Setting Up The Secure L2Tp Connection; L2Tp With Ipsec Control And Data Frames; Figure 22: L2Tp With Ipsec Application; Figure 23: L2Tp/Ipsec Connection - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - IP SERVICES CONFIGURATION GUIDE 2010-10-01 Configuration Manual

JunosE 11.3.x IP Services Configuration Guide

Setting Up the Secure L2TP Connection

L2TP with IPSec Control and Data Frames

278

Figure 22: L2TP with IPSec Application

Figure 23 on page 278 gives an overview of the process used to set up a secure connection
between the client PC and an E Series router that is acting as a VPN provider.

Figure 23: L2TP/IPSec Connection

To set up the secure connection shown in Figure 23 on page 278:
Obtain an IP address from your ISP, using a normal B-RAS termination.
1.
IKE signals a security association (SA) between the client PC and the E Series router
2.
that is acting as a VPN provider.
SAs are established to secure data traffic.
The IPSec connection secures L2TP traffic.
Set up an L2TP tunnel and session between the client PC (the LAC) and the E Series
3.
router (the LNS).
The tunnel runs over the SAs that IKE established.
L2TP and IPSec define control and data messages used for L2TP/IPSec. Figure 24 on
page 279 shows an L2TP control frame encapsulated by IPSec. The shaded area shows
the encrypted portion of the frame.
Copyright © 2010, Juniper Networks, Inc.