End-to-end QoS routing framework for differentiated services networks

Differentiated services (DiffServ) is the latest model proposed by Internet engineering task force (IETF) to support quality of service (QoS) in the Internet. It has flexibility and scalability advantages over the earlier model, namely, integrated services (IntServ). Currently, the DiffServ model is the preferred architecture widely accepted by Internet providers and the networking research community. The goal of the DiffServ model is to avoid maintaining large amount of state information in core routers, and carry out aggregate resource reservation at edge routers. Therefore, DiffServ calls for a very different routing framework from IntServ. In this paper, we propose two new QoS-based routing algorithms under the single service, multiple options (SiMO) framework for DiffServ architectures. These are kth-shortest QoS routing (kthQoSR) and maximum energy value QoS routing (EVQoSR). We also introduce QoS extensions to OSPF and compare it to our SiMO routing protocols. Our core routing strategy in SiMO, kthQoSR, is executed at the path level and selects one or more routes from a set of computed routes according to defined selection metrics. On the other hand, EVQoSR is a link level, online distributed routing algorithm. Through extensive simulations, we demonstrate that our proposed SiMO routing framework can achieve better route qualities in terms of load balancing, and network throughput. (C) 2002 Elsevier Science B.V. All rights reserved.