Abstract

Survivability is an important requirement in optical transport networks. Under 1+1-path based protection mechanism, a connection consists of two "diverse" paths, one of which could be designated as primary (e.g., the shorter hop path) and the other as backup. The signal is transmitted by the source on both paths. Under no-failure condition, the receiver selects the primary path signal, and upon failure, it switches to the backup path signal. 1+1- path protection is characterized by simplicity and low restoration latency (receiver switching time of typically few to 10 msec) and meets the design target of 50 msec associated with restoration in SONET/SDH rings. Thus, in spite of its bandwidth expensive nature, many carriers currently plan to implement this as the first restoration protocol as they deploy or evolve to optical mesh networks.

© 2005 Optical Society of America