Failure recovery in all-optical ULH networks

After many years of research and industry efforts, ultra long haul (ULH) technologies for DWDM transport are maturing, and carriers are deploying such technology for high capacity and capital savings. Unlike opaque optical networks, how best to recover an all-optical ULH network after failure is still uncertain. This paper analyzes four recovery schemes in this area ranging from restoration speed and restoration cost. Our results suggest that the proposed hot-standby scheme would benefit from both fast restoration and cost efficiency comparing to other schemes.