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play_arrow Overview
- play_arrow Understanding Multicast
play_arrow Managing Group Membership
play_arrow Configuring Protocol Independent Multicast
- play_arrow Understanding PIM
  - PIM Overview
  - PIM on Aggregated Interfaces
- play_arrow Configuring PIM Basics
- play_arrow Routing Content to Densely Clustered Receivers with PIM Dense Mode
- play_arrow Routing Content to Larger, Sparser Groups with PIM Sparse Mode
- play_arrow Configuring Designated Routers
  - Understanding Designated Routers
  - Configuring a Designated Router for PIM
- play_arrow Receiving Content Directly from the Source with SSM
- play_arrow Minimizing Routing State Information with Bidirectional PIM
  - Example: Configuring Bidirectional PIM
- play_arrow Rapidly Detecting Communication Failures with PIM and the BFD Protocol
  - Configuring PIM and the Bidirectional Forwarding Detection (BFD) Protocol
- play_arrow Configuring PIM Options
  - Example: Configuring Nonstop Active Routing for PIM
  - Configuring PIM-to-IGMP and PIM-to-MLD Message Translation
- play_arrow Verifying PIM Configurations
play_arrow Configuring Multicast Routing Protocols
- play_arrow Connecting Routing Domains Using MSDP
  - Examples: Configuring MSDP
  - Configuring Multiple Instances of MSDP
- play_arrow Handling Session Announcements with SAP and SDP
  - Configuring the Session Announcement Protocol
  - Verifying SAP and SDP Addresses and Ports
- play_arrow Facilitating Multicast Delivery Across Unicast-Only Networks with AMT
  - Example: Configuring Automatic IP Multicast Without Explicit Tunnels
- play_arrow Routing Content to Densely Clustered Receivers with DVMRP
  - Examples: Configuring DVMRP
play_arrow Configuring Multicast VPNs
play_arrow General Multicast Options
- play_arrow Bit Index Explicit Replication (BIER)
- play_arrow Prevent Routing Loops with Reverse Path Forwarding
  - Examples: Configuring Reverse Path Forwarding
- play_arrow Use Multicast-Only Fast Reroute (MoFRR) to Minimize Packet Loss During Link Failures
- play_arrow Enable Multicast Between Layer 2 and Layer 3 Devices Using Snooping
- play_arrow Configure Multicast Routing Options
- play_arrow Controller-Based BGP Multicast Signaling
  - Controller-Based BGP Multicast Signaling
play_arrow Troubleshooting
- play_arrow Knowledge Base
  - Knowledge Search
  - JTAC Certified Step-by-Step Troubleshooting: Junos OS Multicast
play_arrow Configuration Statements and Operational Commands
- Junos CLI Reference Overview

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English

Example: Configuring MLD Snooping on SRX Series Devices

date_range 23-Nov-23

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You can enable MLD snooping on a VLAN to constrain the flooding of IPv6 multicast traffic on a VLAN. When MLD snooping is enabled, SRX Series Firewall examines MLD messages between hosts and multicast routers and learns which hosts are interested in receiving multicast traffic for a multicast group. Based on what it learns, the device then forwards IPv6 multicast traffic only to those interfaces connected to interested receivers instead of flooding the traffic to all interfaces.

This example describes how to configure MLD snooping:

Requirements

This example uses the following software and hardware components:

One SRX Series Firewall
Junos OS Release 18.1R1

Before you configure MLD snooping, be sure you have:

Configured the vlan100 VLAN on the device
Assigned interfaces ge-0/0/0, ge-0/0/1, ge-0/0/2, and ge-0/0/3 to vlan100
Configured ge-0/0/3 as a trunk interface.

Overview and Topology

In this example, interfaces ge-0/0/0, ge-0/0/1, and ge-0/0/2 on the device are in vlan100 and are connected to hosts that are potential multicast receivers. Interface ge-0/0/3, a trunk interface also in vlan100, is connected to a multicast router. The router acts as the MLD querier and forwards multicast traffic for group 2001:db8::1 to the device from a multicast source.

Topology

The example topology is illustrated in Figure 1.

Figure 1: Example MLD Snooping Topology

In this example topology, the multicast router forwards multicast traffic to the device from the source when it receives a memberhsip report for group 2001:db8::1 from one of the hosts—for example, Host B. If MLD snooping is not enabled on vlan100, then the device floods the multicast traffic on all interfaces in vlan100 (except for interface ge-0/0/3). If MLD snooping is enabled on vlan100, the device monitors the MLD messages between the hosts and router, allowing it to determine that only Host B is interested in receiving the multicast traffic. The device then forwards the multicast traffic only to interface ge-0/0/1.

This example shows how to enable MLD snooping on vlan100. It also shows how to perform the following optional configurations, which can reduce group join and leave latency:

Configure immediate leave on the VLAN. When immediate leave is configured, the device stops forwarding multicast traffic on an interface when it detects that the last member of the multicast group has left the group. If immediate leave is not configured, the device waits until the group-specific membership queries time out before it stops forwarding traffic
Configure ge-0/0/3 as a static multicast-router interface. In this topology, ge-0/0/3 always leads to the multicast router. By statically configuring ge-0/0/3 as a multicast-router interface, you avoid any delay imposed by the device having to learn that ge-0/0/3 is a multicast-router interface.

Configuration

To configure MLD snooping on a device:

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the commands into the CLI at the [edit] hierarchy level, and then enter commit from configuration mode.

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set interfaces ge-0/0/0 unit 0 family ethernet-switching interface-mode access
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members vlan100
set interfaces ge-0/0/1 unit 0 family ethernet-switching interface-mode access
set interfaces ge-0/0/1 unit 0 family ethernet-switching vlan members vlan100
set interfaces ge-0/0/2 unit 0 family ethernet-switching interface-mode access
set interfaces ge-0/0/2 unit 0 family ethernet-switching vlan members vlan100
set interfaces ge-0/0/3 unit 0 family ethernet-switching interface-mode trunk
set interfaces ge-0/0/3 unit 0 family ethernet-switching vlan members vlan100
set vlans vlan100 vlan-id 100
set routing-options nonstop-routing
set protocols mld-snooping vlan vlan100 query-interval 200
set protocols mld-snooping vlan vlan100 query-response-interval 0.4
set protocols mld-snooping vlan vlan100 query-last-member-interval 0.1
set protocols mld-snooping vlan vlan100 robust-count 4
set protocols mld-snooping vlan vlan100 immediate-leave
set protocols mld-snooping vlan vlan100 interface ge-0/0/1.0 host-only-interface
set protocols mld-snooping vlan vlan100 interface ge-0/0/0.0 group-limit 50
set protocols mld-snooping vlan vlan100 interface ge-0/0/2.0 static group 2001:db8::1
set protocols mld-snooping vlan vlan100 interface ge-0/0/3.0 multicast-router-interface

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode in the CLI User Guide.

To configure MLD snooping:

Configure the access mode interfaces.

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[edit interfaces]
user@host# set ge-0/0/0 unit 0 family ethernet-switching interface-mode access
user@host# set ge-0/0/0 unit 0 family ethernet-switching vlan members vlan100
user@host# set ge-0/0/1 unit 0 family ethernet-switching interface-mode access
user@host# set ge-0/0/1 unit 0 family ethernet-switching vlan members vlan100
user@host# set ge-0/0/2 unit 0 family ethernet-switching interface-mode access
user@host# set ge-0/0/2 unit 0 family ethernet-switching vlan members vlan100

Configure the trunk mode interface.

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[edit interfaces]
user@host# set ge-0/0/3 unit 0 family ethernet-switching interface-mode trunk
user@host# set ge-0/0/3 unit 0 family ethernet-switching vlan members vlan100

Configure the VLAN.

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[edit vlans vlan100]
user@host# set vlans v100 vlan-id 100

Configure nonstop routing

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[edit]
user@host# set routing-options nonstop-routing

Configure the limit for the number of multicast groups allowed on the ge-0/0/1.0 interface to 50.
```
[edit vlans vlan100]
user@host# set protocols mld-snooping vlan vlan100 interface ge-0/0/0.0 group-limit 50
```
Configure the device to immediately remove a group membership from an interface when it receives a leave message from that interface without waiting for any other MLD messages to be exchanged.
```
[edit vlans vlan100]
user@host# set protocols mld-snooping vlan vlan100 immediate-leave
```

Statically configure interface ge-0/0/2.0 as a multicast-router interface.

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[edit vlans vlan100]
user@host# set protocols mld-snooping vlan vlan100 interface ge-0/0/2.0 static group 2001:db8::1

Configure an interface to be an exclusively router-facing interface (to receive multicast traffic).
```
[edit vlans vlan100]
user@host# set protocols mld-snooping vlan vlan100 interface ge-0/0/3.0 multicast-router-interface
```
Configure an interface to be an exclusively host-facing interface (to drop MLD query messages).
```
[edit vlans vlan100]
user@host# set protocols mld-snooping vlan vlan100 interface ge-0/0/1.0 host-only-interface
```

Configure the IGMP message intervals and robustness count.

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[edit vlans vlan100]
uer@host# set protocols mld-snooping vlan v100 query-interval 200
uer@host# set protocols mld-snooping vlan v100 query-response-interval 0.4
uer@host# set protocols mld-snooping vlan v100 query-last-member-interval 0.1
uer@host# set protocols mld-snooping vlan v1 robust-count 4 

If you are done configuring the device, commit the configuration.
```
user@host# commit
```

Results

From configuration mode, confirm your configuration by entering the show protocols mld-snooping command. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.

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[edit]
user@host# show protocols mld-snooping
    vlan vlan100 {
        query-interval 200;
        query-response-interval 0.4;
        query-last-member-interval 0.1;
        robust-count 4;
        immediate-leave;
        interface ge-0/0/1.0 {
            host-only-interface;
        }
        interface ge-0/0/0.0 {
            group-limit 50;
        }
        interface ge-0/0/2.0 {
            static {
                group 2001:db8::1;
            }
        }
        interface ge-0/0/3.0 {
            multicast-router-interface;
        }
    }

Verifying MLD Snooping Configuration

To verify that MLD snooping is enabled on the VLAN and the MLD snooping forwarding interfaces are correct, perform the following task:

Verifying MLD Snooping Interface Membership on VLAN vlan100

Purpose
Action
Meaning

Purpose

Verify that MLD snooping is enabled on vlan100 and that the multicast-router interface is statically configured:

Action

From operational mode, enter the show mld snooping membership command.

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user@host> show mld snooping membership
Instance: default-switch 

Vlan: vlan100 

Learning-Domain: default 
Interface: ge-0/0/0.0, Groups: 0 
Interface: ge-0/0/1.0, Groups: 0 
Interface: ge-0/0/2.0, Groups: 1 
    Group: 2001:db8::1 
        Group mode: Exclude 
        Source: :: 
        Last reported by: Local 
        Group timeout:       0 Type: Static 

Meaning

MLD snooping is running on vlan100, and interface ge-0/0/3.0 is a statically configured multicast-router interface. Because the multicast group 2001:db8::1 is listed, at least one host in the VLAN is a current member of the multicast group and that host is on interface ge-0/0/1.0.

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Multicast Protocols User Guide

ON THIS PAGE

Example: Configuring MLD Snooping on SRX Series Devices

Requirements

Overview and Topology

Topology

Configuration

Procedure

CLI Quick Configuration

Step-by-Step Procedure

Results

Verifying MLD Snooping Configuration

Verifying MLD Snooping Interface Membership on VLAN vlan100

Purpose

Action

Meaning

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Multicast Protocols User Guide

ON THIS PAGE

Example: Configuring MLD Snooping on SRX Series Devices

Requirements

Overview and Topology

Topology

Configuration

Procedure

CLI Quick Configuration

Step-by-Step Procedure

Results

Verifying MLD Snooping Configuration

Verifying MLD Snooping Interface Membership on VLAN vlan100

Purpose

Action

Meaning

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