NGL03-1: Towards AQM Cooperation for Guaranteed Delays and Mitigated Loss in Diffserv-aware MPLS Networks

Diffserv over MPLS networks is a widely accepted approach to considerably improve networks\´ ability to support delay-sensitive applications such as voice over IP. In such networks, over-provisioning and careful admission control are still needed, although insufficient to ensure guaranteed QoS performance. Increased end-to-end loss rates and delays experienced by a service are mostly due to one or few congested switches along the label switched path "LSP" while the other routers are in relaxed conditions. In this paper, we tackle this issue by extending the traditional local management of congestions into a cooperative process involving all switches along the service path at network operator\´s scale. Going from AQM limitation, we propose a network self-managing framework that dynamically re-adjusts switches\´ parameters throughout the LSP, at the point where congestion would most likely occur. In this way, the prospective congestion impact is absorbed through balancing the routers aggressiveness without reconsidering other traffic engineering strategies (e.g., re-routing decision). While considering QoS guarantees along a given service path, network loss ratio is reduced. This obviously allows network operators to further exploit theirs underlying resources by accepting more QoS-enabled services.