Routing in the PSTN (original) (raw)

Routing in the PSTN is the process of forwarding telephone calls between the constituent telephone networks that comprise the public switched telephone network (PSTN). Telephone calls are routed across a network of potentially many switching systems, often owned by different telephone carriers. Switching systems are connected with trunks. Each switch may have many neighbors. Neighboring switches owned by different operators are connected at interconnect points.