The Feasibility Analysis on Tree-Based EPON-FTTH Protection Architecture – The Art of Access Control System

Ethernet Passive Optical Network (EPON) was proposed to overcome the bandwidth bottleneck at the Access Network due to its simplicity, cost effectiveness and wide spread deployment. A failure in access networks can cause serious problem, because access network transmit aggregated high-speed traffic from hundreds of subscribers. Protection and restoration mechanisms have been applied in backbone networks, but access networks are not considered significantly in the scope of survivability. Towards that, this paper describes our recent approach toward advanced customer access network through the development of an access control system (ACS). The ACS focuses on providing survivability through the OXADM restoration scheme against failure by means of dedicated and shared protection that is applied in FTTH-EPON. A next feature is the high speed restoration achieved by automatic re-routing using fiber status monitoring. Each OXADM has a node controller which receives reports on the status periodically from access control system (ACS). When a failure is detected, The ACS will send a command to the related OXADM to be activated. We highlighted also the activation mechanism to enable the OXADM be installed near the customer premises to perform the restoration without the need of other media. To support the activation process we introduced three ports ONU to efficiently and feasibly the restoration scheme proposed.