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Internet Access Guide

Introduction Dial-Up Cable Modem ADSL GPRS
WiMAX Satellite Comparison How to Choose FTTH


 

Internet Access Guide : Fiber-To-The-Home (FTTH)

How much data rate a FTTH subscriber can get? It depends on the architecture of the ODN, the capacity provided per optical interface in the CO, and the number of subscribers served by the optical module in the CO. Like DSL/cable, FTTH is offered in several service levels. It is usually in different download/upload (DL/UL) rates and/or bundled services. The DL/UL rates are usually higher than DSL/cable rates, e.g. 15 - 30 Mbps for download and 2 - 5 Mbps for upload. The DL/UL rates may be adjusted over time by FTTH service providers based on competition and bandwidth requirement of popular applications.

However, a FTTH subscriber must remember that the quoted DL/UL speeds apply only to the link between him/her to the service provider's PoP. Say for instance, you visit a website stored in a Web hosting server somewhere on the Internet, the bandwidth pipe that connects the said Web server to the Internet also affects your download speed. And the fact that the pipe is also shared among all other visitors will become another factor that affects your download speed. So, in many cases you would end up getting lower DL/UL rates than those stated in commercials.

real download and upload speeds depend on many layers in telecommunication network
Picture: End-to-end bandwidth pipe
Real download and upload rates depend on the available end-to-end network capacity.

In a typical home network, a Fast Ethernet backbone has symmetrical transfer rate of 100 Mbps, while average DSL/cable modem download rate is below 2 Mbps and upload rate is lower than that. The capacity ISPs or network operators have in their backbone is in giga bits per second (Gbps) order and moves toward tera bits per second (Tbps). So, the last mile (DSL/cable) becomes a bandwidth bottleneck. FTTH lowers the bandwidth gap between a subscriber LAN (and his/her PC's internal processor) and the Internet.

FTTH enables the delivery of multimedia applications in very good quality, such as video and photo sharing, telemedicine, telecommuting, distant learning, and video monitoring. Each type of application has a unique bandwidth (read: capacity) requirement. For example, a HDTV requires 15 - 20 Mbps, HSI (high speed Internet) 5 - 10 Mbps, and a POTS 64 kbps. FTTH also has lower latency and less jitter than other access methods that makes it very suitable for real-time application, such as VoIP and interactive game.

 
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