Asymmetric Digital Subscriber Line (ADSL)

Document ID: 12871

Contents

Introduction
Prerequisites
      Requirements
      Components Used
      Conventions
Configure
      Network Diagram
      Configurations
Verify
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Related Information

Introduction

The sample configuration described in this document enables a PC connected to a Cisco 675 Asymmetric Digital Subscriber Line (ADSL) router to connect via a Cisco 6100 Advanced Digital Subscriber Line Access Multiplexer (ADSLAM) and Cisco LightStream® 1010 to a Cisco 7x00 series router using RFC1483 (Bridging). This configuration allows data to be routed to the Internet or other services. The specific equipment used in this configuration is not required. For example, the Cisco 675 can be replaced with a Cisco 677 or a Cisco 678. Also, the LightStream 1010 is an additional piece of equipment which is not necessary. If it were removed and the ADSLAM was directly connected to the 7x00 series router, the result would be the same.

This sample configuration shows RFC1483 Bridging set up between the Cisco 675 and the Cisco 7x00 routers. A PC connected at the customer premises obtains an IP address from the Cisco 7x00 router using Dynamic Host Configuration Protocol (DHCP). The default gateway is the Bridged Virtual Interface (BVI) on the Cisco 7x00 router. This allows the bridged packets to be routed as necessary. This configuration allows for a cookie cutter rollout. Because all the boxes have the same configuration, the cost of rollout and documentation is significantly reduced.

The code for the Cisco IOS®-based routers and switches can be copied and pasted to your configurations, but the 675 router uses the Cisco Broadband Operating System (CBOS) and this code cannot be copied and pasted. The commands for configuring the router are also included in this sample configuration.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on this hardware and services:

• PC or workstation

• Cisco 675 ADSL customer premises equipment (CPE)

• ADSL service from your local Telco

• Cisco 6100 ADSLAM with SCM, NI-1, CAP ATU-C

• Cisco LightStream 1010

• Cisco 7x00 series router

The information in this document is based on these software versions:

• Cisco IOS Release 12.0(3c)W5(9) for LightStream 1010

• Cisco IOS Release 12.0(7)T for Cisco 7x00 series router

• CBOS Release 2.3.0.053 for Cisco 675 ADSL router

• Viewrunner 2.4.1

• Sytem software 2.4.10 for Cisco 6100 ADSLAM

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Configure

In this section, you are presented with the information to configure the features described in this document.

Note: Use the Command Lookup Tool ( registered customers only) to find more information on the commands used in this document.

Network Diagram

This document uses this network setup:

Configurations

A permanent virtual connection (PVC) must be configured on the Cisco 6100 ADSLAM allowing the test subsciber to connect. The virtual path identifier/virtual channel identifier (VPI/VCI) configuration must be recorded for use on the Cisco 7x00 series router when you configure the ATM port and create the PVP on the Cisco LightStream 1010.

This sample configuration shows a virtual path on the Cisco LightStream 1010. This path allows the LS1010 to pass through the cells from the ADSLAM to the terminating router, or to another ATM switch.

cbos#show run
[[ Spanning Tree = Section Start ]]
MAC Bridge = enabled, rfc1483

cbos#set bridging rfc1483 enabled
You must use "write" then reboot for changes to take effect.

cbos#write
NVRAM written.

cbos#reboot

interface ATM 0/1/2
 no ip address
 no ip directed-broadcast
 no atm ilmi-keepalive
 atm pvp 1 interface ATM 0/0/2 1

ip dhcp excluded-address 172.22.40.1 172.22.40.25
!
!
ip dhcp pool 0
   network 172.22.40.0 255.255.255.0
   default-router 172.22.40.9 
   dns-server <dns server ip address> 
   netbios-name-server <wins server ip address>
!         
!
bridge irb
!
!
interface ATM 2/0
 no ip address
 no ip directed-broadcast
 no atm ilmi-keepalive
!
!
interface ATM 2/0.1 point-to-point
 no ip directed-broadcast
 pvc 1/35 
  encapsulation aal5snap
!
 bridge-group 1
!
!
interface ATM 2/0.2 point-to-point
 no ip directed-broadcast
 pvc 1/36 
  encapsulation aal5snap
!
 bridge-group 1!
!
interface FastEthernet 4/0
 ip address 172.22.32.1 255.255.255.0
 no ip directed-broadcast
!
!
interface BVI 1
 ip address 172.22.40.9 255.255.255.0
 no ip directed-broadcast
!
!
bridge 1 protocol ieee
 bridge 1 route ip

Verify

Use this section to confirm that your configuration works properly.

The Output Interpreter Tool ( registered customers only) (OIT) supports certain show commands. Use the OIT to view an analysis of show command output.

Note: Refer to Important Information on Debug Commands before you use debug commands.

Use these commands on the Cisco 7x00 series router:

• show atm vc—Shows whether the correct PVC was established.

• debug spantree events—Displays bridging topology events.

• show spanning-tree—Shows the topology of the bridging structure.

Use these commands on the Cisco 675 CPE:

• show interface wan0—Shows trained up speed for the DSL link.

• show interface wan0-0—Shows RFC1483 information.

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Related Information

• Asymmetric Digital Subscriber Line (ADSL) Support Page
• Technical Support & Documentation - Cisco Systems