Abstract: A flexible mechanism for routers to select the egress point for each destination prefix, herein referred to as tunable inter-domain egress (TIE) selection, comprises the step of ranking possible points of egress according to a metric, allowing network administrators to satisfy diverse goals, such as traffic engineering and robustness to equipment failures. A weighting function is discussed whereby known hot potato routing can be weighted against a fixed ranking scheme. TIE has been applied to data of two different autonomous systems posing different problems solved using integer-programming and multi-commodity flow techniques, respectively, to tune the TIE according to the weighting function to satisfy network-wide objectives. Experiments with traffic, topology and routing data from two different backbone networks demonstrate that TIE is both simple (for the routers) and expressive (for the network administrators) and can be practically applied in traffic engineering.

Abstract: A flexible mechanism and method for routers to select the egress point for each destination comprises identifying a plurality of points of egress from an autonomous system, ranking the plurality of points of egress according to a metric having variable and fixed terms, selecting a point of egress having the smallest rank, and transmitting packets from a point of ingress via a path to the selected point of egress. The metric is across a plurality of destinations and respective possible points of egress from the autonomous system and the metric is m(i, p, e) equaling ?(i, p, e)·d(G,i,e)+?(i, p, e) where a and ? are configurable values, i is the identity of the router, p is the destination, G is an undirected weighted graph, the d function is the interior gateway protocol distance and e is a point of egress.