Next generation PON systems - Current status

Gigabit-capable Passive Optical Network (PON) systems, such as GPON (standardized in ITU-T Rec. G.984 series) and 1G-EPON (IEEE 802.3ah, now part of IEEE 802.3-2008) have been standardized and are now being mass-deployed in various markets around the world. With the continuous increase in bandwidth demand generated by consumer and business applications, the need for a new, higher capacity access architecture is more than obvious. Therefore, one of the principal requirements for next-generation PON (ngPON) is to provide a substantial increase of the bandwidth available to end-subscribers, when compared with GPON and 1G-EPON. Additionally, considering the Capital Expenditure (CAPEX) investment made for deploying gigabit-capable PON systems, ngPON must be able to protect the investment of the legacy networks by ensuring a subscriber seamless migration from GPON/1G-EPON to ngPON. ngPON systems are currently under standardization in two Standard Development Organizations (SDOs), i.e. 10G-EPON in IEEE, as part of P802.3av, and NG-PON in FSAN/ITU-T. The IEEE P802.3av standard focuses only on extensions to the existing 1G-EPON specifications in order to support 10 Gbit/s operation, including symmetric and asymmetric data-rates. On the other hand, NG-PON recommendations cover the complete system, starting from Physical Medium Dependent (PMD), followed by framing and medium access, and ending with security and service provisioning mechanisms. NG-PON systems are divided into two major groups, i.e. NG-PON1 and NG-PON2, based on their characteristics of co-existence with legacy GPON systems. Other SDOs focus on operational, architectural, and management aspects of the existing and future PON systems, e.g. BroadBand Forum (BBF, former DSL Forum).