Layering as optimization decomposition: Questions and answers

Mung Chiang, Steven H. Low, A. Robert Calderbank, John C. Doyle

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

10 Scopus citations


Network protocols in layered architectures have historically been obtained on an ad-hoc basis, and much of the recent cross-layer designs are conducted through piecemeal approaches. Network protocols may instead be holistically analyzed and systematically designed as distributed solutions to some global optimization problems in the form of generalized Network Utility Maximization (NUM), providing insight on what they optimize and on the structures of network protocol stacks. In the form of 10 Questions and Answers, this paper presents a short survey of the recent efforts towards a systematic understanding of "layering" as "optimization decomposition". The overall communication network is modeled by a generalized NUM problem, each layer corresponds to a decomposed subproblem, and the interfaces among layers are quantified as functions of the optimization variables coordinating the subproblems. Furthermore, there are many alternative decompositions, each leading to a different layering architecture. Industry adoption of this unifying framework has also started. Here we summarize the current status of horizontal decomposition into distributed computation and vertical decomposition into functional modules such as congestion control, routing, scheduling, random access, power control, and coding. We also discuss under-explored future research directions in this area. More importantly than proposing any particular crosslayer design, this framework is working towards a mathematical foundation of network architectures and the design process of modularization.

Original languageEnglish (US)
Title of host publicationMilitary Communications Conference 2006, MILCOM 2006
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Print)1424406188, 9781424406180
StatePublished - Jan 1 2006
EventMilitary Communications Conference 2006, MILCOM 2006 - Washington, D.C., United States
Duration: Oct 23 2006Oct 25 2006

Publication series

NameProceedings - IEEE Military Communications Conference MILCOM


OtherMilitary Communications Conference 2006, MILCOM 2006
Country/TerritoryUnited States
CityWashington, D.C.

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


  • Adaptive coding
  • Congestion control
  • Cross-layer design
  • Distributed algorithm
  • Lagrange duality
  • MAC
  • Network architecture
  • Network utility maximization
  • Optimization
  • Power control
  • Reverse engineering
  • Routing
  • Scheduling
  • Stochastic control
  • TCP/IP


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