Module-first matching schemes for scalable input-queued space-space-space clos-network packet switches

Chuan Bi Lin, Roberto Rojas-Cessa

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Clos-network switches were proposed as a scalable architecture for the implementation of large-capacity circuit switches. In packet switching, the three-stage Clos-network architecture uses small switches as modules to assemble a switch with large number of ports or aggregated ports with high data rates. Current schemes for configuration of input-queued threestage Clos-network (IQC) switches involve port matching and path routing assignment, in that order. The implementation of a scheduler capable of matching thousands of ports in large-size switches is complex because of the large port count. To decrease the scheduler complexity for such switches (e.g., 1024 ports or more), we propose a configuration scheme for IQC switches that hierarchizes the matching process. In a practical scenario our scheme performs routing first and port matching thereafter. This approach applies the reduction concept of Clos networks to the matching process. The application of this approach results in a feasible size of schedulers for up to Exabit-capacity switches, an independent configuration of the middle stage modules from port matches, a reduction of the matching communication overhead between different stages, and a release of the switching function to the last-stage modules in a 3-stage switch. We show that the switching performance of the proposed approach using weightbased and weightless selection schemes is high under uniform and nonuniform traffic.

Original languageEnglish (US)
Title of host publicationICC 2008 - IEEE International Conference on Communications, Proceedings
Number of pages5
StatePublished - 2008
EventIEEE International Conference on Communications, ICC 2008 - Beijing, China
Duration: May 19 2008May 23 2008

Publication series

NameIEEE International Conference on Communications
ISSN (Print)0536-1486


OtherIEEE International Conference on Communications, ICC 2008

All Science Journal Classification (ASJC) codes

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


  • Clos-network switch
  • Input queued
  • Matching
  • Scheduler design
  • Space-space-space switch


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