Method for scheduling, writing, and reading data inside the partitioned buffer of a switch, router or packet processing device

• US 7,903,687 B2
• Filed: 04/01/2005
• Issued: 03/08/2011
• Est. Priority Date: 04/01/2005
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chang, Chih-jen, Damon, Philippe, Vaidhyanathan, Natarajan, Calvignac, Jean Louis, Verplanken, Fabrice Jean, Verrilli, Colin Beaton, Basso, Claude
• Primary Examiner(s): Yao; Kwang B
• Assistant Examiner(s): DUDA, ADAM K
• Application Number:
  US11/096,363
• Publication Number:
  US 20060221989A1
• Time in Patent Office: 2,167 Days
• Field of Search: 370/60, 370/84, 370/218, 370/230, 370/235, 370/392, 370/395, 370/412, 370/428, 370470-474, 709/233, 710/5, 710/6, 710/56, 710/58, 710/60, 710/71, 712/405
• US Class Current: 370/471
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers
• CPC Class Codes: H04L 49/9031 Wraparound memory, e.g. overrun or underrun detection

Abstract

A method for receiving packets in a computer network are disclosed. The method include providing at least one receive port, a buffer, a scheduler, and a wrap port. The buffer has an input coupled with the at least one receive port and an output. The scheduler has a first input coupled to the output of the buffer, a second input coupled to the wrap port, and an output.

Claims

1. A method for receiving packets in a computer network, the computer network including a network interface, the method comprising:

providing a plurality of received packets from at least one receive port to a buffer having an input and an output, the input coupled with the at least one receive port;

allowing a plurality of wrap packets to be received in a wrap port wherein the wrap port comprises hardware logic between transmit and receive sides of the network interface; and

selectively providing a portion of the plurality of received packets and a portion of the plurality of wrap packets to a scheduler having a first input, a second input, and an output, the output of the buffer coupled with the first input of the scheduler and the wrap port coupled with the second input.

2. The method of claim 1 wherein the buffer has a receive threshold.

3. The method of claim 2 wherein the at least one receive port is a ten gigabit per second port.

4. The method of claim 3 wherein the selectively providing further includes:

if there is no internal wrap packet and the buffer is not empty, reading from the buffer;

if there is an internal wrap packet, the buffer is not empty and the threshold has not been reached, alternatively reading from the buffer and the wrap port; and

if the threshold has been reached, reading from the buffer.

5. The method of claim 2 wherein the at least one port comprises two ports and the two ports include a first port and a second port.

6. The method of claim 5 wherein the buffer is divided into a first portion corresponding to the first port and a second portion corresponding to the second port.

7. The method of claim 6 wherein the first port and the second port is each an one gigabit per second port.

8. The method of claim 7 wherein the first portion of the buffer and the second portion of the buffer each has a maximum capacity of half of a buffer capacity.

9. The method of claim 7 wherein the selectively providing further includes:

if there is no internal wrap packet, the first portion of the buffer is not empty and the second portion of the buffer is not empty, alternatively reading from the first portion and the second portion of the buffer;

if there is no internal wrap packet and either the first portion of the buffer is not empty or the second portion of the buffer is not empty, reading exclusively from a not empty portion of the buffer;

if there is an internal wrap packet, the buffer is not empty and the threshold has not been reached, alternatively reading from the first portion of the buffer, the second portion of the buffer, and the wrap port; and

if there is an internal wrap packet and the threshold has been reached or exceeded for the first portion of the buffer or the second portion of the buffer, reading from the first portion or the second portion of the buffer.

10. A non transitory computer-readable medium containing a program for receiving packets in a computer network, the program including instructions for:

providing a plurality of received packets from at least one receive port to a buffer having an input and an output, the input coupled with the at least one receive port;

allowing a plurality of wrap packets to be received in a wrap port; and

selectively providing a portion of the plurality of received packets and the plurality of wrap packets to a scheduler having a first input, a second input, and an output, the output of the buffer coupled with the first input of the scheduler and the wrap port coupled with the second input.

11. The non transitory computer-readable medium of claim 10 wherein the buffer has a receive threshold.

12. The non transitory computer-readable medium of claim 11 wherein the at least one receive port is a ten gigabit per second port.

13. The non transitory computer-readable medium of claim 12 wherein the selectively providing instructions further include instructions for:

if there is no internal wrap packet and the buffer is not empty, reading from the buffer;

if there is an internal wrap packet, the buffer is not empty and the threshold has not been reached, alternatively reading from the buffer and the wrap port; and

if the threshold has been reached, reading from the buffer.

14. The non transitory computer-readable of claim 10 wherein the at least one receive port comprises two receive ports ant the two receive ports include a first port and a second port.

15. The non transitory computer-readable medium of claim 14 wherein the buffer is divided into a first portion corresponding to the first port and a second portion corresponding to the second port.

16. The non transitory computer-readable medium of claim 15 wherein the first port and the second port is each an one gigabit per second port.

17. The non transitory computer-readable medium of claim 16 wherein the first portion of the buffer and the second portion of the buffer each has a maximum capacity of half of a buffer capacity.

18. The non transitory computer-readable medium of claim 16 wherein the selectively providing instructions further includes instructions for:

if there is no internal wrap packet, the first portion of the buffer is not empty and the second portion of the buffer is not empty, alternatively reading from the first portion and the second portion of the buffer;

if there is no internal wrap packet and either the first portion of the buffer is not empty or the second portion of the buffer is not empty, reading exclusively from a not empty portion of the buffer;

if there is an internal wrap packet, the buffer is not empty and the threshold has not been reached, alternatively reading from the first portion of the buffer, the second portion of the buffer, and the wrap port; and

if there is an internal wrap packet and the threshold has been reached or exceeded for the first portion of the buffer or the second portion of the buffer, reading from the first portion or the second portion of the buffer.