Abstract

A method and apparatus are disclosed for selectively accessing and independently sizing connection identification tables within a network switch. Upon receipt of a data unit, such as an asynchronous transfer mode cell at an input port of an Input Output Module, a plurality of selection bits are inserted into the cell header which are used to select one of a plurality of connection identifiers. The VPI/VCI addresses are mapped into a connection identifier and the connection identifier is also inserted within the respective cell header. The connection identifier may comprise an unicast connection identifier, a multicast connection identifier, or a redundant unicast identifier. The unicast, multicast and redundant identifiers are either stored in separate tables at call setup and the tables are independently selectable via use of the selection bits stored within the cell header. Alternatively, the selection bits are employed to specify a register which points to the first address for the respective type of identifiers. Thus, identifiers of a particular connection type are accessible via a base address plus an offset address. In the described manner, tables or portions of tables containing connection identifiers may be flexibly and independently sized.