Cross-layer techniques for failure restoration of IP multicast with applications to IPTV

Broadcast TV distribution over an IP network requires stringent QoS constraints, such as low latency and loss. Streaming content in IPTV is typically delivered to distribution points on an IP backbone using IP multicast protocols such as Protocol Independent Multicast Source Specific Mode (PIM-SSM). Link-restoration using MPLS or layer-2 Fast Reroute (FRR) is a proven failure restoration technique. Link-based FRR creates a pseudo-wire or tunnel in parallel to the IP adjacencies (links); and thus, single link failures are transparent to the Interior Gateway Protocol (IGP) such as OSPF. Although one may choose the back-up path's IGP link weights to avoid traffic overlap during any single physical link failure, multiple failures may still cause traffic overlap with FRR. We present a cross-layer restoration approach that combines both FRR-based restoration for single link failure and “hitless” (i.e., without loss) PIM tree reconfiguration algorithms to prevent traffic overlap when multiple failures occur.