Example: Configuring IGMP Snooping on Switches
Internet Group Management Protocol (IGMP) snooping constrains the flooding of IPv4 multicast traffic on VLANs on a device. With IGMP snooping enabled, the device monitors IGMP traffic on the network and uses what it learns to forward multicast traffic to only the downstream interfaces that are connected to interested receivers. The device conserves bandwidth by sending multicast traffic only to interfaces connected to devices that want to receive the traffic, instead of flooding the traffic to all the downstream interfaces in a VLAN.
This example describes how to configure IGMP snooping:
This example requires Junos OS Release 11.1 or later on a QFX Series product.
Before you configure IGMP snooping, be sure you have:
Configured the employee-vlan VLAN
Assigned interfaces ge-0/0/1, ge-0/0/2, and ge-0/0/3 to employee-vlan
Overview and Topology
In this example you configure an interface to receive multicast traffic from a source and configure some multicast-related behavior for downstream interfaces. The example assumes that IGMP snooping was previously disabled for the VLAN.
Table 1 shows the components of the topology for this example.
Table 1: Components of the IGMP Snooping Topology
employee-vlan, tag 20
Interfaces in employee-vlan
ge-0/0/1, ge-0/0/2, ge-0/0/3
Multicast IP address for employee-vlan
To configure basic IGMP snooping on a switch:
CLI Quick Configuration
To quickly configure IGMP snooping, copy the following commands and paste them into a terminal window:
set igmp-snooping vlan employee-vlan
set igmp-snooping vlan employee-vlan interface ge-0/0/3 static group 18.104.22.168
set igmp-snooping vlan employee-vlan interface ge-0/0/2 multicast-router-interface
set igmp-snooping vlan employee-vlan robust-count 4
Configure IGMP snooping:
- Enable and configure IGMP snooping on the VLAN employee-vlan:
- Configure a interface to belong to a multicast group:
- Configure an interface to forward IGMP queries received
from multicast routers.
user@switch# set igmp-snooping vlan employee-vlan interface ge-0/0/2 multicast-router-interface
- Configure the switch to wait for four timeout intervals
before timing out a multicast group on a VLAN:
user@switch# set igmp-snooping vlan employee-vlan robust-count 4
Check the results of the configuration: