Technical Documentation

Example: Configuring Multicast VLAN Registration on EX Series Switches

Multicast VLAN registration (MVR) allows hosts that are not part of a multicast VLAN (MVLAN) to receive multicast streams from the MVLAN, allowing the MVLAN to be shared across the Layer 2 network and eliminating the need to send duplicate multicast streams to each requesting VLAN in the network. Hosts remain in their own VLANs for bandwidth and security reasons.

This example describes how to configure MVR on EX Series switches:

Requirements

This example uses the following hardware and software components:

  • One EX Series switch
  • JUNOS Release 9.6 or later for EX Series switches

Before you configure MVR, be sure you have:

Overview and Topology

In a standard Layer 2 network, a multicast stream received on one VLAN is never distributed to interfaces outside that VLAN. If hosts in multiple VLANs request the same multicast stream, a separate copy of that multicast stream is distributed to the requesting VLANs.

MVR introduces the concept of a multicast source VLAN (MVLAN), which is created by MVR and becomes the only VLAN over which multicast traffic flows throughout the Layer 2 network. Multicast traffic can then be selectively forwarded from interfaces on the MVLAN (source ports) to hosts that are connected to interfaces (multicast receiver ports) that are not part of the multicast source VLAN. When you configure an MVLAN, you assign a range of multicast group addresses to it. You then configure other VLANs to be MVR receiver VLANs, which receive multicast streams from the MVLAN. The MVR receiver ports comprise all the interfaces that exist on any of the MVR receiver VLANs.

Note: You cannot configure a VLAN that contains an access port to be an MVR source VLAN.

You can configure MVR to operate in one of two modes: transparent mode (the default mode) or proxy mode. Both modes allow MVR to forward only one copy of a multicast stream to the Layer 2 network.

In transparent mode, the switch receives one copy of each IPTV multicast stream and then replicates the stream only to those hosts that want to receive it, while forwarding all other types of multicast traffic without modification. Figure 1 shows how MVR operates in transparent mode.

In proxy mode, the switch acts as a proxy for the IGMP multicast router in the MVLAN for MVR group memberships established in the MVR receiver VLANs and generates and sends IGMP packets into the MVLAN as needed. Figure 2 shows how MVR operates in proxy mode.

This example shows how to configure MVR in both transparent mode and proxy mode on an EX Series switch. The topology includes a video server that is connected to a multicast router, which in turn forwards the IPTV multicast traffic in the MVLAN to the Layer 2 network.

Figure 1 shows the MVR topology in transparent mode. Interfaces P1 and P2 on Switch C belong to service VLAN s0 and MVLAN mv0. Interface P4 of Switch C also belongs to service VLAN s0. In the upstream direction of the network, only non-IPTV traffic is being carried in individual customer VLANs of service VLAN s0. VLAN c0 is an example of this type of customer VLAN. IPTV traffic is being carried on MVLAN mv0. If any host on any customer VLAN connected to port P4 requests an MVR stream, switch C takes the stream from VLAN mv0 and replicates that stream onto port P4 with tag mv0. IPTV traffic, along with other network traffic, flows form port P4 out to the Digital Subscriber Line Access Multiplexer (DSLAM) D1.

Figure 1: MVR Topology in Transparent Mode

Image g020404.gif

Figure 2 shows the MVR topology in proxy mode. Interfaces P1 and P2 on switch C belong to MVLAN mv0 and customer VLAN c0. Interface P4 on switch C is an access port of customer VLAN c0. In the upstream direction of the network, only non-IPTV traffic is being carried on customer VLAN c0. Any IPTV traffic requested by hosts on VLAN c0 is replicated untagged to port P4 based on streams received in MVLAN mv0. IPTV traffic flows from port P4 out to an IPTV-enabled device in Host 1. Other traffic, such as data and voice traffic, also flows from port P4 to other network devices in Host 1.

Figure 2: MVR Topology in Proxy Mode

Image g020403.gif

For information on VLAN tagging, see Understanding Bridging and VLANs on EX Series Switches.

Configuration

To configure MVR perform these tasks:

CLI Quick Configuration

To quickly configure MVR in proxy mode, copy the following commands and paste them into the switch terminal window. To quickly configure MVR in transparent mode (the default mode), do not copy and paste the final command line in the following block of lines:


[edit protocols igmp-snooping]
set vlan mv0 data-forwarding source groups 225.10.0.0/16
set vlan v2 data-forwarding receiver source-vlans mv0
set vlan v2 data-forwarding receiver install
set vlan mv0 proxy source-address 10.1.1.1

Step-by-Step Procedure

To configure MVR, perform these tasks:

  1. Configure mv0 to be an MVLAN:

    [edit protocols igmp-snooping]
    user@switch# set vlan mv0 data-forwarding source groups 225.10.0.0/16

    Note: You cannot configure a VLAN that contains an access port to be an MVR source VLAN.

  2. Configure v2 to be a multicast receiver VLAN with mv0 as its source:

    [edit protocols igmp-snooping]
    user@switch# set vlan v2 data-forwarding receiver source-vlans mv0

  3. (Optional) Install forwarding entries in the multicast receiver VLAN v2:

    [edit protocols igmp-snooping]
    user@switch# set vlan v2 data-forwarding receiver install

  4. (Optional) Configure MVR in proxy mode:

    [edit protocols igmp-snooping]
    user@switch# set vlan mv0 proxy source-address 10.1.1.1

Results

Check the results of the configuration:

[edit protocols igmp-snooping]
user@switch# show
vlan mv0 {
proxy {
source-address 10.1.1.1;
}
data-forwarding {
source {
groups 225.10.0.0/16;
}
}
}
vlan v2 {
data-forwarding {
receiver {
source-vlans mv0;
install;
}
}
}

Published: 2009-07-23