Product specifications

Chapter 6: Connection Management Efficient Networks
®
Router family
Command Line Interface Guide
Page 6-26 Efficient Networks
®
L2TP Tunneling - Virtual Dial-Up
This section has four parts:
• The Introduction provides a general overview of L2TP tunneling.
• The L2TP Concepts section explains LNS, L2TP client, LAC, dial user,
tunnels, and sessions.
• Configuration describes preliminary configuration steps and verification steps
and lists commands associated with the configuration of L2TP and PPP
sessions.
• The Sample Configurations section provides two examples with step-by-step
instructions: a simple L2TP client configuration example and a complete LNS
and L2TP client configuration example.
Advantages of Tunneling
L2TP (Layer 2 Tunneling Protocol) is used to forward a PPP link from a remote site to
a corporate site across the Internet, thus creating virtual paths called tunnels.
Because tunneling involves encapsulating data, packets can be 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.