L2Tp Dial-Out Overview - Juniper JUNOSE 11.1.X - BROADBAND ACCESS CONFIGURATION GUIDE 6-4-2010 Configuration Manual

Chapter 14
Configuring L2TP Dial-Out

L2TP Dial-Out Overview

This chapter describes the Layer 2 Tunneling Protocol (L2TP) dial-out feature on your
E Series router. This chapter includes the following sections:
L2TP Dial-Out Overview on page 411
L2TP Dial-Out Platform Considerations on page 418
L2TP Dial-Out References on page 418
Before You Configure L2TP Dial-Out on page 419
Configuring L2TP Dial-Out on page 419
Monitoring L2TP Dial-Out on page 421
L2TP dial-out provides a way for corporate virtual private networks (VPNs) that use
Broadband Remote Access Server (B-RAS) to dial out to remote offices that have only
narrowband dial-up access. The L2TP network server (LNS) function is deployed in
networks that have a combination of broadband and narrowband access.
A remote site can communicate on demand with the home site with a normal L2TP
access concentrator (LAC) to LNS session. When the communication finishes, the
remote site terminates the session. However, if the home site wishes to communicate
with the remote site and no incoming call is currently established, the home site
needs a method to dial out to the remote site. This method is L2TP dial-out, which
uses the L2TP outgoing call support defined in RFC 2661 Layer Two Tunneling
Protocol " L2TP" (August 1999).
Figure 10 on page 412 shows the dial-out model in which the LNS initiates L2TP
sessions and provides enough information to the narrowband LAC so that it can
complete the dial-out from the home site to the remote site.
L2TP Dial-Out Overview
411