Device and method for limiting delay by substantial elimination of duplicate synchronous data frames in a communication system

• US 5,515,385 A
• Filed: 03/09/1994
• Issued: 05/07/1996
• Est. Priority Date: 03/09/1994
• Status: Expired due to Term

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Neagle, William A., Fulling, Frank J.
• Primary Examiner(s): Envall, Jr., Roy N.
• Assistant Examiner(s): MOISE, EMMANUEL LIONEL
• Application Number:
  US08/209,085
• Time in Patent Office: 790 Days
• Field of Search: 371/32, 371/41, 370/17, 370/94.1, 370/108, 370/109, 370/110, 370/118, 375/8, 341/50, 341/51, 341/60, 341/61
• US Class Current: 714/748
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085

Abstract

The method (100, 200) and data communication equipment (300, 400) utilizing the method to substantially eliminate duplicate synchronous data frames thus limiting delay for a synchronous data system having error correcting protocol. Duplicate synchronous data frames are eliminated for timeouts where a communication channel becomes unusable for timeout that exceeds a preselected value.

Claims

1. Data communication equipment (DCE) for limiting maximum delay for synchronous data transmission, comprising:

A) a data terminal equipment (TX DTE) interface, operably coupled to receive data for synchronous transmission from an external data source,

B) first random access memory (RAM), operably coupled to the TX DTE interface and to a controller, for buffering data to be forwarded to a data compressor and, in response to a first control signal from the controller, clearing and initializing its data RAM,

C) the data compressor, operably coupled to the first RAM and to the controller, for compressing the buffered data in accordance with a predetermined compression scheme to provide compressed data for transmission, and for, in response to a second control signal from the controller, initializing its data compression scheme,

D) an error corrector, operably coupled to the data compressor and to the controller, for forwarding data to a second RAM and for, in response to a third control signal from the controller, resetting a transmit condition and transmitting a break request to a remote DCE (data communication equipment),

E) the second RAM, operably coupled to the controller and to the error corrector, for buffering data for forwarding to a transmission data pump and for, in response to a fourth control signal from the controller, clearing and initializing its data RAM,

F) the transmission data pump, operably coupled to the second RAM, for facilitating data transmission to a remote DCE utilizing a communication interface,

G) the communication interface, operably coupled to the transmission data pump, for transmitting the data to the remote DCE,

H) a line monitor, operably coupled to the transmission data pump, for;

H1) upon determining that data transfer state between the transmission data pump and the remote DCE indicates that data transfer has ceased, sending a first signal to a line outage timer signaling the line outage timer to start timing,

H2) upon determining that data transfer state between the transmission data pump and the remote DCE indicates that data transfer has restarred, sending a second signal to the line outage time signaling the line outage timer to stop timing,

I) the line outage timer, operably coupled to the line monitor, for;

I1) upon receiving a first signal from the line monitor, starting timing,

I2) upon receiving a second signal from the line monitor, stopping timing,

I3) where the time from starting to stopping exceeds a predetermined delay time, sending a reset signal to the controller,

I4) where the time from starting to stopping is less than a predetermined delay propagation value, refraining from sending a reset signal, and

J) the controller, operably coupled to the line outage timer for sending the first control signal, second control signal, third control signal, and fourth control signal, respectively to the first RAM, the data compressor, the error corrector, and the second RAM, for clearing and initializing the respective RAMs, for reinitializing the data compressor, and, for resetting a transmit and receive protocol state in, and indicating that a break request (to a remote DCE) is to be sent by, the error corrector.

2. The device of claim 1 wherein, in response to the break request from the error corrector, the remote DCE clears and initializes the data RAM of said remote DCE, and resets the remote DCE data compressor and remote DCE error corrector protocol states.

3. Data communication system for substantially eliminating duplicate synchronous data frames in DCEs, thereby limiting a maximum delay for synchronous data transmission, comprising:

a first DCE, comprising;

A) transmit data terminal equipment (TX DTE) interface, operably coupled to receive data for synchronous transmission from an external data source,

B) first random access memory (RAM), operably coupled to the TX DTE interface and to a first controller, for buffering data to be forwarded and, in response to a first control signal from the first controller, clearing and initializing its data RAM,

C) a data compressor, operably coupled to the first RAM and to the first controller, for compressing the buffered data in accordance with a predetermined compression scheme to provide compressed data for transmission, and, in response to a second control signal from the first controller, reinitializing its data compression scheme,

D) a first error corrector, operably coupled to the data compressor and to the first controller, for forwarding data to a second RAM and for, in response to a third control signal from the first controller, resetting a transmit condition and transmitting a break request to a remote DCE (data communication equipment),

E) the second RAM, operably coupled to the first controller and to the first error corrector, for buffering data for forwarding to a transmission data pump and for, in response to a fourth control signal from the first controller, clearing and initializing its data RAM,

F) the transmission data pump, operably coupled to the second RAM, for facilitating transmission to a remote DCE utilizing a first communication interface,

G) the first communication interface, operably coupled to the transmission data pump, for transmitting data to a second communication interface of the remote DCE,

H) a line monitor, operably coupled to the transmission data pump, for;

H1) upon determining that data transfer between the transmission data pump and a receiving data pump of the remote DCE has ceased, sending a first signal to a line outage timer signaling the line outage timer to start timing,

H2) upon determining that data transfer between the transmission data pump and the receiving data pump of the remote DCE has restarted, sending a second signal to the line outage time signaling the line outage timer to stop timing,

I) the line outage timer, operably coupled to the line monitor, for;

I1) upon receiving a first signal from the line monitor, starting timing,

I2) upon receiving a second signal from the line monitor, stopping timing,

I3) where the time from starting to stopping exceeds a predetermined delay propagation value, sending a reset signal to the first controller,

I4) where the time from starting to stopping is less than a predetermined delay propagation value, refraining from sending a reset signal,

J) the first controller, operably coupled to the line outage timer for sending the first control signal, second control signal, third control signal, and fourth control signal, respectively to the first RAM, the data compressor, the error corrector, and the second RAM, for clearing and initializing the respective RAMs, for reinitializing the data compressor, and, for resetting a transmit and receive protocol state in, and indicating that a break request (to a remote DCE) is to be sent by, the error corrector,

and a second DCE, comprising;

K) the second communication interface, operably coupled to the first communication interface, for receiving the data at the remote DCE and forwarding the data to a third RAM,

L) a receiving data pump, operably coupled to the second communication interface, for facilitating forwarding the data to a third RAM,

M) the third RAM, operably coupled to the receiving data pump and to a second controller, for buffering and for, in response to a fifth control signal from the second controller, clearing and initializing its data RAM,

N) a second error corrector, operably coupled to the second controller and to the third RAM, for forwarding data to a second data decompressor and for forwarding the break indication to the second controller, and resetting error correction states upon receiving a break request,

O) the second data decompressor, operably coupled to the second error corrector, to the second controller and to a fourth RAM, for decompressing the data in accordance with a predetermined decompression scheme to provide decompressed data, and for, in response to a sixth control signal, reinitializing its data decompression scheme,

P) said fourth random access memory (RAM), operably coupled to the data second decompressor and to the second controller, for buffering data and for, in response to a seventh control signal from the second controller that is generated in response to the break indication, clearing and initializing the fourth data RAM, and

Q) RX data terminal equipment (RX DTE) interface, operably coupled to the fourth RAM, for outputting received data.