Product specifications

Chapter 6: Connection Management Efficient Networks
®
Router family
Command Line Interface Guide
Page 6-50 Efficient Networks
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Tunnel Server
Function
The L2TP tunnel server receives tunnel "calls" and controls the tunnel once it is
created. It is responsible for multiple tunnels simultaneously. The server can run as a
service on a network server or as a stand-alone device on the network.
Location
The L2TP tunnel server is usually located at the edge of a LAN where it connects to
the WAN. Generally, the tunnel server will be attached on both sides of the firewall.
This allows tunnel traffic to access the tunnel server from the exposed WAN and be
transported to the private LAN without going through the firewall. Sometimes tunnel
servers are placed completely behind the firewall and only tunnel traffic is allowed
through the firewall for access to the private LAN.
LAN-based Tunnel Client
Function
The LAN-based L2TP tunnel client initiates "calls" to the tunnel servers to which it
needs to connect. Once the tunnel is established, the server takes control of the
tunnel management. The L2TP tunnel client can be a stand-alone device or run as a
service on a network server. This type of tunnel client must initiate calls to the tunnel
server whenever LAN traffic needs to be forwarded and disconnect the call when the
traffic stops. The LAN-based tunnel client manages the tunnel creation on behalf of
the workstations on the LAN and is transparent to them.
Location
It is usually located on the boundary where the LAN and WAN meet, but it can reside
anywhere on the LAN. This device can initiate calls, but cannot receive calls, so it can
be located either inside of the firewall or across it.
Workstation-based Tunnel Client
Function
The workstation-based L2TP tunnel client initiates "calls" to the tunnel servers to
which it needs to connect, but it can only support the workstation creating the tunnel.
This type of tunnel client can only support one workstation unlike the LAN-based
client which supports multiple workstations. This is software that runs on a
workstation and is ideal for remote users who carry laptop computers and need
access to the tunnel from different locations.