With increasing number of mission critical applications and associated traffic volume on commercial and DoD IP networks, it is becoming increasingly critical for the network infrastructure to be more aware of the Quality of Service (in a broad sense of the word) requirements and use this awareness in routing, differential treatment of packets, in management-level resource provisioning and allocation. In this paper, we focus on the implication of these requirements on the routing architecture and protocols. In particular, we argue that the inter domain routing protocols like the Border Gateway Protocol (BGP) and its integration with the Interior Gateway Protocol (IGP) need to account for the diversity in the QoS requirements of the applications, users, and mission. The solution we suggest involves allowing multiple inter-AS routes for the same source destination pair, propagation of multiple routes, and of multiple QoS-affecting metrics in the BGP UPDATE messages. These enhancements allow routes to be matched with application requirements and hence allow satisfaction of applications QoS requirements at minimal cost. In order to keep the solution scalable, we limit the propagation of information to non-dominated routes, and design a small set of QoS metrics. Details of the protocols and quantitative analysis will be presented in future papers. Our approach, along with IntServe and DiffServe based QoS capabilities, and traffic engineering extensions of intra domain routing protocols, will provide a framework for end-to-end QoS-aware networking.
