Chapter 8. WAN Basics

This chapter covers the following topics:

• WAN Switching Services

• Network Interfaces

• WAN Architecture

Wide area network (WAN) connectivity enables individuals and organizations to take advantage of internetworking services such as Frame Relay, Asynchronous Transfer Mode (ATM), and the Internet. Local area networks (LAN) enable communication and resource-sharing within an enterprise or campus setting. WANs connect two or more LANs.

NOTE

The "wide" in wide area network implies a geographic separation between network sites; however, this separation is not always the case. By definition, a WAN is a government (FCC)-regulated public network or privately owned network that crosses into the public network environment. If the geographical separation crosses over a public thoroughfare, a WAN is required to make the connection.

A number of telecommunications services are used for WAN communications, such as a switched (shared) or dedicated service. For the LAN user, these LAN and WAN services and components combine, creating the illusion of one large end-to-end virtual network. Because of this virtual network illusion, the WAN is often represented as a cloud, as shown Figure 8-1.

Figure 8-1. A WAN "Cloud"