Abstract: A method and apparatus for routing calls in a switched digital network and a processor for use in such a network are provided in which tables of call control information store information for different categories of call control information in separate parts of the table or in separate tables. The information in the tables is available for different network entities to share in routing calls. The separation of different categories of information simplifies the task of making changes to call control tables and can allow certain of the separate tables to be portable across the network.

Abstract: A first terminal makes a call over an ISDN link to a second terminal. Both terminals support a plurality of possible protocols to be used on the ISDN B channel. The calling terminal builds the protocol stack for the desired protocol prior to requesting the call from the network. When it is notified of the B channel selected, it can then attach the already formed protocol stack to the relevant B channel. Similarly, the called terminal starts to build the desired protocol stack immediately on receipt of the call. When the protocol stack is complete, is then accepts the call from the network, and can attach the protocol stack immediately to the relevant B channel.