Performance Enhancement of an AF Service Using TCP-Aware Marking and Dynamic WRED

Performance analysis of relative service using TCP‐aware marking and dynamic WRED

“…In the AF framework, fair service provisioning means that flows or aggregates sharing the same resources obtain bandwidth in proportion to their contracted guaranteed capacity. In [19] it is shown how classic RED congestion notification is not dependent upon the number of active flows, a conclusion confirmed by our findings in [2,3] where we have also shown that the feedback provided by classic WRED is not very successful in service differentiation. The authors of [19] propose adaptive RED according to which the average queue length is constantly observed and updated.…”

“…When combined for Relative service provisioning, with the aid of MPLS explicit routing, TWAM and DWRED are shown to outperform current AF mechanisms, achieving adaptability under transient load, fair differentiation and high performance. Early results of the work presented here are available in [3]. Together with the generic framework of our earlier work [2], the proposed mechanisms and specific configuration guidelines provided here contribute to the realization and practical implementation of AF-based services in production DiffServ-enabled networks.…”

“…In our previous work [2,3], we have demonstrated how the adaptation of the min th , max th parameters of WRED according to the bandwidth-delay (BW * D) product of a link achieves a bounded average queue size of approximately {0.2 . .…”

“…In this way, DWRED incorporates fluctuations in available resources by exploiting the implicit indication provided by the congestion windows of TCP flows and staying in accordance with the result presented in [2,3]. DWRED uses the value of W cwnd LSP j as the indication of the end-to-end throughput of LSP AF j , with the proposed value for max th embodying all related parameters otherwise addressed by the bandwidth-delay product, including the number of hops on the particular LSP.…”

“…DWRED provides a simple but efficient WRED configuration methodology, applicable to different environments. In its generic form, as initially evaluated in [2,3], DWRED is nothing but a means to dynamically configure an AQM mechanism in backbone routers of the best-effort Internet. In the following sections, it will be experimentally verified how the use of DWRED in the framework of the Relative service (as specified in expressions (11) and (12)) combined with the TWAM can achieve fair allocation as well as very high utilization of available resources (up to 100%).…”