Twisted pair ethernet hub for a star local area network

In a star local area network in which a plurality of stations are connected to a common hub, each of said stations including means for generating a collision detect signal, the improvement in said hub comprising:

• selection logic for selecting a preferred station and a preferred station frame from among ones of said plurality of stations that attempt to transmit a frame simultaneously,
• said selection logic including a precedence algorithm logic, the ones of said plurality of stations that attempt to transmit a frame that are not selected being designated as non-preferred stations;
• said preferred station frame including a destination address;
• a switching control connected to said selection logic for allowing said preferred station frame transmitted from said preferred station to pass through said common hub to said plurality of stations;
• a destination address decoder for decoding said destination address of said selected frame to thereby identify a destination station of said preferred station;
• a collision detector connected to said switching logic for detecting a collision detect signal from said non-preferred stations that attempt to transmit a frame;
• said switching logic including a buffer for storing said preferred station frame from said preferred station, upon a condition that said collision detector detects a collision detect signal from said destination station;
• boundary detection means for detecting a logical boundary between transmitted frames;
• a retransmit logic connected to said boundary detection logic and to said buffer for retransmitting said preferred station frame from said buffer to said destination station immediately after detection of said logical boundary between transmitted frames;
• and,
• a collision frame generator connected to said buffer for generating a collision frame upon a condition that said preferred station frame is not successfully retransmitted from said buffer after a predetermined number of attempts.

A method of transmitting message frames within a star local area network in which a plurality of stations are connected to a common hub, comprising the steps of:

• A. selecting a preferred station from among ones of said plurality of stations that attempt to transmit a frame simultaneously, said selecting being done by performing a precedence algorithm at said common hub, the ones of said plurality of stations that attempt to transmit a frame that are not selected being designated as non-preferred stations;
• B. allowing a preferred station frame transmitted from said preferred station to pass through said common hub to said plurality of stations;
• C. sensing collisions in all of said non-preferred stations that attempt to transmit a frame;
• D. stopping transmission at all of said non-preferred stations that sense a collision;
• E. storing said preferred frame from said preferred station in a buffer in said hub, upon a condition that a destination station receiving from said preferred station transmits a destination station frame;
• F. retransmitting said preferred station frame from said buffer to said destination station immediately after a logical boundary between transmitted frames, upon a condition that a collision occurs between said preferred station and said destination station;
• and,
• G. generating a collision frame at said common hub upon a condition that said preferred station frame is not successfully retransmitted from said buffer after a predetermined number of attempts.