In the case of a VMAN, a packet is tagged with a VMAN tag in addition to a possible VLAN tag. This is to provide VLAN aggregation for all customer traffic in the VMAN ring. Each customer is given its own VLAN, and traffic from all customers can be tunneled on a single VMAN tag into the metro ring to an outside Broadband Remote Access Server (BRAS). In a VMAN network, multicast traffic can be distributed over a separate VLAN in the metro core. These packets are not subjected to VMAN tunneling. Thus, IPTV service can be provided on this multicast VLAN on a VMAN network.
MVR deployment in a VMAN environment is not any different from that in an EAPS environment, since a separate multicast VLAN on the metro ring is used for multicasting. However, it provides interesting capabilities to MSPs for their video offerings. Different service bundles can be offered on separate VLANs. Packets are not forwarded to any metro link segments where a stream is not required.
MVR in a VMAN Environment illustrates an example design for MVR in a VMAN environment. Any multicast packet entering on MVlan is forwarded on MVlan to the next switch. These multicast packets are not tunneled.
With MVR, switches on the VMAN do not have to run any routing protocol. If MVR is enabled on the multicast VLAN, MVlan, traffic is pulled from the IPTV server. Such multicast packets egressing from the CE port are always untagged. The downstream DSLAM distributes untagged multicast packets to the respective subscriber VLANs.
The following is a typical configuration for Switch 1 in the above figure:
create vman vman2 configure vman vman2 tag 300 configure vman vman2 add port 2:2-2:3 untagged configure vman vman2 add port 1:1,1:2 tagged enable port 2:* enable port 1:* create vlan mvlan configure vlan mvlan tag 200 configure vlan mvlan add port 1:1,1:2 tag configure mvr add vlan mvlan enable mvr