Granularity of QoS Routing in MPLS Networks

  • Ying-Dar Lin
  • Nai-Bin Hsu
  • Ren-Hung Hwang
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2092)


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.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Ying-Dar Lin
    • 1
  • Nai-Bin Hsu
    • 1
  • Ren-Hung Hwang
    • 2
  1. 1.Dept of Computer and Info. ScienceNational Chiao Tung UniversityHsinchuTaiwan
  2. 2.Dept of Computer Science and Info. Eng.National Chung Cheng UniversityChiayiTaiwan

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