Configuring for ISDN and Analog Calls

Enabling Remote IP Users to Dial in to IP Networks

This section includes the base configuration to enable IP clients to access network resources by dialing through the access server. Configure remote IP dialin before you enter any commands for IPX or AppleTalk, even if you are setting up an IPX- or AppleTalk-only network.

Enter the following access server configuration sequentially, first entering the commands featured in the "Entering Configuration Mode" section (enter your own addresses, host names, and passwords where appropriate).

Entering Configuration Mode

To enter configuration mode, follow these steps:

Step 1 Connect a console to the access server and turn on the access server. If you need instructions to connect a terminal console to the access server, refer to the access server hardware installation guide.

Step 2 To start configuration mode, enter the following commands:

Would you like to enter the initial dialog? [yes]: no

Router> enable

Router#

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# hostname as5200

as5200(config)# enable password irongate

Proceed with the "Configuring Security" section.

Configuring Security

To set up a base security and local database, enter the following commands starting in global configuration mode:

as5200(config)# aaa new-model
as5200(config)# aaa authentication login default local
as5200(config)# aaa authentication login console none
as5200(config)# aaa authentication ppp default if-needed local
as5200(config)# username jojackso password <password>
as5200(config)# username wmays password <password>
as5200(config)# username bruth password <password>
as5200(config)# username hwilliam password <password>

Proceed with the "Configuring the ISDN Switch Type" section.

Configuring the ISDN Switch Type

To configure the ISDN switch servicing your T1 PRI or E1 PRI lines, enter the following command in global configuration mode. The switch type can be obtained from your telephone service provider:

as5200(config)# isdn switch-type primary-5ess

Proceed with the "Configuring the Controllers" section.

Configuring the Controllers

Your access server is configured with a Dual T1 PRI card or a Dual E1 PRI card. Use one of the following procedures to configure your access server.

Configuring T1 Controllers

To configure the T1 controllers, which accept incoming calls and send outgoing calls through ISDN PRI lines, follow these steps:

Step 1 Enable the T0 controller:

as5200(config)# controller T1 0

as5200(config-controller)#

Step 2 Set the framing and line code type. The framing and line code you configure must match your telco's offering. In most cases, these values are esf and b8zs.

as5200(config-controller)# framing esf

as5200(config-controller)# linecode b8zs

Step 3 Configure one T1 line to serve as the primary or most stable clock source line. (The other T1 line is configured as the secondary clock source line, which you enter later in this procedure.)

as5200(config-controller)# clock source line primary

Most T1 lines provide stable clocking, so choosing the correct primary and secondary clock source is not a vital part of the configuration. However, do not configure the clock source as internal unless you are performing back-to-back advanced testing between two routers in a network simulated environment (such as in a router lab).

Step 4 Specify how you want to configure all 24 channels. To configure all channels for ISDN PRI, enter the following command:

as5200(config-controller)# pri-group timeslots 1-24

as5200(config-controller)# exit

as5200(config)#

If you are not running ISDN PRI but want to configure a channelized T1 to accept voice calls, substitute the pri-group timeslots 1-24 command with the cas-group 1 timeslots 1-24 type e&m-fgb command on both T1 controllers. This command configures the E&M (ear and mouth) analog signal on each timeslot:

as5200(config-controller)# cas-group 1 timeslots 1-24 type e&m-fgb

as5200(config-controller)# exit

as5200(config)#

Alternatively, you can configure a channelized T1 that is not running PRI ISDN with the channel-group 1 timeslots 1-24 command on both T1 controllers:

as5200(config-controller)# channel-group 1 timeslots 1-24

as5200(config-controller)# exit

as5200(config)#

Step 5 Configure the T1 controller. This controller's configuration is identical to the one you entered on the T0 controller except that it is used as the secondary clock source line:

as5200(config)# controller T1 1

as5200(config-controller)# framing esf

as5200(config-controller)# linecode b8zs

as5200(config-controller)# clock source line secondary

as5200(config-controller)# pri-group timeslots 1-24

as5200(config-controller)# exit

as5200(config)#

Proceed with the "Configuring the ISDN D Channel Serial Interfaces" section.

Configuring E1 Controllers

To configure the E1 controllers, which accept and send incoming and outgoing calls through ISDN PRI lines, follow these steps:

Step 1 Enable the E0 controller:

as5200(config)# controller E1 0

as5200(config-controller)#

Step 2 Set the framing and line code type. The framing and line code you configure must match your telco's offering:

as5200(config-controller)# framing crc4

as5200(config-controller)# linecode hdb3

Step 3 Configure one E1 line to serve as the primary or most stable clock source line. (The other E1 line is configured as the secondary clock source line, which you enter later in this procedure.)

as5200(config-controller)# clock source line primary

Most E1 lines provide stable clocking, so choosing the correct primary and secondary clock source is not a vital part of the configuration. However, do not configure the clock source as internal unless you are performing back-to-back advanced testing between two routers in a network simulated environment (such as in a router lab).

Step 4 Specify how you want to configure all 30 channels. To configure all channels for ISDN PRI, enter the following command:

as5200(config-controller)# pri-group timeslots 1-31

as5200(config-controller)# exit

as5200(config)#

Alternatively, you can configure a channelized E1 that is not running PRI ISDN with the channel-group 1 timeslots 1-31 command on both T1 controllers:

as5200(config-controller)# channel-group 1 timeslots 1-31

as5200(config-controller)# exit

as5200(config)#

Step 5 Configure the E1 controller. This controller's configuration is identical to the one you entered on the E0 controller except that it is used as the secondary clock source line:

as5200(config)# controller E1 1

as5200(config-controller)# framing crc4

as5200(config-controller)# linecode hdb3

as5200(config-controller)# clock source line secondary

as5200(config-controller)# pri-group timeslots 1-31

as5200(config-controller)# exit

as5200(config)#

Proceed with the "Configuring the ISDN D Channel Serial Interfaces" section.

Configuring the ISDN D Channel Serial Interfaces

After you configure the controller, two corresponding D channel serial interfaces are instantly created. For Dual T1 PRI cards, serial interface 0:23 is the D channel for the T0 controller, and serial interface 1:23 is the D channel for T1 controller. For Dual E1 PRI cards, serial interface 0:15 is the D channel for the E0 controller, and serial interface 1:15 is the D channel for E1 controller.

You must configure each serial interface to receive incoming and send outgoing modem signaling.

To configure the ISDN D channel serial interfaces, follow these steps:

Step 1 Specify the D channel of the first PRI line:

as5200(config)# interface Serial 0:23

or, for E1 PRI

as5200(config)# interface Serial 0:15

as5200(config-if)#

Step 2 Configure all incoming voice calls to go to the modems.

as5200(config-if)# isdn incoming-voice modem

Because some telcos charge more for ISDN data calls, you might want to configure the isdn incoming-voice data command to process ISDN calls as voice calls, which provides you with data service at a voice billing rate. However, incoming modem calls will not be passed to the modems with this command enabled. Native ISDN calls are directed like a protocol.

Step 3 Wrap these configurations together under the umbrella of a dialer interface, which modularizes the configuration. The dialer interface serves as the parent interface that contains additional protocol characteristics:

as5200(config-if)# dialer rotary-group 1

as5200(config-if)# exit

This command also creates one interface with one address, which is helpful for the hunt group provided by the phone company.

Step 4 Specify the D channel for the second PRI line and give it the same channel configurations you set for the first PRI line:

as5200(config-if)# interface Serial 1:23

or, for E1 PRI

as5200(config-if)# interface Serial 1:15

as5200(config-if)# isdn incoming-voice modem

as5200(config-if)# dialer rotary-group 1

as5200(config-if)# exit

as5200(config)#

Continue on to the "Creating Interfaces for Asynchronous and ISDN Dialin Services" section.

Creating Interfaces for Asynchronous and ISDN Dialin Services

This section describes how to configure the access server interfaces that enable dial in clients to make remote asynchronous and ISDN connections to the access server.

To configure remote services, you must configure three interrelated interfaces on the access server. The loopback interface makes the network appear as if the dialin users exist on one Ethernet segment. The loopback interface has the following four types of neighboring interfaces used for dialin operations: ISDN interface, dialer interface, group asynchronous interface, and asynchronous interface. Figure 3-2 shows an internal view of the components used to process incoming ISDN and analog calls on an access server.

Figure 3-2 : Internal View of Access Server Call Processing Components

All dial in users exist on one dialin subnet. Remote asynchronous users dial in through the group asynchronous interface to the access server. Remote ISDN users dial in through the ISDN dialer interface to the access server. Figure 3-3 shows an external view of how remote users dial in to the access server.

Figure 3-3 : External View of Access Server Call Processing Components

Configuring the Loopback and Ethernet Interfaces

The loopback 0 interface is a virtual IP interface carrying all the dialin users, and it exists only in the access server. You assign an IP network number to the loopback interface, then let each asynchronous interface borrow this network number.

To configure the loopback and Ethernet interface, follow these steps:

Step 1 Create interface loopback 0, which is the logical IP subnet containing all the dial in users' addresses:

as5200(config)# interface loopback 0

%LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to up

as5200(config-if)#

Step 2 Give the loopback interface an IP address using an existing subnet reserved for asynchronous dialin users (such as subnet 172.16.254.254):

as5200(config-if)# ip address 172.16.254.254 255.255.255.0

as5200(config-if)# exit

as5200(config)#

Step 3 Configure Ethernet interface 0 and assign it an IP address from the subnet address on the network to which you are enabling dialin access:

as5200(config)# interface Ethernet 0

as5200(config-if)# ip address 172.16.1.1 255.255.255.0

as5200(config-if)# exit

as5200(config)#

Proceed with the "Creating the Group Asynchronous Interface" section.

Creating the Group Asynchronous Interface

A group asynchronous interface is the parent interface that applies protocol characteristics to specified asynchronous ports. To configure the group asynchronous interface, follow these steps:

Step 1 Enter the following commands to configure the group asynchronous interfaces:

as5200(config)# interface Group-Async 1

as5200(config-if)# ip unnumbered Loopback 0

as5200(config-if)# ip tcp header-compression passive

as5200(config-if)# encapsulation ppp

as5200(config-if)# async mode interactive

as5200(config-if)# ppp authentication chap pap

as5200(config-if)# group-range 1 48

or, for E1 PRI

as5200(config-if)# group-range 1 60

Building configuration...

as5200(config-if)#

Step 2 Assign dialin clients an IP address from a pool of addresses named default. The pool is defined later in this procedure:

as5200(config-if)# peer default ip address pool default

Step 3 Specify the packets that keep the asynchronous links up. This command derives its definition from the dialer list command, which is configured in the "Configuring the ISDN Dialer Interface" section:

as5200(config-if)# dialer-group 1

as5200(config-if)# exit

Step 4 Assign a pool of IP addresses (in this example, from 172.16.254.1 to 172.16.254.48 for T1 PRI and from 172.16.254.1 to 172.16.254.60 for E1 PRI), all of which are on the same IP subnet as loopback interface 0.

as5200(config)# ip local pool default 172.16.254.1 172.16.254.48

or, for E1 PRI

as5200(config)# ip local pool default 172.16.254.1 172.16.254.60

as5200(config)#

Proceed with the "Configuring the ISDN Dialer Interface" section.

Configuring the ISDN Dialer Interface

The ISDN dialer interface is the parent interface that holds the central protocol characteristics for the two ISDN D channels that are part of dialer rotary-group 1. The previous section "Configuring the ISDN D Channel Serial Interfaces" described how to configure the ISDN D channels on serial interfaces.

To configure the ISDN dialer interface, follow these steps:

Step 1 Enable both D channels to access their core protocol intelligence from interface dialer 1:

as5200(config)# interface Dialer 1

Step 2 Associate all ISDN users with the subnet configured on loopback interface 0:

as5200(config-if)# ip unnumbered Loopback 0

Step 3 Configure PPP on the dialer interface:

as5200(config-if)# encapsulation ppp

Step 4 Assign a common IP address pool. PPP packets coming through an asynchronous line and an ISDN line share this common IP pool. The default address pool is specified in the "Creating the Group Asynchronous Interface" section.

as5200(config-if)# peer default ip address pool default

Step 5 Enable the access server to build dynamic mapping of IP addresses to the ISDN B channels:

as5200(config-if)# dialer in-band

Step 6 Specify the dialer group number for this interface:

as5200(config-if)# dialer-group 1

Step 7 Define the number of seconds that a line is idle before it hangs up. The default is 300 seconds (5 minutes):

as5200(config-if)# dialer idle-timeout 3600

The dialer list command defines the interesting traffic, which is the traffic that resets the idle-timeout or triggers a dial if the line is down and you have a number to send.

Step 8 Enable PPP multilink, which uses multiple bundled B channels from the remote user who is likely to be running BRI with two available B channels:

as5200(config-if)# ppp multilink

Step 9 Enable CHAP and PAP authentication on dialer interface 1:

as5200(config-if)# ppp authentication chap pap

as5200(config-if)# exit

Step 10 Specify which packets reset the idle timer. Ping packets cannot reset the idle timer with this configuration. In this case, any IP packet resets the timer:

as5200(config)# dialer-list 1 protocol ip permit

Proceed with the "Configuring Modem Lines" section.

Configuring Modem Lines

To configure the modem lines, use the following series of commands:

as5200(config)# line 1 48
! or, for E1 PRI
as5200(config)# line 1 60
as5200(config-line)# modem InOut
as5200(config-line)# modem autoconfigure type microcom_hdms
as5200(config-line)# transport input all
as5200(config-line)# stopbits 1
as5200(config-line)# rxspeed 57600 (or rxspeed 64000 for E1 PRI)
as5200(config-line)# txspeed 57600 (or txspeed 64000 for E1 PRI)
as5200(config-line)# flowcontrol hardware
as5200(config-line)# login local
as5200(config-line)# autoselect during-login
as5200(config-line)# autoselect ppp

Proceed with the "Defining a Routing Protocol and Domain Name" section.

Defining a Routing Protocol and Domain Name

To complete the configuration, you must define a routing protocol and a domain name. You also can specify a domain name server to resolve host names and IP addresses.

as5200(config)# router eigrp 202
as5200(config-router)# network 172.16.0.0
as5200(config-router)# exit
as5200(config)# ip domain-name cisco.com
as5200(config)# ip name-server 172.16.99.99

Proceed with the "Enabling DNS and NBNS Services for PPP Users" section.

Enabling DNS and NBNS Services for PPP Users

Dialin clients using PPP and applications such as CiscoRemote, Windows NT, and Windows '95 need domain name service (DNS) and NetBIOS Name Service (NBNS) address information as described in RFC 1877. Use the following procedure to enter parameters to enable Telnet users to gather this information transparently as part of the PPP negotiation:

Step 1 Specify the list of available DNS servers:

as5200(config)# async-bootp dns-server 172.16.10.100 172.16.39.67

Step 2 Specify the list of available NBNS servers:

as5200(config)# async-bootp nbns-server 172.16.200.200 172.16.201.200

as5200(config)# exit

Step 3 This completes the IP configuration. Save the running configuration to startup configuration:

as5200# copy running-config startup-config

#########[OK]

as5200#

Proceed with the "Configuring the Access Server to Accept Dialin Calls from the Cisco 753 and Cisco 1004" section if you want to enable ISDN and analog calls to enter the access server from a Cisco 753 or Cisco 1004 router.

Configuring the Access Server to Accept Dialin Calls from the Cisco 753 and Cisco 1004

This section explains how to enable a remote ISDN user to dial in to an access server through a Cisco 753 or Cisco 1004 on an IP network. See Figure 3-4.

Figure 3-4 : Sample Addressing Scheme for ISDN Routers Dialing in to the Access Server

aaa new-model
aaa authentication login default local
aaa authentication login console none
aaa authentication ppp default if-needed local
username jojackso password 
username wmays password 
username bruth password 
username hwilliam password 
!

isdn switch-type primary-5ess

! T1 PRI controller configuration

controller T1 0
 framing esf
 linecode b8zs
 clock source line primary
 pri-group timeslots 1-24
!
controller T1 1
 framing esf
 linecode b8zs
 clock source line secondary
 pri-group timeslots 1-24

or

! E1 PRI controller configuration

controller E1 0
 framing crc4
 linecode hdb3
 clock source line primary
 pri-group timeslots 1-31
!
controller E1 1
 framing crc4
 linecode hdb3
 clock source line secondary
 pri-group timeslots 1-31


!
interface Serial0:23
! or, for E1 PRI
interface Serial0:30
 isdn incoming-voice modem
 dialer rotary-group 1
!
interface Serial1:23 
! or, for E1 PRI
interface Serial1:30

 isdn incoming-voice modem
 dialer rotary-group 1
!
interface Loopback0
 ip address 172.16.254.254 255.255.255.0
!
interface Ethernet0
 ip address 172.16.1.1 255.255.255.0
!
interface Group-Async1
 ip unnumbered Loopback0
 ip tcp header-compression passive
 encapsulation ppp
 async mode interactive
 peer default ip address pool default
 dialer-group 1
 ppp authentication chap pap default 
 group-range 1 48
! or, for E1 PRI
 group-range 1 60
!
interface Dialer1
 ip unnumbered Loopback0
 encapsulation ppp
 peer default ip address pool default
 ip local pool default 172.16.254.1 172.16.254.48
! or, for E1 PRI
 ip local pool default 172.16.254.1 172.16.254.60 
 dialer in-band
 dialer-group 1
 dialer idle-timeout 3600
 ppp multilink
 ppp authentication chap pap default 

line 1 48
! or, for E1 PRI
line 1 60
 autoselect during-login
 autoselect pppmodem InOut
 modem autoconfigure type microcom_hdms

 transport input all
 stopbits 1
 rxspeed 57600 (64000 for E1 PRI)
 txspeed 57600 (64000 for E1 PRI)
 flowcontrol hardware
 login local

as5200 eigrp 202
 network 172.16.0.0

ip domain-name cisco.com
ip name-server 172.16.99.99
!
async-bootp dns-server 172.16.10.100 172.16.39.67
async-bootp nbns-server 172.16.200.200 172.16.201.200

dialer-list 1 protocol ip permit
ipx routing 0060.3ef1.6f74

interface Loopback0
 ipx network FEFEFE

interface Ethernet 0
 ipx network 123ABCD encapsulation SAP

interface Group-Async1
 group-range 1 48
! or, for E1 PRI
 group-range 1 60

 ipx ppp-client Loopback0

interface Dialer1
 ipx unnumbered loopback 0
 dialer map ipx FEFEFE.0000.0c00.1234 name stock
 dialer map ipx FEFEFE.0000.0c00.4567 name john
 dialer map ipx FEFEFE.0000.0c00.89AB name cisco
 dialer-list 1 protocol ipx permit

appletalk routing
appletalk virtual-net 2 ATCP Zone
appletalk cable-range 1-1 1.120
appletalk zone Ethernet