Network Hierarchy
Networks can be classified according to the geographical coverage, the access hierarchy, the topology, the technologies used and the services provided.
Depending on their geographical coverage networks can be divided into the following hierarchy:
- Local networks which are operational inside a small physical area within a kilometer or less, e.g. LAN, PBX
- Wide area networks (WAN) which cover a larger physical area with a ten to hundred kilometer radius, e.g. FDDI, FR, ATM
- Nationwide networks which provide nationwide backbones where local or wide area networks are attached, e.g. PDH, SDH
- International networks which interconnect nationwide networks using satellite or undersea fiber links, e.g. PDH, SDH.