Group List Last Adv | Allied Telesis AR400 guide

Multiple potential IGMP queriers > Explanation of Multiple potential IGMP queriers

To see the difference between a switch acting as a Snooper and a switch acting as a Querier, compare the IGMP snooping table for switch 1 (above) with its IGMP table (below). They seem to contradict each other. The IGMP snooping table tells us that switch 1 is aware that it is receiving the group 224.12.13.14 and will send all groups (including this one) out port 49 towards the IGMP Querier, switch 2. However, the IGMP table shows that IGMP has not registered any interested clients—the group list is empty.

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)
Disabled All-groups ports	None
Interface Name	vlan100
Other Querier timeout ... 214 secs
Group List
------------------------------------------------------------------------

This disparity between the IGMP snooping table and the IGMP table simply shows that switch 1 is acting as a Snooper because it did not become the Querier. The IGMP table on switch 1 has no entries because no Report message has been seen on switch 1. The disparity does not appear in the output for switch 2, because switch 2 is the Querier. The IGMP and IGMP snooping tables show the same group entries on switch 2.

Manager Switch 2> 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)
Disabled All-groups ports	None

Interface Name	vlan100	(DR)
IGMP Proxy	Off
Group List
Group. 224.12.13.14	Last Adv. 172.31.0.222		Refresh time 228 secs
Ports 2

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

Page 19 AlliedWare™ OS How To Note: IGMP

Image 19

Allied Telesis AR400 manual Group List Last Adv, AlliedWare OS How To Note Igmp

Contents

Introduction Contents Example of bad choices for timer values Query solicitation rapid recovery from topology changesHow clients leave groups queries and timers Configurable Igmp timers and counters Products and software versions this note applies to 4 AlliedWare OS How To Note Igmp Igmp feature Software versions Products Igmp overview 5 AlliedWare OS How To Note IgmpQueriers and Snoopers Messages 6 AlliedWare OS How To Note Igmp MAC address, hex 7 AlliedWare OS How To Note IgmpChoosing group addresses IP address, binary Avoid x.0.0.y, x.0.1.y, x.128.0.y, and x.128.1.y 8 AlliedWare OS How To Note Igmp Igmp snooping 9 AlliedWare OS How To Note IgmpExample 10 AlliedWare OS How To Note Igmp Configure switch Explanation of Igmp snooping 11 AlliedWare OS How To Note Igmp 12 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 235 Group Last Adv 13 AlliedWare OS How To Note Igmp Group List Entry timeout 247 secs Ports When a client leaves a group14 AlliedWare OS How To Note Igmp Multiple potential Igmp queriers 15 AlliedWare OS How To Note Igmp 16 AlliedWare OS How To Note Igmp Other Querier timeout .. secs When there are no group members17 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 Ports Group List 19 AlliedWare OS How To Note IgmpGroup List Last Adv 20 AlliedWare OS How To Note Igmp Igmp proxy 21 AlliedWare OS How To Note Igmp 22 AlliedWare OS How To Note Igmp Switch 3 is an Igmp Proxy Explanation of Igmp proxy Group List Entry timeout 122 secs Ports NoneAll Groups Entry timeout 145 Secs Ports 23 AlliedWare OS How To Note Igmp 24 AlliedWare OS How To Note Igmp Group Entry timeout Secs Ports 25 AlliedWare OS How To Note Igmp Group Entry timeout 182 secs Ports 26 AlliedWare OS How To Note Igmp Query solicitation rapid recovery from topology changesHow query solicitation works Initial state 27 AlliedWare OS How To Note Igmp 28 AlliedWare OS How To Note Igmp Why convergence takes so long without query solicitationExample 29 AlliedWare OS How To Note Igmp Explanation from the perspective of switch 2, the snooper 30 AlliedWare OS How To Note Igmp All Groups Entry timeout 236 secs Ports Shows this entry Explanation from the perspective of switch 1, the querierGroup Entry timeout 18 secs Ports 31 AlliedWare OS How To Note Igmp 32 AlliedWare OS How To Note Igmp Group Entry timeout 115 secs Ports Speeding up Igmp convergence in a non-looped topology 33 AlliedWare OS How To Note Igmp Switch 1 sends GQ 34 AlliedWare OS How To Note Igmp Igmp filtering controlling multicast distribution 35 AlliedWare OS How To Note Igmp Set switch port=1 igmpfilter=1 Types command36 AlliedWare OS How To Note Igmp 37 AlliedWare OS How To Note Igmp Switch 3 is also an Igmp Snooper Received Passed Dropped 38 AlliedWare OS How To Note Igmp No group memberships 39 AlliedWare OS How To Note Igmp 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 Modify switch 2 Configuration When we deny groups instead of replacing them46 AlliedWare OS How To Note Igmp 47 AlliedWare OS How To Note Igmp Group 224.12.13.11 Entry timeout 255 secs Ports 224.12.13.12 Static Igmp 48 AlliedWare OS How To Note Igmp 49 AlliedWare OS How To Note Igmp Switch 2 is an Igmp Snooper 50 AlliedWare OS How To Note Igmp 51 AlliedWare OS How To Note Igmp Group Entry timeout Infinity PortsExplanation of Static Igmp MulticastPkts 675826 When we add a static entry on another switchModify switch 3 Configuration 52 AlliedWare OS How To Note Igmp 53 AlliedWare OS How To Note Igmp All Groups Entry timeout 247 secs Ports 54 AlliedWare OS How To Note Igmp 55 AlliedWare OS How To Note Igmp Group Entry timeout Infinity Ports 5,26 MulticastPkts 36350 56 AlliedWare OS How To Note IgmpMulticastPkts 14756 Group Entry timeout Infinity Ports None When a static entry’s port goes down57 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 Igmp 59 AlliedWare OS How To Note Igmp Snooper timer values Describes the new behaviour Comparing the Querier and Snooper timers60 AlliedWare OS How To Note Igmp Consequences for high-loss and high-lag networks Igmp fast leave 61 AlliedWare OS How To Note Igmp 62 AlliedWare OS How To Note Igmp Switch 1 is an Igmp Querier Explanation of Igmp fast leave 63 AlliedWare OS How To Note Igmp Fast Leave Off When fast leave is disabledGroup Entry timeout 2 secs Ports 64 AlliedWare OS How To Note Igmp 65 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 None 66 AlliedWare OS How To Note Igmp When you set fast leave on all interfaces 67 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 commands 68 AlliedWare OS How To Note Igmp Timer and counter relationships Configurable Igmp timers and counters69 AlliedWare OS How To Note Igmp Software versions Initial configurationEach example modifies the following base configuration 70 AlliedWare OS How To Note Igmp 71 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 Interval Last Member Query Interval 255 10secs Potential problems with changing these countersHow to change these counters 73 AlliedWare OS How To Note Igmp Last Member Query Count 74 AlliedWare OS How To Note Igmp What this counter does Potential problems with changing this counterHow to change this counter Robustness Variable How to change this timer Default Query IntervalWhat this timer does Potential problems with changing this timer Query Response Interval 77 AlliedWare OS How To Note IgmpQuery Response Interval 100 10secs Synchronisation of timers Default Timeout Interval78 AlliedWare OS How To Note Igmp 79 AlliedWare OS How To Note Igmp Default Timeout Interval = 2*130 + 100/10 = 270 seconds Query Response Interval 200 10secs Default Timeout Interval = 2*125 + 100/10 = 260 secondsDefault Timeout Interval 280 Secs 80 AlliedWare OS How To Note Igmp 81 AlliedWare OS How To Note Igmp Default Timeout Interval 180 Secs 82 AlliedWare OS How To Note Igmp Default Query Interval 200 Secs Default Timeout Interval 410 83 AlliedWare OS How To Note Igmp Example of bad choices for timer valuesImagine the following changes to the configuration Commands to configure these settings are Last 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 short 85 AlliedWare OS How To Note Igmp For more information, see Synchronisation of timers on Stopping snoopers from snooping non-IGMP messages 86 AlliedWare OS How To Note Igmp 87 AlliedWare OS How To Note Igmp Ports 24 Configure the router88 AlliedWare OS How To Note Igmp Router uses Ospf Ports 25 89 AlliedWare OS How To Note Igmp Disabling All Groups entry for a port Disabled All-groups Ports90 AlliedWare OS How To Note Igmp Preventing an All Groups entry for a port Enabling All Groups entry again Check the group entry timeout valuesReset port 24’s packet counters Entry timeout 216 Secs MulticastPkts Check the group entry timeout values againEntry timeout Secs 92 AlliedWare OS How To Note Igmp Entry timeout 259 Secs Enable Igmp debugging93 AlliedWare OS How To Note Igmp MulticastPkts 914 94 AlliedWare OS How To Note Igmp Controlling which addresses create All Groups entries 95 AlliedWare OS How To Note Igmp 96 AlliedWare OS How To Note Igmp Configuring switch224.0.0.5 97 AlliedWare OS How To Note Igmp 98 AlliedWare OS How To Note Igmp Configuring switches 1Adding other router addresses 99 AlliedWare OS How To Note Igmp Returning to the default list224.0.0.254 100 AlliedWare OS How To Note Igmp Using the other routermode options Statically specifying that a port is a router port 101 AlliedWare OS How To Note IgmpCheck 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 Vlan Igmp debugging 103 AlliedWare OS How To Note IgmpClient 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 group Snooped ports change Manager Switch 3 del vlan=100 port=5105 AlliedWare OS How To Note Igmp Port entry times out Report is filtered out 106 AlliedWare OS How To Note IgmpPort in the All Groups list is unplugged Output for show ip igmp changes 107 AlliedWare OS How To Note Igmp State Forwarding Switch108 AlliedWare OS How To Note Igmp Appendix STP state 109 AlliedWare OS How To Note Igmp Manager Switch 3 show stp port=25-26