System and method for transferring data packets through a communication system

• US 8,885,478 B2
• Filed: 08/18/2008
• Issued: 11/11/2014
• Est. Priority Date: 02/17/2006
• Status: Active Grant

• Current Assignee: SMSC Europe GmbH (Microchip Technology Incorporated)
• Original Assignee: SMSC Europe GmbH (Microchip Technology Incorporated)
• Inventors: Mueller, Rainer P., Ho, Horace C., Heck, Patrick, Knapp, David, Rolfes, Kevin
• Primary Examiner(s): Kao, Jutai
• Application Number:
  US12/193,328
• Publication Number:
  US 20090080462A1
• Time in Patent Office: 2,276 Days
• Field of Search: None
• US Class Current: 370/236
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/18 End to end
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/266 Stopping or restarting the source, e.g. X-on or X-off
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A communication system, network, interface, and port architecture are provided for transporting data across a network. The network can be arranged by connecting the ports in a daisy chain fashion to achieve a ring architecture or topology. The network forwards data according to a specific network protocol. A first port forwards frames having a preemptive acknowledge field before the payload. A second port receives these frames, stores them in a frame buffer and modifies the preemptive acknowledge field according to its available frame buffer capacity. Said first port controls its data flow according to the modified preemptive acknowledge field.

Claims

1. A communication port within a first node of a closed loop ring network of nodes, the communication port comprising:

a framer configured to generate frames having at least;

a start identifier for marking a beginning of a frame;

a destination address field to identify a receiving port within a second node of the closed loop ring network;

a preemptive acknowledge field which is configured to be encoded by the receiving port of said second node; and

a data field comprising transmission data, wherein said preemptive acknowledge field is positioned in front of said data field;

an input coupled for receiving a frame sent from said second node, wherein the frame sent from said second node comprises an encoded preemptive acknowledge field, which is used to give information to said communication port within said first node about a frame buffer receiving the frames within said second node.

2. The communication port of claim 1, wherein the first node further comprises a decoder for decoding the encoded preemptive acknowledge field included within the frame sent from the second node, and wherein the communication port is configured for proceeding with or ceasing sending additional transmission data to the receiving port dependent upon the decoded preemptive acknowledge field.

3. The communication port of claim 2, wherein the communication port is configured for transmitting frames of the additional transmission data upon determining, from the decoded preemptive acknowledge field, that the frame buffer of said receiving port can store a full frame.

4. The communication port of claim 2, wherein the communication port is configured for delaying transmission of frames of the additional transmission data upon determining, from the decoded preemptive acknowledge field, that the frame buffer of said receiving port cannot store a full a frame.

5. The communication port of claim 2, wherein the communication port is configured for delaying transmission of frames of the additional transmission data upon determining, from the decoded preemptive acknowledge field, that the preemptive acknowledge field of the frame sent to receiving port has not been modified by the receiving port.

6. The communication port of claim 2, wherein the communication port is configured for increasing the frame rate upon determining, from the decoded preemptive acknowledge field, that the frame buffer of said receiving port can store a full a frame.

7. The communication port of claim 2, wherein the communication port is configured for reducing the frame rate upon determining, from the decoded preemptive acknowledge field, that the frame buffer of said receiving port cannot store a full a frame.

8. The first communication port of claim 2, wherein the communication port is configured for reducing the frame rate upon determining, from the decoded preemptive acknowledge field, that the preemptive acknowledge field of the frame sent to receiving port has not been modified by the receiving port.

9. The communication port of claim 2, wherein the communication port is configured for entering a sequence to handle an exception upon determining, from the decoded preemptive acknowledge field, that the preemptive acknowledge field of the frame sent to receiving port has not been modified by the receiving port.

10. The communication port of claim 2, wherein the communication port is further configured for transmitting a frame having the size of an available buffer space on the receiving port.

11. A communication port within a first node of a closed loop ring network of nodes, the communication port comprising:

a frame buffer for storing frames; and

an encoder for encoding information in a preemptive acknowledge field of a frame about the status of the frame buffer, wherein the encoder is configured to modify a preemptive acknowledge field of a frame received from a second node of the closed loop ring network depending on space availability of the frame buffer, and wherein the encoder is configured for encoding information in the preemptive acknowledge field indicating that said frame buffer can store a full frame or said frame buffer cannot store a full frame, and wherein the first node further comprises another communication port, which is configured to generate a new frame depending on the encoded information in the preemptive acknowledge field.

12. The communication port of claim 11, wherein the encoded information in the preemptive acknowledge field causes the other communication port to generate the new frame absent a data field.

13. The communication port of claim 11, wherein the encoder is configured to encode a delay time in said preemptive acknowledge field.

14. A closed loop ring communication system, comprising:

a first node configured to generate frames having at least;

a start identifier for marking a beginning of a frame;

a destination address field to identify a receiving port of another node;

a preemptive acknowledge field which is configured to be encoded by the receiving port; and

a data field comprising transmission data, wherein said preemptive acknowledge field is positioned in front of said data field; and

a second node communicatively coupled to the first node, wherein a receiving port of the second node comprises;

a frame buffer for storing frames; and

an encoder for encoding information in the preemptive acknowledge field of a frame received from the first node about the status of the frame buffer within the second node.

15. The communication system of claim 14, wherein the first node is further configured for:

receiving a frame sent from the second node;

decoding the preemptive acknowledge field of the frame sent from the second node; and

proceeding with or ceasing sending additional transmission data to the second communication port dependent upon the decoded preemptive acknowledge field of the frame sent from the second node.

16. The communication system of claim 14, wherein the encoder included within the receiving port of the second node is configured to modify the preemptive acknowledge field of the frame received from the first node.

17. The communication system of claim 14, wherein the second node is configured to generate a new frame having a preemptive acknowledge field different from the preemptive acknowledge field of the frame received from the first node.

18. A bus node within a ring network of nodes, comprising:

a first communication port configured to generate frames having at least;

a start identifier for marking a beginning of a frame;

a destination address field to identify a receiving port;

a preemptive acknowledge field which is configured to be encoded by the receiving port; and

a data field comprising transmission data, wherein said preemptive acknowledge field is positioned in front of said data field; and

a second communication port communicatively coupled to the first communication port, wherein the second communication port comprises;

a frame buffer for storing frames; and

an encoder for modifying a preemptive acknowledge field of a frame received from another node of the ring network dependent upon a status of the frame buffer.

19. The bus node of claim 18, wherein the second communication port is further configured for:

receiving the frame sent from the other node of the ring network;

decoding the preemptive acknowledge field of the frame received from the other node of the ring network; and

proceeding with or ceasing sending additional transmission data to the other node dependent upon the decoded preemptive acknowledge field.

20. A method for communication between a first port and a second port in a communication system, comprising:

generating in a first port a frame having at least;

a destination address field to identify one or more receiving ports;

a preemptive acknowledge field which is configured to be encoded by the one or more receiving ports; and

a data field comprising transmission data, wherein said preemptive acknowledge field is positioned in front of said data field;

transmitting the frame via a transmission line to the one or more receiving ports;

evaluating in succession at ports along the transmission line the destination address field and determining whether the frame is to be received at the respective ports; and

evaluating space availability of a frame buffer associated with a receiving port and modifying the preemptive acknowledge field of the frame received over the transmission line from the first port depending on the space availability of the frame buffer within the receiving port.

21. The method of claim 20, further comprising:

encoding, at the receiving port, information in said preemptive acknowledge field of the frame received from the first port, wherein said information includes a space availability of the frame buffer;

forwarding the frame with the preemptive acknowledge field encoded with said information to the first port;

decoding, at the first port, said encoded preemptive acknowledge field including said information; and

proceeding with or ceasing sending additional transmission data from the first port to the one or more receiving ports dependent upon said decoded preemptive acknowledge field including said information.

22. The method of claim 21, wherein the step of encoding the information in said preemptive acknowledge field comprises encoding information indicative that said frame buffer can store a full frame or said frame buffer cannot store a full frame.

23. The method of claim 20, further comprising:

generating, at the receiving port, a new frame having a preemptive acknowledge field comprising information, wherein said information includes a space availability of the frame buffer;

forwarding the new frame to the first port;

decoding, at the first port, said encoded preemptive acknowledge field including said information; and

proceeding with or ceasing sending additional transmission data from the first port to the one or more receiving ports dependent upon said decoded preemptive acknowledge field including said information.

24. The method of claim 20, further comprising:

forwarding the preemptive acknowledge field of the frame unmodified to the first port upon evaluating that the frame buffer of the receiving port is full or has at least reached a certain limit;

determining, at the first port, that the preemptive acknowledge field of the frame is unmodified; and

ceasing sending additional transmission data from the first port to the one or more receiving ports.