Method for explicit data rate control in a packet communication environment without data rate supervision

• US 6,298,041 B1
• Filed: 04/27/1999
• Issued: 10/02/2001
• Est. Priority Date: 11/01/1996
• Status: Expired due to Term

• Current Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Original Assignee: Packeteer Incorporated (Gen Digital Inc.)
• Inventors: Packer, Robert L.
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US09/300,036
• Time in Patent Office: 889 Days
• Field of Search: 370/229-238
• US Class Current: 370/231
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0018 based on latency requirement
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 1/1832 Details of sliding window management
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/193 at the transport layer, e.g. TCP related
• CPC Class Codes: H04L 47/20 Traffic policing
• CPC Class Codes: H04L 47/225 Determination of shaping rate, e.g. using a moving window
• CPC Class Codes: H04L 47/2408 for supporting different services, e.g. a differentiated services [DiffServ] type of service
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/323 Discarding or blocking control packets, e.g. ACK packets
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers

Abstract

A method for explicit data rate control is introduced into a packet communication environment (10) which does not have data rate supervision by adding latency to the acknowledgment (ACK) packet and by adjusting the size of the flow control window associated with the packet in order to directly control the data rate of the source data at the station (12 or 14) originating the packet.

Claims

1. A method for controlling data rate of data packets transmitted between a plurality of transmission stations, said method comprising:

transferring information between first and second ones of said plurality of transmission stations by sending first and second units of source packets from said first one of said transmission stations to said second one of said transmission stations and receiving an acknowledgment packet, from said second one of said transmission stations, by said first one of said transmission station, with said acknowledgment packet being received by said first one of said transmission stations before transmission of said second unit of source packets without sensing for congestion in media between said first transmission station and said second transmission station; and

varying said data rate by sending said acknowledgment packet at a selected delay.

2. The method according to claim 1 wherein varying said data rate includes generating substitute acknowledgment packets for said acknowledgment packets in response to a quantity of source packets associated with one of said first and second units of source packets, said substitute acknowledgment packets being generated independent of one of the variables selected from the group consisting of time, range of data being acknowledged, window size being advertised to said second one and number of acknowledgments, from said first one of said transmission stations.

3. The method according to claim 1 wherein said first and second ones transfer information over a data path and varying said data rate is implemented at a third one of transmission stations, disposed in said data path, between said first one and said second one.

4. The method according to claim 1 wherein varying said data rate includes receiving, by said first one, a substitute acknowledgment containing data, with said first one increasing a quantity of source packets included in said first unit in response to said data.

5. The method according to claim 1 wherein varying said data rate includes delaying, by said second one, transmission of said acknowledgment packet to said first one, defining a transmission delay, with said transmission delay being a function of a number of source packets received by said second one.

6. The method according to claim 1 wherein said first unit is transmitted through a transmission window having a predetermined capacity, with said acknowledgment packet being transmitted after said second one receives all of said source packets associated therewith, said acknowledgment packet specifying a sequence value of data being acknowledged that establishes a trailing edge boundary on a window of data transmission, and further including selecting substitute sequence values to establish a limit on explicit rate of emission of packets between said first and second ones, and generating a plurality of substitute acknowledgment packets, each having one of said substitute sequence values, in place of said acknowledgment packet, said substitute acknowledgment packets specifying an amount of data acknowledged to indirectly control size of said window of data transmission.

7. The method according to claim 1 wherein said first unit includes a single source packet.

8. The method according to claim 1 wherein said second unit includes a single source packet.

9. An apparatus for controlling data rate of data packets transmitted between a plurality of transmission stations, comprising:

means for transferring information between first and second ones of said plurality of transmission stations by sending first and second units of source packets from said first one to said second one and receiving an acknowledgment packet, from said second one by said first one, with said acknowledgment packet being received by said first one before transmission of said second unit of source packets without sensing for congestion in media between said first transmission station and said second transmission station; and

means, in data communication with said means for transferring, for varying said data rate by sending said acknowledgment packet at a selected delay.

10. The apparatus according to claim 9 wherein said means for varying said data rate includes means for generating substitute acknowledgment packets for said acknowledgment packets in response to a quantity of source packets associated with one of said first and second units of source packets, said substitute acknowledgment packets being generated independent of one of the variables selected from the group consisting of time, range of data being acknowledged, window size being advertised to said second one and number of acknowledgments, from said first one of said transmission stations.

11. The apparatus according to claim 9 wherein said first and second ones transfer information over a data path and means for varying said data rate includes a third one of transmission stations, disposed in said data path, between said first one and said second one that includes means for generating a substitute acknowledgment, in response to receipt of an acknowledgment packet, containing data, with said first one increasing a quantity of source packets included in said first unit in response to said data.

12. The apparatus according to claim 9 wherein means for varying said data rate includes means for delaying transmission of said acknowledgment packet, by said second one to said first one, thereby defining a transmission delay, with said transmission delay being a function of a number of source packets received by said second subset.

13. The apparatus according to claim 9 wherein said means for transferring includes means for transmitting said first unit through a transmission window having a predetermined capacity, with said acknowledgment packet being transmitted after said second subset receives all of said source packets associated therewith, said acknowledgment packet specifying a sequence value of data being acknowledged that establishes a trailing edge boundary on a window of data transmission, and further including means for substituting sequence values to establish a limit on explicit rate of emission of packets from between said first and second ones, and means for generating a plurality of substitute acknowledgments, each having one of said substitute sequence values, in place of said acknowledgment packet, with said substitute acknowledgment packets specifying an amount of data acknowledged to indirectly control size of said window of data transmission.