Patent ID: 6616350
Filing Date: 2003-09-09
Classification: H04J

Abstract:
A local node for use in a synchronous optical network ring, said local node comprising:a first group of working transmission lines for exchanging data with a first remote node in the network; a first protection line associated with said first group of working transmission lines, said first protection line being capable of exchanging data with the first remote node in the network; a second group of working transmission lines for exchanging data with a second remote node in the network, different from the first remote node; a second protection line associated with said second group of working transmission lines, said second protection line being capable of exchanging data with the second remote node in the network; a control unit operative to monitor said first and second groups of working transmission lines and: a) upon detection of a data transmission impairment of a first type over any one of the lines in the first group of working transmission lines, invoke a first protection switch event causing re-routing of optical signals from the working transmission line on which the data transmission impairment of the first type has been detected to said first protection line; b) upon detection of a data transmission impairment of a second type between said local node and the first remote node, invoke a second protection switch event causing re-routing of optical signals from a particular working transmission line of said first group of working transmission lines to said second protection line.