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 Title: |
US5644577:
Preserving data frame continuity across full-duplex LAN interface with disparate data capacities
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Christensen, Kenneth Jussi; Apex, NC
Haas, Lee Clyde; Raleigh, NC
Noel, Jr., Francis Edward; Durham, NC
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| Assignee: |
International Business Machines Corporation, Armonk, NY
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| Published / Filed: |
1997-07-01
/ 1995-11-06
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| Application Number: |
US1995000553945
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| IPC Code: |
Advanced:
H04L 12/28;
H04L 12/44;
H04L 12/56;
H04L 13/08;
H04L 29/02;
H04L 29/06;
Core:
more...
IPC-7:
H04J 3/07;
H04J 3/12;
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| ECLA Code: |
H04L12/56D; H04L29/06; H04L29/06C5;
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| U.S. Class: |
Current:
370/506;
370/528;
Original:
370/506;
370/528;
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| Field of Search: |
370/061,77,80,82,84,102,110.1,110.4,111,13,56,94.1,420,423,424,505-508,434,465,470,472,476,522,528,527,276,537,538
375/237,363,372
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| Priority Number: |
| 1995-11-06 |
US1995000553945 |
| 1994-06-09 |
US1994000257265 |
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| Abstract: |
Data capacity mismatches between a communication node, including end node work stations, and a communication link usually require large buffer storage to prevent the loss of transmitted data frames due to transmission of an incomplete frame. Transmitted data frame continuity is maintained in the present invention by using small FIFO buffers in the node to store small portions of a data frame as data is sent and received. In addition, the data frame is maintained by stretching the transmitted frame on the link when necessary to prevent loss of the frame and compress the stretched frame when it is received from the link. The stretching and compressing is accomplished by inserting and removing non-data symbols, or command code words, in the transmitted and received string of data words. Small FIFO buffers (much less than a data frame in data capacity) operate on the fly to transmit and receive data without requiring contiguous transmission of a complete frame. At the sending node, non-data symbols are inserted in the frame between data words to fill gaps between strings of data bytes. At the receiving node, the non-data symbols are stripped from the received data frame to separate non-data symbols from data bytes. The non-data symbols are encoded command code words used to communicate status between the transmitting node and the receiving node. Transmitted encoded commands convey to a receiving node the status information of the transmitting node. The commands include Ready and Busy to indicate to the node at the opposite end of the link the status of the receive FIFO buffer in the node sending the commands.
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| Attorney, Agent or Firm: |
Cockburn, Joscelyn G. ;
Knearl, Homer L. ;
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| Primary / Asst. Examiners: |
Olms, Douglas W.; Nguyen, Chau T.
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| Maintenance Status: |
E3 Expired Check current status
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| INPADOC Legal Status: |
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Family Legal Status Report
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| Parent Case: |
This is a continuation of application Ser. No. 08/257,265 filed on Jun. 9, 1994 now abandoned.
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| Designated Country: |
DE FR GB
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| Family: |
Show 4 known family members
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First Claim:
Show all 20 claims |
What is claimed is:
1. In a communication network having nodes and communication links that do not have matched data capacity and duplex transmission between a first node at one end of a communication link and a second node at the opposite end of the communication link, a method at the first node for preserving the continuity of a first node data frame transmitted from the first node to the second node and for passing status information back from the first node to the second node, the status information indicating the status of buffering data strings at the first node, the data strings being a part of a second node data frame being transmitted to the first node from the second node, said method at the first node comprising the steps of:
- (a) if data capacity of the link is greater than data buffering capacity of the first node, detecting where gaps will occur between data strings in the first node data frame to be transmitted from the first node to the second node;
- (b) stretching the first node data frame by inserting first node status information in the gaps before the first node data frame is transmitted so that the first node data frame is continuous and becomes a stretched data frame;
- (c) transmitting the stretched data frame;
- (d) receiving at the first node the second node data frame transmitted from the second node;
- (e) buffering at the first node the second node data frame received by step (d);
- (f) detecting from step (e) the data filled state of a buffer buffering the second node data frame at the first node and providing status information indicating the data filled state of the buffer buffering the second node data frame at the first node; and
- step (b) responsive to step (f) for inserting the first node status information into the gaps whereby data frame continuity is maintained and first node status information is passed back to the second node.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 18 U.S. patent(s) that reference this one
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