Chapter5.Dial Technology Background

Chapter 5. Dial Technology Background

Dial is an essential part of remote access infrastructures because it is one of the easiest means by which a traveling user can obtain network access. For connectivity at home, in most cases, it provides the cheapest form of Internet access. Dial also provides an inexpensive, reliable backup solution when broadband alternatives are not available because of circuit outages or maintenance windows .

Dialup networking seems simplistic in terms of how it works. The steps to establish a connection include modem train-up, authentication, and establishment of a Point-to-Point Protocol (PPP). After you complete these steps, you have a PPP connection from client to server, which allows you to pass traffic.

The difficult part of dialup networking is overcoming its limitations to get the best possible connection speed and the most stable connection. Dial is a technology that everyone has at their fingertips, but it is limited in certain areas because of the telephone company (telco) infrastructure. This chapter covers some of the details regarding dial and its limitations. It also provides some tips on how to overcome these limitations. The main focus of this chapter is not the detailed, but the essential technology background information, which is, in most cases, sufficient when troubleshooting dial issues. This chapter includes the following sections:

• Overview of existing modems

• Typical telco issues, including digital pads and line code errors

• Authentication options for dial

• Extensive information about one of the most commonly used protocols in dial environmentPPP