First, let's have a look at a typical network structure that can be found in this form or similar forms in many companies:
The corporate network is based on the internal network (LAN) in the headquarters. This LAN is connected to the outside world in three ways:
- A subsidiary is connected to the LAN, typically using a leased line.
- 2 PCs dial into the central network via modem or ISDN connections (Remote Access Service – RAS).
- The central LAN has a connection to the Internet so that its users can access the Web, and send and receive e-mail.
All connections to the outside world are based on dedicated lines, i.e. switched or leased lines. Dedicated lines are very reliable and secure. On the other hand, they involve high costs. In general, the costs for dedicated lines are dependent on the distance. Especially in the case of long-distance connections, keeping an eye out of cost-effective alternatives can be worthwhile.
The appropriate hardware must be available in the headquarters for every type of required connection (analog dial-up, ISDN, leased lines). In addition to the original investment costs, ongoing costs are also incurred for the administration and maintenance of this equipment.
