Abstract: From the viewpoint of user and operator, optic
al networks are in dire need of fault tolerations, especially recovery from mult
ifault. A multifault recovery survivability mechanism for optical networks w
as presented. The corresponding improvement solutions for the problem in classic
al subgraphy routing method from three aspects was provided and analyzed respect
ively: the shared risk link groups（SRLG） restoration into the subgraph routing
method; a routing principle into the subgraph routing method； the second fault
restoration method based on the subgraph routing. Simulation results are showed
from the point of view of effective utilization.

Key words: Survivability, fault recovery, optical networks, subgraph routing, Shared risk link group