Diffserv’s Assured Forwarding PHB: What Assurance does the Customer Have?

This paper examines issues related to assuring the throughput performance parameters of a Service Level Agreement in an Assured Forwarding based Diffserv-capable IP network. In an effort to understand the kinds of quantifiable parameters that can be included in a contract, the analysis of detailed studies on throughput are presented. Seven different factors are discussed which can bias bandwidth assurance for equal paying customers. Design options for various Traffic Conditioning schemes at the edge of the network to mitigate the effect of these factors are also discussed. The scope of network for which such schemes are viable is assessed. There are open issues that need to be addressed before such schemes can achieve their desired effect on the general Internet.