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

• US 6,038,216 A
• Filed: 11/01/1996
• Issued: 03/14/2000
• 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:
  US08/742,994
• Time in Patent Office: 1,229 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 in a digital data packet communication environment employing TCP/IP protocols and having a plurality of digital packet transmission stations interconnectable in paths, wherein said data packet communication environment lacks explicit end-to-end data rate supervision, wherein communication includes the steps of:

causing a first digital packet transmission station at a first end to send at least a first source packet to a second digital packet transmission station at a second end;

waiting at said first digital packet transmission station for at least one acknowledgment packet before sending additional source packets;

causing said second digital packet transmission station to send an acknowledgment packet toward said first digital packet transmission station after receipt of said at least one first source packet, the method comprising the steps of;

establishing a limit on explicit rate of emission of packets from said first transmission station to said second transmission station;

invoking said limit upon transmission of said acknowledgment packet from said second digital packet transmission station to said first digital packet transmission station;

thereafter

inserting a latency based on said limit at any point traversed by said acknowledgment packet between said second transmission station and said first transmission station.

2. The method according to claim 1 further including:

generating substitute acknowledgment packets at said point of latency in response to groupings of packets from said first digital packet transmission station, said substitute acknowledgment packets being generated without correlation to at least one of the following variables selected from the group consisting of time, range of data being acknowledged, window size being advertised to said second transmission station and number of acknowledgments, from said groupings of packets from said first digital packet transmission station.

3. The method according to claim 1 wherein said latency inserting step is implemented at a third digital packet transmission station between said first digital packet transmission station and said second digital packet transmission station.

4. The method according to claim 1 wherein said latency inserting step is implemented at said first digital packet transmission station.

5. The method according to claim 1 wherein said latency inserting step is implemented at said second digital packet transmission station.

6. A method for controlling data rate of data packets in a digital data packet communication environment employing TCP/IP protocols and having a plurality of digital packet transmission stations interconnectable in paths, wherein said data packet communication environment lacks explicit end-to-end data rate supervision, wherein communication includes the steps of:

causing a first digital packet transmission station at a first end to send at least a first source packet through a transmission window having a preselected capacity to a second digital packet transmission station at a second end;

waiting at said first digital packet transmission station for at least one acknowledgment packet before sending additional source packets;

causing said second digital packet transmission station to send an acknowledgment packet toward said first digital packet transmission station after receipt of said at least one first source packet, wherein said acknowledgment packet specifies a sequence value of data which is being acknowledged, said sequence value of data being useful to establish a trailing edge boundary on a window of data transmission, the improvement comprising;

selecting substitute sequence values to establish a limit on explicit rate of emission of packets from said first transmission station to said second transmission station; and

inserting a plurality of substitute acknowledgment packets, each having one of said substitute sequence values, in place of said acknowledgment packet, said substitute acknowledgement packets specifying an amount of data acknowledged to indirectly control size of said window of data transmission.

7. The method according to claim 6 wherein said substitute acknowledgment packets are scheduled in time and sequence.

8. The method according to claim 6 further including:

generating said substitute acknowledgment packets at an inter-path point in response to groupings of packets from said first digital packet transmission station, said substitute acknowledgment packets being generated without correlation to at least one of the following variables selected from the group consisting of time, range of data being acknowledged, window size being advertised to said second transmission station and number of acknowledgments, from said groupings of packets from said first digital packet transmission station.

9. The method according to claim 6 wherein said inserting step is implemented at a third digital packet transmission station between said first digital packet transmission station and said second digital packet transmission station.

10. The method according to claim 6 wherein said inserting step is implemented at said first digital packet transmission station.

11. The method according to claim 6 wherein said inserting step is implemented at said second digital packet transmission station.

12. A method for controlling data rate of data packets in a digital data packet communication environment employing TCP/IP protocols and having a plurality of digital packet transmission stations interconnectable in paths, wherein said data packet communication environment lacks explicit end-to-end data rate supervision, wherein communication includes the steps of:

causing a first digital packet transmission station at a first end to send at least a first source packet through a transmission window having a preselected capacity to a second digital packet transmission station at a second end;

waiting at said first digital packet transmission station for at least one acknowledgment packet before sending additional source packets;

causing said second digital packet transmission station to send an acknowledgment packet toward said first digital packet transmission station after receipt of said at least one first source packet, wherein said acknowledgment packet includes a window size indicator that specifies an allowable range of transmission of data beyond a range of data acknowledged as a window size to be advertised from said second data transmission station to said first data transmission station, said indicator being useful to establish a leading edge boundary on said window of data transmission, the improvement comprising;

selecting a substitute indicator for said window size indicator to establish a limit on explicit rate of emission of packets from said first transmission station to said second transmission station; and

inserting said substitute indicator into said acknowledgment packet.

13. The method according to claim 12 further including:

selecting substitute indicator values to establish a limit on explicit rate of emission of packets from said first transmission station to said second transmission station;

generating a plurality of substitute acknowledgment packets, each having one of said substitute indicator values; and

causing said plurality of substitute acknowledgment packets to be transmitted toward said first digital packet transmission station.

14. The method according to claim 12 wherein said indicator inserting step is implemented at a third digital packet transmission station between said first digital packet transmission station and said second digital packet transmission station.

15. The method according to claim 12 wherein said indicator inserting step is implemented at said first digital packet transmission station.

16. The method according to claim 12 wherein said indicator inserting step is implemented at said second digital packet transmission station.

17. An apparatus for controlling data rate of said data packets in a digital data packet communication environment employing TCP/IP protocols and having a plurality of digital packet transmission stations interconnectable in paths, wherein said data packet communication environment lacks explicit end-to-end data rate supervision, wherein said communication environment includes:

means for causing a first digital packet transmission station at a first end to send at least a first source packet to a second digital packet transmission station at a second end;

means for waiting at said first digital packet transmission station for at least one acknowledgment packet before sending additional source packets;

means for causing said second digital packet transmission station to send an acknowledgment packet toward said first digital packet transmission station after receipt of said at least one first source packet, the improvement comprising;

means for establishing a limit on explicit rate of emission of packets from said first transmission station to said second transmission station;

means for providing said limit upon transmission of said acknowledgment packet from said second digital packet transmission station to said first digital packet transmission station; and

means for invoking, said limit at any point traversed by said acknowledgment packet between said second transmission station and said first transmission station.

18. An apparatus for controlling data rate of data packets in a digital data packet communication environment employing TCP/IP protocols and having a plurality of digital packet transmission stations interconnectable in paths, wherein said data packet communication environment lacks explicit end-to-end data rate supervision, wherein said communication environment includes:

means for causing a first digital packet transmission station at a first end to send at least a first source packet through a transmission window having a preselected capacity to a second digital packet transmission station at a second end;

means for waiting at said first digital packet transmission station for at least one acknowledgment packet before sending additional source packets;

means for causing said second digital packet transmission station to send an acknowledgment packet toward said first digital packet transmission station after receipt of said at least one first source packet, wherein said acknowledgment packet specifies a sequence value of data which it is being acknowledged, said sequence value of data being useful to establish a trailing edge boundary on a window of data transmission, the improvement comprising;

means for selecting substitute sequence values to establish a limit on explicit rate of emission of packets from said first transmission station to said second transmission station; and

means for inserting 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.

19. An apparatus for controlling data rate of data packets in a digital data packet communication environment employing TCP/IP protocols and having a plurality of digital packet transmission stations interconnectable in paths, wherein said data packet communication environment lacks explicit end-to-end data rate supervision, wherein communication environment includes:

means for causing a first digital packet transmission station at a first end to send at least a first source packet through a transmission window having a preselected capacity to a second digital packet transmission station at a second end;

means for waiting at said first digital packet transmission station for at least one acknowledgment packet before sending additional source packets;

means for causing said second digital packet transmission station to send an acknowledgment packet toward said first digital packet transmission station after receipt of said at least one first source packet, wherein said acknowledgment packet includes a window size indicator that specifics an allowable range of transmission of data beyond a range of data acknowledged as a window size to be advertised from said second data transmission station to said first data transmission station, said indicator being useful to establish a leading edge boundary on said window of data transmission, the improvement comprising;

means for selecting a substitute indicator for said window size indicator to establish a limit on explicit rate of emission of packets from said first transmission station to said second transmission station; and

means for inserting said substitute indicator into said acknowledgment packet.