Multicast VLAN configuration· 1

Introduction to multicast VLAN·· 1

Multicast VLAN configuration task list 2

Configuring multicast VLAN·· 2

Configuration prerequisites 3

Configuring user port attributes 3

Configuring multicast VLAN ports 4

Displaying and maintaining multicast VLAN·· 5

Multicast VLAN configuration example· 5

 

This chapter includes these sections:

·          Introduction to multicast VLAN

·          Multicast VLAN configuration task list

·          Configuring multicast VLAN

·          Displaying and maintaining multicast VLAN

·          Multicast VLAN configuration example

 

NOTE: ·      The term "switch" or "device" in this chapter refers to the switching engine on a WX3000E wireless switch. ·      The WX3000E series comprises WX3024E and WX3010E wireless switches. ·      The port numbers in this chapter are for illustration only.

Introduction to multicast VLAN

In the traditional multicast programs-on-demand mode shown in Figure 1, , when hosts— Host A, Host B and Host C—that belong to different VLANs require multicast programs-on-demand service, the Layer 3 device—Router A—must 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 Multicast transmission without multicast VLAN

 

The multicast VLAN feature configured on the Layer 2 device is the solution to this issue. With the multicast VLAN feature, the Layer 3 device replicates the multicast traffic only in the multicast VLAN instead of making a separate copy of the multicast traffic in each user VLAN. This saves network bandwidth and lessens the burden on the Layer 3 device.

As shown in Figure 2, Host A, Host B and Host C are in three different user VLANs. All the user ports (ports with attached hosts) on Switch A are hybrid ports. On Switch A, configure VLAN 10 as a multicast VLAN, assign all the user ports to this multicast VLAN, and enable IGMP snooping in the multicast VLAN and all the user VLANs.

Figure 2 Port-based multicast VLAN

 

After the configuration, if Switch A receives an IGMP message on a user port, it tags the message with the multicast VLAN ID and relays it to the IGMP querier, so that IGMP snooping can uniformly manage the router ports and member ports in the multicast VLAN. When forwarding multicast data to Switch A, Router A needs to send only one copy of multicast traffic to Switch A in the multicast VLAN, and Switch A distributes the traffic to all the member ports in the multicast VLAN.

 

NOTE: ·      For more information about IGMP snooping, router ports, and member ports, see the chapter “IGMP snooping configuration.” ·      For more information about VLAN tags, see the Layer 2 Configuration Guide.

 

Multicast VLAN configuration task list

Complete the following tasks to configure multicast VLAN:

Task	Remarks
Configuring user port attributes	Required
Configuring multicast VLAN ports	Required

 

Configuring multicast VLAN

When configuring port-based multicast VLAN, you need to configure the attributes of each user port and then assign the ports to the multicast VLAN.

 

NOTE: ·      A user port can be configured as a multicast VLAN port only if it is of the Ethernet or Layer 2 aggregate interface type. ·      In Ethernet interface view or Layer 2 aggregate interface view, the configuration is effective on only the current port. In port group view, the configuration is effective on all  ports in the current port group.

 

Configuration prerequisites

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

·          Create VLANs as required

·          Enable IGMP snooping in the VLAN to be configured as a multicast VLAN

·          Enable IGMP snooping in all the user VLANs

Configuring user port attributes

Configure the user ports as hybrid ports that permit packets of the specified user VLAN to pass, and configure the user VLAN to which the user ports belong as the default VLAN.

Configure the user ports to permit packets of the multicast VLAN to pass and untag the packets. Thus, after receiving multicast packets tagged with the multicast VLAN ID from the upstream device, the Layer 2 device untags the multicast packets and forwards them to its downstream device.

Follow these steps to configure user port attributes:

To do...	Use the command...	Remarks
Enter system view	system-view	—
Enter interface view or port group view	interface interface-type interface-number	Required Use either command
	port-group { manual port-group-name | aggregation agg-id }
Configure the user port link type as hybrid	port link-type hybrid	Required Access by default
Specify the user VLAN that comprises the current user port or ports as the default VLAN	port hybrid pvid vlan vlan-id	Required VLAN 1 by default
Configure the current user port or ports to permit packets of the specified multicast VLAN or VLANs to pass and untag the packets	port hybrid vlan vlan-id-list untagged	Required By default, a hybrid port permits only packets of VLAN 1 to pass.

 

NOTE: For more information about the port link-type, port hybrid pvid vlan, and port hybrid vlan commands, see the Layer 2 Command Reference.

 

Configuring multicast VLAN ports

In this approach, you need to configure a VLAN as a multicast VLAN and then assign user ports to this multicast VLAN by either adding the user ports in the multicast VLAN or specifying the multicast VLAN on the user ports. These two configuration methods give the same result.

Configuring multicast VLAN ports in multicast VLAN view

Follow these steps to configure multicast VLAN ports in multicast VLAN view:

To do...	Use the command...	Remarks
Enter system view	system-view	—
Configure the specified VLAN as a multicast VLAN and enter multicast VLAN view	multicast-vlan vlan-id	Required Not a multicast VLAN by default
Assign ports to the multicast VLAN	port interface-list	Required By default, a multicast VLAN has no ports.

 

Configuring multicast VLAN ports in interface view or port group view

Follow these steps to configure multicast VLAN ports in interface view or port group view:

To do…	Use this command…	Remarks
Enter system view	system-view	—
Configure the specified VLAN as a multicast VLAN and enter multicast VLAN view	multicast-vlan vlan-id	Required Not a multicast VLAN by default.
Return to system view	quit	—
Enter interface view or port group view	interface interface-type interface-number	Required Use either command.
	port-group manual port-group-name
Assign the current port or ports to the multicast VLAN	port multicast-vlan vlan-id	Required By default, a user port does not belong to any multicast VLAN.

 

NOTE: ·      You cannot configure multicast VLAN on a device with multicast routing enabled. ·      The VLAN to be configured as a multicast VLAN must exist. ·      A port can belong to only one multicast VLAN.

 

Displaying and maintaining multicast VLAN

To do…	Use the command…	Remarks
Display multicast VLAN  information	display multicast-vlan [ vlan-id ] [ | { begin | exclude | include } regular-expression ]	Available in any view

 

Multicast VLAN configuration example

Network requirements

·          As shown in Figure 3, Router A connects to a multicast source (Source) through GigabitEthernet1/0/1, and to Switch A through GigabitEthernet1/0/2. IGMPv2 is required on Router A. IGMPv2 Snooping is required on Switch A. Router A acts as the IGMP querier.

·          The multicast source sends multicast data to multicast group 224.1.1.1. Host A, Host B, and Host C are receivers of the multicast group, and the hosts belong to VLAN 2 through VLAN 4 respectively.

·          Configure the port-based multicast VLAN feature on Switch A so that Router A just sends multicast data to Switch A through the multicast VLAN and Switch A forwards the multicast data to the receivers that belong to different user VLANs.

Figure 3 Network diagram for port-based multicast VLAN configuration

 

Configuration procedure

1.        Configure IP addresses

Configure the IP address and subnet mask for each interface as per Figure 3. The detailed configuration steps are omitted here.

2.        Configure Router A

# Enable IP multicast routing, enable PIM-DM on each interface, and enable IGMP on the host-side interface GigabitEthernet 1/0/2.

<RouterA> system-view

[RouterA] multicast routing-enable

[RouterA] interface gigabitethernet 1/0/1

[RouterA-GigabitEthernet1/0/1] pim dm

[RouterA-GigabitEthernet1/0/1] quit

[RouterA] interface gigabitethernet 1/0/2

[RouterA-GigabitEthernet1/0/2] pim dm

[RouterA-GigabitEthernet1/0/2] igmp enable

3.        Configure Switch A

# Enable IGMP snooping globally.

<SwitchA> system-view

[SwitchA] igmp-snooping

[SwitchA-igmp-snooping] quit

# Create VLAN 10, assign GigabitEthernet 1/0/1 to VLAN 10, and enable IGMP snooping in this VLAN.

[SwitchA] vlan 10

[SwitchA-vlan10] port gigabitethernet 1/0/1

[SwitchA-vlan10] igmp-snooping enable

[SwitchA-vlan10] quit

# Create VLAN 2 and enable IGMP snooping in the VLAN.

[SwitchA] vlan 2

[SwitchA-vlan2] igmp-snooping enable

[SwitchA-vlan2] quit

The configuration for VLAN 3 and VLAN 4 is similar. The detailed configuration steps are omitted.

# Configure GigabitEthernet 1/0/2 as a hybrid port. Configure VLAN 2 as the default VLAN. Configure GigabitEthernet 1/0/2 to permit packets of VLAN 2 and VLAN 10 to pass and untag the packets when forwarding them.

[SwitchA] interface gigabitethernet 1/0/2

[SwitchA-GigabitEthernet1/0/2] port link-type hybrid

[SwitchA-GigabitEthernet1/0/2] port hybrid pvid vlan 2

[SwitchA-GigabitEthernet1/0/2] port hybrid vlan 2 untagged

[SwitchA-GigabitEthernet1/0/2] port hybrid vlan 10 untagged

[SwitchA-GigabitEthernet1/0/2] quit

The configuration for GigabitEthernet 1/0/3 and GigabitEthernet 1/0/4 is similar. The detailed configuration steps are omitted.

# Configure VLAN 10 as a multicast VLAN.

[SwitchA] multicast-vlan 10

# Assign GigabitEthernet 1/0/2 and GigabitEthernet 1/0/3 to VLAN 10.

[SwitchA-mvlan-10] port gigabitethernet 1/0/2 to gigabitethernet 1/0/3

[SwitchA-mvlan-10] quit

# Assign GigabitEthernet 1/0/4 to VLAN 10.

[SwitchA] interface gigabitethernet 1/0/4

[SwitchA-GigabitEthernet1/0/4] port multicast-vlan 10

[SwitchA-GigabitEthernet1/0/4] quit

4.        Verify the configuration

# View the multicast VLAN information on Switch A.

[SwitchA] display multicast-vlan

 Total 1 multicast-vlan(s)

 

 Multicast vlan 10

   port list:

    GE1/0/2                 GE1/0/3                 GE1/0/4

# View the IGMP snooping multicast group information on Switch A.

[SwitchA] display igmp-snooping group

  Total 1 IP Group(s).

  Total 1 IP Source(s).

  Total 1 MAC Group(s).

 

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

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

  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).

            GE1/0/1                (D)

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

      IP group address:224.1.1.1

        (0.0.0.0, 224.1.1.1):

          Host port(s):total 3 port(s).

            GE1/0/2                (D)

            GE1/0/3                (D)

            GE1/0/4                (D)

    MAC group(s):

      MAC group address:0100-5e01-0101

          Host port(s):total 3 port(s).

            GE1/0/2

            GE1/0/3

            GE1/0/4

The output shows that IGMP snooping is maintaining the router ports and member ports in VLAN 10.