An access network connects customer premises to a serving wire center (SWC), which is a central office (CO) where access lines converge.
Types of Access Networks
Access networks are characterized by the type of transmission medium and include: twisted pair, coaxial cable, fiber optic, wireless, and hybrid networks. This site is primarily concerned with wireline networks, and wireline access methods.
Convergence Via Fiber Access
Fiber optics provides more capacity, higher reliability, and longer reach than other transmission media. Fiber-to-the-premise (FTTP) can readily support convergence and is the preferred access method in the long term. However, running fiber all the way to the customer premise is very expensive, and it will be a long time before fiber-to-the-premise is fully deployed.
Convergence Via Coax Access
Coaxial cable (coax) can support bandwidths sufficient for convergence, and coax access networks are widely deployed throughout the U.S. Click here to read a paper on convergence based on hybrid fiber coax (HFC) access networks. This paper was originally published in the International Engineering Consortium's Annual Review of Communications 2000. Note that I no longer favor the backbone architecture described in the paper, which involves an all-optical backbone network.
Convergence Via Twisted Pair Access
Convergence can be supported over twisted pair access lines using very-high-rate digital subscriber line (VDSL) techniques. VDSL involves running fiber to the customers' neighborhood so that the twisted pair access lines are greatly shortened. Click here to read a paper describing how convergence can be fully supported over existing twisted pair access lines. This paper was originially published the International Engineering Consortium's comprehensive report on Broadband Services, Application, and Networks: Enabling Technologies and Business Models (copyright 2004).
Supporting the "Triple Play"
Click here to read a paper describing how the VDSL architecture described above can support the "triple play" of services, i.e. voice, video, and data communications, over existing telephone lines. This paper was originally published in the International Engineering Consortium's comprehensive report on Achieving the Triple Play: Technologies and Business Models for Success (copyright 2006).