L2Tp/Pptp - TP-Link SafeStream TL-ER6020 User Manual

outgoing SPI value are different. However, the Incoming SPI value must match the Outgoing SPI value
at the other end of the tunnel, and vice versa. The connection status on the remote endpoint of this
tunnel is as the following figure shows. The SPI value is obtained via auto-negotiation.

3.5.3 L2TP/PPTP

Layer 2 VPN tunneling protocol consists of L2TP (Layer 2 Tunneling Protocol) and PPTP (Point to
Point Tunneling Protocol).
Both L2TP and PPTP encapsulate packet and add extra header to the packet by using PPP (Point to
Point Protocol). Table depicts the difference between L2TP and PPTP.
Protocol Media
PPTP IP network
IP network of
UDP, frame relay
L2TP virtual circuit,
X.25 virtual
circuit
3.5.3.1 L2TP/PPTP Tunnel
On this page, you can configure the L2TP/PPTP VPN.
Choose the menu VPN→L2TP/PPTP→L2TP/PPTP Tunnel to load the following page.
Tunnel Length of Header
Single tunnel 6 bytes at least
Multiple tunnels 4 bytes at least
-94-
Authentication
Not supported
Supported