Mixed topology data switching system

• US 6,463,065 B1
• Filed: 06/28/1999
• Issued: 10/08/2002
• Est. Priority Date: 11/17/1998
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Rivers, James R., Petersen, Brian A., Devanagondi, Harish R.
• Primary Examiner(s): Yao, Kwang Bin
• Assistant Examiner(s): JONES, PRENELL P
• Application Number:
  US09/340,577
• Time in Patent Office: 1,198 Days
• Field of Search: 370/242-245, 370/252, 370/522, 370/244, 370/397, 370/401-405, 370/466-468, 370/376, 370/452, 370/223-2, 370/258, 370/458, 370/428-429, 370/460, 370/406, 370/430, 370/403-407, 331/355, 331/358, 455/445-450, 455/442, 379/88.18, 712/28, 712/23, 712/32, 714/49
• US Class Current: 370/412
• CPC Class Codes: H04L 12/44 Star or tree networks
• CPC Class Codes: H04L 2012/5651 Priority, marking, classes
• CPC Class Codes: H04L 2012/5667 IP over ATM
• CPC Class Codes: H04L 47/13 in a LAN segment, e.g. ring or bus
• CPC Class Codes: H04L 47/2433 Allocation of priorities to traffic types
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 49/00 Packet switching elements
• CPC Class Codes: H04L 49/103 using a shared central buffer; using a shared memory
• CPC Class Codes: H04L 49/108 using shared central buffer
• CPC Class Codes: H04L 49/3072 Packet splitting
• CPC Class Codes: H04L 49/309 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

Methods and apparatus for enabling communication between a source network device and one or more destination network devices are disclosed. A system enabling communication between a source network device and one or more destination network devices includes a switch and a ring interconnect. The switch is adapted for connecting to the source network device and the one or more destination network devices. More particularly, the switch is capable of storing data provided by the source network device and retrieving the data for the one or more destination network devices. The ring interconnect is adapted for connecting the source network device and the one or more destination network devices to one another. In addition, the ring interconnect is capable of passing one or more free slot symbols along the ring interconnect. Thus, the ring interconnect is capable of expanding when one or more of the free slot symbols are each replaced by a frame notify message indicating that the data has been stored by the switch for retrieval by the one or more destination network devices.

Claims

1. A method of enabling communication among a plurality of network devices, the plurality of network devices being connected to one another via a ring interconnect and being connected to a switch, the method comprising:

sending data from one of the plurality of network devices to the switch for storage;

receiving a frame storage message from the switch at the one of the plurality of network devices, the frame storage message indicating that the data has been stored; and

sending a frame notify message from the one of the plurality of network devices on the ring interconnect in response to receiving the frame storage message, the frame notify message being addressed to one or more of the plurality of network devices and indicating that the data has been stored by the switch for retrieval by the one more of the plurality of network devices.

2. The method as recited in claim 1, further including:

retrieving the frame notify message from the ring interconnect, the frame notify message indicating whether the network devices to which the frame notify message has been addressed were capable of accepting the frame notify message.

3. The method as recited in claim 2, further including:

providing an indication of a retrieval count in the frame notify message, the retrieval count indicating a number of network devices that remain to retrieve the frame notify message.

4. The method as recited in claim 3, further including:

decrementing the retrieval count equivalent to a number of network devices that were unable to accept the frame notify message.

5. The method as recited in claim 3, further including:

modifying the frame notify message such that a modified frame notify message is created; and

placing the modified frame notify message on the ring interconnect.

6. The method as recited in claim 5, wherein modifying includes:

indicating whether the network device retrieving the frame notify message was capable of storing information provided in the frame notify message.

7. The method as recited in claim 6, where indicating includes:

indicating that the retrieval count is to be decremented when the network device is not capable of storing information provided in the frame notify message.

8. The method as recited in claim 2, wherein retrieving is performed by selected ones of the network devices to which the frame notify message was addressed.

9. The method as recited in claim 2, wherein retrieving is performed by the one of the plurality of network devices that sent the frame notify message on the ring interconnect.

10. The method as recited in claim 9, further including:

discarding the frame notify message.

11. A system that enables communication between a source network device and one or more destination network devices, comprising:

a switch adapted for connecting to the source network device and the one or more destination network devices, the switch being capable of storing data provided by the source network device and retrieving the data for the one or more destination network devices; and

a ring interconnect, the ring interconnect adapted for connecting the source network device and the one or more destination network devices to one another, the ring interconnect being capable of passing one or more free slot symbols along the ring interconnect, the ring interconnect being capable of expanding when one or more of the free slot symbols are each replaced by a frame notify message indicating that the data has been stored by the switch for retrieval by the one or more destination network devices.

12. The system as recited in claim 11, further including:

a latency buffer coupled to the ring interconnect, the latency buffer being adapted for holding traffic redirected from the ring interconnect to create space on the ring interconnect for the frame notify message.

13. The system as recited in claim 11, further including:

a data buffer capable of storing the data; and

a buffer table including a retrieval count field adapted for specifying a number of times that the data is to be read from the data buffer.

14. The system as recited in claim 13, wherein the buffer table further includes a buffer owner field identifying a source of the data stored in the data buffer.

15. The system as recited in claim 11, wherein the data includes a plurality of portions the system further including:

a data buffer having a plurality of buffers, each one of the plurality of portions being stored in a different one of the plurality of buffers; and

a buffer table including a plurality of entries associated with the plurality of buffers, each one of the plurality of entries including a retrieval count field specifying a number of times that one of the plurality of portions is to be read from the data buffer.

16. The system as recited in claim 15, wherein each one of the plurality of entries in the buffer table further includes a next buffer field identifying a buffer in the data buffer, the next buffer field of one of the plurality of entries in the buffer table identifying a next buffer in the data buffer, the next buffer storing a next one of the plurality of portions.

17. The system as recited in claim 13, wherein the buffer table identifies a thread that stored the data.

18. The system as recited in claim 17, wherein the thread is associated with the source network device.

19. The system as recited in claim 11, wherein the one or more destination network devices each have at least one notify queue in which at least a portion of information in the frame notify message is stored when the frame notify message is removed from the ring interconnect.

20. The system as recited in claim 11, wherein the source network device is adapted for replacing one of the one or more idle symbols with a frame notify message.

21. The system as recited in claim 20, wherein the one or more destination network devices are adapted for retrieving the data from the switch in response to the frame notify message.

22. The system as recited in claim 20, wherein the one or more destination network devices are adapted for modifying the frame notify message to indicate whether the frame notify message could be accepted and placing the modified frame notify message on the ring interconnect.

23. The system as recited in claim 20, wherein the one or more destination devices are adapted for modifying the frame notify message to indicate a capability of the one or more destination devices to accept the data.

24. A switch having an associated memory, comprising:

one or more interfaces adapted for connecting to a source network device and one or more destination network devices; and

a controller adapted for storing data received from the source network device in the associated memory, sending a frame storage message to the source network device, wherein the frame storage message indicates that the data has been successfully stored, and retrieving the data from the associated memory in response to a request by one of the one or more destination devices.

25. The switch as recited in claim 24, wherein the controller is further adapted for decrementing the number of pending retrievals associated with the data in response to a request from the source network device, wherein the number of pending retrievals indicates a number of the one or more destination network devices that remain to retrieve the data.

26. A data switching system, comprising:

a source network device;

one or more destination network devices;

a switch connected to the source network device and the one or more destination network devices, the switch being capable of storing data provided by the source network device and retrieving the data for the one or more destination network devices; and

a ring interconnect connecting the source network device and the one or more destination network devices to one another, the ring interconnect adapted for transmitting a notify message among the source network device and the one or more destination network devices, the notify message being sent from the source network device and being addressed to the one or more destination network devices and indicating that data has been stored for retrieval by the one or more destination network devices.

27. The system as recited in claim 26, wherein the one or more destination network devices are adapted for modifying the notify message to indicate whether the one or more destination network devices are capable of retrieving the data and placing the modified notify message on the ring interconnect.

28. The system as recited in claim 26, wherein the source network device and the one or more destination network devices are each connected to the switch via an associated switch interconnect.

29. The system as recited in claim 28, wherein the source network device is adapted for sending the data to the switch via the associated switch interconnect.

30. The system as recited in claim 28, wherein the switch is adapted for sending a storage message to the source network device via the associated switch interconnect, the storage message indicating that the data has been stored by the switch.

31. The system as recited in claim 30, wherein the source network device is adapted for placing the notify message on the ring interconnect in response to receiving the storage message from the switch.

32. The system as recited in claim 26, further including:

a data buffer coupled to the switch for storing the data provided to the switch, the data buffer including;

a general memory available to a plurality of users associated with one or more network devices, the one or more network devices including the source to network device; and

a plurality of dedicated memory segments, each one of the plurality dedicated memory segments being associated with one of the plurality of users.