High speed transmission line interface

• US 5,301,186 A
• Filed: 06/28/1991
• Issued: 04/05/1994
• Est. Priority Date: 06/28/1991
• Status: Expired due to Term

• Current Assignee: Enterasys Networks Incorporated (Extreme Networks, Inc.)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Walton, Andrew J., Galuszka, Robert J., Bryant, Stewart F.
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): HSU, ALPUS
• Application Number:
  US07/722,684
• Time in Patent Office: 1,012 Days
• Field of Search: 370/24, 370/32, 370/58.1, 370/58.2, 370/58.3, 370/60, 370/67, 370/85.1, 370/85.2, 370/85.9, 370/85.11, 370/94.1, 370/100.1, 370/13, 370/14, 375/7, 371/37.1, 371/37.2, 371/37.7, 371/7, 371/11.1, 371/11.2, 371/11.3, 371/47.1, 371/48, 340/825.06, 340/825.16, 340/825.17
• US Class Current: 370/216
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A high performance data link interface includes receive and transmit data framing paths. The data link interface interlocks certain communication link control signals, such as the CCITT standard data set signals, with data being received or transmitted through the interface to correlate a transmission error directly to a particular data transmission for rapid and efficient error recovery.

Claims

1. A data link interface adapted to be coupled to a full duplex synchronous data transmission line, which comprises:

a receive data line interface device and a transmit data line interface device, each adapted to be coupled to the receive and transmit data paths of the synchronous data transmission line, respectively;

wherein said receive data line interface device comprises a receive data framing device to frame serial data received from the receive data path of the synchronous data transmission line into receive frames, a receive data FIFO buffer coupled to said receive data framing device to store the receive frames and a receive data interface device coupled to said receive data framing device to store the receive frames in the receive data FIFO buffer, the receive data FIFO buffer being adapted to be coupled to a receive data processor for the transmission of the receive frames to the receive data processor;

wherein the receive data line interface device receives serial data via the receive data path of the synchronous data transmission line and the transmit data line interface device transmits serial data to the transmit data path of the synchronous data transmission line;

wherein said receive data framing device receives a data set signal from a remote device via the synchronous data transmission line to monitor connectivity between the transmit data line interface device and the remote device over the synchronous data transmission line, the receive data framing device operating to frame and store portions of a frame in said receive data FIFO buffer when the data set signal indicates connectivity and to abort framing and storing portions of a frame and to generate and store an error status message in the receive data FIFO buffer when the data set signal does not indicate connectivity.

2. The data link interface of claim 1, wherein said receive data framing device aborts framing and storing portions of a frame a predetermined period of time after the data set signal first indicates no connectivity.

3. The data link interface of claim 2, wherein said receive data framing device is controlled by said receive data processor to selectively abort framing and storing portions of a frame a predetermined period of time after the data set signal first indicates no connectivity.

4. A data link interface adapted to be coupled to a full duplex synchronous data transmission line, which comprises:

a receive data line interface device and a transmit data line interface device, each adapted to be coupled to the receive and transmit data paths of the synchronous data transmission line, respectively;

wherein said receive data line interface device comprises a receive data framing device to frame serial data received from the receive data path of the synchronous data transmission line into receive frames, a receive data FIFO buffer coupled to said receive data framing device to store the receive frames and a receive data interface device coupled to said receive data framing device to store the receive frames in the receive data FIFO buffer, the receive data FIFO buffer being adapted to be coupled to a receive data processor for the transmission of the receive frames to the receive data processor;

wherein the receive data line interface device receives serial data via the receive data path of the synchronous data transmission line and the transmit data line interface device transmits serial data to the transmit data path of the synchronous data transmission line;

wherein said transmit data line interface device comprises a transmit data framing device to transmit frames as serial data to the transmit data path of the synchronous data transmission line, a transmit data FIFO buffer coupled to said transmit data framing device to store transmit frames and a transmit data interface device coupled to said transmit data processor to receive transmit frames from the transmit data processor for storage in said transmit data FIFO buffer;

wherein said transmit data framing device is adapted to receive a data set signal from a remote device via the synchronous data transmission line to monitor connectivity between the transmit data line interface device and the remote device over the synchronous data transmission line, the transmit data framing device operating to generate and transmit data from a frame stored in said transmit data FIFO buffer when the data set signal indicates connectivity and to abort transmission of said data, flush said transmit data FIFO buffer and generate and transmit an error status message to the transmit data processor when the data set signal does not indicate connectivity.

5. The data link interface of claim 4, wherein said transmit data framing device aborts transmission of serial data a predetermined period of time after the data set signal first indicates no connectivity.

6. The data link interface of claim 5, wherein said transmit data framing device is controlled by said transmit data processor to selectively abort transmission of serial data a predetermined period of time after the data set signal first indicates no connectivity.

7. A data link interface adapted to be coupled to a full duplex synchronous data transmission line, which comprises:

a data framing device for coupling to the data transmission line for framing data from a component coupled to said data framing device; and

a line coupled to the data framing device and to the data transmission line to carry a data set signal received from a remote device via the synchronous data transmission line to the data framing device so that the data framing device can directly monitor connectivity between said data framing device and the remote device over the synchronous data transmission line.