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:
Jan. 31, 2006
Filed:
Jun. 02, 1999
Pierre A. Humblet, Cambridge, MA (US);
Bruce D. Miller, North Reading, MA (US);
Raj Shanmugaraj, Groton, MA (US);
Steven Sherry, Needham, MA (US);
Peter B. Beaulieu, Plaistow, NH (US);
Michael W. Fortuna, Fremont, NH (US);
Michael C. Yip, Wellesley, MA (US);
William Abraham, Windham, NH (US);
Pierre A. Humblet, Cambridge, MA (US);
Bruce D. Miller, North Reading, MA (US);
Raj Shanmugaraj, Groton, MA (US);
Steven Sherry, Needham, MA (US);
Peter B. Beaulieu, Plaistow, NH (US);
Michael W. Fortuna, Fremont, NH (US);
Michael C. Yip, Wellesley, MA (US);
William Abraham, Windham, NH (US);
Alcatel Communications, Inc., Plano, TX (US);
Abstract
A system and method for fast and reliable failure notification and accelerated switchover for path protection in a communications network having several overlapping areas of nodes interconnected by communications links is described. Upon a failure event involving one of the communications links, a failure message is broadcast identifying the failed link, the broadcast being confined within the areas which include the failed link. A reliable transmission protocol is provided wherein at one or more of the nodes, a LAPD protocol unnumbered information frame containing the failure message is sent to connected nodes. The failure message is resent in another unnumbered information frame after a time interval unless an unnumbered acknowledgment frame containing or referencing the failure message is received from the connected node. A method of path protection includes establishing plural working paths through the nodes. For each working path, an associated protection path is precalculated. A priority is assigned to each working path and associated protection path. A protection path is precalculated for each area through which a particular working path traverses. Upon a failure event, working paths that include the failed link are switched to their respective protection paths. Higher priority protection paths can preempt lower priority paths that share at least one link. At each node, linked lists for protection path activation, working path deactivation and path preemption are implemented upon a failure event.