Wide Area Networks and Open Standards

Abstract

The previous chapter concentrated on point-to-point links. In this chapter we use these links to build a Wide Area Network (WAN). WANs are to be contrasted with Local Area Networks (LANs), which are discussed in the next chapter. A simple distinction between WANs and LANs is that WANs are designed to cover a large geographical area, whilst LANs are designed for a restricted area, e.g. an office building or factory. Another way of distinguishing between WANs and LANs, this time in terms of the network parameters t p (end-to-end propagation delay) and H (holding time), is that the factor a = t p /H is, say, ≥ 10 for WANs and < 10 for LANs, as discussed in chapter 7 on latency.