Multicasting in a shared address space

• US 20050147114A1
• Filed: 02/13/2004
• Published: 07/07/2005
• Est. Priority Date: 01/05/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Topside Research LLC
• Inventors: Wong, Ken, Haywood, Chris, Stewart, Heath, Reiner, Thomas, Garrigue, Michael de la
• Granted Patent: US 7,539,190 B2
• Time in Patent Office: Days
• US Class Current: 370/432
• CPC Class Codes: G06F 13/1673 using buffers
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: G06F 13/404 with address mapping
• CPC Class Codes: G06F 13/4282 on a serial bus, e.g. I2C bus, SPI bus on daisy chain buses G06F13/4247
• CPC Class Codes: H04L 49/103 using a shared central buffer; using a shared memory
• CPC Class Codes: H04L 49/201 Multicast operation; Broadcast operation

Abstract

There is disclosed apparatus and methods of multicasting in a shared address space. There may be defined a number of portions of the address space. There may be groups of the portions, and data units addressed to one portion within the group may be re-addressed to the other portions

Claims

1. A method of multicasting data units having destination addresses in a shared address space, the switch having a plurality of ports, wherein respective individual portions of the address space are associated with each of the ports, respective multicast portions are associated with at least some of the ports, and wherein the multicast portions have associations with one other, the method comprising, for a given data unit

if the destination address is in the individual portion associated with one of the ports, then forwarding the data unit for transmission out the associated port

if the destination address is in the multicast portion associated with one of the ports, then

forwarding the data unit for transmission out the port associated with the multicast portion encompassing the destination address

forwarding the data unit for transmission out the ports associated with multicast portions associated with the multicast port encompassing the destination address, wherein the forwarded data unit is revised to specify a destination address within the respective multicast address.

2. The method of multicasting in a shared address space of claim 1 wherein the individual portions are unique within the shared address space with respect to one another.

3. The method of multicasting in a shared address space of claim 1 wherein the multicast portions are unique within the shared address space with respect to one another.

4. A switch for multicasting in a shared address space, the switch comprising

a buffer for storing data units, the data units having a destination address

a first port having a first address portion in the shared address space

a second port having a second address portion in the shared address space logic to

cause data units in the buffer having a destination address in the first address portion to be forwarded for transmission out the first port without being removed from the buffer and then replace the destination address with an address in the second address portion

cause data units in the buffer having a destination address in the second portion to be forwarded for transmission out the second port.

5. The switch for multicasting in a shared address space of claim 4 wherein

the first address portion has a first size

the second address portion has a second size

the second size is substantially equal to the first size.

6. The switch for multicasting in a shared address space of claim 5 wherein the second size is exactly equal to the first size.

7. The switch for multicasting in a shared address space of claim 4 wherein

the first address portion has a first base address

the second address portion has a second base address

the first base address and the second base address differ by only a single digit.

8. The switch for multicasting in a shared address space of claim 4, wherein the shared address space comprises a shared memory address space, and the switch has logic to transmit data units through the first port and the second port via memory mapped I/O into the shared address space.

9. The switch for multicasting in a shared address space of claim 4 having at least three ports, wherein the logic supports all of the ports having the characteristics defined for the first port.

10. The switch for multicasting in a shared address space of claim 4 wherein the logic is further to cause data units in the buffer having a destination address in the second portion to be forwarded for transmission out the second port and be removed from the buffer.

11. The switch for multicasting in a shared address space of claim 4

wherein the first port has a third address portion in the shared address space

wherein the second port has a fourth address portion in the shared address space

wherein the logic is further to

cause data units in the buffer having a destination address in the third address portion to be forwarded for transmission out the first port and be removed from the buffer

cause data units in the buffer having a destination address in the fourth portion to be forwarded for transmission out the second port and be removed from the buffer.

12. The switch for multicasting in a shared address space of claim 4 wherein the first portion comprises only a portion of a pre-existing address portion in the shared address space assigned to the first port.

13. A switch for multicasting in a shared address space, the switch comprising

a buffer

logic to store data units into the buffer

a first port having a first address portion in the shared address space, the first address portion including an individual portion and a multicast portion

a second port having a second address portion in the shared address space including an individual portion and a multicast portion

logic to

cause data units in the buffer having a destination address in the individual portion of the first address portion to be forwarded for transmission out the first port and be removed from the buffer

cause data units in the buffer having a destination address in the individual portion of the second portion to be forwarded for transmission out the second port and be removed from the buffer

cause data units in the buffer having a destination address in the multicast portion of the first address portion to be forwarded for transmission out the first port without being removed from the buffer and then replace the destination address with an address in the multicast portion of the second address portion

cause data units in the buffer having a destination address in the multicast portion of the second portion to be forwarded for transmission out the second port.

14. The switch for multicasting in a shared address space of claim 13 further comprising

a third port having a third address portion in the shared address space including an individual portion and a multicast portion

logic to

cause data units in the buffer having a destination address in the individual portion of the third address portion to be forwarded for transmission out the third port and be removed from the buffer

replace the destination address of data units in the buffer having a destination address in the multicast portion of the second address portion with an address in the multicast portion of the third address portion

cause data units in the buffer having a destination address in the multicast portion of the third portion to be forwarded for transmission out the third port.

15. The switch for multicasting in a shared address space of claim 13 wherein

the multicast portion of the first address portion has a first size

the multicast portion of the second address portion has a second size

the second size is substantially equal to the first size.

16. The switch for multicasting in a shared address space of claim 15 wherein the second size is exactly equal to the first size.

17. The switch for multicasting in a shared address space of claim 13 wherein

the multicast portion of the first address portion has a first base address

the multicast portion of the second address portion has a second base address

the first base address and the second base address differ by only a single digit.

18. The switch for multicasting in a shared address space of claim 13, wherein the shared address space comprises a shared memory address space, and the switch has logic to transmit data units through the first port and the second port via memory mapped I/O into the shared address space.

19. The switch for multicasting in a shared address space of claim 13 having at least three ports, wherein the logic supports all of the ports having the characteristics defined for the first port.

20. The switch for multicasting in a shared address space of claim 13 wherein the logic is further to cause data units in the buffer having a destination address in the multicast portion of the second address portion to be forwarded for transmission out the second port and be removed from the buffer.

21. The switch for multicasting in a shared address space of claim 13, wherein the first address portion includes a broadcast portion, and the second address portion includes a broadcast portion, the switch further comprising

a third port having a third address portion in the shared address space including an individual portion, a multicast portion and a broadcast portion

logic to

cause data units in the buffer having a destination address in the individual portion of the third address portion to be forwarded for transmission out the third port and be removed from the buffer

cause data units in the buffer having a destination address in the broadcast portion of the first address portion, the second address portion or the third address portion to be forwarded for transmission out the first port, the second port and the third port with the destination address set to an address in the broadcast portion of the respective address portion for the respective port.

22. A method of multicasting in a shared address space, the switch having a buffer, a first port and a second port, the method comprising

associating a first address portion in the shared address space with the first port, the first address portion including an individual portion and a multicast portion

associating a second address portion in the shared address space with the second port, the second address portion including an individual portion and a multicast portion

storing data units in the buffer, the data units including a destination address in the shared address space

if a data unit in the buffer has a destination address in the individual portion of the first address portion, then

forwarding the data unit for transmission out the first port

removing the data unit from the buffer

if a data unit in the buffer has a destination address in the multicast portion of the first address portion, then

forwarding the data unit for transmission out the first port

replacing the destination address of the data unit with an address in the multicast portion of the second address portion

forwarding the data unit for transmission out the second port

removing the data unit from the buffer

if a data unit in the buffer has a destination address in the individual portion of the second address portion, then

forwarding the data unit for transmission out the second port

removing the data unit from the buffer.

23. The method of multicasting in a shared address space of claim 22 wherein the shared address space comprises a shared memory address space, the method further comprising

transmitting data units through the first port via memory mapped I/O into the shared memory address space

transmitting data units through the second port via memory mapped I/O into the shared memory address space.

24. The method of multicasting in a shared address space of claim 22 wherein

the multicast portion of the first address portion has a first size

the multicast portion of the second address portion has a second size

the second size is substantially equal to the first size.

26. The method of multicasting in a shared address space of claim 22, wherein there is a third port, the method further comprising providing characteristics defined for the first port for the second port and the third port.

27. The method of multicasting in a shared address space of claim 22 further comprising,

if a data unit in the buffer has a destination address in the individual portion of the second address portion, then

forwarding the data unit for transmission out the second port

removing the data unit from the buffer.

28. The method of multicasting in a shared address space of claim 22, wherein the first address portion includes a broadcast portion and the second address portion includes a broadcast portion, the method further comprising

associating a third address portion in the shared address space with a third port, the third address portion including an individual portion, a multicast portion and a broadcast portion

if a data unit in the buffer has a destination address in the individual portion of the third address portion, then

forwarding the data unit for transmission out the third port

removing the data unit from the buffer

if a data unit in the buffer has a destination address in the broadcast portion of the first address portion, the second address portion or the third address portion, then

forwarding the data unit for transmission out the first port, the second port and the third port with the destination address set to an address in the broadcast portion of the respective address portion for the respective port

removing the data unit from the buffer.

25. The method of multicasting in a shared address space of claim 0 wherein the second size is exactly equal to the first size.