Browse Prior Art Database

RELIABLE LLC INTEGRATION WITH MAC LAYER DATA SENT MESSAGE

IP.com Disclosure Number: IPCOM000008528D
Original Publication Date: 1998-Mar-01
Included in the Prior Art Database: 2002-Jun-20
Document File: 2 page(s) / 100K

Publishing Venue

Motorola

Related People

Tim Spets: AUTHOR [+2]

Abstract

In a connection oriented LLC (Logical Link Control OS1 layer 2 data link layer) when an endpoint sends data packets to the peer a re-trans- mission timer is started. If an acknowledgment is not received and the re-transmission timer times out, the data packets will be re-transmitted.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 50% of the total text.

Page 1 of 2

MOTVROLA Technical Developments

RELIABLE LLC INTEGRATION WITH MAC LAYER DATA SENT MESSAGE

by Tim Spets and Karen Brailean

  In a connection oriented LLC (Logical Link Control OS1 layer 2 data link layer) when an endpoint sends data packets to the peer a re-trans- mission timer is started. If an acknowledgment is not received and the re-transmission timer times out, the data packets will be re-transmitted.

In a network where data packets are traveling over a link where delays can vary greatly due

to contention with other traffic, the setting of the re-transmission timer is less deterministic. This publication deals with the integration and additional uses for a notification message, called Data Sent message, that the LLC uses to notify Layer 3 when the data was actually transmitted to the peer. (The layer 3 use of this message is specifically for iDEN session state tracking which is beyond the scope of this publication).

The following is the implementation and added features of the Data Sent message.

  The LLC data re-transmission timer becomes a two part timer (Figure 1). Initially the LX sends the data packet(s) and the first timer will be started to insure that the Data Sent message will not be lost (confirmation timer). The second timer is the actual re-transmission timer that is started when the data sent message from the transmitter is received by the LLC. If the confirmation timer expires due to loss of Data Sent message (Figure 2), the retransmission

timer is started by default and the Layer 3 entity is notified that the notification message was received.

  The Data Sent message can also provide the LLC with information if the data packets were sent or not. If they were dropped at the transmitter due to contention or loss of channel (Figure 3), the LLC can use this information to avoid starting the re-transmission timer and immediately re-schedule the data packets that were not sent for re-transmission.

  The LLC needs to track the Data Sent messages in the case where a LLC entity may have multiple data packe...