Lancom Systems 7111 VPN - Manual (Page 10)

LANCOM 7111 VPN – LANCOM 8011 VPN
̈ Chapter 1: Introduction
10
EN
Conventional network infrastructure
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 head-
quarters. This LAN is connected to the outside world in three ways:
ᕡ A subsidiary is connected to the LAN, typically using a leased line.
ᕢ PCs dial into the central network via modem or ISDN connections (Remote
Access Service – RAS).
ᕣ 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 con-
nections, 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
ᕡ ᕢ ᕣ
Head Office
Workstation in
remote access,
e.g. homework Internet
LAN
LAN
Subsidiary
ISDN ISDN