The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 18, 2004
Filed:
Nov. 01, 2000
Simon Love, Edinburgh, GB;
Graham S. Pollock, Cupertino, CA (US);
Agilent Technologies, Inc., Palo Alto, CA (US);
Abstract
A method of synchronizing the operation of a plurality of measurement probes enables multi-point measurements of a communications network. The method comprises the step of collecting data packets from a data stream of the communications network using the plurality of probes. The data packets are collected after a predetermined start time. The method further comprises the steps of determining a hash value array from an invariant portion of the sampled data packets, and comparing the hash value array to a start hash mask. Collection by a probe of a data packet that produces a hash value array that matches the start hash mask is used as a synchronization event. The method of the present invention allows multiple measurement probes observing the same data stream at different physical locations to be synchronized such that all of the probes observe the same set of packets being carried by the data stream. The method also allows statistical control over the frequency of packet matches within a data stream to the start hash mask. Moreover, the method of the present invention depends only on passive access to the physical links of the network. As such it will not degrade the performance or availability of the network.