System for detecting and reporting data flow imbalance between computers using grab rate outflow rate arrival rate and play rate

• US 5,864,678 A
• Filed: 05/08/1996
• Issued: 01/26/1999
• Est. Priority Date: 05/08/1996
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Riddle, Guy G.
• Primary Examiner(s): LUU, LE HIEN
• Application Number:
  US08/646,936
• Time in Patent Office: 993 Days
• Field of Search: 370/232, 370/460, 370/253, 370/233, 345/501, 371/20.1, 395/872, 395/200.34, 395/200.65, 395/200.61, 395/200.62, 386/85, 358/412
• US Class Current: 709/235
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/43 Assembling or disassembling of packets, e.g. segmentation and reassembly [SAR]
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A method and apparatus for detecting and reporting flow imbalance of a data stream. A grab rate signal is generated measuring the rate at which a source machine can sequence and compress data from an input. Next, an outflow rate is generated measuring the rate at which the source machine can transmit the compressed data out to a network. When the compressed data arrives at a destination machine from the network, an arrival rate signal is generated measuring the rate at which the destination machine can re-sequence the compressed data for playback and decompression. Finally, a play rate signal is generated measuring the rate at which the destination machine can decompress and play the data to an output. The four rates are used in determining a flow imbalance signal and reporting the imbalance so that the user may correct any deficiencies in the data stream by modifying the quality/size or compression method used for the data transaction from the source.

Claims

1. A method of detecting flow imbalance of data transacted between a source and a destination, said method comprising the steps of:

generating a grab rate signal which is a representation of a first measured rate at which said data is processed to be transmitted out of said source and to said destination and a outflow rate signal which is a representation of a second measured rate at which said processed data is assembled and transmitted from said source;

generating an arrival rate signal which is a representation of a third measured rate at which said processed data is received and reassembled at said destination and a play rate signal which is a representation of a fourth measured rate at which said processed data is unprocessed and output from said destination;

comparing said grab rate signal, said outflow rate signal, said arrival rate signal and said play rate signal according to a specified formula to generate a flow imbalance signal; and

reporting at said source than an imbalance occurred if said flow imbalance signal exceeds a certain threshold signal.

2. A method of detecting flow imbalance according to claim 1 wherein said data includes multimedia data.

3. A method of detecting flow imbalance according to claim 1 wherein said step of comparing includes the steps of:

generating a maximum flow rate signal by finding a maximum among said grab, outflow, arrival and play rate signals;

generating a minimum flow rate signal by finding a minimum among said grab, outflow, arrival and play rate signals; and

generating said ratio of flow imbalance signal by comparing said maximum flow rate signal by said minimum flow rate signal.

4. A method of detecting flow imbalance according to claim 1 wherein said steps of generating said grab rate signal and outflow rate signal and generating said arrival rate signal and said play rate signal is performed using a moving average.

5. A method of detecting flow imbalance according to claim 1 wherein detection is performed on a periodic basis while said data us transacted between said source and said destination.

6. A method of detecting flow imbalance according to claim 1 further comprising the step of reporting at said source than an imbalance occurred if several ratio of imbalance signals generated over a certain time interval all exceed a certain threshold.

7. An apparatus for detecting flow imbalance of data, said apparatus comprising:

a network;

a source machine coupled to an input which generates said data wherein said source machine is coupled to said input to generate a grab rate signal which is a representation of a first measured rate at which said data is processed to be transmitted out of said machine, further wherein said source machine is coupled to said network to generate an outflow rate signal which is a representation of a second measured rate at which said processed data is assembled and transmitted from said source machine;

a destination machine coupled to said network to receive said data from said source machine and to generate an arrival rate signal which is a representation of a third measured rate at which said processed data is received and reassembled at said destination machine, further wherein said destination machine is coupled to an output to play said data and coupled to said output to generate a play rate signal which is a representation of a fourth measured rate at which said processed data is unprocessed and output on said destination machine, said destination machine coupled to said network to send said arrival rate signal and said play rate signal to said source machine; and

a processor computes a flow imbalance of data transacted between said source machine and said destination machine utilizing said grab rate signal, said outflow rate signal, said arrival rate signal, and said play rate signal.

8. An apparatus for detecting flow imbalance of data, said apparatus comprising:

a network;

a source machine coupled to an input which generates said data wherein said source machine is coupled to said input to generate a grab rate signal which is a representation of a first measured rate at which said data is processed to be transmitted out of said source machine, further wherein said source machine is coupled to said network to generate an outflow rate signal which is a representation of a second measured rate at which said processed data is assembled and transmitted from said source machine; and

a plurality of destination machines coupled said network to each receive said data, each of said destination machines coupled to said network to generate its own arrival rate signal which is a representation of a third measured rate at which said processed data is received and reassembled at said destination machine, further wherein each of said destination machines is coupled to its own output to play said data and coupled to its own output to generate its own play rate signal which is a representation of a fourth measured rate at which said processed data is unprocessed and output on said destination machine, said destination machines coupled to said network to send said arrival rate signals and said play rate signals to said source machine; and

a processor computes flow imbalance of data transacted between said source machine and said destination machines utilizing said grab rate signal, said outflow rate signal, said arrival rate signals, and said play rate signals.

9. In a computer system, an apparatus for detecting flow imbalance of data, said apparatus comprising:

a processor coupled to a network to transmit a data stream over said network wherein said processor computes a measured grab rate and a measured outflow rate and is coupled to said network to receive a measured play rate and an measured arrival rate; and

a memory coupled to said processor to compute a flow imbalance utilizing said grab rate, said outflow rate, said play rate and said arrival rate, further wherein said memory is coupled to said processor and to said network to store said flow imbalance and said grab rate, said outflow rate, said arrival rate and said play rate.

10. In a computer system, an apparatus for detecting flow imbalance of data, said apparatus comprising:

a processor coupled to a bus to transmit a data stream over said bus wherein said processor computes a measured grab rate and a measured outflow rate and is coupled to said bus to receive a measured play rate and an measured arrival rate; and

a memory coupled to said processor to compute a flow imbalance utilizing said grab rate, said outflow rate, said play rate and said arrival rate, further wherein said memory is coupled to said processor and to said bus to store said flow imbalance and said grab rate, said outflow rate, said arrival rate and said play rate.