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:
Jun. 12, 2001
Filed:
Jun. 09, 1998
Richard Glenn Kusyk, Kanata, CA;
Nortel Networks Limited, Montreal, CA;
Abstract
A method and apparatus for hitless path switching whereby synchronous traffic is re-directed from an alternate path back over a primary path. A trace message is inserted at an originating path terminal into an information signal and the information signal is transmitted along the primary path and the alternate path. The information signal experiences different delays along the primary and alternate paths. The receiving path terminal is provided with two pointer processors, one for the primary path and one for the alternate path. The pointer processors use a first and a second buffer, respectively, for storing a number of frames of the respective information signal. The information signals arrive at the selector phase aligned, after the pointer processors perform positive and negative stuffing, respectively. Alignment is determined by the relationship 0≦(W,+W,)−2R−M≦1, where were M is the size of the buffers, R is the read address, W,is the current write address in the first buffer, and W,is the write address in the second buffer.