Concurrent round-robin dispatching scheme in a Clos-network switch

E. Oki, Z. Jing, R. Rojas-Cessa, H. Jonathan Chao

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


A Clos-network switch architecture is attractive because of its scalability. Previously proposed implementable dispatching schemes from the first stage to the second stage, such as random dispatching, are not able to achieve a high throughput unless the internal bandwidth is expanded. This paper proposes a concurrent round-robin dispatching (CRRD) scheme for a Clos-network switch, to overcome the throughput limitation of the random dispatching scheme. The CRRD scheme provides high switch throughput without expanding internal bandwidth. CRRD implementation is very simple because only simple round-robin arbiters are adopted. In CRRD, the round-robin arbiters concurrently perform the matching between requesting cells and output links in each first-stage module to dispatch the cells to available second-stage modules. We show that CRRD achieves 100% throughput under uniform traffic. When the offered load reaches 1.0, the pointers of round-robin arbiters at the first-stage and second-stage modules are effectiv ely desynchronized and contention is avoided.

Original languageEnglish (US)
Title of host publicationIEEE International Conference on Communications
Number of pages5
Publication statusPublished - 2001
EventInternational Conference on Communications (ICC2001) - Helsinki, Finland
Duration: Jun 11 2000Jun 14 2000


OtherInternational Conference on Communications (ICC2001)



  • Arbitration
  • Clos-network switch
  • Dispatching
  • Packet switch
  • Throughput

ASJC Scopus subject areas

  • Media Technology

Cite this

Oki, E., Jing, Z., Rojas-Cessa, R., & Chao, H. J. (2001). Concurrent round-robin dispatching scheme in a Clos-network switch. In IEEE International Conference on Communications (Vol. 1, pp. 107-111)