Cisco 1801, Configuration Manual

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C H A P T E R
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Cisco 1800 Series Integrated Services Routers (Fixed) Software Configuration Guide
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Configuring PPP over ATM with NAT
The Cisco 1801, Cisco 1802, and Cisco 1803 access 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 like a dial network.
Figure 4-1 shows 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
1 Small business with multiple networked devices—desktops, laptop PCs, switches
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Fast Ethernet LAN interface (inside interface for NAT, 192.168.1.1/24)
3 PPPoA Client—Cisco 1801, Cisco 1802, or Cisco 1803 router
4 Point at which NAT occurs
5 ATM WAN interface (outside interface for NAT)
6
PPPoA session between the client and a PPPoA server at the ISP