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Configuring Multicast VLAN Registration on EX Series Switches

 

Multicast VLAN registration (MVR) enables hosts that are not part of a multicast VLAN (MVLAN) to receive multicast streams from the MVLAN, sharing the MVLAN across multiple VLANs in a Layer 2 network. Hosts remain in their own VLANs for bandwidth and security reasons but are able to receive multicast streams on the MVLAN.

MVR is not enabled by default on switches that support MVR. You must explicitly configure a switch with a data-forwarding source MVLAN and associate it with one or more data-forwarding MVR receiver VLANs. When you configure one or more VLANs on a switch to be MVR receiver VLANs, you must configure at least one associated source MVLAN. However, you can configure a source MVLAN without associating MVR receiver VLANs with it at the same time.

The overall purpose and benefits of employing MVR are the same on switches that use Enhanced Layer 2 Software (ELS) configuration style and those that do not use ELS. However, there are differences in MVR configuration and operation on the two types of switches.

Configuring Multicast VLAN Registration on EX Series Switches with ELS

The following are configuration frameworks we recommended for MVR to operate smoothly on EX Series switches that support Enhanced Layer 2 Software (ELS) configuration style in single-tier or multiple-tier access layers:

  • In an access layer with a single tier of switches, where a switch is connected to a multicast router in the upstream direction, and has host trunk or access ports connecting to downstream multicast receivers:

    • Configure MVR on the receiver VLANs to operate in proxy mode.

    • Statically configure the upstream interface to the multicast router as a multicast router port in the MVLAN.

    • Configure the translate option on MVR receiver VLANs that have trunk ports, so hosts on those trunk ports receive the multicast packets tagged for their own VLANs.

  • In an access layer with multiple tiers of switches, with a switch connected upstream to the multicast router and a path through one or more downstream switches to multicast receivers:

    • Configure MVR on the receiver VLANs to operate in proxy mode on the uppermost switch that is directly connected to the upstream multicast router.

    • Configure MVR on the receiver VLANs to operate in transparent mode for the remaining downstream tiers of switches.

    • Statically configure a multicast router port to the switch in the upstream direction on each tier for the MVLAN.

    • On the lowest tier of MVR switches (connected to receiver hosts), configure MVLAN tag translation for MVR receiver VLANs that have trunk ports, so hosts on those trunk ports receive the multicast stream with the packets tagged with their own VLANs.

Note

When enabling MVR on ELS switches, depending on your multicast network requirements, you can have some MVR receiver VLANs configured in proxy mode and some in transparent mode that are associated with the same MVLAN, because the MVR mode setting applies individually to an MVR receiver VLAN. The mode configurations described here are only recommendations for smooth MVR operation in those topologies.

The following constraints apply when configuring MVR on ELS EX Series switches:

  • MVR is supported on VLANs running IGMP version 2 (IGMPv2) only.

  • You can configure up to 10 MVLANs on an EX4300 or EX4300 multigigabit switch, up to 5 MVLANs on EX2300 and EX3400 switches, and up to a total of 4K MVR receiver VLANs and MVLANs together.

  • A VLAN can be configured as either an MVLAN or an MVR receiver VLAN, not both. However, an MVR receiver VLAN can be associated with more than one MVLAN.

  • An MVLAN can be the source for only one multicast group subnet, so multiple MVLANs configured on a switch must have unique multicast group subnet ranges.

  • You can configure an interface in both an MVR receiver VLAN and its MVLAN only if it is configured as a multicast router port in both VLANs.

  • You cannot configure proxy mode with the install option to also install forwarding entries on an MVR receiver VLAN. In proxy mode, IGMP reports are sent to the upstream router only in the context of the MVLAN. Multicast sources will not receive IGMP reports on the MVR receiver VLAN , and multicast traffic will not be sent on the MVR receiver VLAN.

  • MVR does not support configuring an MVLAN or MVR receiver VLANs on private VLANs (PVLANs).

To configure MVR on ELS EX Series switches that support MVR:

  1. Configure a data-forwarding multicast source VLAN as an MVLAN:

    For example, configure VLAN mvlan as an MVLAN for multicast group subnet 233.252.0.0/8:

  2. Configure one or more data-forwarding MVR receiver VLANs associated with the source MVLAN:

    For example, configure two MVR receiver VLANs v10 and v20 associated with the MVLAN named mvlan:

  3. On a switch in a single-tier topology or on the uppermost switch in a multiple-tier topology (the switch connected to the upstream multicast router), configure each MVR receiver VLAN on the switch to operate in proxy mode:

    For example, configure the two MVR receiver VLANs v10 and v20 (associated with the MVLAN named mvlan) from the previous step to use proxy mode:

    Note

    On ELS switches, the MVR mode setting applies to individual MVR receiver VLANs. All MVR receiver VLANS associated with an MVLAN are not required to have the same mode setting. Depending on your multicast network requirements, you might want to configure some MVR receiver VLANs in proxy mode and others that are associated with the same MVLAN in transparent mode.

  4. In a multiple-tier topology, for the remaining switches that are not the uppermost switch, configure each MVR receiver VLAN on each switch to operate in transparent mode. An MVR receiver VLAN operates in transparent mode by default if you do not set the mode explicitly, so this step is optional on these switches.

    For example, configure two MVR receiver VLANs v10 and v20 that are associated with the MVLAN named mvlan to use transparent mode:

    Note

  5. Configure a multicast router port in the upstream direction for the MVLAN on the MVR switch in a single-tier topology or on the MVR switch in each tier of a multiple-tier topology:

    For example, configure a multicast router interface ge-0/0/10.0 for the MVLAN named mvlan:

  6. On an MVR switch connected to the receiver hosts with trunk or access ports (applies only to the lowest tier in a multiple-tier topology), configure MVLAN tag translation on MVR receiver VLANs that have trunk ports, so hosts on the trunk ports can receive the multicast stream with the packets tagged with their own VLANs:

    For example, a switch connects to receiver hosts on MVR receiver VLAN v10 using a trunk port, but reaches receiver hosts on MVR receiver VLAN v20 on an access port, so configure the MVR translate option only on VLAN v10:

  7. (Optional and applicable only to MVR receiver VLANs configured in transparent mode) Install forwarding entries for an MVR receiver VLAN as well as the MVLAN:
    Note

    This option cannot be configured for an MVR receiver VLAN configured in proxy mode.

    For example:

Figure 1 illustrates a single-tier access layer topology in which MVR is employed with an MVLAN named mvlan and receiver hosts on MVR receiver VLANs v10 and v20. A sample of the recommended MVR configuration for this topology follows the figure.

Figure 1: MVR in a Single-Tier Topology
MVR in a Single-Tier Topology

The MVR switch in Figure 1 is configured in proxy mode, connects to the upstream multicast router on interface INTF-1, and connects to receiver hosts on v10 using trunk port INTF-2 and on v20 using access port INTF-3. The switch is configured to translate MVLAN tags in the multicast stream into the receiver VLAN tags only for v10 on INTF-2.

Figure 2 illustrates a two-tier access layer topology in which MVR is employed with an MVLAN named mvlan, MVR receiver VLANs v10 and v20, and receiver hosts connected to trunk port INTF-4 on v10 and access port INTF-5 on v20. A sample of the recommended MVR configuration for this topology follows the figure.

Figure 2: MVR in a Multiple-Tier Topology
MVR in a Multiple-Tier Topology

The upper switch in Figure 2 connects to the upstream multicast router on INTF-1, and the lower switch connects to the upper switch on INTF-3, both configured as trunk ports and multicast router interfaces in the MVLAN. The upper switch is configured in proxy mode and the lower switch is configured in transparent mode for all MVR receiver VLANs. The lower switch is configured to translate MVLAN tags in the multicast stream into the receiver VLAN tags for v10 on INTF-4.

Upper Switch:

Lower Switch:

Viewing MVLAN and MVR Receiver VLAN Information on EX Series Switches with ELS

On EX Series switches with the Enhanced Layer 2 Software (ELS) configuration style that support MVR, you can use the show igmp snooping data-forwarding command to view information about the MVLANs and MVR receiver VLANs configured on a switch, as follows:

user@host> show igmp snooping data-forwarding

MVLANs are listed as Type: MVR Source Vlan with the associated group subnet range and MVR receiver VLANs. MVR receiver VLANs are listed as Type: MVR Receiver Vlan with the associated source MVLANs and configured options (proxy or transparent mode, VLAN tag translation, and installation of receiver VLAN forwarding entries).

In addition, the show igmp snooping interface and show igmp snooping membership commands on ELS EX Series switches list MVR receiver VLAN interfaces under both the MVR receiver VLAN and its MVLAN, and display the output field Data-forwarding receiver: yes when MVR receiver ports are listed under the MVLAN. This field is not displayed for other interfaces in an MVLAN listed under the MVLAN that are not in MVR receiver VLANs.

Configuring Multicast VLAN Registration on non-ELS EX Series Switches

When you configure MVR on EX Series switches that do not support Enhanced Layer 2 Software (ELS) configuration style, the following contraints apply:

  • MVR is supported on VLANs running IGMP version 2 (IGMPv2) only.

  • A VLAN can be configured as an MVLAN or an MVR receiver VLAN, but not both. However, an MVR receiver VLAN can be associated with more than one MVLAN.

  • An MVLAN can be the source for only one multicast group subnet, so multiple MVLANs configured on a switch must have disjoint multicast group subnets.

  • After you configure a VLAN as an MVLAN, that VLAN is no longer available for other uses.

  • You cannot enable multicast protocols on VLAN interfaces that are members of MVLANs.

  • If you configure an MVLAN in proxy mode, IGMP snooping proxy mode is automatically enabled on all MVR receiver VLANs of this MVLAN. If a VLAN is an MVR receiver VLAN for multiple MVLANs, all of the MVLANs must have proxy mode enabled or all must have proxy mode disabled. You can enable proxy mode only on VLANs that are configured as MVR source VLANs and that are not configured for Q-in-Q tunneling.

  • You cannot configure proxy mode with the install option to also install forwarding entries for received IGMP packets on an MVR receiver VLAN.

To configure MVR on switches that do not support ELS:

  1. Configure the VLAN named mv0 to be an MVLAN:
  2. Configure the MVLAN mv0 to be a proxy VLAN:
  3. Configure the VLAN named v2 to be an MVR receiver VLAN with mv0 as its source:
  4. Install forwarding entries in the MVR receiver VLAN: