Provider-Level Service Agreements for Inter-domain QoS Delivery

In the current Internet, business relationships and agreements between peered ISPs do not usually make specific guarantees on reachability, availability or network performance. However, in the next generation Internet, where a range of Quality of Service (QoS) guarantees are envisaged, new techniques are required to propagate QoS-based agreements among the set of providers involved in the chain of inter-domain service delivery. In this paper we examine how current agreements between ISPs should be enhanced to propagate QoS information between domains, and, in the absence of any form of central control, how these agreements may be used together to guarantee end-to-end QoS levels across all involved domains of control/ownership. Armed with this capability, individual ISPs may build concrete relationships with their peers where responsibilities may be formally agreed in terms of topological scope, timescale, service levels and capacities. We introduce a new concept of QoS-proxy peering agreements and propose a cascade of inter-domain Service Level Specifications (SLSs) between directly attached peers: each ISP meeting the terms of the SLSs agreed with upstream peers by being responsible for its own intra-domain service levels while relying on downstream peers to fulfill their SLSs.