Computer network switching system

• US 5,274,631 A
• Filed: 03/11/1991
• Issued: 12/28/1993
• Est. Priority Date: 03/11/1991
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Kalpana, Inc. (Cisco Systems, Inc.)
• Inventors: Bhardwaj, Vinod K.
• Primary Examiner(s): Chin, Wellington
• Application Number:
  US07/667,675
• Time in Patent Office: 1,023 Days
• Field of Search: 370/60, 370/60.1, 370/85.12, 370/85.13, 370/85.14, 370/94.1, 370/94.2, 370/94.3
• US Class Current: 370/401
• CPC Class Codes: H04L 49/201 Multicast operation; Broadcast operation
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/3018 Input queuing
• CPC Class Codes: H04L 49/3027 Output queuing
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches

Abstract

A network switching system is described. The network switching system comprises a first port coupled to a source, a second port coupled to a destination, and multiplexer means coupled to the first port and the second port for transferring data between the first port and the second port by selectively connecting the first port with the second port. The data is transferred from the source to the destination through the first port, the multiplexer means, and the second port. The network switching system further includes processing means coupled to the multiplexer means for assisting transmission of the data by receiving the data from the first port when the first port does not indicate a port for the destination. A method of transferring data from a source to a destination via a network switching system is also described.

Claims

1. A network switching system, comprising:

a first port coupled to a first plurality of data processing devices, including a source;

a second port coupled to a second plurality of data processing devices, including a destination;

a third port coupled to a third plurality of data processing devices;

multiplexer means coupled to the first port, the second port, and the third port for transferring data between the first port, the second port, and the third port by selectively connecting two of the first, second, and third ports, wherein when the data is transferred from the source to the destination through the first port, the multiplexer means couples the first port with the second port;

processing means coupled to the multiplexer means for assisting in a transmission of the data by receiving the data from the first port when the first port does not indicate a port for the destination, wherein if the first port does not indicate a port of the destination, the data is first transferred from the first port to the processing means via the multiplexer means and the processing means then transfers the data to the second port and the third port via the multiplexer means to search for the destination, wherein if the first port indicates that the second port includes the destination, then the data is transferred to the second port via the multiplexer means without being transferred to the processing means.

2. The network switching system of claim 1, wherein the multiplexer means further comprises means for accepting a serial address from the first port, the second port, the third port, and the processing means.

3. The network switching system of claim 2, wherein the serial address is comprised of (a) a first bit corresponding to the first port;

(b) a second bit corresponding to the second port;

(c) a third bit corresponding to the third port; and

(d) a fourth bit corresponding to the processing means.

4. The network switching system of claim 1, wherein the first port further includes a first memory and the second port includes a second memory, wherein the third port further includes a third memory.

5. The network switching system of claim 4, wherein the first memory stores (A) the relationship of each of the second plurality of data processing devices with the second port, (B) the relationship of each of the first plurality of data processing devices with the first port, and (C) the relationship of each of the third plurality of data processing devices with the third port, wherein the second memory stores (D) the relationship of each of the second plurality of data processing devices with the second port, (E) the relationship of each of the first plurality of data processing devices with the first port, and (F) the relationship of each of the third plurality of data processing devices with the third port, wherein the third memory stores (G) the relationship of each of the first plurality of data processing devices with the first port, (H) the relationship of each of the second plurality of data processing devices with the second port, and (I) the relationship of each of the third plurality of data processing devices with the third port.

6. The network switching system of claim 5, wherein the first port further includes means for removing the relationship of the first port and the source if the source does not communicate with the first port within a predetermined period of time, and wherein the second port further includes means for removing the relationship of the second port and the destination if the destination does not communicate with the second port within the predetermined period of time.

7. The network switching system of claim 5, wherein the first port further includes means for inspecting both (A) the data and (B) the first memory in order to find a port address of the second port, and means for appending the port address to the data before transmission.

8. The network switching system of claim 7, wherein the second port further includes means for stripping the port address off the data before the data is transferred to the destination.

9. The network switching system of claim 4, wherein the processing means further includes means for inspecting the data, the first memory, the second memory, and the third memory in order to find a port address of the first port, the second port, and the third port.

10. The network switching system of claim 4, wherein the processing means further includes means for updating the first memory and the second memory and the third memory.

11. The network switching system of claim 1, wherein the first port further includes a first-in first-out queue coupled to the multiplexer means for transferring the data.

12. The network switching system of claim 11, wherein the first-in first-out queue includes an additional bit that indicates the end of a first datum.

13. The network switching system of claim 1, wherein the second port further includes a first-in first-out queue, coupled to the multiplexer means, for receiving the data.

14. The network switching system of claim 1, wherein the first port further includes means for storing statistics regarding transfer of the data.

15. The network switching system of claim 1, further comprising a fourth part, wherein the multiplexer means further comprises means for providing parallel data transmission for other data among the third and fourth ports and the processing means while the data is being transferred from the first port to the second port via the multiplexer means.

16. The network switching system of claim 1, wherein the first port further includes means for hash computing a destination address contained in the data to shorten the time for processing the data.

17. The network switching system of claim 1, wherein the data is transferred from the first port to the second port without being fully buffered in the first port before transmission.

18. A method of transferring data from a source to a destination via a network switching system, comprising the steps of:

(A) sending the data from the source to a first port;

(B) inspecting the data for a destination address stored in the data in the first port, wherein the destination address indicates the data is sent to the destination;

(C) sending the data to processing means via multiplexer means if the first port fails to indicate a port that is coupled to the destination indicated by the destination address of the data, wherein the processing means then accesses a plurality of ports via the multiplexer means for the port that is coupled to the destination indicated by the destination address;

(D) sending the data directly to a second port via the multiplexer means without sending the data to the processing means if the second port is coupled to the destination indicated by the destination address and if the first port indicates that the second port is coupled to the destination;

(E) sending the data to the destination from the second port.

19. The method of claim 18, wherein the step (B) further includes the steps of (1) searching for a port address of the second port corresponding to the destination address, and (2) appending the port address to the data before transmission if the port address is found.

20. The method of claim 19, wherein the step of appending appends a port address of the processing means if the step of searching fails to find the port address of the second port.

21. The method of claim 18, wherein at step (D) the data is sent directly from the first port to the second port via multiplexer means when the first port stores the destination address.

22. The method of claim 18, wherein the step (C) further includes the step of finding the destination address in the second port.

23. The method of claim 18, wherein the step (C) further includes the step of broadcasting by sending the data to the plurality of ports.