The AN is not IGMP/MLD aware and multicast replication is performed in the BNG. Multicast streams are sent directly to the hosts using their unicast MAC addresses. HQoS adjustment is not needed as multicast traffic is flowing through subscriber queues. From the BNG perspective this deployment model has the following characteristics:
IGMP/MLD states are kept per hosts. Each host can be registered to multiple IGMP/MLD groups.
MLD uses link-local as source address, which makes it difficult to associate with the originating host. MLD (S,G) are always first associated with a IPv6 WAN host if available. If this WAN host terminate its IPv6 session (with lease expiry, session terminate, and so on), the (S,G) is then associated with any remaining WAN host. Only when there are no more WAN hosts available, are the (S,G) associated with the PD host, if any.
IGMP/MLD Joins are accepted only from the active subscriber hosts. In other words antispoofing is in effect for IGMP/MLD messages.
IGMP/MLD statistics can be displayed per host, per group or per subscriber.
Multicast traffic is forwarded through subscriber queues using unicast destination MAC address of the destination host.
Multiple copies of the same multicast stream can be generated per SAP. The number of copies depends on the number of hosts on the SAP that are registered to the same multicast group (channel). In other words, the number of multicast streams on the SAP is equal to the number of groups registered across all hosts on this SAP.
Traffic statistics are kept per the host queue. In case that multicast statistics need to be separated from unicast, the multicast traffic should be classified in a subscriber separate queue.
HQoS Adjustment is not needed as traffic is flowing within the subscriber queues and is automatically accounted in HQoS.
Multicast traffic can be explicitly classified into forwarding classes and consequently directed into needed queues.
MCAC is supported.
profiled-traffic-only mode defined under sub-sla-mgmt is supported. This mode (profiled-traffic-only) is used to save the number of queues in 1:1 model (sub-sla-mgmt-> no multi-sub-SAP) by preventing the creation of the SAP queues. Because multicast traffic is not using the SAP queue, enabling this feature does not have any effect on the multicast operation.
This model is shown in Figure: 1:1 model.
