Hitless Protection Switching Method for Passive Optical Network

The Passive Optical Network (PON) shares transmission facilities to provide broadband services economically. To enhance network survivability, ITU-T Rec. G.983.5 defines some protection switching methods. These methods, however, always bring about signal loss when switching is performed. Moreover, a network operator often has to replace one optical fiber cable with another that takes a different route due to constructions like social infrastructure renewal. If hitless switching is available, the operator can carry out that activity anytime without impacting users, and can also offer higher-grade broadband services. Thus the hitless protection technology for PON systems is very attractive and useful. This paper proposes hitless switching methods for PON systems based on the PON’s unique features. We also present a specific hitless protection method for GE-PON as a design example. Index Terms Network reliability, Network survivability, Network protection, Hitless switching, PON, GE-PON