System and method for decrementing a reference count in a multicast environment

• US 6,895,481 B1
• Filed: 07/03/2002
• Issued: 05/17/2005
• Est. Priority Date: 07/03/2002
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Potter, Kenneth H., Lee, William R., Mitten, John W.
• Primary Examiner(s): Moazzami, Nasser
• Assistant Examiner(s): HO, THANG H
• Application Number:
  US10/189,660
• Time in Patent Office: 1,049 Days
• Field of Search: 711/154, 709/250, 370/498
• US Class Current: 711/154
• CPC Class Codes: H04L 12/1854 with non-centralised forwarding system, e.g. chaincast

Abstract

A method for decrementing a reference count in a multicast environment is provided that includes receiving an access request for a particle stored in a memory element. The memory unit is then accessed in response to the access request, the particle being read from the memory element. The particle includes a plurality of data segments, a selected one or more of which includes a first reference count associated with the particle. The particle is then presented to a target that generated the access request. The first reference count associated with the selected one or more data segments is then decremented in order to generate a second reference count. At least one of the plurality of data segments with the second reference count is then written to the memory element.

Claims

1. A method for decrementing a reference count in a multicast environment, comprising:

receiving an access request for a particle stored in a memory element, wherein the particle includes a plurality of data segments, a selected one or more of the data segments including a reference count;

accessing the memory element in response to the access request;

reading the particle from the memory element;

presenting the particle to a target that generated the access request;

decrementing the first reference count associated with the selected one or more of the data segments in order to generate a second reference count;

writing at least one of the plurality of the data segments with the second reference count to the memory element; and

preventing access to an address associated with the particle until the data segment with the second reference count is written to the memory element.

2. The method of claim 1, further comprising:

communicating the access request to the memory element by the target; and

communicating the address and a multicast read indicator with the access request such that access to the address is prevented until the data segment with the second reference count is written to the next the memory element.

3. The method of claim 1, further comprising:

managing one or more access requests for one or more particles included within the memory element with a queue manager, the access requests being generated by one or more targets that seek to access one or more particles within the memory element.

4. The method of claim 1, further comprising:

decrementing the first reference count a selected number of times using a particle interface such that the second reference count is generated, the particle interface being coupled to the target.

5. A system for decrementing a reference count in a multicast environment, comprising:

means for receiving an access request for a particle stored in a memory element, wherein the particle includes a plurality of data segments, a selected one or more of the data segments including a reference count;

means for accessing the memory element in response to the access request;

means for reading the particle from the memory element;

means for presenting the particle to a target that generated the access request;

means for decrementing the first reference count associated with the selected one or more of the data segments in order to generate a second reference count;

means for writing at least one of the plurality of the data segments with the second reference count to the memory element; and

means for preventing access to an address associated with the particle until the data segment with the second reference count is written to the memory element.

6. The system of claim 5, further comprising:

means for communicating the access request to the memory element by the target; and

means for positioning the address and a multicast read indicator in the access request such that access to the address is prevented until the data segment with the second reference count is written to the memory element.

7. The system of claim 5, further comprising:

means for managing one or more access requests for one or more particles included within the memory element with a queue manager, the access requests being generated by one or more targets that seek to access one or more particles within the memory element.

8. The system of claim 5, further comprising:

means for decrementing the first reference count a selected number of times such that the second reference count is generated.

9. A computer readable medium having code for decrementing a reference count in a multicast environment, the code operable to:

receive an access request for a particle stored in a memory element, wherein the particle includes a plurality of data segments, a selected one or more of the data segments including a reference count;

access the memory element in response to the access request;

read the particle from the memory element;

present the particle to a target that generated the access request;

decrement the first reference count associated with the selected one or more of the data segments in order to generate a second reference count;

write at least one of the plurality of the data segments with the second reference count to the memory element; and

prevent access to an address associated with the particle until the data segment with the second reference count is written to the memory element.

10. The code of claim 9, further operable to:

communicate the access request to the memory element by the target; and

position the address and a multicast read indicator in the access request such that access to the address is prevented until the data segment with the second reference count is written to the memory element.

11. The code of claim 9, further operable to:

manage one or more access requests for one or more particles included within the memory element with a queue manager, the access requests being generated by one or more targets that seek to access one or more particles within the memory element.

12. The code of claim 9, further operable to:

decrement the first reference count a selected number of times such that the second reference count is generated.

13. An apparatus for decrementing a reference count in a multicast environment, comprising:

a memory arbiter operable to generate an access request for a particle stored in a memory element, wherein the particle includes a plurality of data segments, a selected one or more of the data segments including a first reference count associated therewith; and

a memory controller operable to receive the access request and to access the memory element in response to the access request, the memory controller reading the particle from the memory element, the particle being presented to a target coupled to the memory arbiter that generated the access request, the first reference count associated with the selected one or more of the data segments being decremented by the memory controller in order to generate a second reference count, wherein at least one of the data segments with the second reference count is written by the memory controller to the memory element, and wherein the memory arbiter is further operable to prevent access to an address associated with the particle until the data segment with the second reference count is written to the memory element.

14. The apparatus of claim 13, wherein the access request includes the address and a multicast read indicator such that access to the address is prevented until the data segment with the second reference count is written to the memory element.

15. The apparatus of claim 13, further comprising:

a queue manager operable to manage one or more access requests for one or more particles included within the memory element, the access requests being generated by one or more targets that seek to access one or more of the particles.

16. The apparatus of claim 15, wherein the queue manager further comprises a particle smoker element coupled thereto that is operable to provide a value to the memory controller for decrementing the first reference count a selected number of times in order to generate the second reference count.

17. The apparatus of claim 13, further comprising:

a pipeline element included within the memory controller and operable to facilitate data exchanges between the memory element and the memory arbiter.

18. The apparatus of claim 13, further comprising:

an application specific integrated circuit (ASIC), the ASIC including the memory arbiter and the memory controller.

19. The apparatus of claim 13, further comprising:

a field programmable gate array (FPGA), the FPGA including the memory arbiter and the memory controller.

20. An apparatus for decrementing a reference count in a multicast environment comprising:

a memory arbiter operable to generate an access request for a particle stored in a memory element, wherein the particle includes a plurality of data segments, a selected one or more of the data segments including a first reference count associated therewith;

a memory controller operable to receive the access request and to access the memory element in response to the access request, the memory controller reading the particle from the memory element, the particle being presented to a target coupled to the memory arbiter that generated the access request, the first reference count associated with the selected one or more of the data segments being decremented by the memory controller in order to generate a second reference count, wherein at least one of the data segments with the second reference count is written by the memory controller to the memory element, the access request including the address and a multicast read indicator such that access to the address is prevented until the data segment with the second reference count is written to the memory element; and

a queue manager operable to manage one or more access requests for one or more particles included within the memory element.