Implementing MLD Snooping

This module describes how to implement MLD snooping on the Cisco NCS 5500 Series Routers.

Table 1. Feature History for MLD Snooping

Release

Modification

Release 6.6.25

This feature was introduced.

MLD Snooping

Multicast Listener Discovery (MLD) snooping provides a way to constrain multicast traffic at Layer 2. By snooping the MLD membership reports sent by hosts in the bridge domain, the MLD snooping application can set up Layer 2 multicast forwarding tables to deliver traffic only to ports with at least one interested member, significantly reducing the volume of multicast traffic.

MLD snooping uses the information in MLD membership report messages to build corresponding information in the forwarding tables to restrict IPv6 multicast traffic at Layer 2. The forwarding table entries are in the form <Route, OIF List>, where:

  • Route is a <*, G> route or <S, G> route.

  • OIF List comprises all bridge ports that have sent MLD membership reports for the specified route plus all multicast router (mrouter) ports in the bridge domain.

For more information regarding MLD snooping, refer the Multicast Configuration Guide for Cisco NCS 5500 Series Routers.

Prerequisites for MLD Snooping

  • The network must be configured with a layer2 VPN.

  • You must be in a user group associated with a task group that includes the proper task IDs. The command reference guides include the task IDs required for each command. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Supported Features and Restrictions for MLD Snooping

  • BVI under bridge domain is supported.

  • Receiver behind L2 ACs in the same L2 bridge domain is supported.

  • Source behind L2 ACs in the same L2 bridge domain is only supported on NCS 5700 fixed port routers and NCS 5700 line cards [Mode: Compatibility; Native].

  • MLDv1 not supported over BVI.

  • EVPN MLD sync is not supported.

  • VPLS is not supported.

  • On the NCS 5700 line cards, MLD snooping can be enabled alongside IGMP snooping only.

  • The router-alert-check disable configuration command is not supported.

  • EVPN dual-home source AA is not supported on the NCS 5500 line cards line cards.

  • Both IGMP and MLD snooping configurations are necessary to enable MLD snooping on the NCS 5700 line cards.

  • EVPN configuration must have the control-word-disable configuration.

  • PIM control packets (join and hello) processing is not supported when snooping is enabled, so a multicast router selection based on PIM packets won't occur.

  • Explicit host tracking.

  • Multicast Admission Control.

  • Security filtering.

  • Report rate limiting.

  • Multicast router discovery.

  • IPv6 multicast is not supported for a multicast source that is behind the BVI interface. For example, the below configuration is not supported: 

    
l2vpn
bridge group 1
  bridge-domain 1
   multicast-source ipv6
   mld snooping profile grp1

  • In an EVPN dual-home AA scenario:

    • If the multicast source and receiver are in the same bridge domain (BD), the receiver might receive permanent traffic duplication.

    • In an EVPN dual-home receiver AA scenario, transient traffic duplication is expected when the DH node role changes from DF to nDF and vice versa.

    • Source=ESI1=BE-X.A, Receiver=ESI1=BE-X.B under the same BD is not supported (where X.A and X.B represent two AC ports for the bundle interface BE).

    • Source=ESI1=BE-X.A (for NCS 5700 line cards), Receiver=ESI2=BE-Y.A (for NCS 5500 line cards) under the same BD is not supported (where X.A and Y.A represent two AC ports for the bundle interface BE).


Note

MLD Snooping is not supported until Cisco IOS XR Release 6.5.3.

Advantages of MLD Snooping

  • In its basic form, it reduces bandwidth consumption by reducing multicast traffic that would otherwise flood an entire VPLS bridge domain.

  • With the use of some optional configurations, it provides security between bridge domains by filtering the MLD reports received from hosts on one bridge port and preventing leakage towards the hosts on other bridge ports.

High Availability (HA) features for MLD

MLD supports the following HA features:

  • Process restarts

  • RP Failover

  • Stateful Switch-Over (SSO)

  • Non-Stop Forwarding (NSF)—Forwarding continues unaffected while the control plane is restored following a process restart or route processor (RP) failover.

  • Line card online insertion and removal (OIR)

Bridge Domain Support for MLD

MLD snooping operates at the bridge domain level. When MLD snooping is enabled on a bridge domain, the snooping functionality applies to all ports under the bridge domain, including:

  • Physical ports under the bridge domain.

  • Ethernet flow points (EFPs)—An EFP can be a VLAN, VLAN range, list of VLANs, or an entire interface port.

  • Ethernet bundles—Ethernet bundles include IEEE 802.3ad link bundles and Cisco EtherChannel bundles. From the perspective of the MLD snooping application, an Ethernet bundle is just another EFP. The forwarding application in the Cisco NCS 5500 Series Routers randomly nominates a single port from the bundle to carry the multicast traffic.


    Note

    The efp-visibility configuration is required when a bridge has attachment circuits as VLAN sub-interfaces from the same bundle-ether or physical interface.

Multicast Router and Host Ports

MLD snooping classifies each port as one of the following:

  • Multicast router ports (mrouter ports)—These are ports to which a multicast-enabled router is connected. Mrouter ports are usually dynamically discovered, but may also be statically configured. Multicast traffic is always forwarded to all mrouter ports, except when an mrouter port is the ingress port.

  • Host ports—Any port that is not an mrouter port is a host port.

Multicast Router Discovery for MLD

MLD snooping discovers mrouter ports dynamically. You can also explicitly configure a port as an emrouter port.

  • Discovery- MLD snooping identifies upstream mrouter ports in the bridge domain by snooping mld query messages and Protocol Independent Multicast Version 2 (PIMv2) hello messages. Snooping PIMv2 hello messages identifies mld nonqueriers in the bridge domain.

  • Static configuration—You can statically configure a port as an mrouter port with the mrouter command in a profile attached to the port. Static configuration can help in situations when incompatibilities with non-Cisco equipment prevent dynamic discovery.

Multicast Traffic Handling for MLD

The following tables describe the traffic handling behavior by MLD mrouters and host ports.

Table 2. Multicast Traffic Handling for a MLDv1 Querier

Traffic Type

Received on MRouter Ports

Received on Host Ports

IP multicast source traffic

Forwards to all mrouter ports and to host ports that indicate interest.

Forwards to all mrouter ports and to host ports that indicate interest.

MLD general queries

Forwards to all ports.

 —

MLD group-specific queries

Forwards to all other mrouter ports.

Dropped

MLDv1 joins

Examines (snoops) the reports.

  • If report suppression is enabled, forwards first join for a new group or first join following a general query for an existing group.

  • If report suppression is disabled, forwards on all mrouter ports.

Examines (snoops) the reports.

  • If report suppression is enabled, forwards first join for a new group or first join following a general query for an existing group.

  • If report suppression is disabled, forwards on all mrouter ports.

MLDv2 reports

Ignores

Ignores

MLDv1 leaves

Invokes last member query processing.

Invokes last member query processing.

Table 3. Multicast Traffic Handling for a MLDv2 Querier

Traffic Type

Received on MRouter Ports

Received on Host Ports

IP multicast source traffic

Forwards to all mrouter ports and to host ports that indicate interest.

Forwards to all mrouter ports and to host ports that indicate interest.

MLD general queries

Forwards to all ports.

 —

MLD group-specific queries

If received on the querier port floods on all ports.

—

MLDv1 joins

Handles as MLDv2 IS_EX{} reports.

Handles as MLDv2 IS_EX{} reports.

MLDv2 reports

  • If proxy reporting is enabled—For state changes or source-list changes, generates a state change report on all mrouter ports.

  • If proxy reporting is disabled—Forwards on all mrouter ports.

  • If proxy reporting is enabled—For state changes or source-list changes, generates a state change report on all mrouter ports.

  • If proxy reporting is disabled—Forwards on all mrouter ports.

MLDv1 leaves

Handles as MLDv2 IS_IN{} reports.

Handles as MLDv2 IS_IN{} reports.

Multicast Listener Discovery over BVI

Multicast IPv6 packets received from core, which has BVI as forwarding interface, is forwarded to access over snooped L2 AC or interface.


Note

  • As per MLDv2 RFC recommendation the MLDv2 reports should carry the Hop-by-Hop options header for the reports to get punted up.

  • MLDv2 is supported over BVI only when BVI is configured as a forwarding interface.

MLD and BVI Overview

Routers use the Internet Group Management Protocol (IGMP) (IPv4) and Multicast Listener Discovery (MLD) (IPv6) to learn whether members of a group are present on their directly attached subnets. Hosts join multicast groups by sending IGMP or MLD report messages.

MLDv1 and MLDv2 are supported on NCS 5500. However, MLDv2 is enabled when you configure MLD by default.

MLDv2 shares feature parity with IGMPv3 with respect to all supported interface types with the exception of PPoE and subinterfaces. MLDv2 enables a node to report interest in listening to packets only from specific multicast source addresses.

A BVI interface is a routed interface representing a set of interfaces (bridged) in the same L2 broadcast domain. MLD join messages coming in or out of this broadcast domain passes through the BVI interface.

Configuration for Routers with Cisco NC57 Line Cards

Table 4. Feature History Table

Feature Name

Release Information

Feature Description

Multicast Listener Discovery over BVI

Release 7.5.1

This feature is now supported on routers that have the Cisco NC57 line cards installed and operate in native and compatible modes.

Routers use MLD to learn whether members of a group are present on their directly attached subnets over BVI interface.

For routers with Cisco NC57 line cards, before configuring MLD over BVI, enable IGMP profile under bridge domain similar to MLD profile configuration. 


router# configure
router(config)# interface BVI100
router(config-bvi)# igmp snooping profile profile-name

Multicast Traffic Over Layer 2 IPv6 Network

Table 5. Feature History Table

Feature Name

Release Information

Feature Description

Multicast Traffic over Layer 2 IPv6 Network

Release 7.9.1

This feature allows you to forward the IPv6 multicast packets only to the interested MLD-snooped Access Controllers (AC), whereas in the default case, the bridge floods the IPv6 multicast packets to all AC.

Routers use Multicast Listener Discovery (MLD) protocol to discover the devices in a network and create route entries in an IPv6 multicast network.

This feature introduces following CLI:

  • multicast-source ipv6

The Multicast Traffic over Layer 2 IPv6 Network (L2MC IPv6) is an optimized forwarding technique, and it helps in saving the bandwidth. By default, the bridge floods IPv6 multicast packets to all AC, whereas the L2MC IPv6 feature allows you to forward the IPv6 multicast packets only to the interested MLD-snooped AC.

When IPv6 multicast packets are received over Layer 2 AC and interfaces, the lookup gets done for Virtual Switch Interfaces (VSI), Groups (G), and Services (S) or for VSI and G. The VSI details show the VLAN or VXLAN segment to which the packet belongs, while the G and S identify the multicast groups and services to which the packet should be forwarded. Based on this lookup, the traffic is forwarded to the interested receivers connected to the Layer 2 AC.

The MLD control packets received over Layer 2 AC are snooped and punted to create the route entries. This route entries are needed to avail the following supports:

  • Layer 2 Multicast IPv6 support.

  • EVPN sync support for IPv4 routes.

Hardware Supported

This feature is supported on routers that have the Cisco NC57 line cards installed and operate in native and compatible modes.

Limitations and Restrictions

  • This feature doesn’t support MLD sync.

  • With L2MC IPv6 support, the existing L2MC IPv4 scale reduces proportionally.

Configuration Example

The L2MC IPv6 feature is not enabled by default. Following is a configuration example that shows how to enable the feature.
router(config)# l2vpn
 router(config-l2vpn)# bridge group 1
 router(config-l2vpn-bg)#bridge-domain 1
 router(config-l2vpn-bg-bd)#multicast-source ipv6
 router(config-l2vpn-bg-bd)#efp-visibility
 router(config-l2vpn-bg-bd)#mld snooping profile prof1
 router(config-l2vpn-bg-bd)#igmp snooping profile prof1
 router(config-l2vpn-bg-bd)#interface TenGigE0/0/0/0
 router(config-l2vpn-bg-bd-ac)#exit
 router(config-l2vpn-bg-bd)#interface TenGigE0/0/0/4.1
 router(config-l2vpn-bg-bd-ac)#exit
 router(config-l2vpn-bg-bd)#interface TenGigE0/0/0/4.2
 router(config-l2vpn-bg-bd-ac)#exit
 router(config-l2vpn-bg-bd)#routed interface BVI1
 router(config-l2vpn-bg-bd-bvi)#exit
 !
 !
 
 
 router(config-l2vpn-bg-bd)#mld snooping profile prof1
 router(config-l2vpn-bg-bd)#internal-querier
!
 router(config-l2vpn-bg-bd)#igmp snooping profile prof1
 router(config-l2vpn-bg-bd)#system-ip-address 1.2.3.4
 router(config-l2vpn-bg-bd)#internal-querier

Note

With BVI configurations, there is no need to have internal queries address configured MLD snooping profile. It implies that you can make BVI as querier under BVI configuration.

Verification

The following command shows the information about group membership in the Layer 2 Forwarding tables. 

router# show mld snooping group

Flags Key: S=Static, D=Dynamic, E=Explicit Tracking

                 Bridge Domain bg1:bd1

Group           Ver GM  Source           PM  Port                     Exp Flg                
Ff12:1:1::1     V2  Exc  -               -   GigabitEthernet0/1/1/0   122  DE
Ff12:1:1::1     V2  Exc  2002:1::1       Inc GigabitEthernet0/1/1/1     5  DE
Ff12:1:1::1     V2  Exc  2002:1::1       Inc GigabitEthernet0/1/1/2 never   S
Ff12:1:1::1     V2  Exc  2002:1::1       Exc GigabitEthernet0/1/1/3     -  DE
Ff12:1:1::1     V2  Exc  2002:1::2       Inc GigabitEthernet0/1/1/0   202  DE
Ff12:1:1::1     V2  Exc  2002:1::2       Exc GigabitEthernet0/1/1/1     -  DE
Ff12:1:1::2     V2  Exc  2002:1::1       Inc GigabitEthernet0/1/1/0   145  DE
Ff12:1:1::2     V2  Exc  2002:1::1       Inc GigabitEthernet0/1/1/1     0  DE
Ff12:1:1::2     V2  Exc  2002:1::1       Exc GigabitEthernet0/1/1/2    11  DE
	

                 Bridge Domain bg1:bd4

Group           Ver GM  Source           PM  Port                     Exp Flg                
Ff24:1:1::2     V1  Exc  -               -   GigabitEthernet0/1/1/0   122  DE
Ff28:1:1::1     V1  -    -               -   GigabitEthernet0/1/1/1    33  DE
Ff29:1:2::3     V1  Exc  -               -   GigabitEthernet0/1/2/0   122  DE
Ff22:1:2::3     V2  Exc  2000:1:1::2     Exc GigabitEthernet0/1/2/1     5  DE

The following command summarizes the number of bridge domains, mrouter ports, host ports, groups, and sources configured on the router. 

router#show mld snooping summary
  Bridge Domains:                                      1
  MLD  Snooping Bridge Domains:                        1
  Ports:                                               3
  MLD  Snooping Ports:                                 3
  Mrouters:                                            0
  STP Forwarding Ports:                                0
  ICCP Group Ports:                                    0
  MLD  Groups:                                         0
    Member Ports:                                      0
  MLD  Source Groups:                                  0
    Static/Include/Exclude:                        0/0/0
    Member Ports (Include/Exclude):                  0/0

IPv6 Multicast Listener Discovery Snooping over BVI

Multicast Listener Discovery (MLD) snooping provides a way to constrain multicast traffic at L2. By snooping the MLD membership reports sent by hosts in the bridge domain, the MLD snooping application can set up L2 multicast forwarding tables. This table is later used to deliver traffic only to ports with at least one interested member, significantly reducing the volume of multicast traffic.

MLDv2 support over BVI enables implementing IPv6 multicast routing over a L2 segment of the network that is using an IPv6 VLAN. The multicast routes are bridged via BVI interface from L3 segment to L2 segment of the network.

MLDv2 snooping over BVI enables forwarding MLDv2 membership reports received over the L2 domain to MLD snooping instead of MLD.

Restrictions

  • You cannot configure ttl-check and disable router-alert-check on the router for mld messages.

  • Static mrouters are not supported for MLD snooping.

  • Querier is supported for MLDV2, but it is not supported on MLDV1.

Configuring Internal Querier for MLD Snooping

This configuration enables a multicast router acting as a MLD querier to send out group-and-source-specific query:

router# config
RP0/0/RP0/CPU0:router(config)# mld snooping profile grp1
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# system-ip-address fe80::1 link-local
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# internal-querier
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# commit
Verification

Use the show mld snooping profile detail command to verify the MLD snooping configuration: 

router# show mld snooping profile detail
Thu Nov 22 13:58:18.844 UTC
MLD  Snoop Profile grp1: 
  System IP Address:                    fe80::1
  Bridge Domain References:             2
  Port References:                      12

MLD  Snoop Profile grp10: 
  System IP Address:                    fe80::5610
  Bridge Domain References:             0
  Port References:                      0

Creating a MLD Snooping Profile

Configuration

/* Enter the global configuration mode */
RP/0/RP0/CPU0:router # configure
/* Enters MLD snooping profile configuration mode and creates a named profile. */
RP/0/RP0/CPU0:router(config)# mld snooping profile default-bd-profile
RP/0/RP0/CPU0:router # commit

The default profile enables MLD snooping. You can commit the new profile without any additional configurations, or you can include additional configuration options to the profile. You can also return to the profile later to add configurations, as described in other tasks in this module.

If you are creating a bridge domain profile, consider the following:

  • An empty profile is appropriate for attaching to a bridge domain. An empty profile enables MLD snooping with default configuration values.

  • You can optionally add more commands to the profile to override default configuration values.

  • If you include port-specific configurations in a bridge domain profile, the configurations apply to all ports under the bridge, unless another profile is attached to a port.

If you are creating a port-specific profile, consider the following:

  • While an empty profile could be attached to a port, it would have no effect on the port configuration.

  • When you attach a profile to a port, MLD snooping reconfigures that port, overriding any inheritance of configuration values from the bridge-domain profile. You must repeat the commands in the port profile if you want to retain those configurations.

You can detach a profile, change it, and reattach it to add commands to a profile at a later time.

Running Configuration

RP/0/RP0/CPU0:router(config)# show running-config
configure
   mld snooping profile default-bd-profile
!

Verification

Verify that the MLD snooping profile is created:

RP/0/RP0/CPU0:router#show mld snooping profile

Profile                                   Bridge Domain       Port
-------                                   -------------       ----
default-bd-profile                                    0          0
grp1                                                  1          2
grp10                                                 1          2

Deactivating MLD Snooping on a Bridge Domain

To deactivate MLD snooping from a bridge domain, remove the profile from the bridge domain:


Note

A bridge domain can have only one profile attached to it at a time.

Configuration

/* Enter the global configuration mode followed by the bridge group and the bridge domain mode */
RP0/0/RP0/CPU0:router# configuration
RP0/0/RP0/CPU0:router(config)# l2vpn
RP0/0/RP0/CPU0:router(config-l2vpn)# bridge group GRP1
RP0/0/RP0/CPU0:router(config-l2vpn-bg)# bridge domain ISP1

/* Detache the MLD snooping profile from the bridge domain. This disables MLD snooping on that bridge domain */
/* Note: Only one profile can be attached to a bridge domain at a time. If a profile is attached, MLD snooping is enabled. 
If a profile is not attached, MLD snooping is disabled. */
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd)# no mld snooping profile 
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd)# commit

Running Configuration

RP0/0/RP0/CPU0:router# show running-config
configuration
l2vpn
 bridge-group GRP1
  bridge-domain ISP1 
   no mld snooping profile
!

Configuring Static Mrouter Ports (MLD)

Prerequisite

MLD snooping must be enabled on the bridge domain for port-specific profiles to affect MLD snooping behavior.


Note

Static mrouter port configuration is a port-level option and should be added to profiles intended for ports. It is not recommended to add mrouter port configuration to a profile intended for bridge domains.

Configuration

/* Enter the global configuration mode */
RP0/0/RP0/CPU0:router# configuration

/* Enter the MLD snooping profile configuration mode and create a new profile or accesses an existing profile.*/
RP0/0/RP0/CPU0:router(config)# mld snooping profile mrouter-port-profile
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# mrouter
/* Configures a static mrouter on a port. */

RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# commit

Running Configuration

RP0/0/RP0/CPU0:router# show running-config
configuration
  mld snooping profile mrouter-port-profile
    mrouter
!

Verification

The below show command output confirms that the mrouter configuration is enabled:
RP0/0/RP0/CPU0:router# show mld snooping profile mrouter-port-profile

MLD  Snoop Profile mrouter-port-profile:

  Static Mrouter:                       Enabled

  Bridge Domain References:             0
  Port References:                      0

Configuring Router Guard (MLD)

To prevent multicast routing protocol messages from being received on a port and, therefore, prevent a port from being a dynamic mrouter port, follow these steps. Note that both router guard and static mrouter commands may be configured on the same port.

Prerequisite

MLD snooping must be enabled on the bridge domain for port-specific profiles to affect MLD snooping behavior.


Note

Router guard configuration is a port-level option and should be added to profiles intended for ports. It is not recommended to add router guard configuration to a profile intended for bridge domains. To do so would prevent all mrouters, including MLD queriers, from being discovered in the bridge domain.

Configuration

/* Enter the global configuration mode and create the Bridge Group GRP1 and the Bridge Domain ISP1*/
RP0/0/RP0/CPU0:router# configuration

/* Enter the MLD snooping profile configuration mode and create a new profile or accesses an existing profile. */
RP0/0/RP0/CPU0:router(config)# mld snooping profile host-port-profile

/* Configure router guard. This protects the port from dynamic discovery.*/
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# router-guard
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd)# commit

Running Configuration

RP0/0/RP0/CPU0:router# show running-config
configuration
 mld snooping profile host-port-profile
  router-guard
 !

Verification

Verify that the router guard config in the named profile is enabled:

RP0/0/RP0/CPU0:router# show mld snooping profile host-port-profile detail
MLD  Snoop Profile host-port-profile:

  Router Guard:                         Enabled

  Bridge Domain References:             0
  Port References:                      0

Configuring Immediate-leave for MLD

To add the MLD snooping immediate-leave option to an MLD snooping profile:

Configuration

/* Enter the global configuration mode. */
RP0/0/RP0/CPU0:router# configuration

/* Enter MLD snooping profile configuration mode and create a new profile or accesses an existing profile. */
RP0/0/RP0/CPU0:router(config)# mld snooping profile host-port-profile
/* Enable the immediate-leave option */ 
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# immediate-leave
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd)# commit

If you add the immediate-leave option:

  • to a profile attached to a bridge domain, it applies to all ports under the bridge.

  • to a profile attached to a port, it applies to the port.

Running Configuration

RP0/0/RP0/CPU0:router# show running-config
configuration
 mld snooping profile host-port-profile
 immediate-leave
!

Verification

Verify that the immediate leave config in the named profile is enabled:

RP0/0/RP0/CPU0:router# show mld snooping profile host-port-profile detail

MLD  Snoop Profile host-port-profile:

  Immediate Leave:                      Enabled
  Router Guard:                         Enabled

  Bridge Domain References:             0
  Port References:                      0

Configuring Internal Querier for MLD

Prerequisite

MLD snooping must be enabled on the bridge domain for this procedure to take effect.

Configuration

/* Enter the global configuration mode. */
RP0/0/RP0/CPU0:router# configuration

/* Enter MLD snooping profile configuration mode and create a new profile or accesses an existing profile. */
RP0/0/RP0/CPU0:router(config)# mld snooping profile internal-querier-profile

/* Configure an IP address for internal querier use. The default system-ip-address value (0.0.0.0) is not valid for the internal querier. 
You must explicitly configure an IP address. Enter a valid link-local IPv6 address. */ 
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# system-ip-address fe80::98 link-local

/* Enable an internal querier with default values for all options.*/
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# internal-querier
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# commit

Running Configuration

RP0/0/RP0/CPU0:router# show running-config
configuration
 mld snooping profile internal-querier-profile
 system-ip-address fe80::98 link-local
 internal-querier
!

Note

Internal Querier is not recommended, when BVI and MLD snooping is configured under a bridge.

Verification

Verify that the internal querier config is enabled: 

RP0/0/RP0/CPU0:router# show mld snooping profile internal-querier-profile detail

MLD  Snoop Profile internal-querier-profile:

  System IP Address:                    fe80::98

  Internal Querier Support:             Enabled

  Bridge Domain References:             0
  Port References:                      0

Configuring Static Groups for MLD

To add one or more static groups or MLDv2 source groups to an MLD snooping profile, follow these steps:

Prerequisite

MLD snooping must be enabled on the bridge domain for port-specific profiles to affect MLD snooping behavior.

Configuration

/* Enter the global configuration mode. */
RP0/0/RP0/CPU0:router# configuration

/* Enter MLD snooping profile configuration mode and create a new profile or accesses an existing profile. */
RP0/0/RP0/CPU0:router(config)# mld snooping profile host-port-profile

/* Configure a static group. */ 
/* Note: Repeat this step to add additional static groups. */
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# static group 239.1.1.1 source 198.168.1.1
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# commit

If you add the static group option:

  • to a profile attached to a bridge domain, it applies to all ports under the bridge.

  • to a profile attached to a port, it applies to the port.

Running Configuration

RP0/0/RP0/CPU0:router# show running-config
configuration
 mld snooping profile host-port-profile
 static group 239.1.1.1 source 198.168.1.1
!

Verification

RP0/0/RP0/CPU0:router# show mld snooping bridge-domain f1:100 detail
 
Bridge Domain        Profile                          Act  Ver  #Ports  #Mrtrs  #Grps   #SGs
-------------        -------                          ---  ---  ------  ------  -----   ----
f1:100               grp1                               Y  v2       3       1   1000   1002

  Profile Configured Attributes:
    System IP Address:                   fe80::99
    Minimum Version:                     1
    Report Suppression:                  Enabled
    Unsolicited Report Interval:         1000 (milliseconds)
    TCN Query Solicit:                   Disabled
    TCN Membership Sync:                 Disabled
    TCN Flood:                           Enabled
    TCN Flood Query Count:               2
    Router Alert Check:                  Disabled
    TTL Check:                           Enabled
    nV Mcast Offload:                    Disabled
    Internal Querier Support:            Disabled
    Querier Query Interval:              125 (seconds)
    Querier LMQ Interval:                1000 (milliseconds)
    Querier LMQ Count:                   2
    Querier Robustness:                  2
    Startup Query Interval:              31 seconds
    Startup Query Count:                 2
    Startup Query Max Response Time:     10.0 seconds
    Mrouter Forwarding:                  Enabled
    P2MP Capability:                     Disabled
    Default IGMP Snooping profile:       Disabled
    IP Address:                          fe80::f278:16ff:fe63:4d81
    Port:                                BVI1000
    Version:                             v2
    Query Interval:                      125 seconds
    Robustness:                          2
    Max Resp Time:                       10.0 seconds
    Time since last G-Query:             97 seconds
  Mrouter Ports:                         1
    Dynamic:                             BVI1000
  STP Forwarding Ports:                  0
  ICCP Group Ports:                      0
  Groups:                                1000
    Member Ports:                        0
  V2 Source Groups:                      1002
    Static/Include/Exclude:              0/1002/0
    Member Ports (Include/Exclude):      1002/0

Configuring MLD Snooping

Configure 

RP0/0/RP0/CPU0:router# configure
/* Create two profiles. */
RP0/0/RP0/CPU0:router(config)# mld snooping profile bridge_profile
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# mld snooping profile port_profile
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# mrouter
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# exit
RP0/0/RP0/CPU0:router(config)#

/* Configure two physical interfaces for L2 support.*/
RP0/0/RP0/CPU0:router(config)# interface GigabitEthernet0/8/0/38
RP0/0/RP0/CPU0:router(config-if)# negotiation auto
RP0/0/RP0/CPU0:router(config-if)# l2transport
RP0/0/RP0/CPU0:router(config-if)# no shut
RP0/0/RP0/CPU0:router(config-if)# exit
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# interface GigabitEthernet0/8/0/39
RP0/0/RP0/CPU0:router(config-if)# negotiation auto
RP0/0/RP0/CPU0:router(config-if)# l2transport
RP0/0/RP0/CPU0:router(config-if)# no shut
RP0/0/RP0/CPU0:router(config-if)# exit

/* Add interfaces to the bridge domain. Attach bridge_profile to the bridge domain and port_profile to one of the Ethernet interfaces. 
The second Ethernet interface inherits MLD snooping configuration attributes from the bridge domain profile.*/
RP0/0/RP0/CPU0:router(config)# l2vpn
RP0/0/RP0/CPU0:router(config-l2vpn)# bridge group bg1
RP0/0/RP0/CPU0:router(config-l2vpn-bg)# bridge-domain bd1
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd)# mld snooping profile bridge_profile
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd-mld-snooping)# interface GigabitEthernet0/8/0/38
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd-mld-snooping-if)# mld snooping profile port_profile
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd-mld-snooping-if)# interface GigabitEthernet0/8/0/39
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd-mld-snooping-if)# exit
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd-mld-snooping)# exit
RP0/0/RP0/CPU0:router(config-l2vpn-bg-bd)# commit

Running Configuration

RP0/0/RP0/CPU0:router# show running-config
configuration
 mld snooping profile bridge_profile
!
mld snooping profile port_profile
   mrouter
!

interface GigabitEthernet0/8/0/38
   negotiation auto
   l2transport
   no shut
   !
!
interface GigabitEthernet0/8/0/39
   negotiation auto
   l2transport
   no shut
   !
!

l2vpn
  bridge group bg1
     bridge-domain bd1
     mld snooping profile bridge_profile
     interface GigabitEthernet0/8/0/38
       mld snooping profile port_profile
     interface GigabitEthernet0/8/0/39
     !
  !
!

Verification

Verify the configured bridge ports.

RP0/0/RP0/CPU0:router# show mld snooping port


                        Bridge Domain f10:109

                                                        State
Port                                               Oper  STP  Red   #Grps   #SGs
----                                               ----  ---  ---   -----   ----
BVI1009                                              Up    -    -       0      0
GigabitEthernet0/8/0/38                              Up    -    -    1000   1000
GigabitEthernet0/8/0/39                              Up    -    -    1000   1000

Configuring MLD Snooping on Ethernet Bundles

This example assumes that the front-ends of the bundles are preconfigured. For example, a bundle configuration might consist of three switch interfaces, as follows:

Configure

/*  Configure the front-ends of the bundles consisting of three switch interfaces.*/
RP0/0/RP0/CPU0:router# configure
RP0/0/RP0/CPU0:router(config)# interface bundle-ether 1
RP0/0/RP0/CPU0:router(config-if)# exit
RP0/0/RP0/CPU0:router(config)# interface GigabitEthernet0/0/0/0
RP0/0/RP0/CPU0:router(config-if)# exit
RP0/0/RP0/CPU0:router(config)# interface GigabitEthernet0/0/0/1
RP0/0/RP0/CPU0:router(config-if)# exit
RP0/0/RP0/CPU0:router(config)# interface GigabitEthernet0/0/0/2
RP0/0/RP0/CPU0:router(config-if)# channel-group 1 mode on
RP0/0/RP0/CPU0:router(config-if)# exit
RP0/0/RP0/CPU0:router(config)# interface GigabitEthernet0/0/0/3
RP0/0/RP0/CPU0:router(config-if)# channel-group 1 mode on
RP0/0/RP0/CPU0:router(config-if)# exit

/* Configure two MLD snooping profiles. */
RP0/0/RP0/CPU0:router(config)# mld snooping profile bridge_profile
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# exit     !
RP0/0/RP0/CPU0:router(config)# mld snooping profile port_profile
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# mrouter
RP0/0/RP0/CPU0:router(config-mld-snooping-profile)# exit

/* Configure interfaces as bundle member links. */ 

RP0/0/RP0/CPU0:router(config)# interface GigabitEthernet0/0/0/0
RP0/0/RP0/CPU0:router(config-if)# bundle id 1 mode on
RP0/0/RP0/CPU0:router(config-if)# negotiation auto
RP0/0/RP0/CPU0:router(config-if)# exit
RP0/0/RP0/CPU0:router(config)# interface GigabitEthernet0/0/0/1
RP0/0/RP0/CPU0:router(config-if)# bundle id 1 mode on
RP0/0/RP0/CPU0:router(config-if)# negotiation auto
RP0/0/RP0/CPU0:router(config-if)# exit
RP0/0/RP0/CPU0:router(config)# interface GigabitEthernet0/0/0/2
RP0/0/RP0/CPU0:router(config-if)# bundle id 2 mode on
RP0/0/RP0/CPU0:router(config-if)# negotiation auto
RP0/0/RP0/CPU0:router(config-if)# exit
RP0/0/RP0/CPU0:router(config)# interface GigabitEthernet0/0/0/3
RP0/0/RP0/CPU0:router(config-if)# bundle id 2 mode on
RP0/0/RP0/CPU0:router(config-if)# negotiation auto
RP0/0/RP0/CPU0:router(config-if)# exit

/* Configure the bundle interfaces for L2 transport. */
RP0/0/RP0/CPU0:router(config)# interface Bundle-Ether 1
RP0/0/RP0/CPU0:router(config-if)# l2transpor
RP0/0/RP0/CPU0:router(config-if)# exit
RP0/0/RP0/CPU0:router(config)# interface Bundle-Ether 2
RP0/0/RP0/CPU0:router(config-if)# l2transpor
RP0/0/RP0/CPU0:router(config-if)# exit

/* Add the interfaces to the bridge domain and attach MLD snooping profiles. */
RP0/0/RP0/CPU0:router(config)# l2vpn
RP0/0/RP0/CPU0:router(config-l2vpn)# bridge group bg1
RP0/0/RP0/CPU0:router(config-l2vpn-bg)# mld snooping profile bridge_profile
RP0/0/RP0/CPU0:router(config-l2vpn-bg-mld-snooping-profile)# interface bundle-Ether 1
RP0/0/RP0/CPU0:router(config-l2vpn-bg-mld-snooping-profile-if)# mld snooping profile port_profile
RP0/0/RP0/CPU0:router(config-l2vpn-bg-mld-snooping-profile-if)# interface bundle-Ether 2
RP0/0/RP0/CPU0:router(config-l2vpn-bg-mld-snooping-profile-if)# commit

Running Configuration

RP0/0/RP0/CPU0:router# show running-config
configuration
 interface Port-channel1
    !
interface GigabitEthernet0/0/0/0
    !
interface GigabitEthernet0/0/0/1
!
    interface GigabitEthernet0/0/0/2
       channel-group 1 mode on
    !
    interface GigabitEthernet0/0/0/3
       channel-group 1 mode on
    !
mld snooping profile bridge_profile
       !
       mld snooping profile port_profile
          mrouter
       !
interface GigabitEthernet0/0/0/0
         bundle id 1 mode on
         negotiation auto
       !
       interface GigabitEthernet0/0/0/1  
         bundle id 1 mode on
         negotiation auto
       !
       interface GigabitEthernet0/0/0/2
         bundle id 2 mode on
         negotiation auto
       !
       interface GigabitEthernet0/0/0/3
         bundle id 2 mode on
         negotiation auto
       !
interface Bundle-Ether 1
          l2transport
          !
       !
       interface Bundle-Ether 2
          l2transport
          !
       !

l2vpn
         bridge group bg1
            bridge-domain bd1
            mld snooping profile bridge_profile
            interface bundle-Ether 1
              mld snooping profile port_profile
            interface bundle-Ether 2
            !
         !
      !

Verification

RP0/0/RP0/CPU0:router# show mld snooping port
Bridge Domain BG1:BD1
State
Port Oper STP Red #Grps #SGs
---- ---- --- --- ----- ----
HundredGigE0/0/0/3 Up - - 1 1
HundredGigE0/0/0/7 Up - - 1 1
HundredGigE0/19/0/11 Up - - 1 1
HundredGigE0/19/0/5 Up - - 1 1
RP/0/RP1/CPU0:Router#