Link switch for a burst-switching communications system

Claim 1

A link switch for a burst-switching communications system, a burst being a plurality of bytes including a destination-port address, an information portion, and a termination portion at the end of the burst, said system including a plurality of switches interconnected by time-divided communications links, each link having a plurality of frames within each second of time, each frame having a plurality of channels, each channel having communications capacity for the transmission of one byte, a byte being a predetermined number of bits, a bit being one binary digit, said link switch comprising: (a) a central memory; (b) link-input processing means coupled with said central memory, said link-input processing means having means for coupling with a communications link, means for receiving bursts on said communications link, and means for accessing said central memory; (c) link-output processing means coupled with said central memory, said link-output processing means having means for coupling with a communications link, means for transmitting bursts on said communications link, and means for accessing said central memory; (d) at least one port, each port providing means for coupling with a control processor, an end-user instrument, or another communications system, said coupling being made via a port-interface circuit; (e) port-input processing means coupled between said central memory and at least one of said ports, said port-input processing means having means for receiving bursts from said port(s) and means for accessing said central memory; (f) port-output processing means coupled between said central memory and at least one of said ports, said port-output processing means having means for transmitting bursts to said port(s) and means for accessing said central memory; (g) memory-management means coupled with said central memory for insuring that at any given time only a single access to said central memory may occur; (h) means for routing a burst through said switch, said routing means having processing capacity sufficient to support an effective transmission rate of at least 1.544 million information-bearing bits per second on each of said communications links coupled with said link switch, said routing means including: (i) means for routing a burst through said switch from an origin port of said switch to a destination port of said same switch; (ii) means for routing a burst through said switch from an origin port of said switch to a link of said switch leading toward the destination port; (iii) means for routing a burst through said switch from a link leading into said switch to a destination port of said switch; and (iv) means for routing a burst through said switch from a link leading into said switch to a link of said switch leading toward the destination port; and (i) means for routing from port to link and from link to link employing dynamic allocation of bursts to channels within links such that any channel is allocated only when a burst is being transmitted therein and said channel is otherwise available for transmission of another burst, said switch after receiving the first byte of a burst and also determining that said burst will be transmitted on a link of said switch leading toward the destination port then transmitting said first byte in the first available channel of a first frame of said link leading toward said destination port and assigning said channel to said burst, said switch after receiving the second or a successive byte of said burst then transmitting said second or successive byte in said assigned channel of the second or successive frame of said link, said switch after transmitting the last byte of said burst then releasing said assigned channel for possible allocation to another burst in the frame immediately following the transmission of the last byte of said burst.