Method and integrated circuit for high-bandwidth network server interfacing to a local area network using CSMA/CD

• US 6,122,667 A
• Filed: 12/19/1997
• Issued: 09/19/2000
• Est. Priority Date: 01/11/1995
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Chung, David H.
• Primary Examiner(s): Rinehart, Mark H.
• Assistant Examiner(s): Prieto, Beatriz
• Application Number:
  US08/994,549
• Time in Patent Office: 1,005 Days
• Field of Search: 709/228, 709/223, 709/230, 709/245, 709/246, 709/250, 709/218, 709/219, 709/229, 709/231, 709/232, 710/40, 710/72, 710/116, 711/149, 714/46, 714/47, 714/48, 395/500.45, 370/466, 370/469, 370/474, 370/359, 370/392, 370/338, 370/445
• US Class Current: 709/228
• CPC Class Codes: H04L 45/7453 using hashing
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9063 Intermediate storage in different physical parts of a node or terminal

Abstract

A single-chip, network interface controller (NIC) integrated circuit (IC) with a host interface and arbiter common to two 10BASE-T ETHERNET local area network (LAN) segments with respective unshielded twisted pair interfaces, encoder-decoders, medium access controllers, first-in first-out register memory arrays, and buffer management. Source-address and destination-address content addressable memories are connected to respective MAC receivers in the-medium access controllers to both learn the addresses of network clients on the two segments and then to transparently bridge packets between the LAN segments. The NIC effectively increases the bandwidth of a server connection to the thus unified network.

Claims

1. A computer-implemented method of improving data throughput in a local area network (LAN) that uses a carrier sense multiple access with collision detection (CSMA/CD) protocol, the method comprising the steps of:

a. logging a medium access controller (MAC) address for each of a plurality of network interface controllers (NICs) communicating packets on a LAN segment subject to packet collisions;

b. determining whether all of the NICs are of a type that can support a collisionless packet exchange mode;

c. returning to the step of logging, when any of the NICs cannot support the collisionless packet exchange mode;

d. entering the collisionless packet exchange mode by transmitting a start packet by a selective one of the plurality of NIC'"'"'s wherein the selective one of the plurality of NICs has a lowest MAC address, when all of the NICs are of the type that can support the collisionless packet exchange mode; and

e. transmitting either a data packet or a protocol packet in a sequence slot of a transmission schedule in a round-robin style, according to the MAC address corresponding to each of the plurality of NICs.

2. The method of claim 1, further comprising the steps of:

a. determining whether a collision has occurred in the collisionless packet exchange mode; and

b. if the collision has occurred, exiting the collisionless packet exchange mode and returning to the step of logging.

3. A network interface controller (NIC) for a local area network (LAN) that uses a carrier sense multiple access with collision detection (CSMA/CD) protocol, comprising:

a. buffer means for logging a medium access controller (MAC) address for each of a plurality of external network interface controllers (NICs) communicating packets on a LAN segment subject to packet collisions;

b. type comparison means for determining whether all the external NICs are of a type that can support a collisionless packet exchange mode;

c. means for restarting the buffer means for logging the MAC address for each of the external NICs, when less than all of the external NICs are of the type that can support the collisionless packet exchange mode;

d. means for entering the collisionless exchange packet mode including MAC transmitter means for transmitting a start packet by a selective one of the external NICs, wherein the selective one of the external NICs has a lowest MAC address; and

e. fill-in means for transmitting either a data packet or a protocol packet in a sequence slot of a transmission schedule in a round-robin style, according to the MAC address corresponding to the external NICs.

4. The NIC of claim 3, further comprising:

a. collision sensing means for determining whether a collision has occurred in the collisionless packet exchange mode; and

b. mode selection means for returning to a non-collisionless mode of operation if the collision has been detected by the collision sensing means.