1IP Tunneling And VPN Technologies

IP Tunneling and VPNs

Overview
The purpose of this module is to explain Virtual Private Network (VPN) concepts and to overview various L2 and L3 tunneling techniques that allow for implementation of VPNs. The access VPN features in Cisco IOS Release 12.1 are explained along with Layer 2 and Layer 3 tunneling mechanisms.

Objectives
Upon completion of this module, you will be able to perform the following tasks: n Explain Virtual Private Network concepts and possibilities

n

Describe Layer-2 tunneling features

n

Configure support for Microsoft Point-to-Point Tunneling Protocol (PPTP) and
Encryption (MPPE)

n

Configure L2TP Dial-in and Virtual Private Dial-up Network (VPDN) for dialin

n

Describe and configure GRE Layer-3 tunneling

Introduction to IP VPNs
Objectives
Upon completion of this module, you will be able to perform the following tasks:

23-2

IP Tunneling and VPNs

n

Define a Virtual Private Network (VPN) and its benefits

n

Describe the various types of VPNs:
–

Access, intranet, extranet

–

Layer 2 versus Layer 3

–

Carrier-provided versus not

Copyright  2001, Cisco Systems, Inc.

What Are VPNs?
Connectivity deployed on a shared infrastructure with the same policies and performance as a private network, with lower total cost of ownership
Regional Sites

Virtual Private
Network

Branches
SoHo
Telecommuters
Mobile Users

Central /HQ

Internet, IP, FR, ATM
© 2001, Cisco Systems, Inc.

Partners

Customers
IP Tunneling and VPNs -5

We will start by defining a VPN.
An academic definition of a VPN is “connectivity deployed on a shared infrastructure with the same policies and performance as a private network, with lower total cost of ownership.”
The infrastructure is public, and can be either the Internet, an IP infrastructure, a
Frame Relay network, or an Asynchronous Transfer Mode (ATM) WAN. Our focus today is on the big “I,” the public Internet and IP VPNs, to the exclusion of
Frame Relay and ATM.

Copyright  2001, Cisco Systems, Inc.

IP