A communication traffic routing apparatus, comprising: a metric information collector operable to collect, from metric information generated by at least one remote route computation element (15, 17, 19, 21, 22, 53, 55, 57, 73, 75, 77) that is capable of computing routes for virtual connections between the routing apparatus and other routing apparatus over an underlying communication system, metric information associated with a plurality of different computed routes for a virtual connection with a destination, and wherein, if said routes span multiple routing domains, said metric information collector is operable to combine metric information for multiple route segments of said routes to determine an end-to-end metric for each route; and a selection module operatively coupled to the metric information collector and operable to select, from the different computed routes, based on the collected metric information, a route for a virtual connection with the destination, wherein the different computed routes comprise a currently selected route of an existing virtual connection that has been established with the destination, wherein the selection module is operable to re-optimize the existing virtual connection by determining, based on the collected metric information, whether the existing virtual connection or a virtual connection over an alternate one of the different computed routes should be used for subsequent communications with the destination, the determining taking into account a minimum margin of improvement over the existing virtual connection, and wherein, if said routes span multiple routing domains, said selection module is operable to perform said step of re-optimizing the existing virtual connection based on said end-to-end metric. a metric information collector operable to collect, from metric information generated by at least one remote route computation element (15, 17, 19, 21, 22, 53, 55, 57, 73, 75, 77) that is capable of computing routes for virtual connections between the routing apparatus and other routing apparatus over an underlying communication system, metric information associated with a plurality of different computed routes for a virtual connection with a destination, and wherein, if said routes span multiple routing domains, said metric information collector is operable to combine metric information for multiple route segments of said routes to determine an end-to-end metric for each route; and a selection module operatively coupled to the metric information collector and operable to select, from the different computed routes, based on the collected metric information, a route for a virtual connection with the destination, wherein the different computed routes comprise a currently selected route of an existing virtual connection that has been established with the destination, wherein the selection module is operable to re-optimize the existing virtual connection by determining, based on the collected metric information, whether the existing virtual connection or a virtual connection over an alternate one of the different computed routes should be used for subsequent communications with the destination, the determining taking into account a minimum margin of improvement over the existing virtual connection, and wherein, if said routes span multiple routing domains, said selection module is operable to perform said step of re-optimizing the existing virtual connection based on said end-to-end metric.