A framework for cooperative inter-domain QoS routing

Currently, a straightforward way to design BGP-based Traffic Engineering (TE) tools for stub Autonomous Systems (AS) is to rely on selfish routing mechanisms. Although TE tools can find an optimal solution, this optimum represents only a local optimum for outbound traffic. Indeed, this is one of the main limitations of the selfish routing approach. This approach makes the TE tools unaware of the effects of their route choices on transit AS throughout the chosen paths, due to uncoordinated routing decisions, and congestion can occur on distant intra- or inter-domain links. Thus, cooperation among AS is the key to avoid the performance degradation and routing instability caused by the selfish routing approach and it would be fundamental for the future QoS-aware Internet. With these objectives in mind this paper presents and discusses a framework for coordinated Inter-domain QoS Routing (QoSR) decisions among stub and downstream AS taking into account multiple traffic QoS constraints and routing preferences. The paper includes a description of the main mechanisms and algorithms that integrate the framework, and finally a discussion of the implementation issues.