The present invention provides improved methods and systems to build an integrated IP network in which high-quality services such as voice and best-effort data services can be provided with higher reliability and lower cost. A new type of
router, called a PACS
router, is disclosed in which the user terminals, computer servers, access routers and other service terminals are connected to the integrated
router. A PACS router includes a packet-switching fabric and a circuit-switching fabric interconnected by
channelized high-speed links. The PACS router creates and uses two types of channels within
channelized high-speed links, which in turn are transported from one router to another via SONET network links. The channels are labeled as either packet-channel or circuit-channel according to the usage of these channels. High-quality services are mapped into a circuit-channel at the service originating router and routed through the circuit-switching fabrics in the routers. The best-effort services, on the other hand, are mapped into a packet-channel, which is terminated in each PACS router where packets from packet-channels are extracted and routed hop-by-hop according to the packet destination header address. A network built with PACS routers uses signaling and routing protocols to segregate traffic into different classes and
route them using circuit-channels and packet-channels depending on
quality of service requirements. Routing high-quality service over circuit-channels eliminates routing
delay typically incurred in packet-switching fabrics, enhances reliability from
software malfunction in the router since existing connection at circuit-switching fabric does not depend on
software control and enhances network
scalability by not having to terminate all traffic into packet-switching fabrics in every PACS router. The circuit-switching fabrics in the PACS routers also provide further
immunity by fast rerouting of failed circuits via alternate routes when a network fault is detected.