Broadband Optical Access Networks

CHAPTER 3

PASSIVE OPTICAL NETWORKS: ARCHITECTURES AND PROTOCOLS

In response to the steadily increasing demand for bandwidth and advanced networking services from residential as well as enterprise customers, passive optical networks (PONs) over the last decade have emerged as a matured access technology that offers flexibility, broad area coverage, and cost-effective sharing of expensive fiber links and networking equipment. Both ITU and IEEE have standardized solutions for PONs operating at gigabit per second line rates [1]. ITU-T extends the early work of the full service access network (FSAN) working group, which brings efficient fiber access to homes by creating ATM-based PON (APON). APON, the first standardized PON solution, supports the legacy of ATM protocols at 622 Mb/s (OC-12) of downstream bandwidth and 155 Mb/s (OC-3) of upstream bandwidth. Since the initialization of APON and an improved solution for ITU-T G.983.1 broadband PON (BPON), newer standards have been investigated to support gigabit rates and packet-based Internet applications. Gigabit PON (GPON) was rectified by ITU-T in the G.984.x Recommendations to support gigabit rates and a mix of TDM, ATM, and Ethernet services, and to enhance security. At approximately the same time, the Ethernet in the first-mile (EFM) 802.3ah study group has standardized Ethernet PON (EPON) to leverage the commercial success of Ethernet as a local area network (LAN) technology. The EFM effort creates a minimal set of extensions to ...