Cisco Systems 520 series manual Configuring PPP over ATM with NAT

C H A P T E R 4

Configuring PPP over ATM with NAT

The Cisco Secure Router 520 ADSL-over-POTS and Cisco Secure Router 520 ADSL-over-ISDN routers support Point-to-Point Protocol over Asynchronous Transfer Mode (PPPoA) clients and network address translation (NAT).

Multiple PCs can be connected to the LAN behind the router. Before traffic from the PCs is sent to the PPPoA session, it can be encrypted, filtered, and so forth. PPP over ATM provides a network solution with simplified address handling and straight user verification, as with a dial network. Figure 4-1shows a typical deployment scenario with a PPPoA client and NAT configured on the Cisco router. This scenario uses a single static IP address for the ATM connection.

Figure 4-1 PPP over ATM with NAT

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ISP

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Small business with multiple networked devices—desktops, laptop PCs, switches

Fast Ethernet LAN interface (inside interface for NAT, 192.168.1.1/24)

PPPoA Client—Cisco Secure Router 520 ADSL-over-POTS or Cisco Secure Router 520 ADSL-over-ISDN router

Point at which NAT occurs

ATM WAN interface (outside interface for NAT)

PPPoA session between the client and a PPPoA server at the ISP

Cisco Secure Router 520 Series Software Configuration Guide

OL-14210-01 4-1