Inter-Domain QoS Routing with Virtual Trunks

This paper addresses the problem of inter-domain QoS routing. We propose a solution based on virtual-trunk type aggregates corresponding to service level agreements (SLA) for data transport between peering domains. We formally state the problem and formulate it in integer linear programming. As a practical solution, we propose an extension to the BGP routing protocol, QoSJNFO, conveying three QoS metrics (light load delay, assigned bandwidth and a congestion alarm), and a path selection algorithm using a combination of these metrics. We present simulation results of QoSJNFO, standard BGP, and BGP with the QoS_NLRI extension, and compare them with the optimal route set provided by the ILP formulation. The results show that our proposal yields better QoS parameters than standard BGP or BGP with the QoS_NLRI extension, since it is able to efficiently avoid congested paths, and that the impact of QoSJNFO in route stability is relatively low.