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USER MANUAL
PrestoAdvancedAD101_AD301_UG_000_UK
Descriptions and non-contractual illustrations in this document are given as an indication only.
M2M Design reserves the right to make any modification
63
GRE Tunnel configuration between PRESTO Advanced Router and third party router
GRE tunnel is a type of a VPN tunnels, but it isn't a secure tunneling method. However, you can
encrypt GRE packets with an encryption protocol such as IPSec to form a secure VPN.
On the diagram below (
Figure 40
) is illustrated simple network with two sites. Idea is to create GRE
tunnel for LAN to LAN (site to site) connectivity.
Figure 40 - GRE tunnel between Cisco router and PRESTO Advanced Router
GRE tunnel is created between Cisco router with GRE functionality on the HQ Site and the PRESTO
Advanced Router on the Remote Network. In this example, it is necessary for both routers to create tunnel
interface (virtual interface). This new tunnel interface is its own network. To each of the routers, it appears
that it has two paths to the remote physical interface and the tunnel interface (running through the tunnel).
This tunnel could then transmit unroutable traffic such as NetBIOS or AppleTalk.
The PRESTO Advanced Router uses Network Address Translation (NAT) where only the mobile IP
address is visible to the outside. All outgoing traffic uses the PRESTO Advanced Router WAN/VPN mobile
IP address. HQ Cisco router acts like gateway to remote network for user in corporate LAN. It also performs
function of GRE server for termination of GRE tunnel. The PRESTO Advanced Router act like default
gateway for Remote Network and GRE server for tunnel.
1.
HQ router requirements:
HQ router require static IP WAN address;
Router or VPN appliance have to support GRE protocol;
Tunnel peer address will be the PRESTO Advanced Router WAN's mobile IP address. For this
reason, a static mobile IP address is preferred on the PRESTO Advanced Router WAN (GPRS) side;
Remote Subnet is remote LAN network address and Remote Subnet Mask is subnet of remote
LAN.