Table of Contents:

Definition and Overview

1. Where Is Access in the Network?

2. Access Evolution Drivers

3. An Overview of Access Alternatives

4. Twisted-Pair Solutions

5. Twisted-Pair Access—Remote

6. Fiber and Coax

7. Wireless

8. All Fiber—PON

9. All Fiber—SONET

10. Conclusion

Self-Test

Glossary

PDF of this tutorial

Internet-access technologies fit into four broad categories:

• twisted pair
• fiber/coax
• wireless
• all fiber

As shown in Figure 3, several technologies and implementations exist within each of these broad categories.

Figure 3. Access Alternatives

Twisted-pair telephone lines are the access media used by the vast majority of individual residential subscribers today. Over time, a number of technologies have been introduced to provide faster data speeds over this medium.

Fiber/coax systems were originally introduced for video-broadcast applications. Because these systems are inherently broadband, techniques have been developed to use this advantage to provide high-speed data transmission, principally for residential Internet access.

Wireless Internet access has two origins: satellite systems established for broadcast video have the ability to distribute Internet data at high speeds, and cellular/personal communications service (PCS) systems are designed to serve mobile users.

The predominant access systems for business users are optical-fiber synchronous optical network (SONET) and synchronous digital hierarchy (SDH) systems. In the future, passive optical network (PON) systems are expected to become an all-fiber access medium for residential users as well.