Configuring IPv6 multicast VLANs 1

IPv6 multicast VLAN overview·· 1

Multicast VLAN configuration task list 2

Configuring a sub-VLAN-based IPv6 multicast VLAN·· 2

Configuration prerequisites 2

Configuring sub-VLAN-based IPv6 multicast VLAN·· 2

Setting the maximum number of forwarding entries for IPv6 multicast VLANs 3

Displaying and maintaining IPv6 multicast VLAN·· 3

IPv6 multicast VLAN configuration examples 4

 

IPv6 multicast VLAN overview

As shown in Figure 1, in the traditional IPv6 multicast programs-on-demand mode, when hosts, Host A, Host B and Host C, that belong to different VLANs, require the same IPv6 multicast programs on demand service simultaneously, the Layer 3 device, Router A, needs to forward a separate copy of the multicast traffic in each user VLAN to the Layer 2 device, Device A. This results in not only waste of network bandwidth but also extra burden on the Layer 3 device.

Figure 1 IPv6 multicast transmission without IPv6 multicast VLAN

 

The IPv6 multicast VLAN feature is the solution to this issue. With the IPv6 multicast VLAN feature, the Layer 3 device needs to replicate the IPv6 multicast traffic only in the IPv6 multicast VLAN instead of making a separate copy of the IPv6 multicast traffic in each user VLAN. This saves the network bandwidth and lessens the burden of the Layer 3 device.

The device supports the sub-VLAN-based IPv6 multicast VLAN feature.

As shown in Figure 2, Host A, Host B and Host C are in three different user VLANs. On Device A, configure VLAN 10 as an IPv6 multicast VLAN, configure all user VLANs as sub-VLANs of this IPv6 multicast VLAN, and enable MLD snooping in the IPv6 multicast VLAN.  

Figure 2 Sub-VLAN-based IPv6 multicast VLAN

 

After the configuration, MLD snooping manages router ports in the IPv6 multicast VLAN and member ports in the sub-VLANs. When forwarding IPv6 multicast data to Device A, Router A needs to send only one copy of IPv6 multicast traffic to Device A in the IPv6 multicast VLAN, and Device A distributes the traffic to the IPv6 multicast VLAN’s sub-VLANs that contain receivers.

Multicast VLAN configuration task list

Complete the following tasks to configure an IPv6 multicast VLAN:

 

Task	Remarks
Configuring a sub-VLAN-based IPv6 multicast VLAN	Required
Setting the maximum number of forwarding entries for IPv6 multicast VLANs	Optional

 

Configuring a sub-VLAN-based IPv6 multicast VLAN

Configuration prerequisites

Before configuring sub-VLAN-based IPv6 multicast VLAN, complete the following tasks:

·           Create VLANs as required.

·           Enable MLD snooping in the VLAN to be configured as an IPv6 multicast VLAN.

Configuring sub-VLAN-based IPv6 multicast VLAN

You need to configure a VLAN as an IPv6 multicast VLAN, and configure user VLANs as sub-VLANs of the IPv6 multicast VLAN.

To configure sub-VLAN-based IPv6 multicast VLAN:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Configure the specified VLAN as an IPv6 multicast VLAN and enter IPv6 multicast VLAN view.	multicast-vlan ipv6 vlan-id	By default, no IPv6 multicast VLAN  is configured.
3.     Configure the specified VLANs as sub-VLANs of the IPv6 multicast VLAN.	subvlan vlan-list	By default, an IPv6 multicast VLAN has no sub-VLANs.

 

NOTE: ·       You cannot configure IPv6 multicast VLAN on a device with IPv6 multicast routing enabled. ·       The VLAN to be configured as an IPv6 multicast VLAN must exist. ·       The VLANs to be configured as the sub-VLANs of the IPv6 multicast VLAN must exist and must not be sub-VLANs of another IPv6 multicast VLAN.

 

Setting the maximum number of forwarding entries for IPv6 multicast VLANs

You can set the maximum number of entries in the MLD snooping forwarding table for IPv6 multicast VLANs. When the number of forwarding entries maintained for the IPv6 multicast VLANs reaches the threshold, the device creates no more forwarding entries until some entries time out or get manually removed.

To set the maximum number of entries in the forwarding table:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Set the maximum number of forwarding entries for IPv6 multicast VLANs.	multicast-vlan ipv6 entry-limit limit	1024 by default

 

NOTE: If the number of existing entries in the MLD snooping forwarding table for the IPv6 multicast VLANs is larger than the limit when you configure it, the system informs you to remove excessive entries. In this case, the system does not automatically remove any existing entries or create new entries.

 

Displaying and maintaining IPv6 multicast VLAN

 

Task	Command	Remarks
Display information about an IPv6 multicast VLAN.	display multicast-vlan ipv6 [ vlan-id ] [ | { begin | exclude | include } regular-expression ]	Available in any view

 

IPv6 multicast VLAN configuration examples

Network requirements

As shown in Figure 3, MLDv1 runs on Router A, and MLD snooping runs on Device A, with Router A acting as the MLD querier.  

The IPv6 multicast source sends IPv6 multicast data to the IPv6 multicast group FF1E::101. Host A, Host B, Host C, and Host D are receivers of the IPv6 multicast group, and they belong to VLAN 2 through VLAN 5 respectively.

Configure the sub-VLAN-based IPv6 multicast VLAN feature on Device A so that Router A just sends IPv6 multicast data to Device A through the IPv6 multicast VLAN and Device A forwards the traffic to the receivers that belong to different user VLANs.

Figure 3 Network diagram

 

Configuration procedure

1.      Enable IPv6 forwarding and configure IPv6 addresses:

Enable IPv6 forwarding on each device and configure an IPv6 address and address prefix for each interface as per Figure 3. (Details not shown)

2.      Configure Router A:

# Enable IPv6 multicast routing, enable IPv6 PIM-DM on each interface, and run MLDv1 on the host-side interface GigabitEthernet 3/1/2.

<RouterA> system-view

[RouterA] multicast ipv6 routing-enable

[RouterA] interface GigabitEthernet 3/1/1

[RouterA-GigabitEthernet3/1/1] pim ipv6 dm

[RouterA-GigabitEthernet3/1/1] quit

[RouterA] interface GigabitEthernet 3/1/2

[RouterA-GigabitEthernet3/1/2] pim ipv6 dm

[RouterA-GigabitEthernet3/1/2] mld enable

3.      Configure Device A:

# Enable MLDv1 snooping globally.

<DeviceA> system-view

[DeviceA] mld-snooping

[DeviceA-mld-snooping] quit

# Create VLAN 2 through VLAN 5 and add GigabitEthernet 3/1/2 into VLAN 11.

[DeviceA] vlan 2

[DeviceA] vlan 2 to 5

# Configure GigabitEthernet 3/1/2 as a trunk port that permits packets from VLAN 2 and VLAN 3 to pass through.

[DeviceA] interface GigabitEthernet 3/1/2

[DeviceA-GigabitEthernet3/1/2] port link-type trunk

[DeviceA-GigabitEthernet3/1/2] port trunk permit vlan 2 3

[DeviceA-GigabitEthernet3/1/2] quit

# Configure GigabitEthernet 3/1/3 as a trunk port that permits packets from VLAN 4 and VLAN 5 to pass through.

[DeviceA] interface GigabitEthernet 3/1/3

[DeviceA-GigabitEthernet3/1/3] port link-type trunk

[DeviceA-GigabitEthernet3/1/3] port trunk permit vlan 4 5

[DeviceA- GigabitEthernet3/1/3] quit

# Create VLAN 10, add GigabitEthernet 3/1/1 to VLAN 10, and enable MLD snooping in this VLAN.

[DeviceA] vlan 10

[DeviceA-vlan10] port GigabitEthernet 3/1/1

[DeviceA-vlan10] mld-snooping enable

[DeviceA-vlan10] quit

# Configure VLAN 10 as an IPv6 multicast VLAN, and configure VLAN 2 through VLAN 5 as its sub-VLANs.

[DeviceA] multicast-vlan ipv6 10

[DeviceA-ipv6-mvlan-10] subvlan 2 to 5

[DeviceA-ipv6-mvlan-10] quit

4.      Configure Router B:

# Enable MLD snooping globally.

<RouterB> system-view

[RouterB] mld-snooping

[RouterB-mld-snooping] quit

# Create VLAN 2, assign GigabitEthernet 3/1/2 to VLAN 2, and enable MLD snooping in the VLAN.

[RouterB] vlan 2

[RouterB-vlan2] port GigabitEthernet 3/1/2

[RouterB-vlan2] mld-snooping enable

[RouterB-vlan2] quit

# Create VLAN 3, assign GigabitEthernet 3/1/3 to VLAN 3, and enable MLD snooping in the VLAN.

[RouterB] vlan 3

[RouterB-vlan3] port GigabitEthernet 3/1/3

[RouterB-vlan3] mld-snooping enable

[RouterB-vlan3] quit

# Configure GigabitEthernet 3/1/1 as a trunk port that permits packets from VLAN 2 and VLAN 3 to pass through.

[RouterB] interface GigabitEthernet 3/1/1

[RouterB-GigabitEthernet3/1/1] port link-type trunk

[RouterB-GigabitEthernet3/1/1] port trunk permit vlan 2 3

5.      Configure Router C:

The configurations required on Router C are similar to those on Router B. (Details not shown)

6.      Verify the configuration:

# View the IPv6 multicast VLAN information on Device A.

[DeviceA] display multicast-vlan ipv6

 Total 1 IPv6 multicast-vlan(s)

 

 IPv6 Multicast vlan 10

   subvlan list:

    vlan 2-5

# View the MLD snooping IPv6 multicast group information on Device A.

[DeviceA] display mld-snooping group

  Total 5 IP Group(s).

  Total 5 IP Source(s).

  Total 5 MAC Group(s).

 

  Port flags: D-Dynamic port, S-Static port, C-Copy port, P-PIM port

  Subvlan flags: R-Real VLAN, C-Copy VLAN

  Vlan(id):2.

    Total 1 IP Group(s).

    Total 1 IP Source(s).

    Total 1 MAC Group(s).

    Router port(s):total 0 port(s).

    IP group(s):the following ip group(s) match to one mac group.

      IP group address:FF1E::101

        (::, FF1E::101):

          Host port(s):total 1 port(s).

            GE3/1/2                (D)

    MAC group(s):

      MAC group address:3333-0000-0101

          Host port(s):total 1 port(s).

            GE3/1/2

 

  Vlan(id):3.

    Total 1 IP Group(s).

    Total 1 IP Source(s).

    Total 1 MAC Group(s).

    Router port(s):total 0 port(s).

    IP group(s):the following ip group(s) match to one mac group.

      IP group address:FF1E::101

        (::, FF1E::101):

          Host port(s):total 1 port(s).

            GE3/1/2                (D)

    MAC group(s):

      MAC group address:3333-0000-0101

          Host port(s):total 1 port(s).

            GE3/1/2

 

  Vlan(id):4.

    Total 1 IP Group(s).

    Total 1 IP Source(s).

    Total 1 MAC Group(s).

    Router port(s):total 0 port(s).

    IP group(s):the following ip group(s) match to one mac group.

      IP group address:FF1E::101

        (::, FF1E::101):

          Host port(s):total 1 port(s).

            GE3/1/3                (D)

    MAC group(s):

      MAC group address:3333-0000-0101

          Host port(s):total 1 port(s).

            GE3/1/3

 

  Vlan(id):5.

    Total 1 IP Group(s).

    Total 1 IP Source(s).

    Total 1 MAC Group(s).

    Router port(s):total 0 port(s).

    IP group(s):the following ip group(s) match to one mac group.

      IP group address:FF1E::101

        (::, FF1E::101):

          Host port(s):total 1 port(s).

            GE3/1/3                (D)

    MAC group(s):

      MAC group address:3333-0000-0101

          Host port(s):total 1 port(s).

            GE3/1/3

 

  Vlan(id):10.

    Total 1 IP Group(s).

    Total 1 IP Source(s).

    Total 1 MAC Group(s).

    Router port(s):total 1 port(s).

            GE3/1/1                (D)

    IP group(s):the following ip group(s) match to one mac group.

      IP group address:FF1E::101

        (::, FF1E::101):

          Host port(s):total 0 port(s).

    MAC group(s):

      MAC group address:3333-0000-0101

          Host port(s):total 0 port(s).

The output shows that MLD snooping is maintaining the router port in the IPv6 multicast VLAN (VLAN 10) and the member ports in the sub-VLANs (VLAN 2 through VLAN 5).