06-IP Multicast Configuration Guide

HomeSupportResource CenterH3C S6850 & S9850 Switch Series Configuration Guides-Release 655x-6W10006-IP Multicast Configuration Guide
04-Multicast VLAN configuration
Title Size Download
04-Multicast VLAN configuration 155.42 KB

Configuring multicast VLANs

Multicast VLAN feature

As shown in Figure 1, Host A, Host B, and Host C are in three different VLANs and the same multicast group. When Switch A (Layer 3 device) receives multicast data for that group, it sends three copies of the multicast data to Switch B (Layer 2 device). This occupies a large amount of bandwidth and increases the burden on the Layer 3 device.

Figure 1 Multicast transmission without the multicast VLAN feature

 

After a multicast VLAN is configured on Switch B, Switch A sends only one copy of the multicast data to the multicast VLAN on Switch B. This method saves network bandwidth and lessens the burden on the Layer 3 device.

Multicast VLAN implementations

Multicast VLANs include sub-VLAN-based multicast VLANs and port-based multicast VLANs.

Sub-VLAN-based multicast VLAN

As shown in Figure 2:

·          Host A, Host B, and Host C are in VLAN 2 through VLAN 4, respectively.

·          On Switch B, VLAN 10 is a multicast VLAN. VLAN 2 through VLAN 4 are sub-VLANs of VLAN 10.

·          IGMP snooping is enabled for the multicast VLAN and its sub-VLANs.

Figure 2 Sub-VLAN-based multicast VLAN

 

IGMP snooping manages router ports in the multicast VLAN and member ports in each sub-VLAN. When Switch A receives multicast data from the multicast source, it sends only one copy of the multicast data to the multicast VLAN on Switch B. Then, Switch B sends a separate copy to each sub-VLAN in the multicast VLAN.

Port-based multicast VLAN

As shown in Figure 3:

·          Host A, Host B, and Host C are in VLAN 2 through VLAN 4, respectively.

·          On Switch B, VLAN 10 is a multicast VLAN. All the user ports are hybrid ports and are assigned to VLAN 10.

·          IGMP snooping is enabled for the multicast VLAN and VLAN 2 through VLAN 4.

Figure 3 Port-based multicast VLAN

 

IGMP snooping manages the router ports and member ports in the multicast VLAN. When Switch A receives multicast data from the multicast source, it sends only one copy of the multicast data to the multicast VLAN on Switch B. Switch B sends a separate copy to each user port in the multicast VLAN.

Restrictions and guidelines: Multicast VLAN configuration

The VLAN to be configured as a multicast VLAN must exist.

If you have configured both a sub-VLAN-based multicast VLAN and a port-based multicast VLAN on a device, the port-based multicast VLAN configuration takes effect.

Do not configure a multicast VLAN on a device that is enabled with IP multicast routing. Otherwise, the system displays errors. Do not enable IP multicast routing on a device that is configured with multicast VLANs. Otherwise, multicast forwarding exceptions occur.

Do not configure a VLAN as a multicast VLAN or a multicast sub-VLAN if the VLAN interface is enabled with PIM or IGMP. Otherwise, the system displays errors. Do not enable PIM or IGMP on a VLAN interface if the VLAN interface belongs to a multicast VLAN or a multicast sub-VLAN. Otherwise, multicast forwarding exceptions occur.

The multicast VLAN feature does not take effect on secondary VLANs. As a best practice, do not configure the multicast VLAN feature for secondary VLANs. For more information about secondary VLANs, see Layer 2LAN Switching Configuration Guide.

Configuring a sub-VLAN-based multicast VLAN

Restrictions and guidelines

The VLANs to be configured as sub-VLANs of a multicast VLAN must exist and cannot be multicast VLANs or sub-VLANs of any other multicast VLAN.

Prerequisites

Before you configure a sub-VLAN-based multicast VLAN, you must complete the following tasks:

·          Create VLANs as required.

·          Enable IGMP snooping for the VLAN to be configured as the multicast VLAN and for the VLANs to be configured as sub-VLANs.

Procedure

1.        Enter system view.

system-view

2.        Configure a VLAN as a multicast VLAN and enter multicast VLAN view.

multicast-vlan vlan-id

By default, a VLAN is not a multicast VLAN.

3.        Assign VLANs to the multicast VLAN as sub-VLANs.

subvlan vlan-list

Configuring a port-based multicast VLAN

Restrictions and guidelines

You can assign user ports to a multicast VLAN in multicast VLAN view or assign a user port to a multicast VLAN in interface view. These configurations have the same priority.

A user port can belong to only one multicast VLAN.

Prerequisites

Before you configure a port-based multicast VLAN, you must complete the following tasks:

·          Create VLANs as required.

·          Enable IGMP snooping for the VLAN to be configured as the multicast VLAN.

·          Enable IGMP snooping for all the VLANs that contain multicast receivers.

·          Configure the attributes of user ports. Make sure the ports can forward packets from the VLAN to be configured as the multicast VLAN and send the packets with the VLAN tag removed. For more information about configuring port attributes, see VLAN configuration in Layer 2—LAN Switching Configuration Guide.

Assigning user ports to a multicast VLAN in multicast VLAN view

1.        Enter system view.

system-view

2.        Configure a VLAN as a multicast VLAN and enter multicast VLAN view.

multicast-vlan vlan-id

By default, a VLAN is not a multicast VLAN.

3.        Assign ports to the multicast VLAN.

port interface-list

Assigning user ports to a multicast VLAN in interface view

1.        Enter system view.

system-view

2.        Configure a VLAN as a multicast VLAN and enter multicast VLAN view.

multicast-vlan vlan-id

By default, a VLAN is not a multicast VLAN.

3.        Return to system view.

quit

4.        Enter Layer 2 interface view.

¡  Enter Layer 2 Ethernet interface view.

interface interface-type interface-number

¡  Enter Layer 2 aggregate interface view.

interface bridge-aggregation interface-number

5.        Assign the port to the multicast VLAN.

port multicast-vlan vlan-id

By default, a port does not belong to any multicast VLAN.

Setting the maximum number of multicast VLAN forwarding entries

About setting the maximum number of multicast VLAN forwarding entries

You can set the maximum number of multicast VLAN forwarding entries on the device. When the upper limit is reached, the device does not create multicast VLAN forwarding entries until some entries age out or are manually removed.

Procedure

1.        Enter system view.

system-view

2.        Set the maximum number of multicast VLAN forwarding entries.

multicast-vlan entry-limit limit

By default, the maximum number of multicast VLAN forwarding entries is 4000.

Display and maintenance commands for multicast VLAN

Execute display commands in any view and reset commands in user view.

 

Task

Command

Display information about multicast VLANs.

display multicast-vlan [ vlan-id ]

Display information about multicast VLAN forwarding entries.

display multicast-vlan forwarding-table [ group-address [ mask { mask-length | mask } ] | source-address [ mask { mask-length | mask } ] | slot slot-number | subvlan vlan-id | vlan vlan-id ] *

Display information about multicast groups in multicast VLANs.

display multicast-vlan group [ source-address | group-address | slot slot-number | verbose | vlan vlan-id ] *

Clear multicast groups in multicast VLANs.

reset multicast-vlan group [ source-address [ mask { mask-length | mask } ] | group-address [ mask { mask-length | mask } ] | vlan vlan-id ] *

 

Multicast VLAN configuration examples

Example: Configuring sub-VLAN-based multicast VLAN

Network configuration

As shown in Figure 4:

·          Layer 3 device Switch A runs IGMPv2 and acts as the IGMP querier. Layer 2 device Switch B runs IGMPv2 snooping.

·          The multicast source sends multicast data to multicast group 224.1.1.1. Receivers Host A, Host B, and Host C belong to VLAN 2, VLAN 3, and VLAN 4, respectively.

Configure a sub-VLAN-based multicast VLAN on Switch B to meet the following requirements:

·          Switch A sends the multicast data to Switch B through the multicast VLAN.

·          Switch B forwards the multicast data to the receivers in different user VLANs.

Figure 4 Network diagram

Procedure

1.        Configure Switch A:

# Enable IP multicast routing.

<SwitchA> system-view

[SwitchA] multicast routing

[SwitchA-mrib] quit

# Create VLAN 20, and assign Twenty-FiveGigE 1/0/2 to the VLAN.

[SwitchA] vlan 20

[SwitchA-vlan20] port twenty-fivegige 1/0/2

[SwitchA-vlan20] quit

# Assign an IP address to VLAN-interface 20, and enable PIM-DM on the interface.

[SwitchA] interface vlan-interface 20

[SwitchA-Vlan-interface20] ip address 1.1.1.2 24

[SwitchA-Vlan-interface20] pim dm

[SwitchA-Vlan-interface20] quit

# Create VLAN 10.

[SwitchA] vlan 10

[SwitchA-vlan10] quit

# Configure Twenty-FiveGigE 1/0/1 as a hybrid port, and assign the port to VLAN 10 as a tagged VLAN member.

[SwitchA] interface twenty-fivegige 1/0/1

[SwitchA-Twenty-FiveGigE1/0/1] port link-type hybrid

[SwitchA-Twenty-FiveGigE1/0/1] port hybrid vlan 10 tagged

[SwitchA-Twenty-FiveGigE1/0/1] quit

# Assign an IP address to VLAN-interface 10, and enable IGMP on the interface.

[SwitchA] interface vlan-interface 10

[SwitchA-Vlan-interface10] ip address 10.110.1.1 24

[SwitchA-Vlan-interface10] igmp enable

[SwitchA-Vlan-interface10] quit

2.        Configure Switch B:

# Enable the IGMP snooping feature.

<SwitchB> system-view

[SwitchB] igmp-snooping

[SwitchB-igmp-snooping] quit

# Create VLAN 2, assign Twenty-FiveGigE 1/0/2 to the VLAN, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 2

[SwitchB-vlan2] port twenty-fivegige 1/0/2

[SwitchB-vlan2] igmp-snooping enable

[SwitchB-vlan2] quit

# Create VLAN 3, assign Twenty-FiveGigE 1/0/3 to the VLAN, and enable IGMP snooping in the VLAN.

[SwitchB] vlan 3

[SwitchB-vlan3] port twenty-fivegige 1/0/3

[SwitchB-vlan3] igmp-snooping enable

[SwitchB-vlan3] quit

# Create VLAN 4, assign Twenty-FiveGigE 1/0/4 to the VLAN, and enable IGMP snooping in the VLAN.

[SwitchB] vlan 4

[SwitchB-vlan4] port twenty-fivegige 1/0/4

[SwitchB-vlan4] igmp-snooping enable

[SwitchB-vlan4] quit

# Create VLAN 10, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 10

[SwitchB-vlan10] igmp-snooping enable

[SwitchB-vlan10] quit

# Configure Twenty-FiveGigE 1/0/1 as a hybrid port, and assign the port to VLAN 10 as a tagged VLAN member.

[SwitchB] interface twenty-fivegige 1/0/1

[SwitchB-Twenty-FiveGigE1/0/1] port link-type hybrid

[SwitchB-Twenty-FiveGigE1/0/1] port hybrid vlan 10 tagged

[SwitchB-Twenty-FiveGigE1/0/1] quit

# Configure VLAN 10 as a multicast VLAN, and assign VLAN 2 through VLAN 4 as sub-VLANs to multicast VLAN 10.

[SwitchB] multicast-vlan 10

[SwitchB-mvlan-10] subvlan 2 to 4

[SwitchB-mvlan-10] quit

Verifying the configuration

# Display information about all multicast VLANs on Switch B.

[SwitchB] display multicast-vlan

Total 1 multicast VLANs.

 

Multicast VLAN 10:

  Sub-VLAN list(3 in total):

     2-4

  Port list(0 in total):

# Display information about multicast groups in multicast VLANs on Switch B.

[SwitchB] display multicast-vlan group

Total 1 entries.

 

Multicast VLAN 10: Total 1 entries.

  (0.0.0.0, 224.1.1.1)

    Sub-VLANs (3 in total):

      VLAN 2

      VLAN 3

      VLAN 4

The output shows that multicast group 224.1.1.1 belongs to multicast VLAN 10. Multicast VLAN 10 contains sub-VLANs VLAN 2 through VLAN 4. Switch B will replicate the multicast data of VLAN 10 to VLAN 2 through VLAN 4.

Example: Configuring port-based multicast VLAN

Network configuration

As shown in Figure 5:

·          Layer 3 device Switch A runs IGMPv2 and acts as the IGMP querier. Layer 2 device Switch B runs IGMPv2 snooping.

·          The multicast source sends multicast data to multicast group 224.1.1.1. Receivers Host A, Host B, and Host C belong to VLAN 2, VLAN 3, and VLAN 4, respectively.

Configure a port-based multicast VLAN on Switch B to meet the following requirements:

·          Switch A sends multicast data to Switch B through the multicast VLAN.

·          Switch B forwards the multicast data to the receivers in different user VLANs.

Figure 5 Network diagram

Procedure

1.        Configure Switch A:

# Enable IP multicast routing.

<SwitchA> system-view

[SwitchA] multicast routing

[SwitchA-mrib] quit

# Create VLAN 20, and assign Twenty-FiveGigE 1/0/2 to the VLAN.

[SwitchA] vlan 20

[SwitchA-vlan20] port twenty-fivegige 1/0/2

[SwitchA-vlan20] quit

# Assign an IP address to VLAN-interface 20, and enable PIM-DM on the interface.

[SwitchA] interface vlan-interface 20

[SwitchA-Vlan-interface20] ip address 1.1.1.2 24

[SwitchA-Vlan-interface20] pim dm

[SwitchA-Vlan-interface20] quit

# Create VLAN 10, and assign Twenty-FiveGigE 1/0/1 to the VLAN.

[SwitchA] vlan 10

[SwitchA-vlan10] port twenty-fivegige 1/0/1

[SwitchA-vlan10] quit

# Assign an IP address to VLAN-interface 10, and enable IGMP on the interface.

[SwitchA] interface vlan-interface 10

[SwitchA-Vlan-interface10] ip address 10.110.1.1 24

[SwitchA-Vlan-interface10] igmp enable

[SwitchA-Vlan-interface10] quit

2.        Configure Switch B:

# Enable the IGMP snooping feature.

<SwitchB> system-view

[SwitchB] igmp-snooping

[SwitchB-igmp-snooping] quit

# Create VLAN 10, assign Twenty-FiveGigE 1/0/1 to the VLAN, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 10

[SwitchB-vlan10] port twenty-fivegige 1/0/1

[SwitchB-vlan10] igmp-snooping enable

[SwitchB-vlan10] quit

# Create VLAN 2, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 2

[SwitchB-vlan2] igmp-snooping enable

[SwitchB-vlan2] quit

# Create VLAN 3, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 3

[SwitchB-vlan3] igmp-snooping enable

[SwitchB-vlan3] quit

# Create VLAN 4, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 4

[SwitchB-vlan4] igmp-snooping enable

[SwitchB-vlan4] quit

# Configure Twenty-FiveGigE 1/0/2 as a hybrid port, and configure VLAN 2 as the PVID of the hybrid port.

[SwitchB] interface twenty-fivegige 1/0/2

[SwitchB-Twenty-FiveGigE1/0/2] port link-type hybrid

[SwitchB-Twenty-FiveGigE1/0/2] port hybrid pvid vlan 2

# Assign Twenty-FiveGigE 1/0/2 to VLAN 2 and VLAN 10 as an untagged VLAN member.

[SwitchB-Twenty-FiveGigE1/0/2] port hybrid vlan 2 untagged

[SwitchB-Twenty-FiveGigE1/0/2] port hybrid vlan 10 untagged

[SwitchB-Twenty-FiveGigE1/0/2] quit

# Configure Twenty-FiveGigE 1/0/3 as a hybrid port, and configure VLAN 3 as the PVID of the hybrid port.

[SwitchB] interface twenty-fivegige 1/0/3

[SwitchB-Twenty-FiveGigE1/0/3] port link-type hybrid

[SwitchB-Twenty-FiveGigE1/0/3] port hybrid pvid vlan 3

# Assign Twenty-FiveGigE 1/0/3 to VLAN 3 and VLAN 10 as an untagged VLAN member.

[SwitchB-Twenty-FiveGigE1/0/3] port hybrid vlan 3 untagged

[SwitchB-Twenty-FiveGigE1/0/3] port hybrid vlan 10 untagged

[SwitchB-Twenty-FiveGigE1/0/3] quit

# Configure Twenty-FiveGigE 1/0/4 as a hybrid port, and configure VLAN 4 as the PVID of the hybrid port.

[SwitchB] interface twenty-fivegige 1/0/4

[SwitchB-Twenty-FiveGigE1/0/4] port link-type hybrid

[SwitchB-Twenty-FiveGigE1/0/4] port hybrid pvid vlan 4

# Assign Twenty-FiveGigE 1/0/4 to VLAN 4 and VLAN 10 as an untagged VLAN member.

[SwitchB-Twenty-FiveGigE1/0/4] port hybrid vlan 4 untagged

[SwitchB-Twenty-FiveGigE1/0/4] port hybrid vlan 10 untagged

[SwitchB-Twenty-FiveGigE1/0/4] quit

# Configure VLAN 10 as a multicast VLAN.

[SwitchB] multicast-vlan 10

# Assign Twenty-FiveGigE 1/0/2 and Twenty-FiveGigE 1/0/3 to VLAN 10.

[SwitchB-mvlan-10] port twenty-fivegige 1/0/2 to twenty-fivegige 1/0/3

[SwitchB-mvlan-10] quit

# Assign Twenty-FiveGigE 1/0/4 to VLAN 10.

[SwitchB] interface twenty-fivegige 1/0/4

[SwitchB-Twenty-FiveGigE1/0/4] port multicast-vlan 10

[SwitchB-Twenty-FiveGigE1/0/4] quit

Verifying the configuration

# Display information about multicast VLANs on Switch B.

[SwitchB] display multicast-vlan

Total 1 multicast VLANs.

 

Multicast VLAN 10:

  Sub-VLAN list(0 in total):

  Port list(3 in total):

    WGE1/0/2

    WGE1/0/3

    WGE1/0/4

# Display dynamic IGMP snooping forwarding entries on Switch B.

[SwitchB] display igmp-snooping group

Total 1 entries.

 

VLAN 10: Total 1 entries.

  (0.0.0.0, 224.1.1.1)

    Host slots (0 in total):

    Host ports (3 in total):

      WGE1/0/2        (00:03:23)

      WGE1/0/3        (00:04:07)

      WGE1/0/4        (00:04:16)

The output shows that IGMP snooping maintains the user ports in the multicast VLAN (VLAN 10). Switch B will forward the multicast data of VLAN 10 through these user ports.