Using TCP models to understand bandwidth assurance in a Differentiated Services network

In this paper, a comprehensive analytical model to predict the bandwidth achieved by aggregates of TCP flows in a DiffServ network is presented. The model predicts achieved bandwidth in three different cases: an over-provisioned network, an under-provisioned network, and a near-provisioned network. In developing the model, we ensure that all parameters are measurable using standard tools and information available from routers and network management tools in today's networks. Simulation was used to establish the validity of the model and understand its scope of applicability and limitations. Using the model, we explain why achieved excess bandwidth is based on factors such as RTT, packet size, and CIR. Finally, we present a novel extension of the model to predict the bandwidth of TCP flows in a Diffserv network with multiple congested nodes.

[1]  A. L. Narasimha Reddy,et al.  Modeling TCP behavior in a differentiated services network , 2001, TNET.

[2]  Biswajit Nandy,et al.  Bandwidth assurance issues for TCP flows in a differentiated services network , 1999, Seamless Interconnection for Universal Services. Global Telecommunications Conference. GLOBECOM'99. (Cat. No.99CH37042).

[3]  Sally Floyd,et al.  Connections with multiple congested gateways in packet-switched networks part 1: one-way traffic , 1991, CCRV.

[4]  Donald F. Towsley,et al.  On achievable service differentiation with token bucket marking for TCP , 2000, SIGMETRICS '00.

[5]  SemkeJeffrey,et al.  The macroscopic behavior of the TCP congestion avoidance algorithm , 1997 .

[6]  Ioannis Lambadaris,et al.  Empirical study of buffer management scheme for Diffserv assured forwarding PHB , 2000, Proceedings Ninth International Conference on Computer Communications and Networks (Cat.No.00EX440).

[7]  Donald F. Towsley,et al.  Modeling TCP throughput: a simple model and its empirical validation , 1998, SIGCOMM '98.

[8]  Matthew Mathis,et al.  The macroscopic behavior of the TCP congestion avoidance algorithm , 1997, CCRV.

[9]  David D. Clark,et al.  Explicit allocation of best-effort packet delivery service , 1998, TNET.

[10]  Victor Firoiu,et al.  A study of active queue management for congestion control , 2000, Proceedings IEEE INFOCOM 2000. Conference on Computer Communications. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies (Cat. No.00CH37064).

[11]  A. L. Narasimha Reddy,et al.  Realizing throughput guarantees in a differentiated services network , 1999, Proceedings IEEE International Conference on Multimedia Computing and Systems.