Table of Contents

Chapter 1 Multicast VLAN Configuration. 1-1

1.1 Introduction to Multicast VLAN. 1-1

1.2 Configuring Multicast VLAN. 1-2

1.3 Displaying and Maintaining Multicast VLAN. 1-3

1.4 IPv4 Multicast VLAN Configuration Example. 1-3

1.5 IPv6 Multicast VLAN Configuration Example. 1-5

 

Chapter 1  Multicast VLAN Configuration

1.1  Introduction to Multicast VLAN

As shown in Figure 1-1, in the traditional multicast programs-on-demand mode, when hosts, Host A, Host B and Host C, belonging to different VLANs require multicast programs on demand service at the same time, 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, Switch A. This results in not only waste of network bandwidth but also extra burden on the Layer 3 device.

Figure 1-1 Before and after multicast VLAN is enabled on the Layer 2 device

To solve this problem, you can enable the multicast VLAN feature on Switch A, namely configure the VLANs to which these hosts belong as sub-VLANs of a multicast VLAN on the Layer 2 device and enable Layer 2 multicast in the multicast VLAN. After this configuration, Router A replicates the multicast data only within the multicast VLAN instead of forwarding a separate copy of the multicast data to each VLAN. This saves the network bandwidth and lessens the burden of the Layer 3 device.

 

 

1.2  Configuring Multicast VLAN

Follow these steps to configure a multicast VLAN:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Configure a specific VLAN as a multicast VLAN	multicast-vlan vlan-id enable	Required Disabled by default
Configure sub-VLANs for a specific multicast VLAN	multicast-vlan vlan-id subvlan vlan-list	Required No sub-VLAN by default.

 

 

 

1.3  Displaying and Maintaining Multicast VLAN

To do…	Use the command…	Remarks
Display information about a multicast VLAN	display multicast-vlan [ vlan-id ]	Available in any view

 

1.4  IPv4 Multicast VLAN Configuration Example

I. Network requirements

l           As shown in Figure 1-2, Router A (multicast router) connects to a multicast source through Ethernet 1/1/2 and to Switch A (an S9500 series Ethernet switch) through Ethernet 1/1/1.

l           PIM-DM is enabled on Ethernet 1/1/1 and Ethernet 1/1/2 of Router A. IGMPv2 is enabled on Router A, and IGMP Snooping is enabled on Switch A. Router A is the IGMP querier.

l           Switch A’s Ethernet 1/1/1 belongs to VLAN 1024, and Ethernet 1/2/1 and Ethernet 1/3/1 are trunk ports, which belong to VLANs 1 through 3 and VLANs 4 through 6 respectively.

l           Switch B and Switch C are common switches that support IGMP Snooping. The ports connecting to Switch A are trunk ports. They belong to VLANs 1 through 3 and VLANs 4 through 6 respectively. IGMP Snooping is enabled on Switch B and Switch C.

l           Hosts A through F belong to VLANs 1 through 6 respectively. Configure these six VLANs as the sub-VLANs of the multicast VLAN 1024 so that the six hosts can receive multicast data.

II. Network diagram

Figure 1-2 Network diagram for IPv4 multicast VLAN configuration

III. Configuration procedure

1)         Configure IP addresses

Configure an IP address and subnet mask for each interface as per Figure 1-2. The detailed configuration steps are omitted here.

2)         Configure Router A

# Enable IP multicast routing, enable PIM-DM on each interface and enable IGMPv2 on Ethernet 1/1/1.

<RouterA> system-view

[RouterA] multicast routing-enable

[RouterA] interface ethernet 1/1/1

[RouterA-Ethernet1/1/1] pim dm

[RouterA-Ethernet1/1/1] igmp enable

[RouterA-Ethernet1/1/1] igmp version 2

[RouterA-Ethernet1/1/1] quit

[RouterA] interface ethernet 1/1/2

[RouterA-Ethernet1/1/2] pim dm

[RouterA-Ethernet1/1/2] quit

 

 

3)         Configure Switch A

# Configure VLAN 1024 as a multicast VLAN and configure VLANs 1 through 6 as sub-VLANs of VLAN 1024.

<SwitchA> system-view

[SwitchA] vlan 1 to 6

[SwitchA] vlan 1024

[SwitchA-vlan1024] port ethernet 1/1/1

[SwitchA-vlan1024] quit

[SwitchA] interface ethernet 1/2/1

[SwitchA-Ethernet1/2/1] port link-type trunk

[SwitchA-Ethernet1/2/1] port trunk permit vlan 1 to 3

[SwitchA-Ethernet1/2/1] quit

[SwitchA] interface ethernet 1/3/1

[SwitchA-Ethernet1/3/1] port link-type trunk

[SwitchA-Ethernet1/3/1] port trunk permit vlan 4 to 6

[SwitchA-Ethernet1/3/1] quit

[SwitchA] multicast-vlan 1024 enable

[SwitchA] multicast-vlan 1024 subvlan 1 to 6

# Enable IGMP Snooping.

[SwitchA] igmp-snooping

[SwitchA-igmp-snooping] quit

[SwitchA] vlan 1024

[SwitchA-vlan1024] igmp-snooping enable

1.5  IPv6 Multicast VLAN Configuration Example

I. Network requirements

l           As shown in Figure 1-3, Router A connects to an IPv6 multicast source (Source) through Ethernet 1/1/1, and to Switch A (an S9500 series Ethernet switch) through Ethernet 1/1/10.

l           MLDv1 is enabled on Router A. MLD Snooping is enabled on Switch A. Router A is the MLD querier on the subnet.

l           Switch A’s Ethernet 1/1/10 belongs to VLAN 1024, and Ethernet 1/1/1 through Ethernet 1/1/3 belong to VLANs 10 through 12 respectively. Hosts A through C are attached to Ethernet 1/1/1 through Ethernet 1/1/3 of Switch A.

l           Configure the IPv6 multicast VLAN feature so that Router A just sends IPv6 multicast data to VLAN 1024 rather than to each VLAN when the three hosts attached to Switch A need the IPv6 multicast data.

II. Network diagram

Figure 1-3 Network diagram for IPv6 multicast VLAN configuration

III. Configuration procedure

1)         Enable IPv6 forwarding and configure IPv6 addresses

Enable IPv6 forwarding on each device and configure the IPv6 address and prefix length for each interface as per Figure 1-3. The detailed configuration steps are omitted here.

2)         Configure Router A

# Enable IPv6 multicast routing, enable IPv6 PIM-DM on each interface, and enable MLD on the receiver-side interface, Ethernet 1/1/10.

<RouterA> system-view

[RouterA] multicast ipv6 routing-enable

[RouterA] interface ethernet 1/1/10

[RouterA-Ethernet1/1/10] pim ipv6 dm

[RouterA-Ethernet1/1/10] mld enable

[RouterA-Ethernet1/1/10] mld version 1

[RouterA-Ethernet1/1/10] quit

[RouterA] interface ethernet 1/1/1

[RouterA-Ethernet1/1/1] pim ipv6 dm

[RouterA-Ethernet1/1/1] quit

 

 

3)         Configure switch A.

# Enable MLD Snooping globally.

<SwitchA> system-view

[SwitchA] mld-snooping

[SwitchA-mld-snooping] quit

# Create VLANs 10 through 12 and add the corresponding ports to the VLANs.

[SwitchA] vlan 10

[SwitchA-vlan10] port ethernet 1/1/1

[SwitchA-vlan10] quit

[SwitchA] vlan 11

[SwitchA-vlan11] port ethernet 1/1/2

[SwitchA-vlan11] quit

[SwitchA] vlan 12

[SwitchA-vlan12] port ethernet 1/1/3

[SwitchA-vlan12] quit

# Create VLAN 1024, add Ethernet 1/1/10 to VLAN 1024, and enable MLD Snooping in this VLAN.

[SwitchA] vlan 1024

[SwitchA-vlan1024] port ethernet 1/1/10

[SwitchA-vlan1024] mld-snooping enable

[SwitchA-vlan1024] quit

# Configure VLAN 1024 as an IPv6 multicast VLAN, and configure VLANs 10 through 12 as its sub-VLANs.

[SwitchA] multicast-vlan 1024 enable

[SwitchA] multicast-vlan 1024 subvlan 10 to 12