Multicast Offload Terminology; Overview Of Multicast Offload - Cisco ASR 9000 Series System Configuration Manual

Multicast Offload Terminology

Multicast Offload Terminology

These are the different terms associated with the Multicast offload solution.
• Unicast ISID: It is the ISID value set in 802.1ah header for unicast data packet to satellite and for all
• Multicast ISID: It is the ISID value set in 802.1ah header for multicast data packet from host to satellite
• Designated Multicast Forwarder: Each satellite selects a host as the designated multicast forwarder
• Backup Multicast Forwarder: Multicast packets received from Backup Multicast forwarder are not
• Active Unicast Host: The unicast customer data traffic is switched through Active Unicast Host while
• Standby Unicast Host: In case of a lost connection to Active Unicast Host due to failures such as cut
• Primary Host: Specifies the Host with the lowest chassis MAC in a Dual head topology.
• Secondary Host: Specifies the Host with a higher chassis MAC than the Primary Host in Dual head

Overview of Multicast Offload

As in the case of existing Satellite nV System architecture, the IGMP snooping protocol runs on the satellite
hosts with full Cisco IOS XR Software feature parity even with offload. The joins received on the satellite
access ports reach the active host and gets processed by the IGMP snoop module.
• The IGMP snoop sync feature running over ICCP protocol synchronizes the joined multicast group
• The hosts independently offload eligible routes to the relevant satellite devices through SDAC. This
• The joins also get propagated to the core by each of the hosts if they have an active link to the core. This
• When traffic comes in from the source, a special indication in the satellite 802.1ah encapsulation header
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data packets from satellite to represent satellite access port. Unicast ISID is used to identify the
Slot/Subslot/Port of a satellite for unicast packets. It is scoped over a satellite.
to represent offloaded Multicast Route (S, G) per Ring.
and replicates multicast packets for all receivers (satellite access ports) for route (S, G) from the designated
multicast forwarder.
replicated on the satellite for access ports.
traversing through the satellite.
cables or connection interface failure, the Standby unicast host shall become the new Active Unicast
Host.
topology.
membership information to the other host. This keeps the IGMP protocol state for receivers joining over
satellite access ports in sync across both hosts.
includes the list of local ports that have expressed interest in this route.
allows better convergence in case of a redundancy switchover on the satellites.
signals the satellite devices about the offloaded route to which this packet belongs to. The host then
transmits the packet out of a dynamically elected master OLE for each route (S,G) on a specific bridge
domain per ring. Then, the satellite devices locally replicate the traffic to all the intended local receivers
on that device.
Configuring Multicast Offload on the Satellite nV System