System and method of real time synchronization through a communication system

• US 9,071,374 B2
• Filed: 10/03/2008
• Issued: 06/30/2015
• Est. Priority Date: 10/04/2007
• Status: Active Grant

• Current Assignee: SMSC Europe GmbH (Microchip Technology Incorporated)
• Original Assignee: SMSC Europe GmbH (Microchip Technology Incorporated)
• Inventors: Green, Christopher, Becker, Claudius
• Primary Examiner(s): Sloms, Nicholas
• Application Number:
  US12/245,005
• Publication Number:
  US 20090092210A1
• Time in Patent Office: 2,461 Days
• Field of Search: 370335-503
• US Class Current: 1/1
• CPC Class Codes: H04J 3/0605 Special codes used as synchronising signal
• CPC Class Codes: H04J 3/0661 using timestamps
• CPC Class Codes: H04J 3/067 Details of the timestamp structure
• CPC Class Codes: H04L 12/44 Star or tree networks

Abstract

A communication system, network, interface, and port architecture are provided for transferring data via a network. The network can be configured by connecting ports in a daisy chain arrangement to achieve a ring architecture or topology. The network transmits data according to a specific protocol. A first port transmits frames containing frame count information which is divided into several pieces, with each piece being transmitted in a single frame. A second port receives the frames, stores them in a frame buffer, and reassembles the frame count information from a plurality of frames.

Claims

1. A communication port, comprising:

a framer for generating frames for transmission over a network, wherein each frame comprises at least a preamble, a data field, and a frame count field;

a transmit frame counter for counting the generated frames; and

wherein a count value of the transmit frame counter is divided into a predetermined number n of segments, wherein n is an integer value greater than 1, and wherein each segment is placed, by the framer, in a respective frame count field of n consecutively generated frames.

2. The communication port according to claim 1, further comprising a stable clock for generating the frames, which can be synchronized with a reference clock selected from a group consisting of a crystal oscillator, an audio source, or video source.

3. The communication port according to claim 1, wherein at least one of the n consecutively generated frames contains a frame count checksum for the frame count fields included within n consecutively generated frames.

4. The communication port according to claim 1, wherein prior to generating the count value, the count value of the transmit frame counter is preset to a predetermined value, a value representing a time of day, or any master time reference.

5. The communication port according to claim 1, wherein the count value of the transmit frame counter is incremented by one only once before a first frame of a set of n consecutive frames is generated, or the count value of the transmit frame counter is incremented by n before a first frame of a set of n consecutive frames is generated.

6. The communication port according to claim 1, further comprising a transmit frame count register for storing the count value of the transmit frame counter for the n consecutively generated frames, wherein the stored count value is used for generating the frame count fields of the n consecutively generated frames.

7. The communication port according to claim 1, wherein at least one of the n consecutively generated frames contains a frame count start identifier defining a first frame of the n consecutively generated frames.

8. The communication port according to claim 1, further comprising a network node at least partially containing said communication port.

9. A communication port, comprising:

a frame decoder for decoding frames received over a network from another communication port, wherein the received frames each comprise at least a preamble, a data field, and a frame count field;

a receive frame counter for counting the received frames; and

a receive frame counter register for reassembling a count value of a transmit frame counter contained within the other communication port by evaluating the frame count field of n consecutively received frames.

10. The communication port according to claim 9, wherein the communication port is configured for identifying a first of n consecutively received frames by evaluating changes in high order bits and low order bits between at least two consecutive sets of the n consecutively received frames, wherein n is an integer value greater than 1.

11. The communication port according to claim 9, further comprising a network node at least partially containing said communication port.

12. A communication system, comprising:

at least one first communication port, comprising;

a framer for generating frames for transmission over a network, wherein each frame comprises at least a preamble, a data field, and a frame count field; and

a transmit frame counter for counting the generated frames;

wherein a count value of the transmit frame counter is divided into a predetermined number n of segments, and wherein each segment is placed, by the framer, in a respective frame count field of n consecutively generated frames; and

at least one second communication port configured for receiving the frames transmitted over the network by the first communication port, decoding the received frames, and reassembling the count value of the transmit frame counter by evaluating the frame count fields of n consecutively generated frames.

13. A method for transmitting frame count information via a communication system by repeating the steps of:

counting a number of frames to be transmitted in a transmit frame counter of a communication port;

storing the number of frames to be transmitted in a transmit frame count register of the communication port;

generating a set of n frames to be transmitted in a framer of the communication port, wherein each frame comprises at least a start identifier for marking a beginning of a frame, a data field, and a frame count field containing only 1/n of a number of bits representing the stored number of frames, wherein n consecutive frame count fields represent the stored number of frames; and

transmitting the frames via the communication system.

14. A method for receiving frame count information from a communication system by repeating the steps of:

receiving a set of n frames at a communication port, wherein each frame comprises at least a start identifier for marking a beginning of a frame, a data field, and a frame count field containing only 1/n of a number of bits representing a stored number of frames transmitted via the communication system, where n consecutive frame count fields represent the stored number of transmitted frames;

storing, in a receive frame counter register of the communication port, the bits contained within the n consecutive frame count fields of the set of n frames; and

compiling, in the receive frame counter register of the communication port, a received number of the transmitted frames from the n consecutive frame count fields.

15. A communication port, comprising:

a framer for generating frames for transmission over a network, wherein each frame comprises at least a preamble, a data field, and a frame count field;

a transmit frame counter for counting bits, bytes, video frames, or time intervals associated with the generated frames; and

wherein a count value of the transmit frame counter is divided into a predetermined number n of segments, wherein n is an integer value greater than 1, and wherein each segment is placed, by the framer, in a respective frame count field of n consecutively generated frames.

16. A communication port, comprising:

a frame decoder for decoding frames received over a network from another communication port, wherein the received frames each comprise at least a preamble, a data field, and a frame count field;

a receive frame counter for counting bits, bytes, video frames, or time intervals associated with the generated frame; and

a receive frame counter register for reassembling a count value of a transmit frame counter contained within the other communication port by evaluating the frame count field of n consecutively received frames, wherein n is an integer value greater than 1.

17. A communication system, comprising:

at least one first communication port, comprising;

a framer for generating frames for transmission over a network, wherein each frame comprises at least a preamble, a data field, and a frame count field; and

a transmit frame counter for counting bits, bytes, video frames, or time intervals associated with the generated frames;

wherein a count value of the transmit frame counter is divided into a predetermined number n of segments, and wherein each segment is placed, by the framer, in a respective frame count field of n consecutively generated frames, wherein n is an integer value greater than 1; and

at least one second communication port configured for receiving the frames transmitted over the network by the first communication port, decoding the received frames, and reassembling the count value of the transmit frame counter by evaluating the frame count fields of n consecutively generated frames.