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:
Sep. 28, 2004
Filed:
Mar. 13, 2000
Tissa Senevirathne, Santa Clara, CA (US);
Van Hunter, Clearwater, FL (US);
Sri Reddy, Los Altos, CA (US);
Nortel Networks Limited, St. Laurent, CA;
Abstract
A method and apparatus selecting between primary switching fabric in an asynchronous transfer mode (ATM) network includes a Tap Mux controller that monitors the signals being transmitted to each of four fabric access devices. As each of the fabric access devices receives nine communication lines, the Tap Mux controller monitors a total for 36 communication lines on the primary switching fabric. Because the switching fabric is completely redundant, however, the Tap Mux controller also monitors a total of 36 communication lines on the protection switching fabric. The Tap Mux controller, therefore, includes logic that defines 72 state machines that each monitor one of the 72 lines. Each state machine, in the described embodiment, initiates a defined length time window and counts errors therein. Protection path switching occurs, for example, only when 10 errors occur on any one of the 36 primary switching fabric lines being received by four fabric access devices therein within a 100 millisecond window initiated at the detection of the first error on the communication line. If 10 errors are not detected within a defined communication window, in the described embodiment, the window is terminated and is only reinitiated upon the detection of the next line error.