Chapter 5. FTTx Access Networks
This chapter covers the following topics:
Fiber to the Curb
Fiber to the Building
Fiber to the Home
Summary
The deployment of optical fiber from the carrier premises (cable head end or telephone central office) deep into the distribution network enables the implementation of xDSL and HFC innovations.
Because xDSL and HFC bring fiber closer and closer to the home, why not finish the job and connect fiber all the way to the home? Fiber access networks, namely Fiber to the Building (FTTB), Fiber to the Curb (FTTC), and Fiber to the Home (FT TH), are technologies to move fiber closer to the home—and, in the case of FTTH, into the home. These are referred to collectively as FTTx.
In particular, fiber to the home (FTTH) is viewed by some carriers and analysts as the Holy Grail of full-service access networks. It promises high bandwidth, immunity to electromagnetic interference, and lower operational costs because it doesn't rust. Why not just remove the metallic elements from the access network entirely? There are good reasons why not, which we explore in due course; first, we look at the promise and the architecture of FTTx networks. That being said, the emphasis of this chapter will be FTTH.
Like cable networks, FTTx networks promise full-service digital networking. Full-service means that a consumer can receive all video, voice, and Internet services from a single carrier, in contrast with today's market, where phone service is delivered by a local phone company, cable TV services from a cable operator, and Internet services from an ISP. Instead, digital telephony, interactive data services, and digital video (digital TV, video on demand, and near video on demand) would come from one service provider.
Much of the impetus behind FTTx among major telco operators is organized by the Full Service Access Network Initiative (FSAN, www.labs.bt.com/profsoc/access ). At the time of this writing, the members of FSAN were Bell Canada, Bell South, British Telecom, Deutsche Telekom, Dutch PTT, Telecom Eireann, France Telecom, GTE, Korea Telecom, NTT, SBC, Singapore Telecom, Swisscom, Telefonica (Spain), Telia (Sweden), Telstra (Australia), Telecom Italia, Bezeq (Israel), Chunghwa Telecom, and U.S. West.
FTTx access networks are objects of research, development, and standardization. Current deployments are in the trial and very early rollout stage. However, FTTx offers the promise of speed in abundance, superior security, and network reliability so as to stimulate telcos around the world to support these innovations.