Abstract: A communications node for handling circuit and packet switching and capable of expansion to include multiple switching matrices, multiple network processors and multiple packet processors is disclosed. Each switch matrix has multipile I/O ports and communications with user interfaces, network interfaces and other system components via bidirectional data links. At least one switch matrix is connected via a bidirectional data link to a packet processor and a network processor. All processors are interconnected via a computer bus. Switch matrices are connected to each other either by a backplane bus or via bidirectional data links.

Abstract: A communications network comprising nodes interconnected by communication lines employs a method of allocating data rates to fragments of line bandwidth which facilitates efficient allocation of available line bandwidth. Each node maintains, for each communication line connected to it, a bit map means having a bit position associated with each fragment available in the line for keeping track of which fragments are available and which are in use. Identification of available bandwidth fragments in the line is then accomplished by finding appropriate bit values in the bit map means; fragments allocated are marked in the bit map means. A node thus need not allocate fragments contiguously, and available bandwidth is equally allocable by either of the two nodes interconnected by a particular line.