Figure 6-2 Virtual Private Network (Vpn) Example - NEC SL1100 Networking Manual

Issue 6.0
6 - 10
The diagram below is example of how a VPN tunnel may be implemented.
The red lines in the diagram show the tunnels that are created through the
Internet. Each network can connect to the others as though they are
connected with private connections (kilostream, etc.), without the issues
relating to NAT.
ADSL
Router
Firewall/
VPN
SL1100
Head Office LAN

Figure 6-2 Virtual Private Network (VPN) Example

When IP address translation is applied to a VoIP packet, the application fails
and the communication path is broken. VoIP packets contain the IP address
information and the ports used as part of its payload. When NAT is applied,
only the header parameter is changed, not the payload data that affects the
process of data packets within the VoIP switch and terminal.
Internet
Mobile Workers
(Software VPN Client)
Network Design Considerations
NEC SL1100
ADSL
Router
Firewall/
VPN
Home Office LAN