Scope And Prerequisites - Cisco ASR 9000 Series System Configuration Manual

Scope and Prerequisites

same packet is sent to the satellite for each of the receivers which can eventually oversubscribe the fabric
bandwidth.
With the increasing scale of satellites over the new topologies, especially the ring topology, it is evident that
the model of Host side replication is not very efficient or scalable. The nV Satellite multicast offload feature
is introduced to solve this problem. This feature allows the Host to forward just the pre-replicated multicast
streams per multicast route (S,G) to the satellites on the ring and offload the per satellite access port replication
to the satellite device itself. The protocols still run on the Cisco IOS-XR Software modules of the Host but
the final replication happens locally on the satellite device based on selective download of routes to the
satellites.
Figure 16: Satellite nV System Multicast Offload Illustration
Without offload, Host 1 (assuming that it is the active for both Satellite 1 and Satellite 2) sends 4 copies to
receivers 1,2,3 and 4 even if they join the same multicast group, (S1,G1). With offload, Host 1 sends 1 copy
and Satellite 1 replicates it twice for receivers 1 and 2 and Satellite 2 replicates it twice for receivers 3 and 4.

Scope and Prerequisites

These are the supported requirements and prerequisites:
• Protocol: IGMP Snooping protocol.
• Satellite topologies: Simple Ring topology with Dual Host, which is a variant of a simple chain with
Cisco ASR 9000 Series Aggregation Services Router nV System Configuration Guide, Release 5.3.x
104
Note There is no support for Satellite nV offload for Layer 3 multicast, IPv6 multicast traffic
or MLD snooping protocol.
single host.
Configuring Multicast Offload on the Satellite nV System