Method and apparatus for time synchronization in a network data processing system
First Claim
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1. A method for synchronizing time in a network data processing system comprising the data processing system implemented steps of:
- receiving a request for time synchronization at a target data processing system, wherein the request is received from a source data processing system;
placing a current target time at the target data processing system in a reply;
sending the reply to the source data processing system;
comparing a current source time from when the reply is received at the source data processing system to the current target time to generate a comparison; and
generating a synchronization factor using the comparison.
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Abstract
A method, apparatus, and computer implemented instructions for synchronizing time in a network data processing system. A request for time synchronization is received at a target data processing system. A current target time at the target data processing system is placed in a reply. The reply is sent to the source data processing system. A current source time from when the reply is received at the source data processing system is compared to the current target time to generate a comparison. A synchronization factor is generated using the comparison.
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Citations
34 Claims
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1. A method for synchronizing time in a network data processing system comprising the data processing system implemented steps of:
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receiving a request for time synchronization at a target data processing system, wherein the request is received from a source data processing system;
placing a current target time at the target data processing system in a reply;
sending the reply to the source data processing system;
comparing a current source time from when the reply is received at the source data processing system to the current target time to generate a comparison; and
generating a synchronization factor using the comparison.
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2. The method of claim Al, wherein the synchronization factor is determined as follows:
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SF=T3−
T2wherein SF is the synchronization factor, T2 is the current target time, and T3 is the current source time when the reply is received.
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3. The method of claim Al, wherein the synchronization factor is determined as follows:
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SF=T3−
T2−
(T3−
T1)/2wherein SF is the synchronization factor, Tl is a source time when the request is sent, T2 is the current source time, and T3 is the current source time when the reply is received.
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4. The method of claim A1 further comprising:
generating a time stamp for a message using the synchronization factor and a current time in the target data processing system.
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5. The method of claim A1 further comprising:
storing the synchronization factor.
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6. A method in a data processing system for synchronizing time, the method comprising:
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sending a synchronization request to a target;
receiving a reply, wherein the reply includes a current time from the target;
identifying a clock skew using the current time from the target; and
generating a time stamp for a message using the clock skew. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 32)
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14. A data processing system comprising:
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a bus system;
a communications unit connected to the bus, wherein data is sent and received using the communications unit;
a memory connected to the bus system, wherein a set of instructions are located in the memory; and
a processor unit connected to the bus system, wherein the processor unit executes the set of instructions to send a synchronization request to a target;
receive a reply, wherein the reply includes a current time from the target;
identify a clock skew using the current time from the target; and
generate a time stamp for a message using the clock skew.
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19. A network data processing system for synchronizing time comprising:
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receiving means for receiving a request for time synchronization at a target data processing system, wherein the request is received from a source data processing system;
placing means for placing a current target time at the target data processing system in a reply;
sending means for sending the reply to the source data processing system;
comparing means for comparing a current source time from when the reply is received at the source data processing system to the current target time to generate a comparison; and
generating means for generating a synchronization factor using the comparison.
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25. A data processing system for synchronizing time, the data processing system comprising:
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sending means for sending a synchronization request to a target;
receiving means for receiving a reply, wherein the reply includes a current time from the target;
identifying means for identifying a clock skew using the current time from the target; and
generating means for generating a time stamp for a message using the clock skew.
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33. A computer program product in a computer readable medium for synchronizing time in a network data processing system, wherein the computer program product:
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first instructions for receiving a request for time synchronization at a target data processing system, wherein the request is received from a source data processing system;
second instructions for placing a current target time at the target data processing system in a reply;
third instructions for sending the reply to the source data processing system;
fourth instructions for comparing a current source time from when the reply is received at the source data processing system to the current target time to generate a comparison; and
fifth instructions for generating a synchronization factor using the comparison.
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34. A computer program product in a computer readable medium for synchronizing time, the computer program product comprising:
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first instructions for sending a synchronization request to a target;
second instructions for receiving a reply, wherein the reply includes a current time from the target;
third instructions for identifying a clock skew using the current time from the target; and
fourth instructions for generating a time stamp for a message using the clock skew.
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Specification