Example: Configuring IGMP Snooping
With IGMP snooping enabled, a switch monitors the IGMP (Internet Group Management Protocol) traffic between hosts and multicast routers and uses what it learns to forward multicast traffic to only the downstream interfaces that are connected to interested receivers. This conserves bandwidth by allowing the switch to send multicast traffic to only those interfaces that are connected to devices that want to receive the traffic (instead of flooding the traffic to all the downstream VLAN interfaces).
This example describes how to configure IGMP snooping:
Requirements
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
Components | Settings |
|---|---|
VLAN name | 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 | 225.100.100.100 |
Configuration
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:
[edit protocols]
set igmp-snooping
vlan employee-vlan
set igmp-snooping vlan employee-vlan
interface ge-0/0/3 static group 225.100.100.100
set igmp-snooping vlan employee-vlan interface ge-0/0/2
multicast-router-interface
set igmp-snooping vlan employee-vlan robust-count 4
Step-by-Step Procedure
Configure IGMP snooping:
- Enable and configure IGMP snooping on the VLAN employee-vlan:
[edit protocols]
user@switch# set igmp-snooping vlan employee-vlan - Configure a interface to belong to a multicast group:
[edit protocols]
user@switch# set igmp-snooping vlan employee-vlan interface ge-0/0/3 static group 225.100.100.100 - Configure an interface to forward IGMP queries received
from multicast routers.
[edit protocols]
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:
[edit protocols]
user@switch# set igmp-snooping vlan employee-vlan robust-count 4
Results
Check the results of the configuration:
