METHOD TO DEFINE SHARED RISK LINK GROUPS IN OPTICAL TRANSPORT SYSTEMS
A method defines shared risk link groups in optical transport systems, in which two optical links sharing at least one single point of failure are considered to be non-disjoint. For each optical link there is measured and recorded a polarization state characteristic and two links having the same characteristic are judged to be non-disjoint and to be in the same shared risk link group.
1 - 7 . (canceled)
8 . A method of defining shared risk link groups in optical transport systems, in which two optical links sharing at least one single point of failure are considered to be non-disjoint, the method which comprises:
measuring for each optical link a polarization state characteristic and recording to polarization state characteristic; and
if two links have the same polarization state characteristic, judging the two links to be non-disjoint and to belong to the same shared risk link group.
9 . The method according to claim 8 , wherein the polarization state characteristic is based on measured changes of the Stokes Vectors of the polarization state at specific locations of the optical link.
10 . The method according to claim 8 , wherein the polarization state characteristic is based on a measured rate of changes of the Stokes Vectors of the polarization state at specific locations of the optical link.
11 . The method according to claim 8 , which comprises measuring the characteristics of the optical links from defined network elements in the optical transport system.
12 . The method according to claim 11 , which comprises measuring the polarization state with Optical-Time-Domain-Reflectometry.
13 . The method according to claim 12 , wherein the Optical-Time-Domain-Reflectometry is part of the transmission equipment in the optical transport system.
14 . The method according to claim 8 , which comprises using the defined shared risk link groups in planning resilient optical networks.