Abstract
Setting the many parameters available to the operator in a QoS-enabled IP network in order to achieve peak performance is a highly non-trivial task. Individual settings are not independent; and their consequences depend upon the traffic and application mix, the behaviour of higher-level protocols, the remainder of the network, and the customer's response. To complicate matters further, settings which optimise mean achievable bandwidth for large files may be very different from those best for Web-browsing applications; and within a single class the preferred values to minimise mean or median delays may be different from those which minimise different percentiles. To study the behaviour of all these, a range of techniques needs to be employed. This paper gives examples of analytic, simulation and experimental approaches, and shows how they are all needed for an in-depth understanding.
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References
Heinanen J, Baker F, Weiss W and Wroclawski J: ‘Assured forwarding PHB group’, draft-ietf-diffserv-af-01 (October 1998).
Gibbens R J, Sargood S K, Kelly F P, Azmoodeh H, Macfadyen R N, and Macfadyen N W: ‘An approach to service level agreements for IP networks with differentiated services’, Royal Society Discussion Meeting on Network Modelling in the 21st Century, December 1999 – http://www.statslab.cam.ac.uk/~richard/research/ topics/royalsoc1999/
May M, Bolot J-C, Jean-Marie A and Diot C: ‘Simple performance models of differentiated services schemes for the Internet’, Proc of Infocom'99 (1999).
Cao J, Cleveland W S, Lin D and Sun D X: ‘Internet traffic tends to Poisson and independent as the load increases’, Bell Labs (2001).
Floyd S: ‘Recommendations on using the ‘gentle’ variant of RED’, (March 2000) – http://www.aciri.org/floyd/red/gentle.html
Macfadyen N W: ‘Traffic characterisation and modelling’, BT Technol J, 20, No 3, pp 14–30 (July 2002).
Bonald T, May M and Bolot J-C: ‘Analytic evaluation of RED performance’, Proc of Infocom 2000, pp 1415–1424 (2000).
Clark D D and Fang W: ‘Explicit allocation of best effort packet delivery service’, MIT Lab for Computer Science – http:// DiffServ.lcs.mit.edu/Papers/exp-alloc-ddc-wf.pdf
Christiansen M, Jeffay K, Ott D and Donelson Smith F: ‘Tuning RED for Web traffic’, SIGCOMM2000 (2000) – http://www.cs.unc.edu/ ~jeffay/talks/SIGCOMM-00.pdf
Claffy K et al: ‘The nature of the beast: recent traffic measurements from an Internet backbone’, INET98 (1998) – http://www.caida.org/ outreach/papers/Inet98/
Stevens W R: ‘TCP/IP Illustrated: The Protocols’, Vol 1, Addison Wesley (1994).
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Carter, S.F., Macfadyen, N.W., Martin, G.A.R. et al. Techniques for the Study of QoS in IP Networks. BT Technology Journal 20, 100–115 (2002). https://doi.org/10.1023/A:1020803911700
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DOI: https://doi.org/10.1023/A:1020803911700