Supporting Bandwidth Guarantees in Buffer-Limited Networks†

Flows traversing a buffer-limited network can suffer rapid throughput deterioration with increasing path length. This paper introduces a distributed transmission scheduling scheme that supports strong bandwidth guarantees for flows routed over a large number of hops, without compromising network utilization. The scheme is defined within a reservation-based transmission control framework. Through randomization at the ingress routers and batch scheduling of transmission requests at the links, it ensures that a fraction of transmissions from each ingress–egress connection consistently experience low blocking probability at every hop. These requests are therefore likely to survive long paths. The scheme supports provable bounds on the expected blocking rate and its tail probability. We compare the bounds achieved under this scheme to those obtained when the blocking probability of each request at a link is equal to the link’s blocking rate. We find that the proposed scheme improves the bounds for connections experiencing blocking at multiple hops without weakening the bounds for other connections.