Logical channel resolution in asynchronous transmission mode communication systems

摘要

An asynchronous transmission mode data cell header includes virtual channel and virtual path identifiers which are resolved into logical channel identifiers at the user interface by two table lookup operations. The virtual path identifier is used to access a virtual path table entry having a variable length pointer value buffered out to a fixed length field by zeros with a binary one at the boundary position. Using the binary one as a marker, the pointer field is extracted and concatenated with a base register value and the lower order bits of the virtual channel identifier, corresponding to the bit position of the binary one marker, to provide an index into a logical channel identifier table. The logical channel identifier is used to associate the data cell attached to that header with the appropriate user data stream.