Success-to-the-top class of service routing

摘要

An originating switch (110) in a packet-based telecommunications network (100) routes calls to a terminating switch using the combination of Success-to-the Top (STT) and Class-of-Service criterion. In routing a call to the terminating switch, the originating switch 110 checks for available bandwidth for the class of service of the call on the direct path (116) between switches. If the path has available bandwidth, the originating switch routes on the direct path. Otherwise, the originating switch searches for the most recently successful one of a plurality the via switches (118₁-118_n) linking the originating and terminating switches to determine whether that via switch can successfully route the call to the terminating switch. If the most recently successful one of the via switches possesses available bandwidth to route the call in accordance with its class of service, the originating switch 110 selects that via switch to route the call. Otherwise, if the most-recently successful via switch can not route the call, the originating switch 110 searches for a next successful via switch. If none of the via switches 118₁-118_n can successfully route the call in accordance with its class of service, the originating switch will either attempt a route advance or crankback the call.