AIS AI2524 user manual Configure Virtual Private Dial-up Networks

AI2524 Router Card User’s Manual

Configure Virtual

Private Dial-up

Networks

Virtual private dial-up networks (VDPN) allow separate and autono- mous protocol domains to share common access infrastructure includ- ing modems, access servers, and ISDN routers. VPDN uses the Level 2 Forwarding protocol (L2F) which permits the tunneling of link level frames.

Using L2F tunneling, an Internet Service Provider (ISP) or other ac cess service can create a virtual tunnel to link a customer's remote sites or remote users with corporate home networks. In particular, a net- work access server at the ISP's Point of Presence (POP) exchanges

PPPmessages with the remote users and communicates by L2F re- quests and responses with the customer's home gateway to set up tun- nels.

L2F passes protocol-level packets through the virtual tunnel between endpoints of a point-to-point connection.

Frames from the remote users are accepted by the ISP POP, stripped of any linked framing or transparency bytes, encapsulated in L2F, and forwarded over the appropriate tunnel. The customer's home gateway accepts these L2F frames, strips the L2F encapsulation, and processes the incoming frames for the appropriate interface.

Note: This implementation of VPDN supports PPP dial-up only.

To configure virtual private dial-up networks, complete these tasks:

zUnderstand VPDNs

zBeginning in global configuration mode, configure a virtual tem- plate for interfaces on a home gateway access server:

zConfigure Incoming VPDN Connections on the Home Gateway

zConfigure Outgoing VPDN Connections on the Network Access Server

Understand Virtual Private Dial-up Networks

VPDN enables users to configure secure networks that take advantag of internet service providers that tunnel the company's remote access traffic through the ISP cloud.

Remote offices or mobile users can connect to their home network using local dial-up services of third parties. The dial-up service pro- vider agrees to forward the company's traffic from the ISP POP to a company-run home gateway. Network configuration and security re- main in the control of the client. The dial-up service provider provides a virtual pipe between the company's sites.

Page 11-26	August 1997
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