Cisco 800 Series Routers Software Configuration Guide - Network Scenarios [Cisco 800 Series Routers]

Table Of Contents

Network Scenarios

Cisco 827 Router Network Connections

Cisco 837 Router Network Connections

Cisco 831 Router Virtual Private Network Connections

Cisco 836 or Cisco SOHO 96 Network Connection

Internet Access Scenarios

Before You Configure Your Internet Access Network

Replacing a Bridge or Modem with a Cisco 827 Router

Configuring the Scenario

Configuration Example

PPP over Ethernet with NAT

Configuring the Virtual Private Dial-Up Network Group Number

Configuring the ATM Interface

Configuring the Dialer Interface

Configuration Example

PPP over Ethernet with NAT Using a Dial-on-Demand PPP-over- Ethernet Connection

Configuring the Virtual Private Dial-Up Network Group Number

Configuring the ATM Interface

Configuring the Dialer Interface

Configuration Example

PPP over ATM with NAT

Configuring the Ethernet Interface

Configuring the Dialer Interface

Configuring the ATM Interface

Configuring NAT

Configuration Example

Configuring Dial Backup over the Console Port

Configuring Dial Backup over the ISDN Interface

Dial Backup Feature Limitations and Configuration

Cisco 836 and 837 Routers and Cisco SOHO 96 and 97 Routers

Cisco 831 and Cisco SOHO 91 Routers

Configuring Dial Backup and Remote Management for the Cisco 837 and Cisco SOHO 97 Routers

Configuring Dial Backup and Remote Management for the Cisco 836 and Cisco SOHO 96 Routers

PPP over ATM with Centrally Managed Addressing and with Dial Backup

Configuring Dial Backup and Remote Management for the Cisco 837 Router

Configuration Example

Configuring Dial Backup and Remote Management for the Cisco 836 Router

Configuring the Cisco 836 Router's ISDN Settings

Configuring Dial Backup and Remote Management Settings

Configuring Backup Interface

Configuring Floating Static Route

Configuring Dialer Watch

Configuration Example

Configuring the Aggregator and ISDN Peer Router

Configuring Remote Management for the Cisco SOHO 97 Router

Configuration Example

Configuring Dial Backup and Remote Management for Cisco 831 Router and Cisco SOHO 91 Router

Configuration Example for the Cisco 831 Router

Configuring Remote Management for the Cisco SOHO 91 Router

Configuration Example

Configuring the DHCP Server

Configuring the Ethernet Interface

Dynamic Addressing Received via IPCP

Configuring the Central Cisco 3620

Configuring the Central RADIUS Server

RFC 1483 Encapsulation with NAT

Configuring the Ethernet Interface

Configuring the ATM Interface

Configuring NAT

Configuration Examples

Integrated Routing and Bridging

Configuring the Default Gateway

Configuring the Ethernet Interface and IRB

Configuring the ATM Interface

Configuring the BVI

Configuring NAT

Configuration Example

Concurrent Routing and Bridging

Specifying CRB and Configuring the Ethernet Interface

Configuring the ATM Interface and Subinterfaces

Configuring Voice Ports

Configuring the POTS Dial Peers

Configuring VoIP Dial Peers for H.323 Signaling

Configuration Example

Voice Scenario

Data Network

Voice Network

Configuration Tasks

Configuring the Class Map, Route Map, and Policy Map

Configuring the Ethernet Interface

Configuring the ATM Interface

Configuring EIGRP

Configuring the POTS Dial Peers

Configuring VoIP Dial Peers for H.323 Signaling

Configuration Examples

Network Scenarios

This chapter provides sample network scenarios and configurations using Cisco 800 series and Cisco SOHO series routers. This chapter is useful if you are building a new network and want examples of features or configurations.

If you already have a network set up and you want to add specific features, see Chapter 7, "Router Feature Configuration."

This chapter includes the following sections:

•Cisco 827 Router Network Connections

•Cisco 837 Router Network Connections

•Cisco 831 Router Virtual Private Network Connections

•Cisco 836 or Cisco SOHO 96 Network Connection

•Internet Access Scenarios

•Configuring Dial Backup over the Console Port

•Configuring Dial Backup over the ISDN Interface

•Configuring the DHCP Server

•Voice Scenario

Each scenario in this chapter is described, and a network diagram and configuration network examples are provided as models on which you can pattern your network. The examples cannot, however, anticipate all of your network needs. You can choose not to use features presented in the examples, and you can choose to add or substitute features that better suit your needs.

Cisco 827 Router Network Connections

Figure 4-1 and Table 4-1 illustrate an example of a network topology employing a Cisco 827 router connecting to the following:

•Public switched telephone network (PSTN)

•Corporate intranet

•Service provider on the Internet

•Service provider data center

Figure 4-1 Cisco 827 Router Network Connections

Callout Number

Description

1

Corporate network connecting through a Cisco 3640 voice gateway

2

Wholesale ISP business

3

ISP POP (data center) with videoconferencing multipoint control units (MCUs) and IP/TV video servers

4

Data and voice local exchange carrier connecting through a Cisco MGX voice gateway

5

Small business or remote user, connecting to the network through a Cisco 827/827-4V router

In the example, the Cisco 827 router sends data or voice packets from the remote user to the service provider or corporate network through high-speed, point-to-multipoint asymmetric digital subscriber line (ADSL) technology.

Cisco 837 Router Network Connections

Figure 4-2 and Table 4-1 show an example of a network topology employing a Cisco 837 router connecting to the following:

•PSTN

•Corporate intranet

•Service provider on the Internet

•Service provider data center

•Dial backup and remote management

Figure 4-2 Cisco 837 Router Network Connections

Callout Number

Description

1

Corporate network connecting through a Cisco 3640 voice gateway

2

Wholesale ISP business

3

ISP POP (data center) with videoconferencing MCUs and IP/TV video servers

4

Dial backup or remote management that keeps the traffic working in case the primary line's traffic shuts down

5

PSTN to serve as an analog modem for dial backup or remote management

6

Small business or remote user, connecting to the network through a Cisco 837 router

In the topology, the Cisco 837 router sends data packets from the remote user to the service provider or corporate network through high-speed, point-to-multipoint ADSL technology.

Cisco 831 Router Virtual Private Network Connections

Figure 4-3 and Table 4-3 show how the Cisco 831 router can be used in a Virtual Private Network (VPN). A Cisco 831 router is linked to the ISP via a digital subscriber line (DSL) or a cable modem. Security is provided via IP security (IPSec) configuration.

Figure 4-3 Cisco 831 Router Virtual Private Network

Callout Number

Description

1

Small business or remote user, connecting to the network through a Cisco 831 router

2

Corporate network connecting through a Cisco router

3

Dial backup, as a failover link when primary line goes down

4

Branch office network connecting through a Cisco router

Cisco 836 or Cisco SOHO 96 Network Connection

Figure 4-4 and Table 4-4 show an example of a network topology employing a Cisco 836 router or a Cisco SOHO 96 router connecting to the following:

•ISDN

•Corporate intranet

•Service provider on the Internet

•Service provider data center

•Dial backup and remote management

Figure 4-4 Cisco 836 Router Network Connections

Callout Number

Description

1

Corporate network connecting through a Cisco 3640 gateway

2

Wholesale ISP business

3

ISP POP (data center) with videoconferencing MCUs and IP/TV video servers

4

Dial backup or remote management that keeps the traffic working in case of primary line shutdown

5

ISDN to serve as an interface for dial backup or remote management

6

Small business or remote user, connecting to the network through a Cisco 836 router

Internet Access Scenarios

This section provides information on the following topics related to Internet access:

•Before You Configure Your Internet Access Network

•Replacing a Bridge or Modem with a Cisco 827 Router

•PPP over Ethernet with NAT

•PPP over Ethernet with NAT Using a Dial-on-Demand PPP-over- Ethernet Connection

•PPP over ATM with NAT

•Configuring Dial Backup over the Console Port

•Configuring Dial Backup and Remote Management for the Cisco 837 and Cisco SOHO 97 Routers

•Configuring Dial Backup and Remote Management for the Cisco 836 and Cisco SOHO 96 Routers

•Configuring the DHCP Server

•Configuring the Ethernet Interface

•RFC 1483 Encapsulation with NAT

•Integrated Routing and Bridging

•Concurrent Routing and Bridging

•Data Network

•Voice Network

Each scenario is described. Also, for each scenario, a network diagram, steps for configuring network scenarios, and a configuration example are provided.

Before You Configure Your Internet Access Network

You need to gather the following information before configuring your network for Internet access:

•Order an ADSL or G.SHDSL line from your public telephone service provider. For ADSL lines, determine that the ADSL signaling type is DMT, also called ANCII T1.413, or just DMT Issue 2. For G.SHDSL, verify that the G.SHDSL line conforms to ITU standard G.991.2 and supports Annex A, for North America, or Annex B, for Europe.

•Gather information to set up a PPP Internet connection, including the PPP client name authentication type and the PPP password.

•Determine the IP routing information, including IP address, and ATM permanent virtual circuits (PVCs). These PVC parameters are typically virtual path identifier (VPI), virtual circuit identifier (VCI), and traffic shaping parameters, if applicable.

•Gather DNS server IP address and default gateways.

Replacing a Bridge or Modem with a Cisco 827 Router

This scenario shows a remote user connected to the Internet. You may want to use a network similar to this one if you want to set up a minimal connection to the Internet and bridge it through the Cisco 827 routers.

This network replaces an Alcatel 1000 bridge or modem with a Cisco 827 or Cisco 827-4V router by using AAL5SNAP encapsulation and bridging (RFC 1483 bridge mode) on the ATM interface.

Figure 4-5 and Table 4-5 show the network topology for this scenario.

Figure 4-5 Replacing a Bridge or Modem with a Cisco 827 Router

Callout Number

Description

1

Small business or remote user, connecting to the network through a Cisco 827 or Cisco 827-4V router

2

The Internet

The Cisco 827 router is configured to act as a bridge on the WAN, so the data packets are bridged through the Cisco 6400 router onto the Internet. This network setup allows the simplicity of bridging data but also maintains router control. This network is very simple, but it limits more complex services, such as stopping broadcast traffic. If you want more services available on your network, you may want to consider some of the others scenarios in this chapter.

Configuring the Scenario

Note If you have only a single ATM PVC for your bridging network, you do not have to configure the protocol bridge broadcast.

This scenario includes configuration tasks and a configuration example. To add additional features to this network, see Chapter 7, "Router Feature Configuration."

After configuring your router, you need to configure the PVC endpoint. For a general configuration example, see the "Cisco 3640 Gateway Configuration Example" section.

Follow the steps below to replace a bridge or modem with the Cisco 827 router, beginning in global configuration mode. Each step includes the same values that are shown in the bridging configuration example at the end of this section.

Command

Task

Step 1

no ip routing

Disable IP routing.

Step 2

bridge 1 protocol ieee

Specify the bridge protocol to define the type of Spanning-Tree protocol.

Step 3

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 4

bridge-group 1

Specify the bridge-group number to which the Ethernet interface belongs.

Step 5

no shutdown

Enable the Ethernet interface.

Step 6

exit

Exit configuration mode for the Ethernet interface and the router.

Step 7

interface ATM 0

Enter configuration mode for the ATM interface.

Step 8

pvc 8/35

Create an ATM permanent virtual circuit (PVC) for each end node with which the router communicates.

Step 9

encapsulation aal5snap

Specify the encapsulation type for the PVC.

Step 10

bridge-group 1

Specify the bridge-group number to which the ATM interface belongs.

Step 11

no shutdown

Enable the ATM interface.

Step 12

exit

Exit configuration mode for the ATM interface.

Configuration Example

The following is a configuration example for this network scenario. You do not have to enter the commands marked "default." These commands appear automatically in the configuration file generated when you use the show running-config command.
no ip routing
!
interface Ethernet0
no ip address
no ip directed-broadcast (default)
bridge-group 1
!
interface ATM0
no ip address
no ip directed-broadcast (default)
pvc 8/35 
encapsulation aal5snap
!
bridge-group 1
!
ip classless (default)
!
bridge 1 protocol ieee
!
end
PPP over Ethernet with NAT

The Cisco 836 and 837 routers and the Cisco SOHO 96 and 97 routers support a PPP-over-Ethernet (PPPoE) client, with Network Addressing Translation (NAT) and with multiple PCs on the LAN. Figure 4-6 and Table 4-6 show a typical deployment scenario for PPPoE support.

Figure 4-6 PPPoE Deployment Scenario

Callout Number

Description

1

Multiple PCs in LAN.

2

Multiple PCs connected in a LAN.

3

Access concentrator, concentrating data and LAN into ATM service over E1/T1 links.

4

PPPoE session, which is initiated on the client side by a Cisco 837 or Cisco SOHO 97 router. If the session has a timeout, or if the session is disconnected, the PPPoE client immediately attempts to reestablish the session.

This section covers the following topics:

•Configuring the Virtual Private Dial-Up Network Group Number

•Configuring the ATM Interface

•Configuring the Dialer Interface

•Configuration Example

Configuring the Virtual Private Dial-Up Network Group Number

Follow the steps below to configure a virtual private dial-up network (VPDN), starting in global configuration mode.

Note Step 1 through Step 4 are not necessary for the Cisco SOHO 96 and 97 routers.

Command

Task

Step 1

vpdn enable

Enable VPDN.

Step 2

vpdn group tag

Set the VPDN group.

Step 3

request-dialin

Specify the dialing direction.

Step 4

protocol pppoe

Specify the protocol type for the VPDN.

Step 5

interface ATM0

mtu 1492

pvc 8/35

Enter configuration mode for the ATM interface. Set the maximum transmission unit (MTU) size and PVC number.

Step 6

pppoe-client dial-pool-number 1

Define the pppoe client in dial pool number 1.

Step 7

interface Dialer 1 ip address negotiated encapsulation ppp dialer-pool 1

Enter configuration mode for the Dialer 1 interface to obtain the IP address via IPCP. Specify the encapsulation type for the PVC using dialer pool number 1.

Configuring the ATM Interface

Follow the steps below to configure the ATM interface, beginning in global configuration mode.

Command

Task

Step 1

interface atm 0

Enter configuration mode for the ATM interface.

Step 2

dsl linerate {number | auto}

Specify the DSL line rate. The range of valid numbers is from 72 to 2312. Note that this command is applicable only to Cisco 828 and SOHO 78 routers.

Step 3

ip address 200.200.100.1 255.255.255.0

Set the IP address and subnet mask for the ATM interface.

Step 4

pvc vpi/vci

Create an ATM PVC for each end node with which the router communcates.

Step 5

ppoe-client dial-pool-number 1

Bind the dialer to the interface.

Step 6

no shutdown

Enable the ATM 0 interface.

Configuring the Dialer Interface

Follow the steps below to configure the dialer interface, starting in global configuration mode.

Command

Task

Step 1

ip route default-gateway-ip-address mask dialer 0

Set the IP route for the default gateway for the Dialer 0 interface.

Step 2

interface dialer 0

Enter the Dialer 0 interface configuration.

Step 3

ip address negotiated

Specify that the IP address is to be negotiated over PPP.

Step 4

ip mtu 1492

Set the size of the IP maximum transmission unit (MTU).

Step 5

encapsulation ppp

Set the encapsulation type to PPP.

Step 6

dialer pool 1

Specify the dialer pool to be used.

Step 7

dialer-group 1

Assign this interface to a dialer list.

Step 8

ppp authentication chap

Set the PPP authentication method to Challenge Handshake Authentication Protocol (CHAP).

Step 9

exit

Exit the Dialer 0 interface configuration.

Step 10

dialer-list 1 protocol ip permit

Create a dialer list for interested packets to be forwarded through the specified interface dialer group.

If you enter the clear vpdn tunnel pppoe command with a PPPoE client session already established, the PPPoE client session terminates, and the PPPoE client immediately tries to reestablish the session.

Configuration Example

The following example shows a configuration of a PPPoE client.
vpdn enable
vpdn-group 1
request-dialin
protocol pppoe
!
interface atm0
no ip address
no atm ilmi-keepalive
pvc 1/100
pppoe-client dial-pool-number 1
!
interface dialer 1
ip address negotiated
ppp authentication chap
dialer pool 1
dialer-group 1
!
dialer-list 1 protocol ip permit
PPP over Ethernet with NAT Using a Dial-on-Demand PPP-over- Ethernet Connection

The Cisco 831, 836, and 837 routers and the Cisco SOHO 91, 96, and 97 routers support a PPP-over-Ethernet (PPPoE) client, using a dial-on-demand PPP-over-Ethernet connection. For a deployment scenario, see Figure 4-6.

Configuring the Virtual Private Dial-Up Network Group Number

Complete the following tasks to configure a VPDN, starting in global configuration mode.

Note These four steps are not necessary for the Cisco SOHO 96 and 97 routers.

Command

Task

Step 1

vpdn enable

Enable VPDN.

Step 2

vpdn group tag

Set the VPDN group.

Step 3

request-dialin

Specify the dialing direction.

Step 4

protocol pppoe

Specify the protocol type for the VPDN.

Configuring the ATM Interface

Follow the steps below to configure the ATM interface, beginning in global configuration mode.

Command

Task

Step 1

interface atm 0

Enter configuration mode for the ATM interface.

Step 2

ip address 200.200.100.1 255.255.255.0

Set the IP address and subnet mask for the ATM interface.

Step 3

pvc vpi/vci

Create an ATM PVC for each end node with which the router communicates.

Step 4

ppoe-client dial-pool-number 1 dial-on-demand

Bind the dialer to the interface.

Step 5

no shutdown

Enable the ATM 0 interface.

Configuring the Dialer Interface

Follow the steps below to configure the dialer interface, starting in global configuration mode.

Command

Task

Step 1

ip route default-gateway-ip-address mask dialer 0

Set the IP route for the default gateway for the Dialer 0 interface.

Step 2

interface dialer 0

Enter Dialer 0 interface configuration.

Step 3

ip address negotiated

Specify that the IP address is to be negotiated over PPP.

Step 4

ip mtu 1492

Set the size of the IP maximum transmission unit (MTU).

Step 5

ip nat outside

Establish the Dialer 0 interface as the outside interface.

Step 6

encapsulation ppp

Set the encapsulation type to PPP.

Step 7

dialer pool 1

Specify the dialer pool to be used.

Step 8

dialer-group 1

Assign this interface to a dialer list.

Step 9

ppp authentication chap

Set the PPP authentication method to Challenge Handshake Authentication Protocol (CHAP).

Step 10

exit

Exit the Dialer 0 interface configuration.

Step 11

dialer-list 1 protocol ip permit

Create a dialer list for packets of interest to be forwarded through the interface dialer group.

If you enter the clear vpdn tunnel pppoe command with a PPPoE client session already established, the PPPoE client session terminates, and the PPPoE client immediately tries to reestablish the session.

Configuration Example

The following example shows a configuration of a PPPoE client.
interface Ethernet0
no ip address
ip tcp adjust-mss 1400
no keepalive
hold-queue 100 out
!
vpdn enable
vpdn-group 1
request-dialin
protocol pppoe
!
interface atm0
no ip address
no atm ilmi-keepalive
pvc 1/100
pppoe-client dial-pool-number 1 dial-on-demand
!
interface dialer 1
ip address negotiated
ppp authentication chap
dialer pool 1
dialer-group 1
!
dialer-list 1 protocol ip permit
PPP over ATM with NAT

This network shows a user connected to the Internet through PPP over ATM and one static IP address. You may want to use this scenario in your network if you want to access the network with ATM support at the endpoints. PPP over ATM provides a network solution with simplified address handling and straight user verification, as you would get in a dial network.

Figure 4-7 and Table 4-7 show the network topology for this scenario.

Figure 4-7 PPP over ATM with NAT

Callout Number

Description

1

Small business or remote user

2

Connection to Ethernet 0 address 192.168.1.1/24 through a dialer interface

3

PPP over ATM PVC 8/35

4

The Internet

In this scenario, the small business or remote user on the Ethernet LAN can connect to the Internet through ADSL. The Ethernet interface carries the data packet through the LAN and offloads it to the PPP connection on the ATM interface. The dialer interface is used to connect to the Internet or the corporate office. The number of ATM PVCs is set by default.

NAT (represented as the dashed line at the edge of the Cisco 827 router) signifies two addressing domains and the inside source address. The source list defines how the packet travels through the network.

This section covers the following topics:

•Configuring the Ethernet Interface

•Configuring the Dialer Interface

•Configuring the ATM Interface

•Configuring NAT

•Configuration Example

To add other features to this network, see Chapter 7, "Router Feature Configuration."

After configuring your router, you need to configure the PVC endpoint. For a general configuration example, see the "Cisco 3640 Gateway Configuration Example" section.

Configuring the Ethernet Interface

Follow the steps below to configure the Ethernet interface, beginning in global configuration mode.

Command

Task

Step 1

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 2

ip address 192.168.1.1 255.255.255.0

Set the IP address and subnet mask for the Ethernet interface.

Step 3

no shutdown

Enable the interface and configuration changes just made to the Ethernet interface.

Step 4

exit

Exit configuration mode for the Ethernet interface.

Configuring the Dialer Interface

Follow the steps below to configure the dialer interface, beginning in global configuration mode.

Command

Task

Step 1

interface dialer 0

Enter configuration mode for the Dialer 0 interface.

Step 2

ip address negotiated

Configure a negotiated IP address.

Step 3

ip nat outside

Set the interface to be connected to the outside network.

Step 4

encapsulation ppp

Specify the encapsulation type for the PVC to be PPP.

Step 5

dialer pool 1

Specify which dialer pool number you are using.

Step 6

exit

Exit configuration mode for the dialer interface.

Configuring the ATM Interface

Follow the steps below to configure the ATM interface, beginning in global configuration mode.

Command

Task

Step 1

interface ATM 0

Enter configuration mode for the ATM interface.

Step 2

pvc 8/35

Create an ATM PVC for each end node with which the router communicates.

Step 3

encapsulation aal5mux ppp dialer

Specify the encapsulation type for the PVC to be aal5mux (PPP) and point back to the dialer interface.

Step 4

dialer pool-member 1

Specify a dialer pool member.

Step 5

no shutdown

Enable the interface and configuration changes just made to the ATM interface.

Step 6

exit

Exit configuration mode for the ATM interface.

Configuring NAT

Follow the steps below to configure NAT, beginning in global configuration mode.

Command

Task

Step 1

ip nat inside source list 1 interface dialer 0 overload

Enable dynamic translation of addresses permitted by the access list to one of addresses specified in the dialer interface.

Step 2

ip route 0.0.0.0.0.0.0.0 dialer

Set the ip route to point to the dialer interface as a default gateway.

Step 3

access-list 1 permit 192.168.1 0 0.0.0.255

Define a standard access list permitting addresses that need translation.

Step 4

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 5

ip nat inside

Establish the Ethernet interface as the inside interface.

Step 6

no shutdown

Enable interface and configuration changes just made to the Ethernet interface.

Step 7

exit

Exit configuration mode for the Ethernet interface.

Configuration Example

In the following configuration example, you do not have to enter the commands marked "default." These commands appear automatically in the configuration file that is generated when you use the show running-config command.
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
no ip directed-broadcast (default)
ip nat inside
!
interface ATM0
no ip address
no ip directed-broadcast (default)
ip nat outside
no atm ilmi-keepalive (default)
pvc 8/35 
encapsulation aal5mux ppp dialer
dialer pool-member 1
!
bundle-enable
!
interface Dialer0
ip address negotiated
no ip directed-broadcast (default)
ip nat outside
encapsulation ppp 
dialer pool 1
!         
ip nat inside source list 1 interface Dialer0 overload
ip classless (default)
ip route 0.0.0.0 0.0.0.0 Dialer 0 (default gateway)
!
access-list 1 permit 192.168.1.0 0.0.0.255
!
end
Configuring Dial Backup over the Console Port

By allowing you to configure a backup modem line connection, dial backup provides protection against WAN downtime. Dial backup is inactive until it is configured. On Cisco 831, Cisco 837, Cisco SOHO 91, and Cisco SOHO 97 routers, both the console port and the auxiliary port in the Cisco IOS software configuration are on the same physical RJ-45 port. Therefore, both ports cannot be activated simultaneously, and the command-line interface (CLI) must be used to enable or disable either one.

Configuring Dial Backup over the ISDN Interface

Like the Cisco 831 and 837 routers and the Cisco SOHO 91 and 97 routers, the Cisco 836 router supports dial-in (for remote management) and dial-out (for dial backup) capabilities across the ISDN interface. The Cisco SOHO 96 router supports only the dial-in feature. Unlike the Cisco 831 and 837 routers and the Cisco SOHO 91 and 97 routers, the dial backup and remote management functions are configured on the Cisco 836 and Cisco SOHO 96 routers through the router's ISDN S/T port.

Note The remote management described next refers to backup remote management, which function allows external control of the router via the ISDN when the ATM link goes down.

Dial Backup Feature Limitations and Configuration

This section discusses the limitations and configuration of the dial backup feature on the Cisco 831, 836, and 837 routers and the Cisco SOHO 91, 96, and 97 routers.

Cisco 836 and 837 Routers and Cisco SOHO 96 and 97 Routers

The following can be used to bring up the dial backup feature in the Cisco IOS software for the Cisco 836 and 837 routers and the Cisco SOHO 96 and 97 routers:

•Backup Interfaces

•Floating Static Routes

•Dialer Watch

For more information on the three features, see "Concepts."

Backup Interfaces

When the device receives an indication that the primary line is down, the backup interface is brought up. You can configure the backup interface to go down (after a specified time) when the primary connection is restored.

The dial-on-demand routing (DDR) backup call is triggered by traffic of interest. Even if the backup interface comes out of standby mode, the router will not trigger the backup call unless it receives traffic of interest for that backup interface.

Floating Static Routes

Floating static routes depend on traffic of interest to trigger the DDR backup call. The router does not actually trigger the backup call unless it receives traffic of interest for that backup interface, even if the router installs the floating static route in the route table.

Floating static routes are independent of line protocol status. This is an important consideration on Frame Relay circuits wherein line protocol may not go down if the data-link connection identifier (DLCI) is inactive. Floating static routes are also encapsulation independent.

Note When static routes are configured, the primary interface protocol must go down in order to activate the floating static route.

Dialer Watch

Only the Extended Interior Gateway Routing Protocol (EIGRP) link-state dynamic routing protocols are supported.

There is a bottleneck in supporting bridging over console backup interfaces because bridging is not supported over slower interfaces such as console ports or auxiliary ports.

In the Cisco 836 and 837 routers, the dial backup feature is supported for the encapsulations identified in Table 4-1.

Table 4-1 Encapsulation Types Supported by Dial Backup Feature—Cisco 836 and 837 Routers

Encapsulation Type (WAN)

Dial Backup Possible

Type of Dial Backup Method

Limitations

PPP over ATM

PPP over Ethernet

Yes

•Backup interface method

•Floating static routes

•Dialer watch

Floating static route and dialer watch need a routing protocol to run in the router. The dialer watch method brings up the backup interface as soon as the primary link goes down. The backup interface is brought down as soon as the dialer timeout is reached and the primary interface is up. Router checks the primary interface only when the dialer timeout expires. The backup interface remains up until the dialer timeout is reached, even though the primary interface is up.

For the dialer watch method, a routing protocol does not need to be running in the router, if the IP address of the peer is known.

RFC 1483 (AAL5, SNAP, and MUX)

Yes

•Backup interface method

•Floating static routes

•Dialer watch

If bridging is done through the WAN interface, it is not supported across the auxiliary port.

Cisco 831 and Cisco SOHO 91 Routers

Support for the dial backup feature on the Cisco 831 router is limited because the Ethernet WAN interface is always up, even when ISP connectivity is down across the modem connected to the Cisco 831 router. Support for dial backup is possible only for the PPPoE environment. The only way to bring up the backup interface is to simultaneously use the dialer watch feature. You also need to add the IP addresses of the peer in the dialer watch command and in the static route command to enable the dial backup when primary line goes down.

For the Cisco SOHO 91 router, only dial-in capability is supported.

Table 4-2 shows the encapsulation types supported by the Cisco 831 router dial backup.

Table 4-2 Encapsulation Types Supported by Dial Backup—Cisco 831 Router

Encapsulation Type

Dial Backup Possible

Type of Dial Backup Method

Limitations

PPPoE

Yes

Dialer watch

Bridging is not supported across a slow interface, for example, an auxiliary port. The peer IP address of the ISP provider is needed to configure the dialer watch command and the IP static route.

Normal IP in cable modem scenario

No

Dialer watch

The IP addresses of the peers are needed for dialer watch to work properly. If a lease time obtained by DHCP is not set short enough (one or two minutes), dial backup will not be supported.

Configuring Dial Backup and Remote Management for the Cisco 837 and Cisco SOHO 97 Routers

Figure 4-8 and Table 4-4 show how dial backup and remote management work in a network system when the primary line goes down.

Figure 4-8 Cisco 837 Router Dial Backup and Remote Management

Callout Number

Description

1

Main WAN link; primary connection to Internet service provider

2

Dial backup; serves as a failover link when primary line goes down

3

Remote management; serves as dial-in access to allow changes or updates to Cisco IOS configurations

Configuring Dial Backup and Remote Management for the Cisco 836 and Cisco SOHO 96 Routers

Figure 4-9, Figure 4-10, and Table 4-11 and Table 4-12 show how dial backup and remote management work in a network system when the primary line goes down. Two scenarios are typical applications of the Cisco 836 and the Cisco SOHO 96 routers. In Figure 4-9, the dial backup link goes through CPE splitter, DSLAM, and CO splitter before connecting to the ISDN switch. In Figure 4-10, the dial backup link goes directly from the Cisco 836 router to the ISDN switch.

Figure 4-9 Cisco 836 Router Dial Backup and Remote Management—Dial Backup Through CPE Splitter, DSLAM, and CO Splitter

Callout Number

Description

1

Primary ADSL interface

2

Dial backup and remote management via ISDN interface; serves as a failover link when primary line goes down

3

Administrator remote management via ISDN interface when the primary ADSL link is down; serves as dial-in access to allow changes or updates to Cisco IOS configuration

Figure 4-10 Cisco 836 Router Dial Backup and Remote Management—Dial Backup Directly from Router to ISDN Switch

Callout Number

Description

1

Primary ADSL interface

2

Dial backup and remote management via ISDN interface; serves as a failover link when primary line goes down

3

Administrator remote management via ISDN interface when the primary ADSL link is down; serves as dial-in access to allow changes or updates to Cisco IOS configuration

PPP over ATM with Centrally Managed Addressing and with Dial Backup

When customer premises equipment such as a Cisco 837 router is connected to an ISP, an IP address is dynamically assigned to the router, or the IP address may be assigned by its peer through the centrally managed function. The dial backup feature can be added to provide a failover route in case the primary line fails.

Configuring Dial Backup and Remote Management for the Cisco 837 Router

Follow the steps below to configure dial backup and remote management for the Cisco 837 router.

Command

Task

Step 1

ip name-server 206.13.28.12

Enter your ISP DNS IP address.

Step 2

ip dhcp pool 1

Configure CPE as a local DHCP server.

Step 3

vpdn enable

Enable VPDN.

Step 4

vpdn-group 1

Specify VPDN group for protocol PPPoE.

Step 5

chat-script Dialout ABORT ERROR ABORT BUSY "" "AT" OK "ATDT 5555102 T" TIMEOUT 45 CONNECT \c

Configure a chat script for a modem.

Step 6

interface Async1

Enter configuration mode for the async interface.

Step 7

interface Dialer3

Enter configuration mode for the dialer interface.

Step 8

dialer watch-group 1

Specify the group number for watch-list.

Step 9

ip nat inside source list 101 interface Dialer3 overload

Establish the Ethernet interface as the inside interface.

Step 10

ip route 0.0.0.0 0.0.0.0 ! (dial backup peer address @ISP)

Set the IP route to point to the dialer interface as a default gateway.

Step 11

access-list 101 permit ip 192.168.0.0 0.0.255.255 any

Define an extended access list permitting addresses that need translation.

Step 12

dialer watch-list 1 ip ! (ATM peer address @ISP) 255.255.255.255

Evaluate the status of the primary link, based on the existence of routes to the peer.

Step 13

line con 0

Enter configuration mode for the console interface.

Step 14

modem enable

Change the console port to auxiliary port function.

Step 15

line aux 0

Enter configuration mode for the auxiliary interface.

Step 16

flow control hardware

Enable hardware signal flow control

Configuration Example

The following configuration example for a Cisco 837 router specifies an IP address for the ATM interface via PPP/IPCP address negotiation and dial backup over the console port.
!
version 12.2
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Router
!
memory-size iomem 20
enable password cisco
!
ip subnet-zero
ip name-server 206.13.28.12
ip name-server 206.13.31.12
ip name-server 63.203.35.55
ip dhcp excluded-address 192.168.1.1
!
ip dhcp pool 1
import all
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1
!
ip audit notify log
ip audit po max-events 100
vpdn enable
!
vpdn-group 1
request-dialin
protocol pppoe
!
! Need to use your own correct ISP phone number
modemcap entry MY-USER_MODEM:MSC=&F1S0=1
chat-script Dialout ABORT ERROR ABORT BUSY "" "AT" OK "ATDT 5555102\T"
TIMEOUT 45 CONNECT \c
!
!
!
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
ip nat inside
ip tcp adjust-mss 1452
hold-queue 100 out
!
interface ATM0
mtu 1492
no ip address
no atm ilmi-keepalive
pvc 0/35
pppoe-client dial-pool-number 1
!
dsl operating-mode auto
!
!Dial backup and remote management physical interface
interface Async1
no ip address
encapsulation ppp
dialer in-band
dialer pool-member 3
async default routing
async dynamic routing
async mode dedicated
ppp authentication pap callin
!
! Primary wan link
interface Dialer1
ip address negotiated
ip nat outside
encapsulation ppp
dialer pool 1
ppp authentication pap callin
ppp pap sent-username account password 7 pass
ppp ipcp dns request
ppp ipcp wins request
ppp ipcp mask request
!
! Dialer backup logical interface
interface Dialer3
ip address negotiated
ip nat outside
encapsulation ppp
no ip route-cache
no ip mroute-cache
dialer pool 3
dialer idle-timeout 60
dialer string 5555102 modem-script Dialout
dialer watch-group 1
!
! Remote management PC ip address
peer default ip address 192.168.2.2
no cdp enable
!
! Need to use your own ISP account and password
ppp pap sent-username account password 7 pass
ppp ipcp dns request
ppp ipcp wins request
ppp ipcp mask request
!
! IP NAT over Dialer interface using route-map
ip nat inside source route-map main interface Dialer1 overload
ip nat inside source route-map secondary interface Dialer3 overload
ip classless
!
! When primary link is up again, distance 50 will override 80 if dial 
backup hasn't timeout
! Multiple routes because peer ip addresses are alternated among them 
when CPE gets connected
ip route 0.0.0.0 0.0.0.0 64.161.31.254 50
ip route 0.0.0.0 0.0.0.0 66.125.91.254 50
ip route 0.0.0.0 0.0.0.0 64.174.91.254 50
ip route 0.0.0.0 0.0.0.0 63.203.35.136 80
ip route 0.0.0.0 0.0.0.0 63.203.35.137 80
ip route 0.0.0.0 0.0.0.0 63.203.35.138 80
ip route 0.0.0.0 0.0.0.0 63.203.35.139 80
ip route 0.0.0.0 0.0.0.0 63.203.35.140 80
ip route 0.0.0.0 0.0.0.0 63.203.35.141 80
ip route 0.0.0.0 0.0.0.0 Dialer1 150
no ip http server
ip pim bidir-enable
!
! PC ip address behind CPE
access-list 101 permit ip 192.168.0.0 0.0.255.255 any
access-list 103 permit ip 192.168.0.0 0.0.255.255 any
!
! Watch multiple ip address because peers are alternated among them 
when CPE gets connected
dialer watch-list 1 ip 64.161.31.254 255.255.255.255
dialer watch-list 1 ip 64.174.91.254 255.255.255.255
dialer watch-list 1 ip 64.125.91.254 255.255.255.255
!
! Dial backup will kick in if primary link is not available 5 minutes 
after CPE starts up
dialer watch-list 1 delay route-check initial 300
dialer-list 1 protocol ip permit
!
! To direct traffic to an interface only if the Dialer gets assigned 
with an ip address
route-map main permit 10
match ip address 101
match interface Dialer1
!
route-map secondary permit 10
match ip address 103
match interface Dialer3
!
!
line con 0
exec-timeout 0 0
!
! Change console to aux function
modem enable
stopbits 1
line aux 0
exec-timeout 0 0
!
! To enable and communicate with the external modem properly
script dialer Dialout
modem InOut
modem autoconfigure discovery
transport input all 
stopbits 1
speed 115200
flowcontrol hardware
line vty 0 4
exec-timeout 0 0
password cisco
login
!
scheduler max-task-time 5000
end
Configuring Dial Backup and Remote Management for the Cisco 836 Router

Follow the steps given in the "Configuring the Cisco 836 Router's ISDN Settings" section to configure dial backup and remote management on the Cisco 836 router's ISDN S/T port.

Configuring the Cisco 836 Router's ISDN Settings

The user must first configure the Cisco 836 router ISDN settings to configure the router interface as a backup interface. Follow the steps below to configure the Cisco 836 router ISDN interface as a backup interface, beginning in global configuration mode.

Note Traffic of interest must be present to activate the backup ISDN line by means of the backup interface and floating static routes methods. Traffic of interest is not needed for the dialer watch to activate the backup ISDN line.

Command

Task

Step 1

isdn switch-type basic-net3

Specify the ISDN switch type.

Step 2

interface BRI0

Enter configuration mode for the ISDN Basic Rate Interface (BRI).

Step 3

encapsulation ppp

Set BRI0 interface encapsulation type to PPP.

Step 4

dialer pool-member 1

Specify the dialer pool membership.

Step 5

isdn switch-type basic-net3

Specify the ISDN switch type.

Step 6

exit

Exit to return to global configuration mode.

Step 7

interface Dialer0

Enter configuration mode for the dialer interface.

Step 8

ip address negotiated

Obtain the IP address from the peer.

Step 9

encapsulation ppp

Specify Dialer 0 encapsulation type as PPP.

Step 10

dialer pool 1

Specify the dialer pool to be used. Dialer pool 1 setting associates Dialer 0 interface with BRI0 because the BRI0 dialer pool-member value is "1."

Step 11

dialer string 384040

Specify the telephone number to be dialed.

Step 12

dialer-group 1

Assign this interface to a dialer group.

Step 13

exit

Exit to return to global configuration mode.

Step 14

dialer-list 1 portocol ip permit

Create a dialer list for packets of interest to be forwarded through the specified interface dialer group. Dialer-list 1 corresponds to dialer-group 1.

Configuring Dial Backup and Remote Management Settings

As described in the "Dial Backup Feature Limitations and Configuration" section, backup interface, static routes, and dialer watch are the three methods used for implementing dial backup and remote management. This section provides detailed procedures for configuring these three methods.

Configuring Backup Interface

Follow the steps below to configure the Cisco 836 router ISDN interface as a backup interface, beginning in global configuration mode.

Command

Task

Step 1

interface ATM0

Enter ATM interface configuration mode.

Step 2

backup interface BRI0

Assign BRI0 as the secondary backup interface.

Configuring Floating Static Route

Static route and dynamic route are the two components of floating static routes. Complete the following steps to configure the static route on the Cisco 836 router ISDN port, beginning in global configuration mode.

Command

Task

Step 1

ip route 0.0.0.0 0.0.0.0 22.0.0.2

Assign the primary route.

Step 2

ip route 0.0.0.0 0.0.0.0 192.168.2.2 150

Assign the lower routing administrative distance value for the backup interface route. 192.168.2.2 is the peer IP address of the backup interface.

Note When the static routes are configured, the primary interface protocol must go down in order to activate the floating static route.

Follow the steps below to configure the dynamic route on the Cisco 836 router ISDN port, beginning in global configuration mode.

Command

Task

Step 1

router rip

Enables RIP routing.

Step 2

network 22.0.0.0

Define the primary interface network. 22.0.0.0 is the network value of the primary interface.

Step 3

ip route 0.0.0.0 0.0.0.0 192.168.2.2 150

Assign the lower routing administrative distance value for the backup interface route. 192.168.2.2 is the peer IP address of the backup interface.

Note The floating static route depends on the routing protocol convergence times when dynamic routing is activated.

Configuring Dialer Watch

Use the following steps to configure the dialer watch on the Cisco 836 router's ISDN port, beginning in global configuration mode.

Command

Task

Step 1

interface Dialer0

Enter configuration mode for the dial backup interface.

Step 2

dialer watch-group 1

Specify the group number for the watch list.

Step 3

exit

Exit to return to global configuration mode.

Step 4

ip route 0.0.0.0 0.0.0.0 22.0.0.2

Assign the primary route. 22.0.0.2 is the peer IP address of the primary interface.

Step 5

ip route 0.0.0.0 0.0.0.0 192.168.2.2 150

Assign the lower routing administrative distance value for the backup interface route. 192.168.2.2 is the peer IP address of the backup interface.

Step 6

dialer watch-list 1 ip 22.0.0.2 255.255.255.255

Assign an IP address to the watch list via the dialer watch command. If the connection on the primary interface is lost and the IP address is unavailable on the Cisco 836 router, the dial-out feature on the backup interface is triggered. 22.0.0.2 is the peer IP address of the primary interface.

Configuration Example

The next three configuration examples shows sample configurations for the three dial backup interface and remote management methods.

The following is an example of configuring dial backup and remote management using the backup interface command.
Cisco836#
!
vpdn enable
!
vpdn-group 1
accept-dialin
protocol pppoe
!
!Specifies the ISDN switch type
isdn switch-type basic-net3
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
hold-queue 100 out
!
!ISDN interface to be used as a backup interface
interface BRI0
no ip address
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
!
interface ATM0
backup interface BRI0
no ip address
no atm ilmi-keepalive
pvc 1/40
encapsulation aal5snap
pppoe-client dial-pool-number 2
!
dsl operating-mode auto
!
! Dial backup interface, associated with physical BRI0 interface. 
Dialer pool 1 associates it with BRI0's dialer pool member 1
interface Dialer0
ip address negotiated
encapsulation ppp
dialer pool 1
dialer idle-timeout 30
dialer string 384040
dialer-group 1
!
! Primary interface associated with physical ATM0's interface, dialer 
pool 2 associates it with ATM0's dial-pool-number2
interface Dialer2
ip address negotiated
ip mtu 1492
encapsulation ppp
dialer pool 2
dialer-group 2
no cdp enable
!
ip classless
!Primary and backup interface given route metric
ip route 0.0.0.0 0.0.0.0 22.0.0.2
ip route 0.0.0.0 0.0.0.0 192.168.2.2 80
ip http server
!
!Specifies interesting traffic to trigger backup ISDN traffic
dialer-list 1 protocol ip permit
The following is an example of configuring dial backup and remote management using floating static routes.
Cisco836#
!
vpdn enable
!
vpdn-group 1
accept-dialin
protocol pppoe
!
!Specifies the ISDN switch type
isdn switch-type basic-net3
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
hold-queue 100 out
!
!ISDN interface to be used as a backup interface
interface BRI0
no ip address
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
!
interface ATM0
no ip address
no atm ilmi-keepalive
pvc 1/40
encapsulation aal5snap
pppoe-client dial-pool-number 2
!
dsl operating-mode auto
!
! Dial backup interface, associated with physical BRI0 interface. 
Dialer pool 1 associates it with BRI0's dialer pool member 1
interface Dialer0
ip address negotiated
encapsulation ppp
dialer pool 1
dialer idle-timeout 30
dialer string 384040
dialer-group 1
!
! Primary interface associated with physical ATM0's interface, dialer 
pool 2 associates it with ATM0's dial-pool-number2
interface Dialer2
ip address negotiated
ip mtu 1492
encapsulation ppp
dialer pool 2
dialer-group 2
!
ip classless
no cdp enable
!Primary and backup interface given route metric (This example using 
static routes, thus atm0 line protcol must be brought down for backup 
interface to function.)
ip route 0.0.0.0 0.0.0.0 22.0.0.2
ip route 0.0.0.0 0.0.0.0 192.168.2.2 150
ip http server
!
!Specifies interesting traffic to trigger backup ISDN traffic
dialer-list 1 protocol ip permit
The following is an example of configuring dial backup and remote management using dialer watch.
Cisco836#
!
vpdn enable
!
vpdn-group 1
accept-dialin
protocol pppoe
!
!Specifies the ISDN switch type
isdn switch-type basic-net3
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
hold-queue 100 out
!
!ISDN interface to be used as a backup interface
interface BRI0
no ip address
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
!
interface ATM0
no ip address
no atm ilmi-keepalive
pvc 1/40
encapsulation aal5snap
pppoe-client dial-pool-number 2
!
dsl operating-mode auto
!
! Dial backup interface, associated with physical BRI0 interface. 
Dialer pool 1 associates it with BRI0's dialer pool member 1. Note 
"dialer watch-group 1" associates a watch list with corresponding 
"dialer watch-list" command
interface Dialer0
ip address negotiated
encapsulation ppp
dialer pool 1
dialer idle-timeout 30
dialer string 384040
dialer watch-group 1
dialer-group 1
!
! Primary interface associated with physical ATM0 interface, dialer 
pool 2 associates it with ATM0's dial-pool-number2
interface Dialer2
ip address negotiated
ip mtu 1492
encapsulation ppp
dialer pool 2
dialer-group 2
no cdp enable
!
ip classless
!Primary and backup interface given route metric
ip route 0.0.0.0 0.0.0.0 22.0.0.2
ip route 0.0.0.0 0.0.0.0 192.168.2.2 80
ip http server
!
!Watch for interesting traffic
dialer watch-list 1 ip 22.0.0.2 255.255.255.255
!Specifies interesting traffic to trigger backup ISDN traffic
dialer-list 1 protocol ip permit
!
Configuring the Aggregator and ISDN Peer Router

The aggregator is typically a concentrator router where the Cisco 836 router ATM PVC will terminate. In the configuration example shown below, the aggregator is configured as a PPPoE server to correspond with the Cisco 836 router configuration example that is given on page 4-41 and page 4-42.

The ISDN peer router is any router that has an ISDN interface and can communicate through a public ISDN network to reach the Cisco 836 router ISDN interface. The ISDN peer router provides Internet access for the Cisco 836 router during the ATM network downtime.

The following is a configuration example of an aggregator used in the Cisco 836 router network.
!
vpdn enable
no vpdn logging
!
vpdn-group 1
accept-dialin
protocol pppoe
virtual-template 1
!
interface Ethernet3
description "4700ref-1"
ip address 40.1.1.1 255.255.255.0
media-type 10BaseT
!
interface Ethernet4
ip address 30.1.1.1 255.255.255.0
media-type 10BaseT
!
interface Virtual-Template1
ip address 22.0.0.2 255.255.255.0
ip mtu 1492
peer default ip address pool adsl
!
interface ATM0
no ip address
pvc 1/40
encapsulation aal5snap
protocol pppoe
!
no atm limi-keepalive
!
ip local pool adsl 22.0.0.1
ip classless
ip route 0.0.0.0 0.0.0.0 22.0.0.1 50
ip route 0.0.0.0 0.0.0.0 30.1.1.2.80
The following is a configuration example of an ISDN peer router used in the Cisco 836 router network.
!
isdn switch-type basic-net3
!
interface Ethernet0
ip address 30.1.1.2 255.0.0.0 
!
interface BRI0
description "to 836-dialbackup"
no ip address
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
!
interface Dialer0
ip address 192.168.2.2 255.255.255.0
encapsulation ppp
dialer pool 1
dialer string 384020
dialer-group 1
peer default ip address pool isdn
!
ip local pool isdn 192.168.2.1
ip http server
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.2.1
ip route 40.0.0.0 255.0.0.0 30.1.1.1
!
dialer-list 1 protocol ip permit
!
Configuring Remote Management for the Cisco SOHO 97 Router

Complete the following steps to configure remote management for the Cisco SOHO 97 router.

Command

Task

Step 1

interface Async1

Enter configuration mode for the async interface.

Step 2

line con 0

Enter configuration mode for the console interface.

Step 3

modem enable

Change the console port to the auxiliary port.

Step 4

line aux 0

Enter configuration mode for the auxiliary interface.

Step 5

flowcontrol hardware

Enable hardware signal flow control.

Configuration Example

The following configuration example for a Cisco SOHO 97 router specifies the IP address for the ATM interface via PPP/IPCP address and supports dial-in maintenance over the console port.
!
!Remote management account
username dialin password cisco
modemcap entry MY_USR_MODEM:MSC=&F1S0=1
!
interface Ethernet0
 ip address 192.168.1.1 255.255.255.0
 ip nat inside
 hold-queue 100 out
!
interface ATM0
 no ip address
 no atm ilmi-keepalive
 pvc 0/35 
  encapsulation aal5mux ppp dialer
  dialer pool-member 1
 !
 dsl operating-mode auto
!
interface Async1
 no ip address
 encapsulation ppp
 dialer in-band
autodetect encapsulation ppp
 async default routing
 async dynamic routing
 async mode dedicated
 pap authentication pap callin
peer default ip address 192.168.2.2
!
ip nat inside source list 101 interface Dialer1 overload
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer1 150
!
no ip http server
ip pim bidir-enable
!
!
access-list 101 permit ip 192.168.0.0 0.0.255.255 any
dialer-list 1 protocol ip permit
!
line con 0
 exec-timeout 0 0
 modem enable
 stopbits 1
line aux 0
 exec-timeout 0 0
 script dialer Dialout
 modem Dialin
 modem autoconfigure discovery
 transport input all
 stopbits 1
 speed 38400
 flowcontrol hardware
line vty 0 4
 login local
!
scheduler max-task-time 5000
end
Configuring Dial Backup and Remote Management for Cisco 831 Router and Cisco SOHO 91 Router

Figure 4-11 and Table 4-13 show how dial backup and remote management work in a DSL modem environment when the primary line goes down. Note that the cable modem environment is currently not supported.

Figure 4-11 Cisco 831 Router Dial Backup and Remote Management in a DSL Modem Environment

Callout Number

Description

1

Main WAN link; primary connection to Internet service provider

2

Dial backup; serves as a failover link when primary line goes down

3

Remote management; serves as a dial-in access to allow change or update of Cisco IOS configurations

Follow the steps below to configure dial backup and remote management for the Cisco 831 router.

Command

Task

Step 1

ip name-server 206.13.28.12

Enter your ISP DNS IP address.

Step 2

ip dhcp pool 1

Configure CPE as a local DHCP server.

Step 3

vpdn enable

Enable VPDN.

Step 4

vpdn-group 1

Specify VPDN group for protocol PPPoE.

Step 5

chat-script Dialout ABORT ERROR ABORT BUSY "" "AT" OK "ATDT 5555102 T" TIMEOUT 45 CONNECT \c

Configure a chap script for a modem.

Step 6

interface Async1

Enter configuration mode for the async interface.

Step 7

interface Dialer3

Enter configuration mode for the dialer interface.

Step 8

ip nat inside source list 101 interface Dialer3 overload

Establish the Ethernet interface as the inside interface.

Step 9

ip route 0.0.0.0 0.0.0.0 ! (dial backup peer address @ISP)

Set the IP route to point to the dialer interface as a default gateway.

Step 10

access-list 101 permit ip 192.168.0.0 0.0.255.255 any

Define an extended access list permitting addresses that need translation.

Step 11

dialer watch-list 1 ip ! (peer address @ISP) 255.255.255.255

Evaluate the status of the primary link, based on the existence of routes to the peer.

Step 12

line con 0

Enter configuration mode for the console interface.

Step 13

modem enable

Change the console port to the auxiliary port.

Step 14

line aux 0

Enter configuration mode for the auxiliary interface.

Step 15

flowcontrol hardware

Enable hardware signal flow control.

Configuration Example for the Cisco 831 Router

The following example configures dial backup and remote management on a Cisco 831 router.
!
version 12.2
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Router
!
memory-size iomem 20
enable password cisco
!
ip subnet-zero
ip name-server 206.13.28.12
ip name-server 206.13.31.12
ip name-server 63.203.35.55
ip dhcp excluded-address 192.168.1.1
!
ip dhcp pool 1
import all
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1
!
ip audit notify log
ip audit po max-events 100
vpdn enable
!
vpdn-group 1
request-dialin
protocol pppoe
!
! Need to use your own correct ISP phone number
modemcap entry MY-USER_MODEM:MSC=&F1S0=1
chat-script Dialout ABORT ERROR ABORT BUSY "" "AT" OK "ATDT 5555102\T"
TIMEOUT 45 CONNECT \c
!
!
!
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
ip nat inside
ip tcp adjust-mss 1452
hold-queue 100 out
!
interface Ethernet1
no ip address
no ip route-cache
no ip mroute-cache
pppoe enable
pppoe-client dial-pool-number 1
!
!Dial backup and remote management physical interface
interface Async1
no ip address
encapsulation ppp
dialer in-band
dialer pool-member 3
async default routing
async dynamic routing
async mode dedicated
ppp authentication pap callin
!
! Primary wan link
interface Dialer1
ip address negotiated
ip mtu 1492
ip nat outside
encapsulation ppp
dialer pool 1
ppp authentication pap callin
ppp pap sent-username account password 7 pass
ppp ipcp dns request
ppp ipcp wins request
ppp ipcp mask request
!
! Dialer backup logical interface
interface Dialer3
ip address negotiated
ip nat outside
encapsulation ppp
no ip route-cache
no ip mroute-cache
dialer pool 3
dialer idle-timeout 60
dialer string 5555102 modem-script Dialout
dialer watch-group 1
!
! Remote management PC ip address
peer default ip address 192.168.2.2
no cdp enable
!
! Need to use your own ISP account and password
ppp pap sent-username account password 7 pass
ppp ipcp dns request
ppp ipcp wins request
ppp ipcp mask request
!
! IP NAT over Dialer interface using route-map
ip nat inside source route-map main interface Dialer1 overload
ip nat inside source route-map secondary interface Dialer3 overload
ip classless
!
! When primary link is up again, distance 50 will override 80 if dial 
backup hasn't timeout
! Multiple routes because peer ip address are alternated among them 
when CPE gets connected
ip route 0.0.0.0 0.0.0.0 64.161.31.254 50
ip route 0.0.0.0 0.0.0.0 66.125.91.254 50
ip route 0.0.0.0 0.0.0.0 64.174.91.254 50
ip route 0.0.0.0 0.0.0.0 63.203.35.136 80
ip route 0.0.0.0 0.0.0.0 63.203.35.137 80
ip route 0.0.0.0 0.0.0.0 63.203.35.138 80
ip route 0.0.0.0 0.0.0.0 63.203.35.139 80
ip route 0.0.0.0 0.0.0.0 63.203.35.140 80
ip route 0.0.0.0 0.0.0.0 63.203.35.141 80
ip route 0.0.0.0 0.0.0.0 Dialer1 150
no ip http server
ip pim bidir-enable
!
! PC ip address behind CPE
access-list 101 permit ip 192.168.0.0 0.0.255.255 any
access-list 103 permit ip 192.168.0.0 0.0.255.255 any
!
! Watch multiple ip addresses because peers are alternated among them 
when CPE gets connected
dialer watch-list 1 ip 64.161.31.254 255.255.255.255
dialer watch-list 1 ip 64.174.91.254 255.255.255.255
dialer watch-list 1 ip 64.125.91.254 255.255.255.255
!
! Dial backup will kick in if primary link is not available 5 minutes 
after CPE starts up
dialer watch-list 1 delay route-check initial 300
dialer-list 1 protocol ip permit
!
! To direct traffic to an interface only if the Dialer gets assigned 
with an ip address
route-map main permit 10
match ip address 101
match interface Dialer1
!
route-map backup permit 10
match ip address 103
match interface Dialer3
!
!
line con 0
exec-timeout 0 0
!
! Change console to aux function
modem enable
stopbits 1
line aux 0
exec-timeout 0 0
!
! To enable and communicate with the external modem properly
script dialer Dialout
modem InOut
modem autoconfigure discovery
transport input all 
stopbits 1
speed 115200
flowcontrol hardware
line vty 0 4
exec-timeout 0 0
password cisco
login
!
scheduler max-task-time 5000
end
Configuring Remote Management for the Cisco SOHO 91 Router

Follow the steps below to configure remote management for the Cisco SOHO 91 router.

Command

Task

Step 1

interface Async1

Enter configuration mode for the async interface.

Step 2

line con 0

Enter configuration mode for the console interface.

Step 3

modem enable

Change the console port to the auxiliary port.

Step 4

line aux 0

Enter configuration mode for the auxiliary interface.

Step 5

flowcontrol hardware

Enable hardware signal flow control.

Configuration Example

The following example shows how to configure a Cisco SOHO 91 router to obtain the IP address for ATM interface via PPP/IPCP address negotiation and shows how to configure and support dial-in maintenance over the console port.
!
!Remote management account
username dialin password cisco
modemcap entry MY_USR_MODEM:MSC=&F1S0=1
!
interface Ethernet0
 ip address 192.168.1.1 255.255.255.0
 ip nat inside
 hold-queue 100 out
!
interface Async1
 no ip address
 encapsulation ppp
 dialer in-band
autodetect encapsulation ppp
 async default routing
 async dynamic routing
 async mode dedicated
 pap authentication pap callin
peer default ip address 192.168.2.2
!
ip nat inside source list 101 interface Dialer1 overload
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer1 150
!
no ip http server
ip pim bidir-enable
!
!
access-list 101 permit ip 192.168.0.0 0.0.255.255 any
dialer-list 1 protocol ip permit
!
line con 0
 exec-timeout 0 0
 modem enable
 stopbits 1
line aux 0
 exec-timeout 0 0
 script dialer Dialout
 modem Dialin
 modem autoconfigure discovery
 transport input all
 stopbits 1
 speed 38400
 flowcontrol hardware
line vty 0 4
 login local
!
scheduler max-task-time 5000
end
Configuring the DHCP Server

Dynamic Host Configuration Protocol (DHCP) is an industry-standard protocol for automatically assigning IP configurations to workstations. DHCP uses a client-server model for address allocation. As administrator, you can configure one or more DHCP servers to provide IP address assignment and other TCP/IP-oriented configuration information to your workstations. DHCP frees you from having to manually assign an IP address to each client. The DHCP protocol is described in RFC 2131.

When configuring a DHCP server, you must configure the server properties, policies, and associated DHCP options.

Note Whenever you change server properties, you must reload the server to load the configuration data from the Network Registrar database.

To configure the DHCP server, you must accept Network Registrar's defaults or supply the data explicitly:

•The IP address of the server's interface (Ethernet card). This interface must have a static IP address that is not assigned dynamically by DHCP.

•The subnet mask, which identifies the network membership of the interface. The subnet mask defaults to the appropriate value, based on the network class of the interface address. In most cases, the subnet mask is 255.255.255.0.

Network Registrar uses the interface named default to provide configurable default values for interfaces that the DHCP server discovers automatically. If you delete the default interface, the DHCP server uses hard-coded default values for port numbers and socket buffer sizes for the interfaces that it autodiscovers.

If you enable discover-interfaces, the DHCP server uses the operating system platform support to enumerate all the active interfaces on the machine and (unless there is an interface configuration with the ignore feature enabled) attempts to listen on all of these. If you disable discover-interfaces, the DHCP server listens on the interface that you specify, as long as it does not have the ignore feature enabled.

Use the dhcp-interface commands to add, remove, and list the IP addresses of your server's hardware cards. Interfaces are named with the IP address and net mask for the physical device.

If you have two interface cards for the server host, use two dhcp-interface create commands to register them both. Use the net mask suffix 16 or 24 as part of the address.
nrcmd> dhcp-interface 192.168.1.12/24 create
nrcmd> dhcp-interface 10.1.2.3/24 create
Use the dhcp-interface set ignore=true command if you want Network Registrar to use only one interface, you have to set all the other ones to be ignored.
nrcmd> dhcp-interface 10.1.2.3/24 set ignore=true
Configuring the Ethernet Interface

Follow the steps below to configure the Ethernet interface, beginning in global configuration mode.

Command

Task

Step 1

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 2

ip address ip-address mask

Set the IP address and subnet mask for the Ethernet interface.

Step 3

no shutdown

Enable the Ethernet interface to change the state from administratively down to up.

Step 4

exit

Exit configuration mode for the Ethernet interface.

For complete information on the Ethernet commands, refer to the Cisco IOS Release 12.0 documentation set. For more general information on Ethernet concepts, see "Concepts."

Dynamic Addressing Received via IPCP

Use the ip address negotiated interface command to enable a Cisco router to automatically negotiate its own registered WAN interface IP address from a central server (via PPP/IPCP). Use the same command to enable all remote hosts to use this single registered IP address to access the global Internet. The following example shows an IPCP configuration.
!
interface ATM0
 no ip address
 no atm ilmi-keepalive
 pvc 0/35 
  encapsulation aal5mux ppp dialer
  dialer pool-member 1
 !
 dsl operating-mode auto
!
interface Dialer1
 ip address negotiated
 ip nat outside
 encapsulation ppp
 dialer pool 1
 dialer-group 1
 ppp authentication pap callin
 ppp pap sent-username ! USER SPECIFIC password ! USER SPECIFIC
 ppp ipcp dns request
 ppp ipcp wins request
 ppp ipcp mask request
!
Configuring the Central Cisco 3620

The following example configures peer and dial backup on the Cisco 3620 router.
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
enable secret password
!
hostname c3620
!
boot system flash slot0:c3620-jk2o3s-mz.121-5.3.T
logging rate-limit console 10 except errors
!
username ISP password ISP
ip subnet-zero
ip name-server !ISP
ip name-server !ISP
ip name-server !ISP
!
no ip finger
!         
ip audit notify log
ip audit po max-events 100
ip audit smtp spam 25111
no ip dhcp-client network-discovery
vpdn enable
no vpdn logging
!
vpdn-group 1
 accept-dialin
  protocol pppoe
  virtual-template 2
!
!
!
chat-script Dialout ABORT ERROR ABORT BUSY "" "AT" OK "ATDT 5555101\T" 
TIMEOUT 45 CONNECT \c
!
modemcap entry MY_USR_MODEM:MSC=&F1S0=1
!
call rsvp-sync
!
!
interface Loopback1
 ip address 21.0.0.2 255.255.255.0
!
interface Loopback2
 ip address 22.0.0.2 255.255.255.0
!
interface Ethernet0/0
 no ip address
 half-duplex
 no cdp enable
!
interface Ethernet0/1
 no ip address
 no ip route-cache
 no ip mroute-cache
 half-duplex
 no cdp enable
!
interface ATM1/0
 no ip address
 no atm ilmi-keepalive
!
interface ATM1/0.1 point-to-point
 pvc 1/40 
  encapsulation aal5mux ppp Virtual-Template1
 !
!
interface ATM1/0.2 point-to-point
 pvc 1/41 
  encapsulation aal5snap
  protocol pppoe
 !
!
interface Virtual-Template1
 ip unnumbered Loopback1
 peer default ip address pool test
!
interface Virtual-Template2
 ip unnumbered Loopback2
 ip mtu 1492
!
interface Async65
 no ip address
 encapsulation ppp
 dialer in-band
 dialer pool-member 1
 autodetect encapsulation ppp
 async default routing
 async dynamic routing
 async mode dedicated
!
interface Dialer0
 ip unnumbered Async65
 encapsulation ppp
 dialer pool 1
 dialer remote-name c837
 dialer string 5555101 modem-script Dialout
 dialer-group 1
 autodetect encapsulation ppp
 no cdp enable
!
ip local pool test 21.0.0.10 21.0.0.200
ip kerberos source-interface any
ip classless
no ip http server
!
dialer-list 1 protocol ip permit
no cdp run
!
!
dial-peer cor custom
!
!
!
!
!
line con 0
 exec-timeout 0 0
 transport input none
line aux 0
 exec-timeout 0 0
 no activation-character
 script dialer Dialout
 no vacant-message
 modem InOut
 modem autoconfigure type MY_USR_MODEM
 transport input all
 transport output telnet
 escape-character NONE
 autohangup
 stopbits 1
 speed 38400
 flowcontrol hardware
line vty 0 4
 exec-timeout 0 0
login
!
end
Configuring the Central RADIUS Server

Remote Authentication Dial-In User Service (RADIUS) enables you to secure your network against unauthorized access. A RADIUS server must be configured in the service provider or corporate network in order for a Cisco 800 series router to use RADIUS client features.

To configure RADIUS on your Cisco 800 series router, you must perform the following tasks:

•Use the aaa new-model global configuration command to enable authentication, authorization, and accounting (AAA). AAA must be configured if you plan to use RADIUS.

•Use the aaa authentication global configuration command to define the method lists for RADIUS authentication.

•Use line and interface commands to enable the defined method lists to be used.

For instructions on configuring a RADIUS client, refer to the Cisco IOS Security Configuration Guide.

RFC 1483 Encapsulation with NAT

This scenario shows a remote user connecting to the Internet through an ATM connection with RFC 1483 encapsulation and NAT. You may want to use this scenario if RFC 1483 connections can be used for the network because there is slightly less overhead with RFC 1483 encapsulation than with PPP.

Figure 4-12 and Table 4-14 show the network topology for this scenario.

Figure 4-12 RFC 1483 Encapsulation with NAT

Callout Number

Description

1

Small business or remote user

2

Connection to Ethernet 0 address 192.168.1.1/24

3

ATM 0 PVC 8/35

4

The Internet

In this scenario, the small business or remote user on the Ethernet LAN can connect to the Internet through ADSL. The Ethernet interface carries the data packet through the LAN and offloads it to the RFC 1483 connection on the ATM interface. The number of ATM PVCs is set by default.

NAT (represented as the dashed line at the edge of the 827 routers) signifies two addressing domains and the inside source address. The source list defines how the packet travels through the network.

The following configuration topics are covered in this section:

•Configuring the Ethernet Interface

•Configuring the ATM Interface

•Configuring NAT

•Configuration Examples

To add additional features to this network, see Chapter 7, "Router Feature Configuration."

After configuring your router, you need to configure the PVC endpoint. For a general configuration example, see the "Cisco 3640 Gateway Configuration Example" section.

Configuring the Ethernet Interface

Complete the following steps to configure the Ethernet interface, beginning in global configuration mode.

Command

Task

Step 1

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 2

ip address 192.168.1.1 255.255.255.0

Set the IP address and subnet mask for the Ethernet interface.

Step 3

no shutdown

Enable the Ethernet interface.

Step 4

exit

Exit configuration mode for the Ethernet interface.

Configuring the ATM Interface

Use this table to configure the ATM interface, beginning in global configuration mode.

Command

Task

Step 1

interface ATM 0

Enter configuration mode for the ATM interface.

Step 2

ip address 200.200.100.1 255.255.255.0

Set the IP address and subnet mask for the ATM interface.

Step 3

pvc 8/35

Create an ATM PVC for each end node with which the router communicates.

Step 4

protocol ip 200.200.100.254 broadcast

Set the protocol broadcast for the IP address.

Step 5

encapsulation type

Specify the encapsulation type for the PVC to be AAL5SNAP or AAL5MUX IP.

Step 6

no shutdown

Enable the ATM interface.

Step 7

exit

Exit configuration mode for the ATM interface.

Configuring NAT

Complete the follow steps to configure NAT, beginning in global configuration mode.

Command

Task

Step 1

ip nat inside source list 1 pool interface ATM0 overload

Enable dynamic translation of addresses permitted by the access list to one of addresses specified in the ATM interface.

Step 2

ip route 0.0.0.0.0.0.0.0 atm0

Set the IP route to point to the ATM interface as a default gateway.

Step 3

access-list 1 permit 192.168.1.0.0.0.0.255

Define a standard access list permitting addresses that need translation.

Step 4

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 5

ip nat inside

Establish the Ethernet interface as the inside interface.

Step 6

exit

Exit configuration mode for the Ethernet interface.

Step 7

interface atm 0

Enter configuration mode for the ATM interface.

Step 8

ip nat outside

Establish the ATM interface as the outside interface.

Step 9

exit

Exit configuration mode for the ATM interface.

Configuration Examples

In the following configuration examples, you do not have to enter the commands marked "default." These commands appear automatically in the configuration file that is generated when you use the show running-config command.

The following example shows an RFC 1483 LLC/SNAP encapsulation over ATM.
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
no ip directed-broadcast (default)
ip nat inside
!
interface ATM0
ip address 200.200.100.1 255.255.255.0
no ip directed-broadcast (default)
ip nat outside
no atm ilmi-keepalive (default)
pvc 8/35 
					 encapsulation aal5snap
	protocol ip 200.200.100.254 broadcast
!
bundle-enable
!
ip nat inside source list 1 interface ATM0 overload
ip classless (default)
ip route 0.0.0.0 0.0.0.0 200.200.100.254
!
access-list 1 permit 192.168.1.0 0.0.0.255
!         
end
The following is an example for configuring RFC 1483 VC-MUX.
ip subnet-zero
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
no ip directed-broadcast (default)
ip nat inside
!
interface ATM0
ip address 200.200.100.1 255.255.255.0
no ip directed-broadcast (default)
ip nat outside
no atm ilmi-keepalive (default)
pvc 8/35 
					 encapsulation aal5mux ip
			 protocol ip 200.200.100.254 broadcast
!
bundle-enable
!
ip nat inside source list 1 interface ATM0 overload
ip classless (default)
ip route 0.0.0.0 0.0.0.0 200.200.100.254
!
access-list 1 permit 192.168.1.0 0.0.0.255
!         
end
Integrated Routing and Bridging

This network shows a user connecting to the Internet using integrated routing and bridging (IRB) to use NAT across a bridged interface. This scenario might work for you if you want to add functionality to an endpoint router without reconfiguring the central site. For example, you can provide an IP address and NAT in a bridged network without having to reconfigure the central site for routing.

Exchanging the bridge for a router enables the addition of features such as voice and quality of service (QoS). IRB provides more secure control of the central site and more efficient use of the WAN link.

Figure 4-13 and Table 4-15 show an IRB Internet scenario.

Figure 4-13 IRB Internet Scenario

Callout Number

Description

1

Small business or remote user

2

Connection to Ethernet 0 address 192.168.1.1/24

3

ATM 0 PVC 8/35

4

The Internet

One side of the network (the WAN, in this scenario) is configured to act as a bridge. The Bridge-Group Virtual Interface (BVI) is configured to act as a routed interface from the WAN bridge-group to the nonbridged LAN interface. From the LAN, the network appears as a router. From the WAN, the network appears as a bridge.

The ATM interface uses AAL5SNAP encapsulation. The number of PVCs is set by default.

NAT (represented as the dashed line at the edge of the Cisco 827 router) signifies two addressing domains and the inside source address. The source list defines how the packet travels through the network.

This section covers the following configuration topics:

•Configuring the Default Gateway

•Configuring the Ethernet Interface and IRB

•Configuring the ATM Interface

•Configuring the BVI

•Configuring NAT

•Configuration Example

To add more features to this network, see Chapter 7, "Router Feature Configuration."

After configuring your router, you need to configure the PVC endpoint. For a general configuration example, see the "Cisco 3640 Gateway Configuration Example" section.

Configuring the Default Gateway

Enter the following command to set the IP route for the default gateway:

ip route default-gateway ip address-mask

Configuring the Ethernet Interface and IRB

Complete the following steps to configure the Ethernet interface and IRB, beginning in global configuration mode.

Command

Task

Step 1

bridge irb

Specify IRB.

Step 2

bridge 1 route ip

Enable IP routing to and from bridge-group 1.

Step 3

bridge 1 protocol ieee

Specify the bridge protocol to define the type of Spanning-Tree Protocol (STP).

Step 4

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 5

ip address 192.168.1.1 255.255.255.0

Set the IP address and subnet mask for the Ethernet interface.

Step 6

no shutdown

Enable the Ethernet interface.

Step 7

exit

Exit configuration mode for the Ethernet interface.

Configuring the ATM Interface

Follow the steps below to configure the ATM interface, beginning in global configuration mode.

Command

Task

Step 1

interface ATM 0

Enter configuration mode for the ATM interface.

Step 2

pvc 8/35

Create an ATM PVC for each end node with which the router communicates.

Step 3

encapsulation aal5snap

Specify the encapsulation type for the PVC.

Step 4

bridge-group 1

Specify the bridge-group number to which the ATM interface belongs.

Step 5

no shutdown

Enable the ATM interface.

Step 6

exit

Exit configuration mode for the ATM interface.

Configuring the BVI

Follow the steps below to configure the BVI, beginning in global configuration mode.

Command

Task

Step 1

interface bvi 1

Enter configuration mode for the BVI.

Step 2

ip address 200.200.100.1 255.255.255.0

Set the IP address and subnet mask for the BVI.

Step 3

exit

Exit configuration mode for Ethernet interface.

Configuring NAT

Follow the steps below to configure NAT, beginning in global configuration mode.

Command

Task

Step 1

ip nat pool test 200.200.100.1 200.200.100.1 255.255.255.0

Create pool of global IP addresses for NAT.

Step 2

access-list 101 permit ip 192.168.1 0.0.0.0.255 any log

Define a standard access list permitting addresses that need translation.

Step 3

ip nat inside source list 101 pool test overload

Enable dynamic translation of addresses permitted by the access list to one of the addresses specified in the pool.

Step 4

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 5

ip nat inside

Establish the Ethernet interface as the inside interface.

Step 6

no shutdown

Enable interface and configuration changes just made to the interface.

Step 7

exit

Exit configuration mode for the Ethernet interface.

Step 8

interface ATM 0

Enter configuration mode for the ATM interface.

Step 9

ip nat outside

Establish the ATM interface as the outside interface.

Step 10

no shutdown

Enable the interface and configuration changes just made to the interface.

Step 11

exit

Exit configuration mode for the ATM interface.

Step 12

interface bvi 1

Enter configuration mode for the BVI.

Step 13

ip nat outside

Establish the BVI as the outside interface.

Step 14

no shutdown

Enable the interface and configuration changes just made to the interface.

Step 15

end

Exit configuration mode for the BVI.

Configuration Example

In the following configuration example, you do not have to enter the commands marked "default." These commands appear automatically in the configuration file that is generated when you use the show running-config command.
bridge irb
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
no ip directed-broadcast (default)
ip nat inside
!
interface ATM0
no ip address
no ip directed-broadcast (default)
ip nat outside
no atm ilmi-keepalive (default)
pvc 8/35 
encapsulation aal5snap
!
bridge-group 1
!
interface BVI1
ip address 200.200.100.1 255.255.255.0
no ip directed-broadcast (default)
ip nat outside
!
ip nat pool test 200.200.100.1 200.200.100.1 netmask 255.255.255.0
ip nat inside source list 101 pool test overload
ip classless (default)
!
bridge 1 protocol ieee
bridge 1 route ip
!
access-list 101 permit ip 192.168.1.0 0.0.0.255 any log
!
ip route 0.0.0.0 0.0.0.0 200.200.100.254 (default gateway)
!
end
Concurrent Routing and Bridging

This network shows a remote user connecting to the Internet using concurrent routing and bridging (CRB) to route voice traffic and bridge data traffic while keeping the two types of traffic separated. This scenario is useful if you want to simplify your network setup for data transmission and then configure voice. The IP address is configured to recognize the difference between data traffic and voice traffic (voice traffic is configured with QoS parameters and virtual circuits). IRB can do routing and bridging on the same interface; CRB does routing and bridging on separate interfaces.

Figure 4-14 and Table 4-16 show a CRB Internet scenario with the voice traffic routed and the data traffic bridged. Both the Cisco 827/827-4v gateway and the Cisco 3640 voice gateway are supporting voice traffic from telephones.

Figure 4-14 CRB Internet Scenario

Callout Number

Description

1

Small business or remote user

2

Ethernet 0 bridge

3

ATM connection, ATM0.1 PVC 1/40 Voice 1.0.0.1/24, ATM0.2 PVC 8/35 data

4

The Internet

Concurrent routing and bridging are accomplished using different subinterfaces under the ATM interface. Each ATM subinterface that is created is treated uniquely in the network.

Data traffic in this scenario is bridged across ATM subinterface 2, using AAL5SNAP encapsulation. A single PVC is created with a vpi/vci value of 8/35.

Voice traffic is routed across ATM0 subinterface 0.1. There is a single PVC created with a VPI/VCI value of 1/40 for voice. The voice subinterface is configured with remote dial peers to determine where outgoing calls are sent and with local dial peers to determine what numbers each port should respond to. Each VoIP dial peer is configured for H.323 signaling.

The following configuration topics are covered in this section:

•Specifying CRB and Configuring the Ethernet Interface

•Configuring the ATM Interface and Subinterfaces

•Configuring Voice Ports

•Configuring the POTS Dial Peers

•Configuring VoIP Dial Peers for H.323 Signaling

•Configuration Example

To add additional features to this network, see Chapter 7, "Router Feature Configuration."

After configuring your router, you need to configure the PVC endpoint. For a general configuration example, see the "Cisco 3640 Gateway Configuration Example" section on page 74.

Specifying CRB and Configuring the Ethernet Interface

Follow the steps below to specify CRB and configure the Ethernet interface, beginning in global configuration mode.

Command

Task

Step 1

bridge crb

Specify CRB.

Step 2

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 3

bridge-group 1

Specify the bridge-group number to which the Ethernet interface belongs.

Step 4

exit

Exit configuration mode for the Ethernet interface and the router.

Step 5

bridge 1 protocol ieee

Specify the bridge protocol to define the type of STP.

Configuring the ATM Interface and Subinterfaces

Follow the steps below to configure the ATM interface and subinterfaces, beginning in global configuration mode.

Command

Task

Step 1

interface ATM 0.1 point-to-point

Specify the ATM0.1 subinterface.

Step 2

ip address 1.0.0.1 255.255.255.0

Set the IP address and subnet mask for the ATM0.1 subinterface.

Step 3

pvc 1/40

Create an ATM PVC for each end node with which the router communicates.

Step 4

encapsulation aal5snap

Specify the encapsulation type for the PVC.

Step 5

protocol ip 1.0.0.2 broadcast

Set the protocol broadcast for the IP address.

Step 6

interface ATM 0.2 point-to-point

Specify the ATM0.2 subinterface.

Step 7

pvc 8/35

Create an ATM PVC for each end node with which the router communicates.

Step 8

encapsulation aal5snap

Specify the encapsulation type for the PVC.

Step 9

bridge-group 1

Specify the bridge-group number to which the Ethernet interface belongs.

Step 10

no shutdown

Enable the ATM interface.

Step 11

exit

Exit configuration mode for the ATM interface.

Configuring Voice Ports

To configure voice ports, you must configure the POTS dial peers and the VoIP dial peers for the signaling type; in this case, the type is H.323.

Configuring the POTS Dial Peers

Complete the following steps to configure the POTS dial peers, beginning in global configuration mode. Table 4-3 shows the destination telephone number and port for each dial peer POTS port.

Command

Task

Step 1

dial-peer voice number POTS

Enter configuration mode for the dial peer.

Step 2

destination-pattern string

Define the telephone number associated with the port.

Step 3

voice port-number

Specify the port number.

Table 4-3 Mapping of Dial Peer Number to Destination Telephone and Port

Dial Peer Number

Destination Pattern

Port

101

14085271111

1

102

14085272222

2

103

14085273333

3

104

14085274444

4

Configuring VoIP Dial Peers for H.323 Signaling

Follow the steps below to configure VoIP dial peers for H.323 signaling, beginning in global configuration mode. Table 4-4 shows the destination telephone number for each voice dial peer.

Command

Task

Step 1

dial-peer voice number VoIP

Enter configuration mode for the dial peer.

Step 2

destination-pattern string

Define the destination telephone number associated with each VoIP dial peer.

Step 3

codec g711ulaw

Specify a codec if you are not using the default codec of g.729.

Step 4

session target ipv4:1.0.0.2

Specify a destination IP address for each dial peer.

Table 4-4 Mapping of VoIP Dial Peers to Destination Telephone Numbers for H.323

VoIP Dial Peer

Destination Pattern

1100

12123451111

1200

12123452222

1300

12123453333

1400

12123454444

Configuration Example

In the following configuration example, you do not have to enter the commands marked "default." These commands appear automatically in the configuration file that is generated when you use the show running-config command.
ip subnet-zero
!
bridge crb
!
interface Ethernet0
no ip address
no ip directed-broadcast (default)
bridge-group 1
!
interface ATM0
no ip address
no ip directed-broadcast (default)
no atm ilmi-keepalive (default)
bundle-enable
!
interface ATM0.1 point-to-point
ip address 1.0.0.1 255.255.255.0
no ip directed-broadcast (default)
pvc voice 1/40 
protocol ip 1.0.0.2 broadcast
encapsulation aal5snap
!
interface ATM0.2 point-to-point
no ip address
no ip directed-broadcast (default)
pvc data 8/35 
encapsulation aal5snap
!
bridge-group 1
!
ip classless (default)
!
bridge 1 protocol ieee
!
voice-port 1
local-alerting
!
voice-port 2
local-alerting
!
voice-port 3
local-alerting
!
voice-port 4
local-alerting
!
dial-peer voice 101 pots
destination-pattern 14085271111
port 1
!
dial-peer voice 1100 voip
destination-pattern 12123451111
codec g711ulaw
session target ipv4:1.0.0.2
!
dial-peer voice 102 pots
destination-pattern 14085272222
port 2
!
dial-peer voice 1200 voip
destination-pattern 12123452222
codec g711ulaw
session target ipv4:1.0.0.2
!
dial-peer voice 103 pots
destination-pattern 14085273333
port 3
!
dial-peer voice 1300 voip
destination-pattern 12123453333
codec g711ulaw
session target ipv4:1.0.0.2
!
dial-peer voice 104 pots
destination-pattern 14085274444
port 4
!
dial-peer voice 1400 voip
destination-pattern 12123454444
codec g711ulaw
session target ipv4:1.0.0.2
!
end
Voice Scenario

This section describes a voice scenario configuration using the Cisco 827 router in an H.323 signaling environment.

Setting up voice on the router actually includes two configurations—one for data and one for voice. When you have completed the configuration for the data scenario, you can add voice by configuring the POTS and VoIP dial peers and voice ports. Scenarios for data and voice are provided in the sections that follow.

Data Network

Figure 4-15 and Table 4-19 show a data network with traffic routing through the Cisco 827 router and then switching on to the ATM interface.

Figure 4-15 Data Network

Callout Number

Description

1

Ethernet connection to a Cisco 827 router

2

Ethernet connection 0/1 at address 172.17.1.1, subnet 255.255.255.0

3

Ethernet connection 0 at 172.17.1.36, subnet 255.255.255.0

The Cisco 827 router is connected through the ATM interface through one PVC. The PVC is associated with a QoS policy called mypolicy. Data traffic coming from the Ethernet must have an IP precedence value of less than 5 (critical) to distinguish it from voice traffic.

EIGRP is configured to send hello packets every 5 seconds to inform neighboring routers that it is functioning. If a particular router does not send a hello packet within a prescribed period, EIGRP assumes that the state of a destination has changed and sends an incremental update.

NAT (represented by the dashed line at the edge of the Cisco 827 router) signifies two addressing domains and the inside source address. The source list defines how the packet travels through the network.

This scenario includes configuration tasks and a configuration example. To add more features to this network, see Chapter 7, "Router Feature Configuration."

After configuring your router, you need to configure the PVC endpoint. For a general configuration example, see the "Cisco 3640 Gateway Configuration Example" section on page 74.

Voice Network

Figure 4-16 and Table 4-20 show a voice network with an 827-4V router and a Cisco 3640 router as the VoIP gateway using H.323 signaling (H.323 gateway).

Figure 4-16 Voice Network

Callout Number

Description

1

Cisco 827-4V router serving as a voice gateway

2

Cisco 3640 router serving as a voice gateway

3

Ethernet 0 connection at address 172.17.1.36, subnet 255.255.255.0

4

Ethernet 1 connection at address 172.17.1.1, subnet 255.255.255.0

5

Cisco 3640 router serving as voice gatekeeper

The Cisco 3640 router is set up on the LAN as a gatekeeper, which provides address translation and control access for the LAN for H.323 terminals and gateways. The gatekeeper may provide other services to the H.323 terminals and gateways, such as managing bandwidth and locating gateways.

In this scenario, the dial endpoint is the Cisco 3640 router, with an IP address of 172.17.1.36 and a subnet mask of 255.255.255.0. This configuration assumes a single-zone setup so that both the Cisco 827-4V router and the Cisco 3640 router are in the same zone.

Dialed numbers are stored by the VoIP session application in the 827-4V router, in this case, H.323. After enough digits are accumulated to match a configured destination pattern, the telephone number is mapped to a dial peer and session target. In this configuration, the dial peer has a session target of RAS, which is a protocol run between the H.323 session protocol gateway and gatekeeper.

The gatekeeper resolves the destination for each dialed number, and the call signal is routed to the Cisco 3640 gateway, which assigns the call to a voice port.

The coder-decoder compression schemes (codecs) are enabled for both ends of the connection, and QoS parameters are configured for IP precedence.

Configuration Tasks

To configure the voice scenario, you must first configure the data network and then configure the voice network.

Configure the data network by following the procedures in these sections:

•Configuring the Class Map, Route Map, and Policy Map

•Configuring the Ethernet Interface

•Configuring the ATM Interface

•Configuring Enhanced IGRP

Then, configure the voice network by following the procedures in these sections:

•Configuring the POTS Dial Peers

•Configuring VoIP Dial Peers for H.323 Signaling

For configuration examples, see the "Configuring the Class Map, Route Map, and Policy Map" section, the "Configuring the Ethernet Interface" section, the "Configuring the ATM Interface" section, the "Configuring EIGRP" section, the "Configuring the POTS Dial Peers" section, and the "Configuring VoIP Dial Peers for H.323 Signaling" section provided in the sections below.

Configuration examples are shown for the Cisco 827-4V router and the gateway and gatekeeper endpoint routers.

After configuring your router, you need to configure the PVC endpoint. For a general configuration example, see the "Cisco 3640 Gateway Configuration Example" section on page 74.

Configuring the Class Map, Route Map, and Policy Map

Follow these steps to configure the class map, route map, and policy map, beginning in global configuration mode.

Command

Task

Step 1

access-lists 101 permit ip any any precedence 5

Configure the access list.

Step 2

class-map voice

Configure the class map.

Step 3

match access-group 101

Assign access list 101 to the class map.

Step 4

route-map data permit 10

Configure the route map.

Step 5

ip precedence routine

Set the IP precedence.

Step 6

policy-map mypolicy

Configure a policy map.

Step 7

class voice

Specify the class for queuing voice traffic.

Step 8

priority 176

Specify the bandwidth for queuing.¹

Step 9

class class-default

Configure the default class for all traffic but voice traffic.

¹Total bandwidth for the policy map may not exceed 75 percent of the total PVC bandwidth.

Configuring the Ethernet Interface

Follow the steps below to configure the Ethernet interface, beginning in global configuration mode.

Command

Task

Step 1

interface ethernet 0

Enter configuration mode for the Ethernet interface.

Step 2

ip address 20.20.20.20 255.255.255.0

Set the IP address and subnet mask for the Ethernet interface.

Step 3

ip policy route-map data

Configure the IP policy route map.

Step 4

ip route-cache policy

Enable fast-switching policy routing.

Step 5

no shutdown

Enable the Ethernet interface.

Step 6

exit

Exit configuration mode for the Ethernet interface.

Configuring the ATM Interface

Complete the following steps to configure the ATM interface, beginning in global configuration mode.

Command

Task

Step 1

interface ATM 0

Enter configuration mode for the ATM interface.

Step 2

ip address 10.10.10.20 255.255.255.0

Set the IP address and subnet mask for the ATM interface.

Step 3

pvc 8/35

Create an ATM PVC for each end node with which the router communicates.

Step 4

encapsulation aal5snap

Specify the encapsulation type for the PVC.

Step 5

protocol ip 10.10.10.36 broadcast

Specify the protocol broadcast for the IP address.

Step 6

service-policy output mypolicy

Specify the service policy for the ATM interface.

Step 7

vbr-nrt 640 640 1

Specify the ATM service class.

Step 8

no shutdown

Enable the ATM interface.

Step 9

exit

Exit configuration mode for the ATM interface.

Configuring EIGRP

Follow the steps below to configure EIGRP, beginning in global configuration mode.

Command

Task

Step 1

router eigrp 100

Enter router configuration mode, and enable EIGRP on the router. The autonomous-system number identifies the route to other EIGRP routers and is used to tag the EIGRP information.

Step 2

network number

Specify the network number for each directly connected network.

Step 3

exit

Exit router configuration mode.

Configuring the POTS Dial Peers

Follow the steps below to configure each POTS dial peer, beginning in global configuration mode.

Command

Task

Step 1

dial-peer voice number POTS

Enter configuration mode for the dial peer

Step 2

destination-pattern string

Define the destination telephone number associated with the VoIP dial peer.

Step 3

port number

Specify the port number.

Configuring VoIP Dial Peers for H.323 Signaling

Follow the steps below to configure VoIP dial peers for H.323 signaling in global configuration mode.

Command

Task

Step 1

dial-peer voice number VoIP

Enter configuration mode for the dial peer.

Step 2

destination-pattern string

Define the destination telephone number associated with each VoIP dial peer.

Step 3

codec g711ulaw

Specify a codec if you are not using the default codec of g.729.

Step 4

ip precedence 5

Set the IP precedence.

Step 5

session target ras

Specify a destination IP address for each dial peer.

Configuration Examples

This section contains the following configuration examples:

•Cisco 827-4V Router Configuration Example

•Cisco 3640 Gateway Configuration Example

•Cisco 3640 Gatekeeper Configuration Example

Cisco 827-4V Router Configuration Example

The following is a configuration example for the Cisco 827-4V router portion of the voice network scenario. You do not have to enter the commands marked "default." These commands appear automatically in the configuration file that is generated when you use the show running-config command.
!
class-map voice
match access-group 101
!
route-map data permit 10
set ip precedence routine
!
policy-map mypolicy
class voice
priority 176
class class-default
fair-queue 16 (default)
!
ip subnet-zero
!
gateway
!
interface Ethernet0
ip address 20.20.20.20 255.255.255.0
no ip directed-broadcast (default)
ip route-cache policy
ip policy route-map data
!
interface ATM0
ip address 10.10.10.20 255.255.255.0
no ip directed-broadcast (default)
no atm ilmi-keepalive (default)
pvc 1/40
service-policy output mypolicy
protocol ip 10.10.10.36 broadcast
vbr-nrt 640 640 1
! 640 is the maximum upstream rate of ADSL
encapsulation aal5snap
!
bundle-enable
h323-gateway voip interface
h323-gateway voip id gk-twister ipaddr 172.17.1.1 1719
h323-gateway voip h323-id gw-820
h323-gateway voip tech-prefix 1#
!
router eigrp 100
network 10.0.0.0
network 20.0.0.0
!
ip classless (default)
no ip http server
!
access-list 101 permit ip any any precedence critical(5)
!
line con 0
exec-timeout 0 0
transport input none
stopbits 1
line vty 0 4
login
!
!
voice-port 1
local-alerting
!
voice-port 2
local-alerting
!
voice-port 3
local-alerting
!
voice-port 4
local-alerting
!
dial-peer voice 10 voip
destination-pattern .......
ip precedence 5
session target ras
!
dial-peer voice 1 pots
destination-pattern 4085258111
port 1
!
dial-peer voice 2 pots
destination-pattern 14085258222
port 2
!
dial-peer voice 3 pots
destination-pattern 14085258333
port 3
!
dial-peer voice 4 pots
destination-pattern 14085258444
port 4
!
end
Cisco 3640 Gateway Configuration Example

The following is a configuration example for the Cisco 3640 gateway portion of the voice network scenario. You do not have to enter the commands marked "default." These commands appear automatically in the configuration file that is generated when you use the show running-config command.
!
class-map voice
match access-group 101
!
policy-map mypolicy
class voice
bandwidth 176
class class-default
fair-queue 16
!
ip subnet-zero
!
cns event-service server
!
voice-port 1/0/0
!
voice-port 1/0/1
!
voice-port 1/1/0
!
voice-port 1/1/1
!
dial-peer voice 10 voip
destination-pattern .......
ip precedence 5
session target ras
!
dial-peer voice 1 pots
destination-pattern 12125253111
port 1/0/0
!
dial-peer voice 2 pots
destination-pattern 12125253222
port 1/0/1
!
dial-peer voice 3 pots
destination-pattern 12125253333
port 1/1/0
!
dial-peer voice 4 pots
destination-pattern 12125253444
port 1/1/1
!
process-max-time 200
gateway 
!
interface Ethernet0/0
ip address 172.17.1.36 255.255.255.0
no ip directed-broadcast
h323-gateway voip interface
h323-gateway voip id gk-twister ipaddr 172.17.1.1 1719
h323-gateway voip h323-id gw-3640
h323-gateway voip tech-prefix 1#
!
interface ATM2/0
ip address 10.10.10.36 255.255.255.0
no ip directed-broadcast
no atm ilmi-keepalive
pvc 8/35 
service-policy output mypolicy
protocol ip 10.10.10.20 broadcast
vbr-rt 1000 600 1
encapsulation aal5snap
!
router eigrp 100
network 10.0.0.0
network 172.17.0.0
!
no ip classless
no ip http server
!
access-list 101 permit ip any any precedence critical (5)
!
line con 0
exec-timeout 0 0
transport input none
line aux 0
line vty 0 4
login
!
!
end
Cisco 3640 Gatekeeper Configuration Example

The following is a configuration example for the H.323 gatekeeper portion of the voice network scenario. You do not have to enter the commands marked "default." These commands appear automatically in the configuration file that is generated when you use the show running-config command.
!
class-map voice
match access-group 101
!
!
policy-map mypolicy
class voice
bandwidth 176
class class-default
fair-queue 16
!
ip subnet-zero
!
ip dvmrp route-limit 20000
!
process-max-time 200
!
interface Ethernet0/0
ip address 172.28.9.83 255.255.255.0
no ip directed-broadcast (default)
!
interface Ethernet0/1
ip address 172.17.1.1 255.255.255.0
no ip directed-broadcast (default)
!
router eigrp 100
network 172.17.0.0
!
ip classless (default)
no ip http server
!
!
gatekeeper
zone local gk-router router.cisco.com 172.17.1.1
zone remote gk-sf1 cisco.com 179.15.2.2
zone remote gk-sf2 lucent.com 180.4.0.1
zone prefix gk-sf1 1415525....
zone prefix gk-sf2 1415527....
!
line con 0
exec-timeout 0 0
transport input none
line aux 0
line vty 0 4
password lab
login
!
end