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. 27, 2008
Filed:
May. 03, 2001
Jon Weil, Coton, GB;
Alex Morrall, Finham, GB;
David Odhams, Epping, GB;
Kenneth Hayward, Kanata, CA;
Loa Andersson, Alvsjo, SE;
Jon Weil, Coton, GB;
Alex Morrall, Finham, GB;
David Odhams, Epping, GB;
Kenneth Hayward, Kanata, CA;
Loa Andersson, Alvsjo, SE;
Nortel Networks Limited, St. Laurent, Quebec, CA;
Abstract
A communications network comprises a lower transport layer and an upper overlay incorporating a plurality of routers. Adjacencies are defined between respective pairs of routers. Path protection is provided by defining a software model of the overlay of the network and defining in the model a hierarchy of protection levels for the main path. Each protection level is characterised by a respective set of one or more broken adjacencies in the model, the adjacencies to be broken being determined from a knowledge of the underlying topology. A protection level is selected and a protection path avoiding the broken adjacencies associated with that protection level is calculated. If this calculated path is not available in the real network, a lower protection level in the hierarchy is selected and the protection path calculation repeated. The process continues until a suitable protection path is identified.