Chapter1.Remote Access Overview

Chapter 1. Remote Access Overview

Remote access is a term that pertains to communication with a data processing facility from a remote location or facility through a data link. This chapter introduces remote access environment specifics and provides brief descriptions of remote access options in the following aspects:

• Management considerations and the pros and cons of remote access solutions

• Defining the remote access population

• Legacy remote access solutions

• Virtual Private Networks (VPNs) over some of the most popular technologies, such as cable modems, xDSL, wireless, and satellite services

• Provisioning of the corporate circuits

As a network administrator or network engineer, you need to identify the specifics of the environment and know the specifics of the solution that you are troubleshooting to set up your expectations accordingly.

Remote access networks are often described as the most difficult type of network to support. In corporate local-area networks (LANs) and wide-area networks (WANs), data centers and network operations centers safeguard the networking infrastructure. However, remote access to an employee's home or from locations while an employee is traveling or working from a customer's premises introduces many components not under a corporation's control.

Within a user's home, there can be wiring problems or limited copper pairs, which can complicate the installation and troubleshooting process. Users can power off their home routers or modems, referred to as customer premises equipment (CPE), at any time. This makes proactive monitoring extremely difficult, if not impossible. Users can install any hardware and software on their home network or computer that might interfere with, or not integrate with, the remote access solution. It is difficult to control the security aspects of a user's home network. Finally, a user might be technically proficient enough to modify the CPE configuration, which can result in additional problems.

While an employee is working on the road from either a hotel or a customer premises, additional complications exist, and sometimes getting answers to specific troubleshooting questions can be impossible. The phone system in a hotel often contributes to dialup connectivity problems. A broadband service offering in a hotel or a customer's firewall can block IPSec traffic for VPN users who are trying to reach their destination point through the Internet.

Some services that the remote user is accustomed to in the corporate environment might be unavailable, not permissible, or have a degradation of quality because of bandwidth, latency, or policy limitations from remote locations. Some of these circumstances might require special setups to meet users' expectations.

For all these reasons, troubleshooting remote access problems can be a difficult and time-consuming process. The purpose of this book is to provide networking professionals with a collection of proven and current troubleshooting techniques for Cisco Systems remote access products and for most remote access service options. Technologies addressed in this book include analog dial, ISDN, Frame Relay, and VPN.