LANCOM 1722 VoIP – LANCOM 1723 VoIP – LANCOM 1724 VoIP – LANCOM 1823 VoIP
Chapter 6: Connecting two networks
69
EN
channel from the caller. An ISDN ID generally consists of the country code
and an MSN.
The
password for the ISDN connection
is an alternative to the ISDN
calling line ID. This is used to authenticate the caller if no ISDN calling line
ID is received. The password must be entered identically at both ends. It
is used for calls in both directions.
The
shared secret
is the central password for the VPN connection's secu-
rity. It must be entered identically at both ends.
Data compression improves transmission speeds without incurring extra
costs. This is the completely different to the bundling of two ISDN chan-
nels by MLPPP (
M
ulti
L
ink-
PPP
): This doubles the bandwidth, although
this generally doubles the connection costs as well.
6.1.2
Settings for the TCP/IP router
In the TCP/IP network, correct addressing is of extreme importance. For net-
work connectivity, it should be observed that both networks are logically sep-
arated. For this reason they require their own network number (e.g. '10.0.1.x'
and '10.0.2.x'). The two network numbers must be different.
Unlike with Internet access, network connectivity makes all of IP addresses
visible in all participating networks, including those in the remote LAN, and
not just that of the router. The computer with the IP address 10.0.2.10 in the
branch-office LAN sees the server 10.0.1.2 at the main office and, with the
appropriate rights, has access to it. The same applies in the other direction.
HEADQUARTER
BRANCH
VPN ROUTER
SERVER
PC
PC
PC
VPN ROUTER
PC
'
server
.
headquarter.company'
'
pc1
.branch.company'
10.0.
1
.2
VPN or ISDN connection
10.0.
2
.10
10.0.
2
.100
(0789) 654321
Branch LAN. IP: 10.0.
2.0
,
Netmask: 255.255.255.0
Domain: '
branch
.company'
10.0.
1
.100
(0123) 123456
Headquarter LAN. IP: 10.0.
1.0
,
Netmask: 255.255.255.0
Domain: '
headquarter
.company'
