Cisco Cisco 6015 IP DSL Switch Leaflet
Configuring a Cisco 1700/2600/3600 ADSL WIC
With a Single IP Address, DHCP, PPPoA, and
PPP−PAP
With a Single IP Address, DHCP, PPPoA, and
PPP−PAP
Document ID: 12958
Contents
Introduction
Prerequisites
Requirements
Components Used
Conventions
Configure
Network Diagram
Configuration
Verify
Troubleshoot
Related Information
Prerequisites
Requirements
Components Used
Conventions
Configure
Network Diagram
Configuration
Verify
Troubleshoot
Related Information
Introduction
The Cisco 1700, 2600, and 3600 Series Routers support the Asymmetric Digital Subscriber Line (ADSL)
WAN Interface Card (WIC). All the three platforms are configured in the same way. However, there are
differences in the hardware and in the Cisco IOS Software release required for each one. Throughout this
document the Cisco 1700/2600/3600 is called the "Cisco ADSL WIC."
WAN Interface Card (WIC). All the three platforms are configured in the same way. However, there are
differences in the hardware and in the Cisco IOS Software release required for each one. Throughout this
document the Cisco 1700/2600/3600 is called the "Cisco ADSL WIC."
This document shows a Cisco ADSL WIC connected to a Cisco 6130 DSL Access Multiplexer (DSLAM). It
terminates on a Cisco 6400 Universal Access Concentrator (UAC). The Cisco ADSL WIC is configured as a
Dynamic Host Configuration Protocol (DHCP) server with PPP over ATM (PPPoA).
terminates on a Cisco 6400 Universal Access Concentrator (UAC). The Cisco ADSL WIC is configured as a
Dynamic Host Configuration Protocol (DHCP) server with PPP over ATM (PPPoA).
The Internet Service Provider (ISP) gives the subscriber a single IP address, 172.18.0.1, for Internet
connectivity. However, the subscriber has a small network of PCs and wants to have Internet access for all the
devices.
connectivity. However, the subscriber has a small network of PCs and wants to have Internet access for all the
devices.
The solution is to configure Network Address Translation (NAT) on the Cisco ADSL WIC. NAT is designed
for IP address simplification and conservation. It enables private IP internetworks that use nonregistered IP
addresses to connect to the Internet. NAT operates on a router that usuallyconnects two networks. It translates
the private (in this case the 10.0.0.0 network) addresses in the internal network to the legal (in this case
172.18.0.1) addresses before the packets are forwarded to another network. As apart of this function, NAT is
configured to advertise only one address (172.18.0.1) for the entire network. This provides additional security
by effectively hiding the entire internal network behind that address.
for IP address simplification and conservation. It enables private IP internetworks that use nonregistered IP
addresses to connect to the Internet. NAT operates on a router that usuallyconnects two networks. It translates
the private (in this case the 10.0.0.0 network) addresses in the internal network to the legal (in this case
172.18.0.1) addresses before the packets are forwarded to another network. As apart of this function, NAT is
configured to advertise only one address (172.18.0.1) for the entire network. This provides additional security
by effectively hiding the entire internal network behind that address.
NAT has a dual function of security and address conservation that is implemented in remote access
environments. An IP address of 10.0.0.1 is manually configured on the Ethernet interface of the Cisco ADSL
WIC. The Cisco ADSL WIC is configured to act as a DHCP server. It leases IP addresses to local LAN
devices attached to its Ethernet network.
environments. An IP address of 10.0.0.1 is manually configured on the Ethernet interface of the Cisco ADSL
WIC. The Cisco ADSL WIC is configured to act as a DHCP server. It leases IP addresses to local LAN
devices attached to its Ethernet network.
This configuration shows NAT configured for the Ethernet and ATM interfaces. The Ethernet0 interface has
an IP address of 10.0.0.1 with a subnet mask of 255.0.0.0. NAT is configured for inside. This means that the
interface is connected to the inside network sthat is subjected to NAT translation. The ATM interface
an IP address of 10.0.0.1 with a subnet mask of 255.0.0.0. NAT is configured for inside. This means that the
interface is connected to the inside network sthat is subjected to NAT translation. The ATM interface