Technical data

Chapter 4. Configuring Special Features 101
transported across networks using different protocols. The advantages for tunneling the PPP protocol are listed
below:
• Different network protocols such as NetBEUI, IPX, and Appletalk can be transported through the Internet
using a tunnel. The protocol packets are encapsulated and routed across the network through the Internet.
• Tunnels provide a way to reduce costs and complexity associated with remote dial-up networking by using a
local ISP: users connect to the remote site by dialing into their local ISP and letting the Internet handle the
long-distance connections, thus avoiding long-distance phone charges.
• Tunneling PPP allows compression of data through the entire tunnel, which translates into greater throughput.
• By allowing encryption over the PPP link, L2TP contributes to more secure networks over the Internet.
• Remote users can access the company network, even if there is a company firewall (provided, of course, that
tunnels can come through the firewall).
Note:
This feature can interoperate with any vendor that supports L2TP - Draft II.
L2TP Concepts
This section defines the major L2TP concepts such as LNS, L2TP client, LAC, and Dial user. These concepts are
illustrated with L2TP client examples. Also described are tunnels and sessions’ creations and destructions.