Browse Prior Art Database

Advanced Synchronous Data Link Control

IP.com Disclosure Number: IPCOM000100358D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 84K

Publishing Venue

IBM

Related People

Kawashima, K: AUTHOR [+3]

Abstract

Described herein is a Data Link Control Protocol which increases a data transmission throughput on a high-speed (greater than 1.5 mega bit per second) communication line that has a large propagation delay (high-speed and large-delay line).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Advanced Synchronous Data Link Control

       Described herein is a Data Link Control Protocol which
increases a data transmission throughput on a high-speed (greater
than 1.5 mega bit per second) communication line that has a large
propagation delay (high-speed and large-delay line).

      HDLC (High Level Data Control) and SDLC (Synchronous Data Link
Control) cannot obtain a high data transmission throughput on the
highspeed and large-delay line due to the following two reasons:

      (1) A sender station can only send (modulo-1) frames
continuously and has to stop sending frames until the sender station
receives a confirmation frame from a receiver station.

      (2) If any frames are lost because of a line error or some bad
condition, the sender station has to retransmit all message frames
after the confirmation frame.  As a result, a communication line is
crowded with duplicated frames and the throughput between two
stations becomes low.

      In order to solve the two problems described above, the new
data link control ASDLC (Advanced Synchronous Data Link Control) has
the following function:

      (A) The sender station can transmit message frames continuously
without waiting for confirmation messages from the receiver station.

      (B) The sender station retransmits only missing message frames
which are specified in an acknowledgement frame from the receiver
station.

      A message frame used in ASDLC has the same format of HDLC and
SDLC except that ASDLC ha...