Design of Self - Healing Algorithm for ATM Networks *

Automat i c and rapid network service restoration (self-healing) w h e n failures occur i s of increasing importance f o r network operations and managemen t as network speed and bandwidth increase. In th is paper, we s tudy the self-healing problem of a n ATM network at the virtual pa th (VP) configuration level. W e analyze the design issues o f self-healing algorithms, and develop a state t rans i t ion and bandwidth division model of individual VPs and links. O n top of t he model, we design a restoration algorithm that searches and activates alternate V P s f o r the failed V P s by combining a prep lan method and a double search method. T h e preplan method activates preassigned backup V P s dynamically, while t he double search method searches f o r alternate VPs f r o m both the source and destination nodes of failed V P s . T h e double search method is also applied t o reconstruction of the backup VP plan. S imula t ions demonstrate tha t our n e w algorithms outper form ezisting preplanned and dynamic self-healing algorithms in both restoration t ime and restoration ratio.