establlishing serial point to point connection

8/14/2019 Establlishing Serial Point to Point Connection

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2000, Cisco Systems, Inc. 12-1

Chapter 12

Establishing SerialPoint-to-PointConnections


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2000, Cisco Systems, Inc. www.cisco.com ICNDv 1.0a12-2


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Upon completion of this chapter, you will beable to perform the following tasks:

Configure HDLC and PPP protocols on a

serial WAN connection

Configure PAP and CHAP authentication on aPPP connection

Verify proper point-to-point HDLC and PPPconfiguration

Objectives


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WAN Overview

ServiceProvider

WANs connect sites

Connection requirements vary depending on

user requirements and cost


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Leased Line

Synchronous serial

Telephone

CompanyCircuit-switched

Asynchronous serial,

ISDN Layer 1

Service

ProviderPacket-switched

Synchronous serial

WAN Connection Types:Layer 1


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Point-to-point orcircuit-switched

connection

CO Switch

Customer PremisesEquipment

Demarcation

Local Loop

WAN service provider toll network

Trunks and switches

Interfacing WAN ServiceProviders

Provider assigns connection parameters tosubscriber

S S

S SS

S S


7/602000, Cisco Systems, Inc. www.cisco.com ICNDv 1.0a12-7

Serial Point-to-PointConnections

Router connections

Network connections at the CSU/DSU

EIA/TIA-232 EIA/TIA-449 EIA-530V.35 X.21

CSU/DSU

End userdevice

ServiceProvider

DTE

DCE



Leased Line

Circuit-switched

PPP, SLIP, HDLC

HDLC, PPP, SLIP

Packet-switched

X.25, Frame Relay, ATM

Typical WAN EncapsulationProtocols: Layer 2

Telephone

Company

Service

Provider



Flag Address Control Data FCS Flag

HDLC

Supports only single protocol environments

Flag Address Control Proprietary Data FCS Flag

Cisco HDLC

HDLC Frame Format

Ciscos HDLC has a proprietary data field to supportmultiprotocol environments



HDLC Command

Router(config-if)#encapsulation hdlc

Enable hdlc encapsulation

HDLC is the default encapsulation onsynchronous serial interfaces



PPP EncapsulationTCP/IPNovell IPXAppleTalk

Multiple protocolencapsulations using

NCPs in PPP

PPP can carry packets from several protocol suitesusing Network Control Programs

PPP controls the setup of several link options usingLCP

Link setup and controlusing LCP in PPP

An Overview of PPP


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Feature How It Operates Protocol

Authentication PAP

CHAPPerform Challenge Handshake

Require a password

CompressionCompress data at source;reproduce data atdestination

Stacker orPredictor

ErrorDetection

Avoid frame looping

Monitor data dropped on link

Multilink Load balancing acrossmultiple links

MultilinkProtocol (MP)

PPP LCP Configuration Options

Quality

Magic Number



PPP Authentication Overview

Two PPP authentication protocols:PAP and CHAP

PPP Session Establishment1 Link Establishment Phase2 Optional Authentication Phase3 Network-Layer Protocol Phase

Dialup orCircuit-Switched

Network

S l i PPP A h i i



Passwords sent in clear text

Peer in control of attempts

Selecting a PPP AuthenticationProtocol

Remote Router(SantaCruz)

Central-Site Router(HQ)

Hostname: santacruzPassword: boardwalk

username santacruzpassword boardwalk

PAP2-Way Handshake

santacruz, boardwalk

Accept/Reject

S l i PPP A h i i



Selecting a PPP AuthenticationProtocol (cont.)

Remote Router(SantaCruz)

Central-Site Router(HQ)

Hostname: santacruzPassword: boardwalk

username santacruzpassword boardwalk

CHAP3-Way Handshake

Challenge

Response

Accept/Reject

Use secret known only to authenticatorand peer



Configuring PPP andAuthentication Overview

ServiceProvider

Verify whoyou are.

Router to BeAuthenticated(The router that initiated the call.)

ppp encapsulation

hostname

username / password

ppp authentication

Authenticating Router(The router that received the call.)

ppp encapsulation

hostname

username / password

ppp authentication

Enabling PPP

Enabling PPP Authentication

Enabling PPP

Enabling PPP Authentication



Configuring PPP

Router(config-if)#encapsulation ppp

Enable PPP encapsulation



Configuring PPP Authentication

Router(config)#hostname name

Assigns a host name to your router

Router(config)#username name passwordpassword

Identifies the username and password ofauthenticating router

C fi i PPP A th ti ti



Configuring PPP Authentication(cont.)

Router(config-if)#ppp authentication{chap | chap pap | pap chap | pap}

Enables PAP and/or CHAP authentication



Configuring CHAP Example

hostname left

username right password sameone

!

int serial 0

ip address 10.0.1.1 255.255.255.0

encapsulation ppp

ppp authentication CHAP

hostname right

username left password sameone

!

int serial 0

ip address 10.0.1.2 255.255.255.0

encapsulation ppp

ppp authentication CHAP

Leftrouter

Rightrouter

PSTN/ISDN



Verifying HDLC and PPPEncapsulation Configuration

Router#show interface s0

Serial0 is up, line protocol is up

Hardware is HD64570

Internet address is 10.140.1.2/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255

Encapsulation PPP, loopback not set, keepalive set (10 sec)

LCP Open

Open: IPCP, CDPCPLast input 00:00:05, output 00:00:05, output hang never

Last clearing of "show interface" counters never

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

38021 packets input, 5656110 bytes, 0 no bufferReceived 23488 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

38097 packets output, 2135697 bytes, 0 underruns

0 output errors, 0 collisions, 6045 interface resets

0 output buffer failures, 0 output buffers swapped out

482 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up


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Verifying PPP Authentication with thedebug ppp authenticationCommand

4d20h: %LINK-3-UPDOWN: Interface Serial0, changed state to up

4d20h: Se0 PPP: Treating connection as a dedicated line

4d20h: Se0 PPP: Phase is AUTHENTICATING, by both

4d20h: Se0 CHAP: O CHALLENGE id 2 len 28 from left"

4d20h: Se0 CHAP: I CHALLENGE id 3 len 28 from right"

4d20h: Se0 CHAP: O RESPONSE id 3 len 28 from left"

4d20h: Se0 CHAP: I RESPONSE id 2 len 28 from right"

4d20h: Se0 CHAP: O SUCCESS id 2 len 44d20h: Se0 CHAP: I SUCCESS id 3 len 4

4d20h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0,

changed state to up

debug ppp authenticationsuccessful CHAP output

Leftrouter

Rightrouter

ServiceProvider


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Visual Objective

pod ros s0A 10.140.1.2B 10.140.2.2C 10.140.3.2D 10.140.4.2E 10.140.5.2

F 10.140.6.2G 10.140.7.2H 10.140.8.2I 10.140.9.2J 10.140.10.2K 10.140.11.2L 10.140.12.2

s1/0 - s2/310.140.1.1 10.140.12.1

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

LL

s010.140.1.2

...

10.13.13.3

s0

10.140.12.2

PPP with CHAP

PPP with CHAP

10.2.2.3


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After completing this chapter, you should beable to perform the following tasks:

Select an appropriate WAN connectionbased on your requirements

Configure HDLC and PPP encapsulationmethods on your point-to-point WAN

connection

Configure CHAP authentication on a PPPconnection

Summary


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1. What are three types of WAN connectionsyou can enable on a Cisco router?

2. What are two examples of point-to-pointencapsulation protocols and what are theadvantages of each?

3. What are some of the PPP LCP options?

Review Questions


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2000, Cisco Systems, Inc. 12-27

Chapter 12

Establishing SerialPoint-to-PointConnections


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Objectives

Upon completion of this chapter, you willbe able to perform the following tasks:

Describe the components that make up ISDNconnectivity

Configure ISDN BRI and legacy dial-on-demand routing (DDR)

Verify DDR operation


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What is ISDN?

Providernetwork

DigitalPBX

Small office

Home office

Voice, data, video, and special services

Telecommuter

Central site


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Standards from the ITU (formerly CCITT)

ISDN Standards

Protocol Key Examples

TelephoneNetwork andISDN

ISDN Concepts,Aspects, andInterfaces

Switching andSignaling

I-Series

Q.921LAPD (Link Access Procedureon the D channel)

Q.931ISDN Network Layer betweenTerminal and Switch

Q-Series

Issue

E-SeriesE.163International Telephone

Numbering PlanE.164International ISDN Addressing

I.100 SeriesConcepts, Structures,Terminology

I.400User-Network Interfaces (UNIs)


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BRI and PRI are used globally for ISDN

Channel Mostly Used for

B Circuit-switched data (HDLC, PPP)

Capacity

64 kbps

D 2BService

providernetwork

NT1

ISDN Access Options

Signaling information (LAPD)D 16/64 kbps

CSU/DSU

23 or 30B

BRI

PRI

D


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31

BRI Call Processing

ISDN

service provider

4

B channel(s)

D channel/SS7 signaling

2 SS7

ISDNSwitch

ISDNSwitch

ISDN Functions and Reference


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ISDN Functions and ReferencePoints

Functions are devices orhardware

Reference points aredemarcations or interfaces

NT1

TATE2

TE1 NT2

Localloop

ExistingTerminal

ISDN Terminal

Terminal

Adapter

R

S T UService

providernetwork


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Cisco ISDN BRI Interfaces

TA

S/T

R

Service

provider

network

Native ISDN interfaceint bri 0

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

NT1

NT1S0

S/T

bri 0

U

bri 0

TE1

NT1

TE1 TE2


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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


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

Configuring ISDN BRI

Specifies the type of ISDN switch withwhich the router communicates

Other configuration requirements vary forspecific providers

Step 1: Specify the ISDN switch type

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


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Sets a B channel SPID required by many serviceproviders

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 ]


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Written Exercise

Local LoopCustomer Premises Service Provider

BRI 0

S 0

Label the functional elements and reference points

W i E i A


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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

Wh I Di l D d


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What Is Dial-on-DemandRouting?

PSTN

ISDNI need to senddata to Dallas.

DallasCorporate

Chicago

Connect when needed

Disconnect when finished

ISDN or PSTN


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When to Use DDR

Headquarters

Telecommuter

VendorPeriodic connections

Small amounts of data


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Generic DDR Operation

1. Route to destination is determined

DCE

Interestingpacket arrives


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2. Interesting packets dictate DDR call

DCE



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3. Dialer information is looked up


Dial connection

ISDN orBasic

Service

DCE


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3. Dialer information is looked up

4. Traffic is transmitted

5. Call is terminated



Dial connection

ISDN orBasic

Service

DCE


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Configuring Legacy DDR

1 Define static routesWhat route do I use?


DCE


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3

1

2

Define static routesWhat route do I use?

Specify interesting trafficWhat trafficenables the link?

Configure the dialer informationWhatnumber do I call?

Configuring DDR


Dial connection

ISDN orBasic

Service

DCE


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Task 2: Specifying Interesting Traffic


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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 telnet

access-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


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Task 3: Configuring theDialer Information

Applies rulesdefined by dialer-listto individual

interfaces

hostname Home

!

isdn switch-type basic-5ess

!

username central password cisco

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 classless

ip route 10.10.0.0 255.255.0.0 10.1.0.2

ip route 10.20.0.0 255.255.0.0 10.1.0.2

!


Both valuesmust match

Task 3: Configuring the


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Central

Task 3: Configuring theDialer Information (cont.)

How do I get tosubnetwork 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 180dialer map ip 10.1.0.2 name Central 5552000

dialer-group 1

no fair-queue


ISDNHome10.1.0.1

bri 0

5551000

bri 0

5552000

10.1.0.2 Subnets10.10.0.010.20.0.0

Legacy DDR Configuration


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Legacy DDR ConfigurationTasks Summarized

1

3

2

hostname Home!

isdn switch-type basic-5ess

!

username central password cisco

interface BRI0

ip address 10.1.0.1 255.255.255.0

encapsulation pppdialer idle-timeout 180

dialer map ip 10.1.0.2 name Central 5552000

dialer-group 1

no fair-queue


!

router ripnetwork 10.0.0.0

!

no ip classless

ip route 10.10.0.0 255.255.0.0 10.1.0.2

ip route 10.20.0.0 255.255.0.0 10.1.0.2


!

Optional Legacy DDR


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Establishes the amount of traffic on linkbefore a second link is enabled

Establishes the idle time before disconnect

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

Optional Legacy DDRCommands

ter(config-if)#dialer load-threshold load

utbound | inbound | either ]

Legacy DDR Using ACLs


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access-list 101 permit tcp any any eq smtp

access-list 101 permit tcp any any eq telnet

dialer-list 1 list 101

!

ip route 192.168.12.0 255.255.255.0 10.108.126.2

ip route 192.168.14.0 255.255.255.0 10.108.126.2

!

interface bri 0

ip address 10.108.126.1 255.255.255.0

dialer-group 1

dialer map ip 10.108.126.2 name B 5551234

!

dialer idle-timeout 300

Access list defininginteresting packetson Cisco A

Static routes to

reach destination

Interfaceconfiguration forDDR

Time to wait

before droppingcall

Legacy DDR Using ACLsConfiguration Example

Subnets192.168.12.0192.168.14.0

10.108.126.1 10.108.126.2

ISDNA B

Verifying Legacy DDR and


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Router#ping or telnet

Router#show dialer

Router#show isdn active

Router#show isdn status

Triggers a link (assuming it is partof interesting traffic)

Displays current status of link, includingamount of time link is connected

When using ISDN, displays callstatus while call is in progress

Displays the status of an ISDNconnection

Router#show ip route Displays all routes, including static

routes

Verifying Legacy DDR andISDN Operation

Verifying Legacy DDR and


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Router#debug dialer Shows call setup and teardown

activity

Clears currently establishedconnections from the interface

Router#debug isdn q921 Shows ISDN layer 2 messages

Router(config-if)#shutdown

Verifying Legacy DDR andISDN Operation (cont.)

Shows ISDN call setup andteardown activityRouter#debug isdn q931


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Review Questions

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

2. How do you configure a Cisco router to

interface to an ISDN switch? Why do youneed 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?

establlishing serial point to point connection

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