Designing Wide Area Networks and Internetworks: A Practical Guide

8. Identifying Backbone Locations

We have seen that many internetworks can most readily be constructed with a high-capacity backbone and with a lower-capacity access infrastructure. How can we determine which locations need to be on the backbone and which can most cost-effectively be served as part of the access infrastructure? It is tempting to think that this is a given, dictated from our traffic requirements. In reality, this determination is no less involved than any of the other aspects of network design with which we must deal.

Let’s begin by reviewing the ways in which the backbone typically differs from the access portion of an internetwork. We’ll then consider how each of these differences might motivate us to include or exclude a particular ...