Smart routing between peers in a point-to-point link based system

• US 7,979,573 B2
• Filed: 04/23/2003
• Issued: 07/12/2011
• Est. Priority Date: 05/15/2002
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Gulati, Manu
• Primary Examiner(s): Burgess; Barbara N
• Application Number:
  US10/421,988
• Publication Number:
  US 20030217177A1
• Time in Patent Office: 3,002 Days
• Field of Search: 709/203, 709/231, 709/236, 709/238, 709/245, 709/246
• US Class Current: 709/238
• CPC Class Codes: H04L 49/252 Store and forward routing

Abstract

Smart routing between peers in a point-to-point link based system begins when a device of a plurality of devices in a point-to-point link interconnected system receives a packet from an upstream link or a downstream link. The processing continues when the device interprets the packet to determine a destination of the packet. If the device is the destination of the packet, the device accepts the packet. If, however, the device is not the destination of the packet, the device forwards the packet on another upstream link or another downstream link without alteration of at least one of: source information of the packet and destination information of the packet.

Claims

1. A method for peer to peer routing in a system that includes a HyperTransport (HT) enabled host device and a plurality of HT enabled devices interconnected via one or more daisy chains of connection based point-to-point links supporting HT packet communications, the method comprises:

receiving by a first interface of a device of the plurality of HT enabled devices, a packet from an upstream link of one of the daisy chains of connection based point-to-point links supporting HT packet communications, wherein the first interface of the device provides a bridge function for HT packet communications;

interpreting, by the device, the packet received at the first interface with the bridge function for HT packet communications to determine whether the packet is part of a request or a response;

when the packet is part of the request, determining the destination of the packet based on an address contained within the packet;

when the device is the destination of the packet, accepting, by the device, the packet; and

when the device is not the destination of the packet and the packet is part of the request, modifying the packet to identify the device as the source of the packet without alteration of destination information of the packet and forwarding the packet by the device, wherein the forwarding the packet further comprises;

comparing the address with an upstream address range associated with an another upstream link;

when the address is within the upstream address range, issuing the packet on the another upstream link of the one of the daisy chains of connection based point-to-point links supporting HyperTransport (HT) packet communications towards the host device;

when the address is not within the upstream address range, comparing the address with a downstream address range associated with an another downstream link;

when the address is within the downstream address range, issuing the packet on the another downstream link of the one of the daisy chains of connection based point-to-point links supporting HyperTransport (HT) packet communications; and

when the address is not within the upstream or downstream address range, issuing the packet on a default link;

when the packet is part of the response, determining the destination of the packet based on a unit identification code contained within the packet.

2. The method of claim 1, wherein the issuing the packet further comprises:

maintaining order of the packet with respect to other packets on the upstream link, the downstream link, or the default link regardless of identity of at least one of;

the destination and a source of the packet, such that plurality of devices treats transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

3. The method of claim 1 further comprises:

utilizing a same path between two given points or nodes for each of the transactions of a system level task.

4. The method of claim 1, wherein, when the packet is part of the response, the determining the destination of the packet further comprises:

determining one of the point-to-point links based on the unit identification code and a mapping of unit identification codes to the point-to-point links; and

issuing the packet on the one of the point-to-point links.

5. The method of claim 4, wherein the issuing the packet further comprises:

maintaining order of the packet with respect to other packets on the one of the point-to-point links regardless of identity of at least one of;

the destination and a source of the packet.

6. The method of claim 5, wherein the maintaining the order of the packet further comprises at least one of:

treating, by the plurality of devices, transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

7. A method for direct peer-to-peer communications among a plurality of devices interconnected to a host device via a daisy chain with point to point links supporting HyperTransport (HT) protocol, the method comprises:

generating, by a first device of the plurality of devices, an HT protocol packet as part of a request that includes destination information that identifies a second device of the plurality of devices and source information that identifies the first device, wherein the first device includes a hybrid function for HT protocol communications;

comparing by the first device, an address of the second device in the destination information with an upstream address range associated with an upstream point-to-point link of the daisy chain supporting HT protocol communications;

when the address of the second device is within the upstream address range, transmitting, by the first device, the packet on the upstream point-to-point link of the daisy chain supporting HT protocol communications towards the host device;

receiving, by another one of the plurality of devices, the packet via the upstream point-to-point link of the daisy chain supporting HT protocol communications, wherein the another one of the plurality of devices includes a hybrid function for HT protocol communications;

interpreting, by the another one of the plurality of devices, the packet to determine a destination of the packet based on the destination information;

when the another one of the plurality of devices is the second device, accepting the packet by the another one of the plurality of devices;

when the another one of the plurality of devices is not a destination of the packet, modifying the packet without alteration of destination information of the packet to include source information that identifies the another one of the plurality of devices and forwarding the packet to the host device via another upstream point-to-point link of the daisy chain supporting HT protocol communications; and

when the address of the second device is not within the upstream address range, comparing the address in the destination information of the packet with a downstream address range associated with a downstream link.

8. The method of claim 7, further comprising:

when the address of the second device is within the downstream address range, transmitting the packet on a downstream link of the daisy chain supporting HT protocol communications.

9. The method of claim 8, wherein the generating the packet further comprises at least one of:

generating the packet as part of a request, wherein the destination information includes an address of the destination; and

generating the packet as part of a response, wherein the destination information includes a unit identification code of the destination.

10. The method of claim 9 further comprises, when the packet is part of the request:

identifying the upstream link when an address of the second device is within an address range associated with the upstream link; and

identifying the downstream link when the address of the second device is within an address range associated with the downstream link.

11. The method of claim 10, wherein, when the packet is part of the request, the forwarding the packet further comprises:

when the address is not within the upstream or downstream address range, issuing the packet on a default link.

12. The method of claim 11, wherein the issuing the packet further comprises:

maintaining order of the packet with respect to other packets on the upstream link, the downstream link, or the default link regardless of identity of at least one of;

the destination and a source of the packet, such that plurality of devices treats transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

13. The method of claim 12 further comprises:

utilizing a same path between two given points or nodes for each of the transactions of a system level task.

14. The method of claim 9, wherein, when the packet is part of a response, the forwarding of the packet further comprises:

determining one of a plurality of point-to-point links based on the unit identification code and a mapping of unit identification codes to the plurality of point-to-point links; and

issuing the packet on the one of the plurality of point-to-point links.

15. The method of claim 14, wherein the issuing the packet further comprises:

maintaining order of the packet with respect to other packets on the one of the point-to-point links regardless of identity of at least one of;

the destination and a source of the packet.

16. The method of claim 15, wherein the maintaining the order of the packet further comprises at least one of:

treating, by the plurality of devices, transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

17. A device capable of smart routing in a system that includes a HyperTransport (HT) enabled host device and a plurality of HT enabled devices interconnected via one or more daisy chains of connection based point-to-point links supporting HT packet communications, the device comprises:

at least one processing module; and

at least one memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to;

receive a packet from an upstream link of one of the daisy chains of connection based point-to-point links supporting HT packet communications; and

provide a bridge function for HT packet communications by;

interpreting the packet to determine whether the packet is part of a request;

when the packet is part of the request, determine the destination of the packet based on an address contained within the packet;

when the device is the destination of the packet, accepting the packet; and

when the packet is part of the request and the device is not the destination of the packet, modifying the packet to identify the device as the source of the packet without alteration of destination information of the packet and forwarding the packet by;

comparing the address with an upstream address range associated with an another upstream link;

when the address is within the upstream address range, issuing the packet on the another upstream link; and

when the address is not within the upstream address range, comparing the address with a downstream address range associated with an another downstream link;

when the address is within the downstream address range, issuing the packet on the another downstream link; and

when the address is not within the upstream or downstream address range, issuing the packet on a default link; and

when the packet is part of a response, determining the destination of the packet based on a unit identification code contained within the packet.

18. The device of claim 17, wherein the memory further comprises operational instructions that cause the processing module to:

interpret the packet to determine whether the packet is part of a response.

19. The device of claim 18, wherein the memory further comprises operational instructions that cause the processing module to, when the packet is part of a response, forward the packet by:

determining one of the point-to-point links based on the unit identification code and a mapping of unit identification codes to the point-to-point links; and

issuing the packet on the one of the point-to-point links.

20. The device of claim 19, wherein the memory further comprises operational instructions that cause the processing module to issue the packet by:

maintaining order of the packet with respect to other packets on the one of the point-to-point links regardless of identity of at least one of;

the destination and a source of the packet.

21. The device of claim 20, wherein the memory further comprises operational instructions that cause the processing module to maintain the order of the packet by at least one of:

treating, by the plurality of devices, transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

22. The device of claim 17, wherein the memory further comprises operational instructions that cause the processing module to issue the packet by:

maintaining order of the packet with respect to other packets on the upstream link, the downstream link, or the default link regardless of identity of at least one of;

the destination and a source of the packet, such that plurality of devices treats transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

23. The device of claim 17, wherein the memory further comprises operational instructions that cause the processing module to:

utilize a same path between two given points or nodes for each of the transactions of a system level task.

24. A system that supports peer-to-peer communications among a plurality of devices that are interconnected to a host device via a daisy chain with connection based point-to-point links supporting HyperTransport (HT) packet communications, the system comprises:

a first device of the plurality of devices that includes a hybrid function for HT protocol communications, wherein the first device includes a first processing module and first memory, wherein the first memory stores operational instructions that cause the first processing module to;

generate an HT protocol packet as part of a request that includes destination information that identifies a second device of the plurality of devices and source information that identifies the first device;

compare an address of the second device in the destination information with an upstream address range associated with an upstream link;

when the address is not within the upstream address range, comparing the address with a downstream address range associated with a downstream link;

when the address of the second device is within the upstream address range, transmit the packet on a upstream point-to-point link of the daisy chain supporting HyperTransport (HT) packet communications of the connection based point-to-point system towards the host device;

another device of the plurality of devices that includes a hybrid function for HT protocol communications, wherein the another device includes another processing module and another memory, wherein the another memory stores operational instructions that cause the another processing module to;

receive the packet via the upstream point-to-point link of the daisy chain supporting HT protocol communications;

interpret the packet to determine a destination of the packet based on the destination information;

when the another one of the plurality of devices is the second device, accept the packet by the another device; and

when the another one of the plurality of devices is not a destination of the packet, modify the packet without alteration of destination information to include source information that identifies the another one of the plurality of devices and forward the packet to the host device via another upstream point-to-point link of the daisy chain supporting HT protocol communications.

25. The system of claim 24, wherein when the address of the second device is within the downstream address range, transmit the packet on the downstream link of the daisy chain supporting HT protocol communications.

26. The system of claim 25, wherein the first memory further comprises operational instructions that cause the first processing module to generate the packet by at least one of:

generating the packet as part of a request, wherein the destination information includes an address of the destination; and

generating the packet as part of a response, wherein the destination information includes a unit identification code of the destination.

27. The system of claim 26, wherein the first memory further comprises operational instructions that cause the first processing module to, when the packet is part of the request:

identify the upstream link when an address of the second device is within an address range associated with the upstream link; and

identify the downstream link when the address of the second device is within an address range associated with the downstream link.

28. The system of claim 27, wherein the another memory further comprises operational instructions that cause the another processing module to, when the packet is part of the request, forward the packet by:

when the address is not within the upstream or downstream address range, issuing the packet on a default link.

29. The system of claim 28, wherein the another memory further comprises operational instructions that cause the another processing module to issue the packet by:

maintaining order of the packet with respect to other packets on the upstream link, the downstream link, or the default link regardless of identity of at least one of;

the destination and a source of the packet, such that plurality of devices treats transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

30. The system of claim 29, wherein the memory further comprises operational instructions that cause the processing module to:

utilize a same path between two given points or nodes for each of the transactions of a system level task.

31. The system of claim 26, wherein the another memory further comprises operational instructions that cause the another processing module to, when the packet is part of a response, forward of the packet by:

determining one of a plurality of point-to-point links based on the unit identification code and a mapping of unit identification codes to the plurality of point-to-point links; and

issuing the packet on the one of the plurality of point-to-point links.

32. The system of claim 31, wherein the another memory further comprises operational instructions that cause the another processing module to issuing the packet by:

maintaining order of the packet with respect to other packets on the one of the point-to-point links regardless of identity of at least one of;

the destination and a source of the packet.

33. The system of claim 32, wherein the another memory further comprises operational instructions that cause the another processing module to maintain the order of the packet by at least one of:

treating, by the plurality of devices, transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

34. A method for smart routing in a system that includes a plurality of devices and a host device interconnected via connection based point-to-point links in a daisy chain supporting HyperTransport (HT) packet communications, the method comprises:

generating, by a device of the plurality of devices, an HT packet as part of a request, wherein the packet includes, at least, destination information, source information and data, wherein the device includes a hybrid HT function for routing HT packet communications in the daisy chain;

determining, by the device, a destination of the packet when part of the request by;

comparing an address of the destination from the destination information with an upstream address range associated with an upstream link;

when the address is within the upstream address range, routing the packet on the upstream link of the point-to-point links in the daisy chain to the host device of the daisy chain supporting HyperTransport (HT) packet communications;

when the address is not within the upstream address range, comparing the address with a downstream address range associated with a downstream link;

when the address is within the downstream address range, routing the packet on the downstream link of the point-to-point links in the daisy chain supporting HyperTransport (HT) packet communications; and

when the address is not within the upstream or downstream address range, providing the packet on a default link.

35. The method of claim 34 further comprises:

generating the packet as part of a response;

when the packet is part of the response, utilizing a unit identification code of the destination to determine the upstream link or the downstream link.

36. The method of claim 35, wherein, when the packet is part of the response, utilizing a unit identification code further comprises:

determining the upstream link or the downstream link based on the unit identification code and a mapping of unit identification codes to the point-to-point links.

37. The method of claim 36, further comprises:

maintaining order of the packet with respect to other packets on the upstream link or the downstream link regardless of identity of at least one of;

the destination and a source of the packet.

38. The method of claim 37, wherein the maintaining the order of the packet further comprises at least one of:

treating, by the plurality of devices, transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet, and wherein the one of the plurality of tasks includes one or more of the transactions.

39. The method of claim 34, wherein the routing the packet further comprises:

maintaining order of the packet with respect to other packets on the upstream link, the downstream link, or the default link regardless of identity of at least one of;

the destination and a source of the packet, such that plurality of devices treats transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

40. The method of claim 34 further comprises:

utilizing a same path utilizes between two given points or nodes for each of the transactions of a system level task.

41. A device capable of smart routing in a system that includes a plurality of devices and a host device interconnected via connection based point-to-point links in a daisy chain supporting HyperTransport (HT) packet communications, the device comprises:

processing module; and

memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to;

generate an HT packet as part of a request or a response, wherein the packet includes, at least, destination information, source information and data;

when the packet is part of the request, utilize an address of the destination information to determine whether a destination of the packet is upstream or downstream from the device in the daisy chain supporting HT packet communications by;

comparing the address with an upstream address range associated with an upstream link;

when the address is within the upstream address range, routing the packet on the upstream link of the point-to-point links in the daisy chain;

when the address is not within the upstream address range, comparing the address with a downstream address range associated with a downstream link;

when the address is within the downstream address range, routing the packet on the downstream link of the point to point links in the daisy chain; and

when the address is not within the upstream or downstream address range, providing the packet on a default link; and

when the packet is part of the response, determining the destination of the packet based on a unit identification code contained within the packet.

42. The device of claim 41, wherein the memory further comprises operational instructions that cause the processing module to provide the packet by:

maintaining order of the packet with respect to other packets on the upstream link, the downstream link, or the default link regardless of identity of at least one of;

the destination and a source of the packet, such that plurality of devices treats transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet.

43. The device of claim 41, wherein the memory further comprises operational instructions that cause the processing module to:

utilize a same path between two given points or nodes for each of the transactions of a system level task.

44. The device of claim 41, wherein the memory further comprises operational instructions that cause the processing module to route the packet when the packet is part of the response by:

determining the upstream link or the downstream link based on the unit identification code and a mapping of unit identification codes to the point-to-point links.

45. The device of claim 44, wherein the memory further comprises operational instructions that cause the processing module to route the packet by:

maintaining order of the packet with respect to other packets on the upstream link or the downstream link regardless of identity of at least one of;

the destination and a source of the packet.

46. The device of claim 45, wherein the memory further comprises operational instructions that cause the processing module to maintain the order of the packet by at least one of:

treating, by the plurality of devices, transactions as belonging to a single stream in accordance with transaction ordering rules, wherein one of the transactions includes the packet, and wherein the one of the plurality of tasks includes one or more of the transactions.