SMART ROUTING BETWEEN PEERS IN A POINT-TO-POINT LINK BASED SYSTEM

• US 20110188504A1
• Filed: 04/16/2011
• Published: 08/04/2011
• Est. Priority Date: 05/15/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Gulati, Manu
• Granted Patent: US 8,571,033 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• 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 smart routing by a device operable 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 the device, 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; and

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.

2. The method of claim 1, further comprising:

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

3. The method of claim 1, further comprising:

generating the packet as part of a response; and

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.

4. The method of claim 1, wherein the routing the packet on the downstream link further comprises:

maintaining order of the packet with respect to other packets in a same transaction on the downstream link such that the plurality of devices treats the packet and the other packets in the same transaction as belonging to a single stream in accordance with transaction ordering rules.

5. The method of claim 1, further comprising:

utilizing a same path between two devices of the plurality of devices for each transaction of a system level task.

6. The method of claim 3, 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.

7. The method of claim 6, 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.

8. The method of claim 7, wherein maintaining the order of the packet further comprises at least one of:

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

9. 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, 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;

determine 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; and

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.

10. The device of claim 9, wherein the memory further comprises operational instructions that cause the processing module to:

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

11. The device of claim 9, wherein the memory further comprises operational instructions that cause the processing module to:

generate the packet as part of a response; and

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

12. The device of claim 9, wherein the memory further comprises operational instructions that cause the processing module to:

when routing the packet on the downstream link, maintain order of the packet with respect to other packets in a same transaction on the downstream link such that the plurality of devices treats the packet and the other packets in the same transaction as belonging to a single stream in accordance with transaction ordering rules.

13. The device of claim 9, wherein the memory further comprises operational instructions that cause the processing module to:

utilize a same path between two devices of the plurality of devices for each transaction of a system level task.

14. The device of claim 11, wherein the memory further comprises operational instructions that cause the processing module to:

when utilizing a unit identification code, determine 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

15. The device of claim 14, wherein the memory further comprises operational instructions that cause the processing module to:

maintain 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.

16. The method of claim 15, wherein the memory further comprises operational instructions that cause the processing module to:

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

17. A method for direct peer-to-peer communications by a first device of 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:

receiving, by an interface with a hybrid function for HT protocol communications in the first device of the plurality of devices, an HT protocol packet as part of a request via an upstream point-to-point link of the daisy chain supporting HT protocol communications;

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

when the first device of the plurality of devices is the destination of the HT protocol packet, accepting the HT protocol packet by the first device of the plurality of devices;

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

18. The method of claim 17, further comprising:

when the first device of the plurality of devices is not the destination of the HT protocol packet, determining whether the destination of the HT protocol packet is within an upstream address range associated with the another upstream point-to-point link of the daisy chain supporting HT protocol communications.

19. The method of claim 17, further comprising:

when the first device of the plurality of devices is not the destination of the HT protocol packet, determining whether the destination of the HT protocol packet is within a downstream address range associated with a downstream point-to-point link of the daisy chain supporting HT protocol communications.

20. The method of claim 19, further comprising:

when the destination of the HT protocol packet is within a downstream address range associated with a downstream point-to-point link of the daisy chain supporting HT protocol communications, transmitting the packet on the downstream point-to-point link of the daisy chain supporting HT protocol communications.