A study on the protection mechanism providing diverse protection demands in ethernet PON

Abstract

PON has the point-to-multipoint downstream and multipoint-to-point upstream structure. Especially EPON among the PON technologies uses Ethernet as a basic transmission protocol. The advantages of EPON are wider bandwidth, lower cost and easy to implement. A failure in network elements can cause serious problems because optical access networks transmit aggregated high-speed data from several hundreds of subscribers. Therefore, the survivability of EPON is necessary and becomes important to provide seamless services and operate the reliable networks. In this thesis, we propose a new protection architecture and its protection algorithms. Our proposed protection architecture, type N, provides the diverse protection demands, a high class user and a universal user, like protection architecture C. However, with adding additional switch to the PON, type N offers higher grade service than type C. Under the single failure occurrence, if another failure occurs, type N can serve high class user, but type C breaks down. We present protection algorithms for our protection architecture using different two EPON messages; MPCP message and OAM message. We detect a failure occurrence using these messages, switch to the recovery module and provide stable transmission. Though MPCP message is not the traditional maintenance intended message but the upstream control functionality message, if we use MPCP, we can control the upstream with no collision, detect network failures and recover from failures in fast time without special OAM function. We show the performance evaluation of our protection architecture. Our protection architecture guarantees 50ms recovery time with using both MPCP message and OAM message. Additionally our protection architecture has the longest MTTF and the smallest break down probability of all protection architectures. In these results, we know that our protection architecture provide stable and reliable services.