Querier Configuration

introduction introduction in an igmp enabled multicast network, devices can assume one of two roles within a network segment querier responsible for sending query messages receives and processes host membership reports (join messages) and leave group messages from hosts maintains awareness of which multicast groups have active receivers (group members) on the segment connected to its interface determines when group members leave by monitoring responses to its queries non querier passively receives host membership reports from hosts tracks which multicast groups have active receivers on its connected segment relies on the querier's activity to determine when group members leave does not initiate queries itself explanation of principles explanation of principles a network segment can have only one querier, so multicast devices must elect the querier through a selection process the election rules are as follows after enabling the querier function, multicast device a will default to being the querier for the current network segment during the igmp protocol startup phase and begin sending query messages to the segment if device a receives a query message from multicast device b with a smaller ip address than its own,device a will switch from querier to non querier status,start the other querier present timer,record device b as the current querier for the segment when device a is in non querier status and receives query messages from querier device b,it will update the other querier present timer if the received query message comes from a new multicast device c (not the previously recorded querier b) and c has a smaller ip address than b,update the querier to device c,refresh the other querier present timer if device a is in non querier status and the other querier present timer expires\ device a will switch to querier status，assume the responsibilities of the querier querier configuration querier configuration operation command description enter the vlan view vlan id enable igmp snooping igmp snooping enable enable querier configuration igmp snooping querier enable configuration example configuration example the router connects to the user network through a device key configurations and operational status are as follows router configuration igmp querier functionality is enabled,querier ip address has been modified network components two end user devices pc a and pc b,intermediate device running igmp snooping multicast operations multicast sources are transmitting data to groups 224 1 1 1 and 225 1 1 1 the router successfully receives join messages from terminals,receives leave messages from terminals,multicast data from sources is properly forwarded to target pcs as designed procedure procedure create vlans on the router and add interfaces connected to the device sonic(config)# vlan 100 sonic(config vlan 100)# igmp snooping enable sonic(config vlan 100)# igmp snooping querier enable sonic(config)# interface ethernet 1 sonic(config if 1)# switchport access vlan 100 creating vlans and adding member interfaces sonic(config)# vlan 100 sonic(config vlan 100)# igmp snooping enable sonic(config)# port group ethernet 1 2 sonic(config port group 1 2)# switchport access vlan 100 change querier ip to 100 1 1 1 sonic(config)# vlan 100 sonic(config vlan 100)# igmp snooping querier ip 100 1 1 1 verify configuration verify configuration view multicast vlan configuration sonic(config)# do show l2 multicast table total l2 multicast forwarding group counters 4 (source,group) interface vlan uvlan mode \ (0 0 0 0,225 1 1 1) ethernet2 vlan100 vlan100 incl ethernet3 vlan100 vlan100 incl (0 0 0 0,224 1 1 1) ethernet2 vlan100 vlan100 incl ethernet3 vlan100 vlan100 incl check querier information and change source address to 100 1 1 1