Packet delay in optical circuit-switched networks

Zvi Rosberg, Andrew Zalesky, Moshe Zukerman

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


A framework is provided for evaluation of packet delay distribution in an optical circuit-switched network. The framework is based on a fluid traffic model, packet queueing at edge routers, and circuit-switched transmission between edge routers. Packets are assigned to buffers according to their destination, delay constraint, physical route and wavelength. At every decision epoch, a subset of buffers is allocated to end-to-end circuits for transmission, where circuit holding times are based on limited and exhaustive circuit allocation policies. To ensure computational tractability, the framework approximates the evolution of each buffer independently. "Slack variables" are introduced to decouple amongst buffers in a way that the evolution of each buffer remains consistent with all other buffers in the network. The delay distribution is derived for a single buffer and an approximation is given for a network of buffers. The approximation entails finding a fixed point for the functional relation between the "slack variables" and a specific circuit allocation policy. An analysis of a specific policy, in which circuits are probabilistically allocated based on buffer size, is given as an illustrative example. The framework is shown to be in good agreement with a discrete event simulation model.

Original languageEnglish
Pages (from-to)341-354
Number of pages14
JournalIEEE/ACM Transactions on Networking
Issue number2
StatePublished - 1 Apr 2006


  • Circuit switching
  • Fixed point approximation
  • Packet delay
  • WDM network

ASJC Scopus subject areas

  • Software
  • Computer Science Applications
  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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