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:
Mar. 01, 2000
Shanwei Cen, Portland, OR (US);
Tektronix, Inc., Beaverton, OR (US);
Abstract
A method and apparatus for non-intrusive measurement of end-to-end properties of network flows uses a passive approach. An ingress monitor non-intrusively intercepts data units as they enter a network path through a network. Likewise an egress monitor non-intrusively intercepts the same data units as they leave the same network path. Each monitor generates a time stamp for each intercepted data unit using a common clock and derives a unique signature for each data unit such that the same data unit has the same signature at the entry as at the exit. Additionally each monitor counts the number of packets received from the network flow at the ingress and egress respectively. The signature, time stamp and packet counter value form an entry which is retained in an entry queue in each monitor. A data correlator coupled to an out-of-band network to which the monitors also are coupled periodically pulls a list of entries from each monitor and correlates the lists by matching signatures. The time stamps for the entries from the respective lists having the same signature are processed to obtain end-to-end latency of the network path, and the difference in counts over a given time period provides end-to-end packet loss measurements.