Abstract: The L4 application in the switch is expanded to permit functions previously performed exclusively in the L5 protocol application. Moreover, the L4 application is programmable by the system operator so that the system operator may expand the predefined set of L4 call management operations to accommodate his call processing requirements. Overall supervision of the call-management operations was previously limited to the L5 applications. However, the ability to program the L4 application enables the system operator to decide which call processing operations will be managed by the L5 applications and which operations will be managed by the L4 application. The system operator may thus define, in the L4 application, a proprietary call model that instructs the switching node to manage all incoming calls, or the system operator may specify the call model on a channel by channel basis. The latter arrangement programs the switching node to use different call-processing protocols among the various channels.

Abstract: An open, high speed, high bandwidth digital communication network for connecting multiple programmable telecommunications switches to form a large capacity, non-blocking switching system. Each network switching node includes circuitry for transmitting and receiving variable-length, packetized information over the network, thus enabling each node to receive information from or transmit information to all other nodes. The network may carry any type of information present in the system including voice, data, video, multimedia, control, configuration and maintenance, and the bandwidth of the network may be divided or shared across various information types. Devices such as voice processing resources may also interface with the network, thereby gaining direct access to all information passing through the network. Also provided are methods and packet structures for communicating information over the network.