Kathleen M Curtis

US Patent:

58056025, Sep 8, 1998

Filed:

Oct 1, 1996

Appl. No.:

8/725653

Inventors:

Leo Cloutier - Bethesda MD
David C. Curtis - Crofton MD
Kathleen P. Curtis - Crofton MD
David D. DeNunzio - Ellicott City MD
William P. Reed - Haddonfield NJ
Robert A. Wolak - Audubon PA

Assignee:

Bell Atlantic Network Services, Inc. - Arlington VA

International Classification:

H04J 306

US Classification:

370516

Abstract:

An arrangement (apparatus and method) for monitoring jitter caused during transport of digitally-coded information in a packet switched network, and for managing network operations in accordance with the detected jitter. The detected jitter is used to determine whether corrective action is necessary, such as rerouting network traffic, or performing network maintenance. The disclosed arrangement detects program clock reference (PCR) values from an MPEG-encoded transport stream, whereby each pair of PCR values represents an expected arrival time of a corresponding stream segment. An actual arrival time for the corresponding stream segment is determined in response to detection of the corresponding PCR values and an independent clock signal. The expected arrival time of the stream segment and the actual arrival time are correlated with an accumulation of expected and actual arrivaimes of previously-received data packet stream segments in order to determine the jitter in the digital data stream. The jitter is corrected by a combination of adaptive buffering techniques and restamping the PCR value with corrected values coinciding with the actual arrival time of the stream segments.