 igmpfilter=136 AlliedWare OS How To Note Igmp 37 AlliedWare OS How To Note Igmp Switch 3 is also an Igmp SnooperReceived Passed Dropped 38 AlliedWare OS How To Note IgmpNo group memberships 39 AlliedWare OS How To Note Igmp40 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 47 AlliedWare OS How To Note Igmp Group 224.12.13.11 Entry timeout 255 secs Ports 224.12.13.12Static Igmp 48 AlliedWare OS How To Note Igmp49 AlliedWare OS How To Note Igmp Switch 2 is an Igmp Snooper50 AlliedWare OS How To Note Igmp Group Entry timeout Infinity Ports 51 AlliedWare OS How To Note IgmpExplanation of Static Igmp MulticastPkts 675826 When we add a static entry on another switchModify switch 3 Configuration 52 AlliedWare OS How To Note Igmp53 AlliedWare OS How To Note Igmp All Groups Entry timeout 247 secs Ports54 AlliedWare OS How To Note Igmp 55 AlliedWare OS How To Note Igmp Group Entry timeout Infinity Ports 5,2656 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 Overview of leave process How clients leave groups queries and timersQuerier timer values 58 AlliedWare OS How To Note Igmp59 AlliedWare OS How To Note Igmp Snooper timer valuesDescribes the new behaviour Comparing the Querier and Snooper timers60 AlliedWare OS How To Note Igmp Consequences for high-loss and high-lag networksIgmp fast leave 61 AlliedWare OS How To Note Igmp62 AlliedWare OS How To Note Igmp Switch 1 is an Igmp QuerierExplanation of Igmp fast leave 63 AlliedWare OS How To Note IgmpFast Leave Off When fast leave is disabledGroup Entry timeout 2 secs Ports 64 AlliedWare OS How To Note Igmp65 AlliedWare OS How To Note Igmp When you enable fast leave on switchIt is safe to ignore the group entry on switch Group Entry timeout Secs Ports None66 AlliedWare OS How To Note Igmp When you set fast leave on all interfaces67 AlliedWare OS How To Note Igmp Multiple host mode for fast leaveTo specify multiple mode, use the command To specify single mode, use either of the commands68 AlliedWare OS How To Note Igmp Configurable Igmp timers and counters Timer and counter relationships69 AlliedWare OS How To Note Igmp Software versions Initial configurationEach example modifies the following base configuration 70 AlliedWare OS How To Note Igmp71 AlliedWare OS How To Note Igmp What these counters do Default values72 AlliedWare OS How To Note Igmp Last Member Query Count and Last Member Query IntervalLast Member Query Interval 255 10secs Potential problems with changing these countersHow to change these counters 73 AlliedWare OS How To Note IgmpLast Member Query Count 74 AlliedWare OS How To Note IgmpWhat this counter does Potential problems with changing this counterHow to change this counter Robustness VariableHow to change this timer Default Query IntervalWhat this timer does Potential problems with changing this timer77 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 79 AlliedWare OS How To Note Igmp Default Timeout Interval = 2*130 + 100/10 = 270 secondsQuery Response Interval 200 10secs Default Timeout Interval = 2*125 + 100/10 = 260 secondsDefault Timeout Interval 280 Secs 80 AlliedWare OS How To Note Igmp81 AlliedWare OS How To Note Igmp Default Timeout Interval 180 Secs82 AlliedWare OS How To Note Igmp Default Query Interval 200 Secs Default Timeout Interval 41083 AlliedWare OS How To Note Igmp Example of bad choices for timer valuesImagine the following changes to the configuration Commands to configure these settings areLast Member Query Interval was set to 5, using the command Problem 1 Last Member Query Interval too shortProblem 2 Query Response Interval short Problem 3 Default Timeout Interval too short85 AlliedWare OS How To Note Igmp For more information, see Synchronisation of timers onStopping snoopers from snooping non-IGMP messages 86 AlliedWare OS How To Note Igmp87 AlliedWare OS How To Note Igmp Ports 24 Configure the router88 AlliedWare OS How To Note Igmp Router uses OspfPorts 25 89 AlliedWare OS How To Note IgmpDisabling All Groups entry for a port Disabled All-groups Ports90 AlliedWare OS How To Note Igmp Preventing an All Groups entry for a portEnabling All Groups entry again Check the group entry timeout valuesReset port 24’s packet counters Entry timeout 216 SecsMulticastPkts Check the group entry timeout values againEntry timeout Secs 92 AlliedWare OS How To Note IgmpEnable Igmp debugging Entry timeout 259 Secs93 AlliedWare OS How To Note Igmp MulticastPkts 914 94 AlliedWare OS How To Note IgmpControlling which addresses create All Groups entries 95 AlliedWare OS How To Note IgmpConfiguring 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 Igmp224.0.0.254 100 AlliedWare OS How To Note Igmp Using the other routermode options101 AlliedWare OS How To Note Igmp Statically specifying that a port is a router portCheck the current Igmp snooping entries Stop port 6 from being a static router port To remove the static configuration, simply delete it102 AlliedWare OS How To Note Igmp Statically add port 6 as a router port attached to Vlan103 AlliedWare OS How To Note Igmp Igmp debuggingClient joins a group Several minutes later the group entry times out IgmpSnoopMembershipQuery setting timer at 2 secs for group104 AlliedWare OS How To Note Igmp Client leaves a groupSnooped ports change Manager Switch 3 del vlan=100 port=5105 AlliedWare OS How To Note Igmp Port entry times out106 AlliedWare OS How To Note Igmp Report is filtered outPort in the All Groups list is unplugged Output for show ip igmp changes 107 AlliedWare OS How To Note IgmpState Forwarding Switch108 AlliedWare OS How To Note Igmp Appendix STP state109 AlliedWare OS How To Note Igmp Manager Switch 3 show stp port=25-26

Initial state:

Final state:

Page 27 AlliedWare™ OS How To Note: IGMP