Forwarding state scalability for multicast provisioning in IP networks

Forwarding state scalability is one of the critical issues that delay the multicast deployment in IP networks. With traditional multicast routing protocols, a forwarding tree is built for each multicast session, and each router is required to maintain a forwarding entry for each multicast session whose distribution tree passes through the router. This poses the multicast forwarding state scalability issue when the number of concurrent multicast sessions is very large. We first present a survey of existing work addressing this scalability issue for providing scalable IP multicast. Then we extend an existing multicast routing protocol, Multicast Extension to OSPF (MOSPF), to scale well with respect to the number of concurrent multicast sessions by introducing tunnel support. This extension aims to reduce the protocol overhead associated with MOSPF. Simulation results show that the extension can significantly reduce multicast forwarding state and computational overhead at routers without affecting the per-destination shortest path characteristic of a resulting tree or introducing extra control overhead.

[1]  Michalis Faloutsos,et al.  Aggregated multicast: an approach to reduce multicast state , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[2]  Ion Stoica,et al.  REUNITE: a recursive unicast approach to multicast , 2000, Proceedings IEEE INFOCOM 2000. Conference on Computer Communications. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies (Cat. No.00CH37064).

[3]  Srinivasan Seshan,et al.  A case for end system multicast , 2002, IEEE J. Sel. Areas Commun..

[4]  Gerald W. Neufeld,et al.  Forwarding state reduction for sparse mode multicast communication , 1998, Proceedings. IEEE INFOCOM '98, the Conference on Computer Communications. Seventeenth Annual Joint Conference of the IEEE Computer and Communications Societies. Gateway to the 21st Century (Cat. No.98.

[5]  D. Estrin,et al.  The MASC/BGMP architecture for inter-domain multicast routing , 1998, SIGCOMM '98.

[6]  David Thaler,et al.  On the aggregatability of multicast forwarding state , 2000, Proceedings IEEE INFOCOM 2000. Conference on Computer Communications. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies (Cat. No.00CH37064).

[7]  Reuven Cohen,et al.  Restricted dynamic Steiner trees for scalable multicast in datagram networks , 1997, Proceedings of INFOCOM '97.

[8]  Randy H. Katz,et al.  An analysis of multicast forwarding state scalability , 2000, Proceedings 2000 International Conference on Network Protocols.

[9]  D. Estrin,et al.  Exploiting the Bandwidth-Memory Tradeoff in Multicast State Aggregation , 1999 .