Multipath routing mechanisms for traffic engineering and quality of service in the Internet.

摘要

The success of the IP architecture is largely due to the simplicity, robustness and scalability that resulted from its the connection-less design methodology. As the Internet evolves, it must support new services such as QoS, and when extensions are made to the EP architecture to support such services, its basic connection-less model must be preserved to retain the scalability and robustness that made it so successful. In the past few years, with the Internet becoming the main communication infrastructure, IP networks are faced with two challenging problems that require immediate attention: traffic engineering and supporting guaranteed services. Providing efficient, robust and scalable solutions to these problems within the framework of the connection-less IP has become extremely important and urgent.; The traffic engineering problem arose mainly because the single-path routing prevalent in IP networks proved very inefficient in the face of rapid growth of the Internet. To improve performance of current IP networks, several solutions based on the multi-protocol label-switching (MPLS) have been proposed by IETF. The main idea in these approaches is to setup alternate paths using label-switching, and distribute traffic over them. There are couple of serious concerns with these approach. First, most of the proposed solutions are not based on any theoretical results on optimal routing. Second, using connection-oriented technology like virtual circuits or MPLS violates its connection-less methodology of IP that contributed to the very success of the Internet. These approaches tend to replace the IP architecture, rather than evolve it. We propose a solution to the traffic engineering problem that addresses these concerns. The key idea in our approach is to use multipaths to implement “near-optimal” routing, while keeping the scalability of data and control plane mechanisms similar to that in today's IP routing. More importantly, the proposed approach preserves the connection-less nature of the IP architecture.; Today, there is a growing need to support real-time applications that require delay and bandwidth guarantees. To address this, the IETF proposed the Intserv architecture and the associated RSVP. This architecture does not scale well to backbone networks that carry large numbers of flows because of the per-flow reservations and per-flow processing that is required in the routers. Several other architectures have also been proposed to support guaranteed services, but most of them are either inefficient in terms of bandwidth utilization, or use connection-oriented approaches such as virtual circuits and MPLS. The main concern with all these architecture, besides scalability, is that they introduce connection-oriented mechanisms in the IP architecture, thus compromising its robustness. We base our approach to this problem on multipaths, and provide a complete solution through a novel architecture, SMART, which adheres to connection-less nature of the IP architecture. We show how multipaths can help achieve scalability and performance of the network, without sacrificing the kind of service guarantees that can be offered to end users.