Granularity of QoS Routing in MPLS Networks
This study investigates how the Constraint-based routing decision granularity significantly affects the scalability and blocking performance of QoS routing in MPLS network. The coarse-grained granularity, such as per-destination, has lower storage and computational overheads but is only suitable for best-effort traffic. On the other hand, the finegrained granularity, such as per-flow, provides lower blocking probability for bandwidth requests, but requires a huge number of states and high computational cost.
To achieve cost-effective scalability, this study proposes using hybrid granularity schemes. The Overflowed cache of the per-pair/flow scheme adds a per-pair cache and a per-flow cache as the routing cache, and performs well in blocking probability with a reasonable overflow ratio of 10% as offered load=0.7. Per-pair/class scheme groups the flows into several paths using routing marks, thus allowing packets to be labelforwarded with a bounded cache.
Unable to display preview. Download preview PDF.
- 1.D. Black, S. Blake, M. Carlson, E. Davies, Z. Wang, and W. Weiss. An architecture for differentiated services. RFC 2475, December 1998.Google Scholar
- 2.K. Nichols, S. Blake, F. Baker, and D. Black. Definition of the differentiated services field (DS Field) in the ipv4 and ipv6 headers. RFC 2474, December 1998.Google Scholar
- 3.T. Li and Y. Rekhter. A provider architecture for differentiated services and traffic engineering(PASTE). RFC 2430, October 1998.Google Scholar
- 4.Y. Bernet, J. Binder, S. Blake, M. Carlson, S. Keshav, E. Davies, B. Ohlman, D. Verma, Z. Wang, and W. Weiss. A framework for differentiated services. draftietf-diffserv-framework-02.txt, February 1999.Google Scholar
- 5.R. Callon, P. Doolan, N. Feldman, A. Fredette, G. Swallow, and A. Viswanathan. A framework for multiprotocol label switching. draft-ietf-mpls-framework-05.txt, September 1999.Google Scholar
- 6.Eric C. Rosen, Arun Viswanathan, and Ross Callon. Multiprotocol label switching architecture. draft-ietf-mpls-arch-06.txt, August 1999.Google Scholar
- 7.Francois Le Faucheur, Liwen Wu, Bruce Davie, Shahram Davari, Pasi Vaananen, Ram Krishnan, and Pierrick Cheval. MPLS support of differentiated services. draft-ietf-mpls-diff-ext-02.txt, October 1999.Google Scholar
- 8.Eric C. Rosen, Yakov Rekhter, Daniel Tappan, Dino Farinacci, Guy Fedorkow, Tony Li, and Alex Conta. MPLS label stack encoding. draft-ietf-mpls-label-encaps-07.txt, September 1999.Google Scholar
- 9.G. Apostolopoulos, R. Guerin, S. Kamat, and S. K. Tripathi. On Reducing the Processing Cost of On-Demand QoS Path Computation. In Proc. of International Conference on Networking Protocols (ICNP), Austin, October 1998.Google Scholar
- 10.G. Apostolopoulos, D. Williams, S. Kamat, R. Guerin, A. Orda, and T. Przygienda. QoS Routing Mechanisms and OSPF extensions. RFC 2676, August 1999.Google Scholar
- 11.J. A. Shaikh. Efficient Dynamic Routing in Wide-Area Networks. PhD thesis, University of Michigan, May 1999.Google Scholar
- 12.Q. Ma, P. Steenkiste, and H. Zhang. Routing High-Bandwidth Traffic in Max-Min Fair Share Networks. In SIGCOMM’96. ACM, August 1996.Google Scholar
- 13.B. M. Waxman. Routing of Multipoint Connections. IEEE JSAC, 6(9):1617–1622, December 1988.Google Scholar
- 14.D. Zappala, D. Estrin, and S. Shenker. Alternate Path Routing and Pinning for Interdomain Multicast Routing. Technical Report 97-655, USC, 1997.Google Scholar