Example for Configuring Basic IGMP Snooping

Owned by Tracy Yang (Unlicensed)
Apr 26, 2023
3 min read

Networking Requirments

Figure 1. IGMP Snooping Networking

As shown in Figure 1, Host A, Host B, and Host C connect to a multicast source through a Layer 2 Switch and a Layer 3 Router to receive multicast data from the Source device.

Perform the following procedures on the Switch to implement IGMP snooping:

  •   Create a VLAN and add interfaces Ge-1/1/1, Ge-1/1/2 and Ge-1/1/3 to the VLAN.
  •   Enable global and VLAN-based IGMP snooping function.
  •   Host C wants to receive multicast data from multicast group 238.255.0.1 stably for a long time, so configure the connecting interface Ge-1/1/1 as a static member port.
  •   To prevent aging of dynamic routing interfaces, configure Ge-1/1/3 as a static router port.

Procedure

Step1         Configure VLAN.

admin@XorPlus# set vlans vlan-id 2
admin@XorPlus# set interface gigabit-ethernet ge-1/1/1 family ethernet-switching native-vlan-id 2
admin@XorPlus# set interface gigabit-ethernet ge-1/1/2 family ethernet-switching native-vlan-id 2
admin@XorPlus# set interface gigabit-ethernet ge-1/1/3 family ethernet-switching native-vlan-id 2

Step2         Enable the global IGMP snooping function.

admin@Xorplus# set protocols igmp-snooping enable true

Step3         Enable the VLAN-based IGMP snooping function.

admin@Xorplus# set protocols igmp-snooping vlan-id 2 enable true

NOTE:

To enable IGMP snooping, both global and VLAN-based IGMP snooping need to be configured. 

  • If only the global IGMP snooping is enabled, IGMP snooping in the VLAN is disabled by default. To enable IGMP snooping in a VLAN, you also need to enable the VLAN-based IGMP snooping function via set protocols igmp-snooping vlan-id enable command.
  • After both global and VLAN-based IGMP snooping are enabled, it will take effect only on interfaces that have already been added to this VLAN enabled IGMP snooping.

Step4          (Optional) Configure the number of times that the querier sends a group-specific query message.

admin@Xorplus# set protocols igmp-snooping last-member-query-count 2

Step5         (Optional) Configure the interval that the querier sends a group-specific query message.

admin@Xorplus# set protocols igmp-snooping last-member-query-interval 2

Step6         (Optional) Configure the maximum response time for IGMP general queries.

admin@Xorplus# set protocols igmp-snooping max-response-time 10

Step7         (Optional) Configure the interval of sending an IGMP general queries.

admin@Xorplus# set protocols igmp-snooping query-interval 60

Step8         (Optional) Enable the membership report suppression function.

admin@Xorplus# set protocols igmp-snooping report-suppression true

Step9         (Optional) Configure the IGMP robustness coefficient.

admin@Xorplus# set protocols igmp-snooping robustness-variable 2

Step10         (Optional) Configure aging time of dynamic router port.

admin@Xorplus# set protocols igmp-snooping router-aging-time 260

Step11      (Optional) Enable the fast leave function to allow member ports in a VLAN to quickly leave the multicast group.

admin@Xorplus# set protocols igmp-snooping vlan-id 2 fast-leave true

Step12      (Optional) Configure the querier in the VLAN.

admin@Xorplus# set protocols igmp-snooping vlan-id 2 querier enable true
admin@Xorplus# set protocols igmp-snooping vlan-id 2 querier address 192.168.12.100
admin@Xorplus# set protocols igmp-snooping vlan-id 2 querier version 2
admin@Xorplus# set protocols igmp-snooping vlan-id 2 querier other-querier-timer 120

Step13      Configure the interface as a static router port in the specified VLAN.

admin@Xorplus# set protocols igmp-snooping vlan-id 2 mrouter interface ge-1/1/3

Step14      Configure a static member interface to the multicast group.

admin@Xorplus# set protocols igmp-snooping vlan-id 2 static group 238.255.0.1 interface ge-1/1/1

Verify the Configuration

  •   You can use the run show igmp-snooping command to view the configuration information of IGMP snooping.   
admin@XorPlus# run show igmp-snooping
Global IGMP Snooping configuration:
-------------------------------------------
IGMP snooping             : Enabled
Report suppression           : Enabled
Robustness variable          : 2
Router aging time            : 260
Max response time            : 10
Query interval               : 60
Last member query count      : 2
Last member query interval    : 2


admin@XorPlus# run show igmp-snooping vlan 2
Vlan 2:
----------------------------------------------
IGMP snooping                    : Enabled
IGMPv2 fast leave                  : Enabled
IGMP querier state                  : Enabled
IGMP querier source ip address        : 192.168.12.100
IGMP other querier timer             : 120
IGMP querier version                : 2  


  • You can use the run show igmp-snooping groups command to show information about multicast group member ports which is used for Layer 2 forwarding, namely, the Layer 2 forwarding table.    
admin@XorPlus# run show igmp-snooping groups 
Vlan      Group                Port List          Type 
--------  ------------------      -----------------   ----------------------
 2      238.255.0.1              ge-1/1/1           Static                                             
                                   ge-1/1/3           Mrouter 
  •   You can use the runshow igmp-snooping querier command to show the configuration information and status of the querier.     
admin@XorPlus# run show igmp-snooping querier vlan 2
Vlan 2:   IGMP switch querier status
--------------------------------------------------------
admin state                    : Enabled
admin version                  : 2
source IP address              : 192.168.12.100
other querier timer            : 120
operational state              : Active
  •   You can use the run show igmp-snooping mrouter command to show the information about IGMP snooping router port.      
admin@XorPlus# run show igmp-snooping mrouter
Vlan      Ports            Type
--------    -------------     ---------
1         ge-1/1/3         Static

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