System and Method for Transferring Data Packets Through a Communication System

• US 20090080462A1
• Filed: 08/18/2008
• Published: 03/26/2009
• 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: Knapp, David, Heck, Patrick, Mueller, Rainer P., Rolfes, Kevin, Ho, Horace C.
• Granted Patent: US 8,885,478 B2
• Time in Patent Office: Days
• US Class Current: 370/476
• 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 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;

a preemptive acknowledge field which is configured for encoding by the receiving port; and

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

2. The communication port of claim 1, further comprising an input for receiving a frame sent from the receiving port, wherein the communication port is further configured for:

decoding a preemptive acknowledge field of the frame sent from the receiving port; and

proceeding with or ceasing sending additional transmission data to the receiving port in dependency of code in the preemptive acknowledge field of the frame sent from the receiving port.

3. The communication port of claim 2, wherein the communication port is configured for transmitting frames of the additional transmission data upon decoding said code that a 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 decoding said code that a 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 detecting said code has not been modified from code in the preemptive acknowledge field of the frame sent to receiving port.

6. The communication port of claim 2, wherein the communication port is configured for increasing the frame rate upon decoding said code that a 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 decoding said code that a 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 detecting said code has not been modified from code in the preemptive acknowledge field of the frame sent to receiving port.

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

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

11. A 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.

12. The communication port of claim 11, wherein the encoder is configured to modify a preemptive acknowledge field of a frame received from another communication port.

13. The communication port of claim 11, wherein the communication port is configured to generate a new frame having said preemptive acknowledge field different from a preemptive acknowledge field of a frame received from another communication port.

14. The communication port of claim 13, wherein the communication port is configured to generate the new frame absent a data field.

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

16. A communication system, 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 for encoding 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 encoding information in a preemptive acknowledge field of a frame about the status of the frame buffer.

17. The communication system of claim 16, wherein the first communication port is further configured for:

receiving a frame sent from the second communication port;

decoding a preemptive acknowledge field of the frame sent from the second communication port; and

proceeding with or ceasing sending additional transmission data to the second communication port in dependency of code in the preemptive acknowledge field of the frame sent from the second communication port.

18. The communication system of claim 16, wherein the encoder is configured to modify a preemptive acknowledge field of a frame received from the first communication port.

19. The communication port of claim 16, wherein the second communication port is configured to generate a new frame having a preemptive acknowledge field different from a preemptive acknowledge field of a frame received from the first communication port.

20. A bus node 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 for encoding 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 encoding information in a preemptive acknowledge field of a frame about the status of the frame buffer.

21. The communication system of claim 20, wherein the first communication port is further configured for:

receiving a frame sent from the second communication port;

decoding a preemptive acknowledge field of the frame sent from the second communication port; and

proceeding with or ceasing sending additional transmission data to the second communication port in dependency of code in the preemptive acknowledge field of the frame sent from the second communication port.

22. The communication system of claim 20, wherein the encoder is configured to modify a preemptive acknowledge field of a frame received from the first communication port.

23. The communication port of claim 20, wherein the second communication port is configured to generate a new frame having a preemptive acknowledge field different from a preemptive acknowledge field of a frame received from the first communication port.

24. 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; and

a preemptive acknowledge field which is configured for encoding by the one or more receiving ports;

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.

25. The method of claim 24, wherein the step of generating the frame comprises generating a frame comprising a data field with transmission data, wherein said preemptive acknowledge field is positioned in front of said data field.

26. The method of claim 24, further comprising:

encoding at the receiving port information in said preemptive acknowledge field according to space available in the frame buffer;

forwarding the frame with the preemptive acknowledge field encoded with the information about the frame buffer status to the first port;

decoding the information about the frame buffer status at the first port; and

proceeding with or ceasing sending additional transmission data from the first port to the one or more receiving ports in dependency of the information about the buffer status.

27. The method of claim 26, 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.

28. The method of claim 24, further comprising:

generating at the receiving port a new frame having a preemptive acknowledge field comprising information according to the space available in the frame buffer;

forwarding the new frame to the first port;

decoding the information about the frame buffer status at the first port; and

proceeding with or ceasing sending additional transmission data from the first port to the one or more receiving ports in dependency of the information about the buffer status.

29. The method of claim 24, further comprising:

forwarding 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;

decoding the information about the frame buffer status at the first port; and

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