© 1999, Cisco Systems, Inc. 13-1 Chapter 13 Completing an ISDN BRI Call.

© 1999, Cisco Systems, Inc. 13-1

Chapter 13

Completing an ISDN BRI Call

© 1999, Cisco Systems, Inc. www.cisco.com ICND—13-2

Objectives Objectives

Upon completion of this chapter, you will be able to perform the following tasks:� Describe the components that make up ISDN

connectivity� Configure ISDN BRI and legacy dial-on-

demand routing (DDR)� Verify DDR operation


What is ISDN?

Providernetwork

Digital PBX

Small office

Home office

Voice, data, video, and special services

Telecommuter

Central site


Standards from the ITU (formerly CCITT)

ISDN Standards

Protocol Key Examples

Telephone Network and ISDN

ISDN Concepts, Aspects, and Interfaces

Switching and Signaling

I-Series

Q.921—LAPD (Link Access Procedure on the D channel)

Q.931—ISDN Network Layer betweenTerminal and Switch

Q-Series

Issue

E-SeriesE.163—International Telephone

Numbering PlanE.164—International ISDN Addressing

I.100 Series—Concepts, Structures, Terminology

I.400—User-Network Interfaces (UNIs)


BRI and PRI are used globally for ISDN

Channel Mostly Used for

B Circuit-switched data (HDLC, PPP)

Capacity

64 kbps

D 2BServiceprovidernetwork

NT1

ISDN Access Options

Signaling information (LAPD)D 16/64 kbps

CSU/DSU

23 or 30B

BRI

PRI

D


3311

BRI Call ProcessingBRI Call Processing

ISDNservice provider

44

B channel(s)

D channel/SS7 signaling

22 SS7

ISDNSwitch

ISDNSwitch


ISDN Functions and Reference Points

� Functions are devices or hardware

� Reference points are demarcations or interfaces

NT1

TATE2

TE1 NT2

Local loop

Existing Terminal

ISDN Terminal

Terminal Adapter

R

S T UServiceprovidernetwork


Cisco ISDN BRI Interfaces

TA

S/T

R

Serviceprovidernetwork

Native ISDN interface—int bri 0

Nonnative ISDN interface—int serial 0(EIA/TIA-232, V.35, X.21)

NT1

NT1S0

S/T

bri 0

U

bri 0

TE1

NT1

TE1 TE2


Many providers and switch types

Services vary by regions and countries

ISDN Switch Types

CO CO

S

S

S

S S

S S

S S

S

S

S S


Router(config)#isdn switch-type switch-type

Configuring ISDN BRI

� Specifies the type of ISDN switch with which the router communicates

� Other configuration requirements vary for specific providers

Step 1: Specify the ISDN switch type

Router(config-if)#isdn switch-type switch-type


� Sets a B channel SPID required by many service providers

Configuring ISDN BRI (cont.)

Step 2: (Optional) Setting SPIDs

� Sets a SPID for the second B channel

Router(config-if)#isdn spid1 spid-number [ ldn ]

Router(config-if)#isdn spid2 spid-number [ ldn ]


Written Exercise

Local LoopCustomer Premises Service Provider

BRI 0

S 0

Label the functional elements and reference points


Written Exercise: Answers

Local LoopCustomer Premises Service Provider

NT1BRI 0

S 0NT1TA

U

U

S/T

S/TR

Label the functional elements and reference points


What Is Dial-on-Demand Routing?

PSTN

ISDNI need to send data to Dallas.

DallasCorporate

Chicago

� Connect when needed

� Disconnect when finished

� ISDN or PSTN


When to Use DDR

Headquarters

Telecommuter

Vendor� Periodic connections

� Small amounts of data


Generic DDR OperationGeneric DDR Operation

1. Route to destination is determined

DCE

“Interesting” packet arrives




2. Interesting packets dictate DDR call

DCE






3. Dialer information is looked up


Dial connection

ISDN or Basic

Service

DCE




3. Dialer information is looked up

4. Traffic is transmitted

5. Call is terminated



Dial connection

ISDN or Basic

Service

DCE


Configuring Legacy DDRConfiguring Legacy DDR

1 Define static routes—What route do I use?


DCE



1

2

Define static routes—What route do I use?

Specify interesting traffic—What traffic enables the link?


DCE


3

1

2

Define static routes—What route do I use?

Specify interesting traffic—What traffic enables the link?

Configure the dialer information—What number do I call?



Dial connection

ISDN or Basic

Service

DCE


Task 1: Defining Static Routes (Route to Destination)

Network prefixand prefix mask

Specify address of next hop router

ip route 10.40.0.0 255.255.0.0 10.1.0.1

ip route 10.10.0.0 255.255.0.0 10.1.0.2ip route 10.20.0.0 255.255.0.0 10.1.0.2

CentralISDNHome

10.1.0.1

bri 05551000

bri 05552000

10.1.0.2 Subnets 10.10.0.0 10.20.0.0

Subnet 10.40.0.0


Task 2: Specifying Interesting Traffic (What Enables the Connection?)

dialer-list 1 protocol ip permit

dialer-list 1 protocol ip list 101

access-list 101 deny tcp any any eq ftpaccess-list 101 deny tcp any any eq telnetaccess-list 101 permit ip any any

Any IP traffic will initiate the link

Any IP traffic, except FTP and Telnet, will initiate the link

Deny FTPDeny Telnet

• Without Access Lists

• With Access Lists (for better control)


Task 3: Configuring the Dialer Information

Applies rules defined by dialer-list to individual interfaces

hostname Home! isdn switch-type basic-5ess!interface BRI0 ip address 10.1.0.1 255.255.255.0 encapsulation ppp dialer idle-timeout 180 dialer map ip 10.1.0.2 name Central 5552000 dialer-group 1 no fair-queue ppp authentication chap!router ripnetwork 10.0.0.0!no ip classlessip route 10.10.0.0 255.255.0.0 10.1.0.2ip route 10.20.0.0 255.255.0.0 10.1.0.2!dialer-list 1 protocol ip permit

Both valuesmust match


Central

Task 3: Configuring theDialer Information (cont.)

How do I get to subnetwork 10.10.0.0?

Number to dial

Remote host nameUsed for PPP CHAP

interface BRI0 ip address 10.1.0.1 255.255.255.0 encapsulation ppp dialer idle-timeout 180 dialer map ip 10.1.0.2 name Central 5552000 dialer-group 1 no fair-queue ppp authentication chap

ISDNHome

10.1.0.1

bri 05551000

bri 05552000

10.1.0.2 Subnets 10.10.0.0 10.20.0.0


Legacy DDR Configuration Tasks Summarized

1

3

2

hostname Home!isdn switch-type basic-5ess!interface BRI0 ip address 10.1.0.1 255.255.255.0 encapsulation ppp dialer idle-timeout 180 dialer map ip 10.1.0.2 name Central 5552000 dialer-group 1 no fair-queue ppp authentication chap!router ripnetwork 10.0.0.0!no ip classlessip route 10.10.0.0 255.255.0.0 10.1.0.2ip route 10.20.0.0 255.255.0.0 10.1.0.2dialer-list 1 protocol ip permit!


� Establishes the amount of traffic on link before a second link is enabled

� Establishes the idle time before disconnect

Router(config-if)#dialer idle-timeout seconds

Optional Legacy DDR Commands

Router(config-if)#dialer load-threshold load [ outbound | inbound | either ]


access-list 101 permit tcp any any eq smtpaccess-list 101 permit tcp any any eq telnetdialer-list 1 list 101!ip route 192.168.12.0 255.255.255.0 10.108.126.2ip route 192.168.14.0 255.255.255.0 10.108.126.2!interface bri 0ip address 10.108.126.1 255.255.255.0dialer-group 1dialer map ip 10.108.126.2 name B 5551234!dialer idle-timeout 300

Access list defininginteresting packets on Cisco A

Static routes to reach destination

Interface configuration for DDR

Time to waitbefore dropping call

Legacy DDR Using ACLs Configuration Example

Subnets 192.168.12.0 192.168.14.0

10.108.126.1 10.108.126.2

ISDNA B


Router#ping or telnet

Router#show dialer

Router#show isdn active

Router#show isdn status

•Triggers a link (assuming it is part of interesting traffic)

•Displays current status of link, including amount of time link is connected

•When using ISDN, displays call status while call is in progress

•Displays the status of an ISDN connection

Router#show ip route•Displays all routes, including static routes

Verifying Legacy DDR and ISDN Operation

Verifying Legacy DDR and ISDN Operation


Router#debug dialer•Shows call setup and teardownactivity

•Clears currently establishedconnections from the interface

Router#debug isdn q921 •Shows ISDN layer 2 messages

Router(config-if)#shutdown

Verifying Legacy DDR and ISDN Operation (cont.)

Verifying Legacy DDR and ISDN Operation (cont.)

•Shows ISDN call setup and teardown activity

Router#debug isdn q931


Visual ObjectiveVisual Objective

pod ro’s bri0A 10.130.0.2B 10.135.0.2C 10.140.0.2D 10.145.0.2E 10.150.0.2F 10.155.0.2G 10.160.0.2H 10.165.0.2I 10.170.0.2J 10.175.0.2K 10.180.0.2L 10.185.0.2

core_ server10.1.1.1

wg_sw_a10.2.2.11

wg_sw_l10.13.13.11

wg_pc_a10.2.2.12

wg_pc_l10.13.13.12

wg_ro_ae0/1 e0/2

e0/2e0/1

e0

e0

fa0/23

core_sw_a10.1.1.2

wg_ro_l

core_ro10.1.1.3

fa0/24 fa0/0

ISDN

...

10.13.13.3

PPP with CHAP

PPP with CHAP

10.2.2.3

s3/0 (pri)

10.130.1/24 … 10.185.0.1/24

bri0

10.185.0.2/24

bri0 10.130.0.2/24


Summary

After completing this chapter, you should be able to perform the following tasks:� Identify the components in an ISDN network � Configure ISDN BRI and legacy dial-on-

demand routing (DDR)� Verify DDR operation using show and debug

commands


Review QuestionsReview Questions

1. Differentiate between a native and a nonnative ISDN BRI interface.

2. How do you configure a Cisco router to interface to an ISDN switch? Why do you need to be specific about the switch type?

3. List and describe the three tasks associated with configuring DDR.

4. Why might you choose to use an access list to define interesting traffic for DDR?

Date post:	12-Jan-2016
Category:	Documents
Upload:	arabella-marjory-bell
View:	219 times
Download:	0 times

© 1999, Cisco Systems, Inc. 13-1 Chapter 13 Completing an ISDN BRI Call.

Documents