Content

| Overview

Initially, TCP/IP networks relied on simple distance vector routing protocols and classful 32-bit IP addressing. These technologies offered a limited capacity for growth. Network designers must now modify, redesign, or abandon these early technologies to build modern networks that can scale to handle fast growth and constant change. This module explores networking technologies that have evolved to meet this demand for scalability.

Scalability is the capability of a network to grow and adapt without major redesign or reinstallation. It seems obvious to allow for growth in a network, but growth can be difficult to achieve without redesign. This redesign may be significant and costly. For example, a network may provide a small company with access to e-mail, the Internet, and shared files. If the company tripled in size and demanded streaming video or e-commerce services, could the original networking media and devices adequately serve these new applications? Most organizations cannot afford to recable or redesign their networks when users are relocated, new nodes are added, or new applications are introduced.

Good design is the key to the capability of a network to scale. Poor design, not an outdated protocol or router, will prevent a network from scaling properly. A network design should follow a hierarchical model to be scalable. This module discusses the components of the hierarchical network design model and the key characteristics of scalable internetworks.