Chapter 1. Introduction to WAN Architectures

The WAN is a place in the network that aggregates various types, speeds, and links running a disparate set of protocols together crossing metropolitan, state, and even country boundaries. The largest example of a WAN is the Internet itself, which can be regarded as the public WAN. The primary purpose of a WAN is to connect users and applications connected to various LANs.

As evident from its definition, the WAN is the central point for all data aggregation coming from various places within an enterprise network. Because of this, it is important to understand not only how a WAN is constructed, but also the underlying business drivers that have been and continue to bring changes to this place in the network.