Lancom Systems 821 - Manual (Page 12)

LANCOM 821 ADSL/ISDN – LANCOM 1621 ADSL/ISDN – LANCOM 1711 VPN
̈ Chapter 1: Introduction
12
EN
An 'Annex A' type LANCOM can only be used with ADSL-over-POTS service.
Similarly, an 'Annex B' device can only be used with ADSL-over-ISDN service.
Retrofitting a device to function with a different telephone system is not pos-
sible.
ADSL-over-ISDN connections also exist that do not operate in conjunction
with ISDN, but which use a conventional analog telephone connection. A
prominent example would be Deutsche Telekom’s T-DSL service.
1.2 Which use does VPN offer?
For LANCOM 1711
VPN and LANCOM
1621 ADSL/ISDN
A VPN (Virtual Private Network) can be used to set up cost-effective, public
IP networks, for example via the ultimate network: the Internet.
The models LANCOM 1621 ADSL/ISDN and LANCOM 1711 VPN are
equipped with 5 channels by default. The additional LANCOM VPN
Option can extend VPN support to 25 active tunnels. The VPN-25
Option also activates the VPN hardware accelerator in the LANCOM
1711 VPN.
While this may sound unspectacular at first, in practice it has profound effects.
To illustrate this, let's first look at a typical corporate network without VPN
technology. In the second step, we will see how this network can be optimized
by the deployment of VPN.