Multi-layer real-time restoration for survivable networks

With the increased bandwidth capabilities offered by fibre optic transmission, the loss of a single fibre-optic cable can affect a vast number of voice circuits. Protection against failure has been an important aspect of most modern transmission systems. There are two approaches towards the survivability of an optical network: the conventional approach which is based on 1:1 protection switching using diverse routes; or the new approach which is based on the rapid reconfiguration of a high-speed digital cross-connect system (DCS). The authors examine the restoration strategy based on DCS reconfiguration, which has a higher potential to provide a high degree of protection and flexibility at lower cost. Five distributed restoration algorithms are examined and compared. A multi-layer real-time restoration algorithm is presented as an effective solution to achieve extremely fast network failure restoration