wide area network(wan)

Wide Area Network

• WAN protocols

• WAN solutions

• Interface and cabling

• configuration

High-Level Data Link Control

• HDLC is the most important data link control protocol

• Widely used which forms basis of other data link control protocols

• Most WAN protocols use HDLC as data link control protocols

HDLC Station Types• Primary station (Unbalanced)

– Controls operation of link– Frames issued are called commands– Maintains separate logical link to each secondary

station

• Secondary station– Under control of primary station– Frames issued called responses

• Combined station (Balanced)– May issue commands and responses

HDLC Link Configurations

• Unbalanced– One primary and one or more secondary

stations– Supports full duplex and half duplex

• Balanced– Two combined stations– Supports full duplex and half duplex

HDLC Transfer Modes (1)

• Normal Response Mode (NRM)– Unbalanced configuration– Primary initiates transfer to secondary– Secondary may only transmit data in response

to command from primary– Used on multi-drop lines– Host computer as primary– Terminals as secondary


• Asynchronous Balanced Mode (ABM)– Balanced configuration– Either station may initiate transmission without

receiving permission– Most widely used– No polling overhead


• Asynchronous Response Mode (ARM)– Unbalanced configuration– Secondary may initiate transmission without

permission form primary– Primary responsible for line– rarely used

Frame Structure

• Synchronous transmission

• All transmissions in frames

• Single frame format for all data and control exchanges

Frame Structure Diagram

Flag Fields

• Delimit frame at both ends• 01111110• May close one frame and open another• Receiver hunts for flag sequence to synchronize• Bit stuffing used to avoid confusion with data containing

01111110– 0 inserted after every sequence of five 1s– If receiver detects five 1s it checks next bit– If 0, it is deleted– If 1 and seventh bit is 0, accept as flag– If sixth and seventh bits 1, sender is indicating abort

Bit Stuffing

• Example with possible errors

Address Field

• Identifies secondary station that sent or will receive frame• Usually 8 bits long• May be extended to multiples of 7 bits

– LSB of each octet indicates that it is the last octet (1) or not (0)

• All ones (11111111) is broadcast

Control Field

• Different for different frame type– Information - data to be transmitted to user (next l

ayer up)• Flow and error control piggybacked on information fra

mes

– Supervisory - ARQ when piggyback not used– Unnumbered - supplementary link control

• First one or two bits of control filed identify frame type

• Remaining bits explained later

Control Field Diagram

Poll/Final Bit

• Use depends on context

• Command frame– P bit– 1 to solicit (poll) response from peer

• Response frame– F bit– 1 indicates response to soliciting command

Information Field

• Only in information and some unnumbered frames

• Must contain integral number of octets

• Variable length

Frame Check Sequence Field

• FCS

• Error detection

• 16 bit CRC

• Optional 32 bit CRC

HDLC Operation

• Exchange of information, supervisory and unnumbered frames

• Three phases– Initialization– Data transfer– Disconnect

Supervisory Frames• Receive Ready --- RR

• Receive Not Ready --- RNR

• Reject --- REJ

• Selective Reject --- SREJ

Unnumbered Frames• Control operations

• Set up and take down communications link

• Maintenance

The unnumbered format.

SABME (SetAsynchronousBalanced Mode)

1111P110 C Request logical connection

DM (DisconnectMode)

1111F000 R Unable to establish or maintain logicalconnection

UI (UnnumberedInformation)

1100P000 C Used for unacknowledged informationtransfer

DISC(Disconnect)

1100P010 C Terminate logical connection

UA (UnnumberedAck )

1100F110 R Acknowledge SABME or DISC

FRMR (FrameReject )

1110F001 R Unacceptable frame report

XID (ExchangeIdentification)

1111*101 C/R Exchange identification information

Operations

• Connection Establishment– SABME ----> – <----- UA

• Data Transfer– I-frames and – S-frames for flow and error control.

• Disconnect– Either entity can issue a DISC.

Examples of Operation (1)

Examples of Operation (2)

Point to Point Data Link Control

• one sender, one receiver, one link: easier than broadcast link:

– no Media Access Control

– no need for explicit MAC addressing

– e.g., dialup link, ISDN line

• popular point-to-point DLC protocols:

– PPP (point-to-point protocol)

– HDLC: High level data link control

PPP Design Requirements [RFC 1557]• packet framing: encapsulation of network-layer datagram in

data link frame – carry network layer data of any network layer protocol (n

ot just IP) at same time– ability to demultiplex upwards

• bit transparency: must carry any bit pattern in the data field• error detection (no correction)• connection liveness: detect, signal link failure to network la

yer• network layer address negotiation: endpoint can learn/config

ure each other’s network address

PPP non-requirements

• no error correction/recovery

• no flow control

• out of order delivery OK

• no need to support multipoint links (e.g., polling)

Error recovery, flow control, data re-ordering all relegated to higher layers!|

PPP Data Frame• Flag: delimiter (framing)

• Address: does nothing (only one option)

• Control: does nothing; in the future possible multiple control fields

• Protocol: upper layer protocol to which frame delivered (eg, PPP-LCP, IP, IPCP, etc)

PPP Data Frame

• info: upper layer data being carried

• check: cyclic redundancy check for error detection

Byte Stuffing

• “data transparency” requirement: data field must be allowed to include flag pattern <01111110>– Q: is received <01111110> data or flag?

• Sender: adds (“stuffs”) extra < 01111110> byte after each < 01111110> data byte

• Receiver: – two 01111110 bytes in a row: discard first byte,

continue data reception– single 01111110: flag byte

Byte Stuffing

flag bytepatternin datato send

flag byte pattern plusstuffed byte in transmitted data

PPP Data Control ProtocolBefore exchanging network-l

ayer data, data link peers must

• configure PPP link (max. frame length, authentication)

• learn/configure network layer information

– for IP: carry IP Control Protocol (IPCP) msgs (protocol field: 8021) to configure/learn IP address

Other DLC Protocols (LAPB,LAPD)

• Link Access Procedure, Balanced (LAPB)– Part of X.25 (ITU-T)– Subset of HDLC - ABM– Point to point link between system and packet switching

network node

• Link Access Procedure, D-Channel– ISDN (ITU-D)– ABM– Always 7-bit sequence numbers (no 3-bit)– 16 bit address field contains two sub-addresses

• One for device and one for user (next layer up)

Other DLC Protocols (LLC)

• Logical Link Control (LLC)– IEEE 802– Different frame format– Link control split between medium access layer (MAC)

and LLC (on top of MAC)– No primary and secondary - all stations are peers– Two addresses needed

• Sender and receiver

– Error detection at MAC layer• 32 bit CRC

– Destination and source access points (DSAP, SSAP)

Other DLC Protocols (Frame Relay) (1)

• Streamlined capability over high speed packet switched networks

• Used in place of X.25• Uses Link Access Procedure for Frame-

Mode Bearer Services (LAPF)• Two protocols

– Control - similar to HDLC– Core - subset of control

Other DLC Protocols (Frame Relay) (2)

• ABM

• 7-bit sequence numbers

• 16 bit CRC

• 2, 3 or 4 octet address field– Data link connection identifier (DLCI)– Identifies logical connection

• More on frame relay later

Other DLC Protocols (ATM)

• Asynchronous Transfer Mode

• Streamlined capability across high speed networks

• Not HDLC based

• Frame format called “cell”

• Fixed 53 octet (424 bit)

• Details later

X.25

• 1976• Interface between host and packet switched

network• Almost universal on packet switched networks and

packet switching in ISDN• Defines three layers

– Physical– Link– Packet

X.25 - Physical

• Interface between attached station and link to node

• Data terminal equipment DTE (user equipment)

• Data circuit terminating equipment DCE (node)

• Uses physical layer specification X.21

X.25 - Link

• Link Access Protocol Balanced (LAPB)– Subset of HDLC– Point to point link between system and packet

switching network node

X.25 - Packet

• External virtual circuits

• Logical connections (virtual circuits) between subscribers

X.25 Use of Virtual Circuits

Virtual Circuit Service

• Virtual Call– Dynamically established

• Permanent virtual circuit– Fixed network assigned virtual circuit

Virtual Call

Packet Format

Multiplexing

• DTE can establish 4095 simultaneous virtual circuits with other DTEs over a single DTC-DCE link

• Packets contain 12 bit virtual circuit number

Virtual Circuit Numbering

Flow and Error Control

• HDLC at the link layer

• Sliding window at the VC layer

Packet Sequences

• Complete packet sequences• Allows longer blocks of data across network with

smaller packet size without loss of block integrity• A packets

– M bit 1, D bit 0

• B packets– The rest

• Zero or more A followed by B

Reset and Restart

• Reset– Reinitialize virtual circuit– Sequence numbers set to zero– Packets in transit lost– Up to higher level protocol to recover lost packets– Triggered by loss of packet, sequence number error,

congestion, loss of network internal virtual circuit

• Restart– Equivalent to a clear request on all virtual circuits– E.g. temporary loss of network access

Asynchronous Transfer Mode (ATM)

Protocol Architecture

• Similarities between ATM and packet switching– Transfer of data in discrete chunks– Multiple logical connections over single physical

interface

• In ATM flow on each logical connection is in fixed sized packets called cells

• Minimal error and flow control– Reduced overhead

• Data rates (physical layer) 25.6Mbps to 622.08Mbps

Protocol Architecture (diag)

ATM Logical Connections

• Virtual channel connections (VCC)• Analogous to virtual circuit in X.25• Basic unit of switching• Between two end users• Full duplex• Fixed size cells• Data, user-network exchange (control) and network-

network exchange (network management and routing)• Virtual path connection (VPC)

– Bundle of VCC with same end points

ATM Connection Relationships

Call Establishment

Using VPs

VP/VC Characteristics

• Quality of service• Switched and semi-permanent channel

connections• Call sequence integrity• Traffic parameter negotiation and usage

monitoring

• VPC only– Virtual channel identifier restriction within VPC

ATM Cells

• Fixed size• 5 octet header• 48 octet information field• Small cells reduce queuing delay for high

priority cells• Small cells can be switched more efficiently• Easier to implement switching of small cells

in hardware

ATM Cell Format

Header Format

• Generic flow control– Only at user to network interface– Controls flow only at this point

• Virtual path identifier• Virtual channel identifier• Payload type

– e.g. user info or network management

• Cell loss priority• Header error control

Generic Flow Control (GFC)• Control traffic flow at user to network interface

(UNI) to alleviate short term overload• Two sets of procedures

– Uncontrolled transmission– Controlled transmission

• Every connection either subject to flow control or not• Subject to flow control

– May be one group (A) default– May be two groups (A and B)

• Flow control is from subscriber to network– Controlled by network side

Single Group of Connections (1)

• Terminal equipment (TE) initializes two variables– TRANSMIT flag to 1– GO_CNTR (credit counter) to 0

• If TRANSMIT=1 cells on uncontrolled connection may be sent any time

• If TRANSMIT=0 no cells may be sent (on controlled or uncontrolled connections)

• If HALT received, TRANSMIT set to 0 and remains until NO_HALT

Single Group of Connections (2)

• If TRANSMIT=1 and no cell to transmit on any uncontrolled connection:– If GO_CNTR>0, TE may send cell on controlled

connection• Cell marked as being on controlled connection• GO_CNTR decremented

– If GO_CNTR=0, TE may not send on controlled connection

• TE sets GO_CNTR to GO_VALUE upon receiving SET signal– Null signal has no effect

Header Error Control

• 8 bit error control field

• Calculated on remaining 32 bits of header

• Allows some error correction

HEC Operation at Receiver

Cell Based Physical Layer

• No framing imposed

• Continuous stream of 53 octet cells

• Cell delineation based on header error control field

Cell Delineation State Diagram

ATM Service Categories

• Real time– Constant bit rate (CBR)– Real time variable bit rate (rt-VBR)

• Non-real time– Non-real time variable bit rate (nrt-VBR)– Available bit rate (ABR)– Unspecified bit rate (UBR)

Real Time Services

• Amount of delay

• Variation of delay (jitter)

ATM Adaptation Layer

• Support for information transfer protocol not based on ATM

• PCM (voice)– Assemble bits into cells– Re-assemble into constant flow

• IP– Map IP packets onto ATM cells– Fragment IP packets– Use LAPF over ATM to retain all IP infrastructure

Adaptation Layer Services

• Handle transmission errors

• Segmentation and re-assembly

• Handle lost and mis-inserted cells

• Flow control and timing

Frame Relay

• Designed to be more efficient than X.25

• Developed before ATM

• Larger installed base than ATM

• ATM now of more interest on high speed networks

Frame Relay Background - X.25

• Call control packets, in band signaling

• Multiplexing of virtual circuits at layer 3

• Layer 2 and 3 include flow and error control

• Considerable overhead

• Not appropriate for modern digital systems with high reliability

Frame Relay - Differences

• Call control carried in separate logical connection• Multiplexing and switching at layer 2

– Eliminates one layer of processing

• No hop by hop error or flow control• End to end flow and error control (if used) are

done by higher layer• Single user data frame sent from source to

destination and ACK (from higher layer) sent back

Advantages and Disadvantages

• Lost link by link error and flow control– Increased reliability makes this less of a

problem

• Streamlined communications process– Lower delay– Higher throughput

• ITU-T recommend frame relay above 2Mbps

User Data Transfer

• One frame type– User data– No control frame

• No inband signaling

• No sequence numbers– No flow nor error control

77

Objectives

• Explain the advantages and disadvantages of various WAN connection types

• Select the appropriate WAN connection types to interconnect multiple sites

• Select the equipment that will suit the specific needs of each site

• select the proper equipment

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

Remote Access Overview

– Remote access networks connect sites– Connection requirements vary depending on

user requirements and cost

Service provider

WAN Connection Types

Telephonecompany

Serviceprovider

Circuit-switched

Dedicated

Packet-switched

Synchronous serial

Asynchronous serial, ISDN

Synchronous serial

Dedicated Connections

– Links are continuously available

Dedicated Serial Connections

CSU/DSUCSU/DSU

CSU/DSUCSU/DSU

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

Circuit Switching Connections

– Circuit switching requires call setup and call teardown– Circuit switching is used in the telephone company networks and works like a

telephone call

Telephonecompanynetwork

Fileserver

E-mailserver

Asynchronous Circuit-Switched Connections

– Connections are made only when traffic dictates a need

Modem

Modem

Modem

EIA/TIA-232

EIA/TIA-232

Telephonecompanynetwork

ISDNserviceprovider

Circuit-Switched ISDN Connections

CSU/DSU

PRI

BRI

NT1

Switch

CSU/DSU

Packet-Switched ConnectionsSynchronousserial

CSU/DSU

– VCs are established– Packet-switched networks generally share

bandwidth, but the cost is cheaper than a leased line

CSU/DSU

Synchronousserial

Typical WAN Protocols

Telephonecompany

Serviceprovider

Circuit-switched

Dedicated

Packet-switched

PPP, SLIP

PPP, HDLC, SLIP

X.25, Frame Relay, ATM

PPP Encapsulation

PPPencapsulation

Link setup and control using LCP in PPP

TCP/IP

IPX

Appletalk

Multiple protocol encapsulations using NCPs in PPP

X.25 and Frame Relay Encapsulations

Frame Relay,X.25

Connection Selection Considerations

– Availability– Bandwidth– Cost– Ease of management– Application traffic– Quality of service and reliability– Access control

Selecting WAN Configuration Types

Increasing

Bandwidth

Requirements

Delay- sensitive

voice/video

File transfer

Client/server

E-mail

Terminalemulation

ISDN, VoFR, VoATM

Or

ISDN

0 1 2 3+

Analogdialup

Or

FrameRelay

Analog dialup

Hours/Day

WAN Connection Speed Comparison

Leased line, Frame Relay

9.6k 56/64 kbps 128 kbps E1/T1 E3/T3

Asynchronous Dialup

ISDN—PRI

X.25, ISDN—BRI

WA

N C

on

nec

tio

n

Theoretical Maximum WAN Speeds

WAN Connection SummaryConnection Type

Leased lines

Frame Relay

Asynchronousdialup

X.25

ISDN

ApplicationsHigh control, full bandwidth, high-cost enterprise networks, and last-mile accessMedium control, shared bandwidth, medium-cost enterprise backbones; branch sitesLow control, shared bandwidth, more bandwidth than dialupLow control, shared bandwidth, variable cost- effective for limited use connections, high reliabilityLow control, shared bandwidth, variable cost- effective for limited use connections like DDR

93

Company Sites

Windows95 PC

Modem

Remote site,remote office/branch office(ROBO)

ISDN/ analog

Telecommuter site,small office/home office (SOHO),mobile (remote telecommuters)

Central site,headquarters,enterprise

Packet-switched service

94

Central Site Considerations

Central site,headquarters,enterprise

ISDN/analog Packet-

switchedservice

– Must provide access to multiple users and control the network costs

95

Branch Office Considerations

ISDN/analog

Packet-switched

service

– Must be able to access the central site

Remote site,remote office/branch office(ROBO)

96

Telecommuter SiteConsiderations

Windows95 PC

Modem

Small office/ home office (SOHO),

mobile (remote telecommuters)

– Must access company information on demand from various remote locations

ISDN/analog

Packet-switched

service

Determining the Appropriate Interfaces—Fixed Interfaces

Fixed-configuration router

Determining Appropriate Interfaces—Modular Interfaces

1-Ethernet 2-WAN interface card module Modular-configuration router

8-port A/S serial module

Serial WAN interface card

99

Summary

• Determine if each site is a central site, branch office, or telecommuter site

• Select the products that will suit the specific needs of each site

• select the proper equipment

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

Review Questions

• Identify the types of WAN connections discussed in this chapter and the appropriate protocols used on each connection.

• Describe the considerations when implementing a WAN connection at a central site, branch office, and telecommuter site.

• Identify available equipment designed for a telecommuter site, a branch office, and a central site.

Assembling and Cabling the WAN

Components

3-101

102

Objectives

• Identify and connect necessary components to connect a central site router to other users

• Identify and connect necessary components to connect a branch office router to other sites

• Identify and connect necessary components to connect a telecommuter site router to other sites

• Identify and connect necessary components to connect a mobile user to other sites

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

103

Typical Network Topology

Windows 95 PC Modem

Branch office

ISDN/analog

Telecommuter site

Central site

Serial

Frame Relay

service

PRI

BRI

BRI

Serial

Async

AAA server

Modem

1-Ethernet 2-WAN card slot network module

Digital modem network module

Central Site Router Equipment4-port serial WAN network module

Module slot 1

Module slot 2

Module slot 3

Module slot 0

1-port CT1/PRI-CSU network module

Branch Office Router Equipment

Console

1603 router—rear view

Flash card slot

1600 router—front view

Ethernet AUI

Serial WAN interface card

Ethernet 10BaseT

ISDN BRI

Telecommuter Site Router Equipment

ISDN BRI U

766 router—rear view

760 router—front view

Console

Ethernet 10BaseT

Power switch

Power connectorISDN BRI S/T Phone 1

Phone 2

107

5

1

3 or 4

5

1

2

2

Assembling the Network

Windows 95 PC

Cisco 700

Internal PCmodem

Branch office

ISDN/analog

Cisco 3600

Telecommuter site

Cisco 1600

Central site

Frame Relay

service

T1 (E1) for PRIRJ-48 (DB-15)

BRI (RJ-45)

BRI (RJ-45)

RJ-11

AAA server

Modem

Serial

EthernetSerialRS232

RJ-11Ethernet

Serial V.35, X.21, RS232,EIA/TIA-449, EIA-530

Serial V.35, X.21, RS232,EIA/TIA-449, EIA-530

Verifying Central Site Installation

Enable LED

MICA module bank LEDs

CN/LP, RXC, RXD,TXC, and TXD LEDs

Enable LED

EnableLED

Remote Alarm, Local Alarm, Loopback,and Carrier Detect LEDs

ActivityLED

LinkLED

Verifying Branch Office Installation

• The system power and OK LEDs indicate the router is on and has successfully booted

CONN LEDSerialSystem power

System OK

Verifying Telecommuter Site Installation

• The ready LED indicates the router is on and has passed its self tests

Ready LED

113

Summary

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

• Identify and connect necessary components to connect a central site router to other users

• Identify and connect necessary components to connect a branch office router to other sites

• Identify and connect necessary components to connect a telecommuter site router to other sites

• Identify and connect necessary components to connect a mobile user to other sites

Review Questions

• Which cables are necessary to make the proper physical asynchronous serial, ISDN, and synchronous serial connections?

• How can you verify that you properly installed a network module into a modular router?

Configuring Asynchronous Connections to a Central Site

with Modems

Objectives

Upon completion of this chapter, youwill be able to perform the following tasks: • Configure an access server for an attached modem

• Use reverse Telnet to configure an external modem

• Configure a modem using autoconfigure

Chapter Activities

Windows 95 PC

Cisco 700

Modem

Branch office

ISDN/analog

Analog host-LAN dialup

Small office

Central site

Frame Relay

Frame Relay

service

PRI

BRI

BRI

Frame Relay

Async

AAA server

Async

A Typical Modem Connection

Analog AnalogDigitalPCM-encoded analog data

Digital Digital

Telco

Switch Switch

ModemModem

Host

The DTE-DCE Interface

• DTE = Data terminal equipment

• DCE = Data communications equipment

DTE DCE

EIA/TIA-232 or X.21

DTEDCE

EIA/TIA-232 or X.21

Modem Signaling—Data

DatatransferGround

TxD RxDGRD

DTE DCE

DB-25 pins

{ 237

237

TxD RxDGRD

Asynchronous communication

Startbit

Stopbit

0 1 1 0 1 0 0

P bits per packet

IdealRX Clock

ActualRX Clock

Asynchronous communications sometimes used for links with short packets.

Modem Control Example

Two ways to terminate an existing connection:• DTE-initiated

—Access server drops DTR

—Modem must be programmed to terminate connection on loss of DTR and restore to saved settings in its NVRAM

• DCE-initiated—Access server detects Carrier Detect (CD) low and

terminates connection

—Modem must be programmed so that CD reflects the state of the carrier

Modem Operation

Buffer

Compressor

Modulator/ demodulator

Buffer

Compressor

Modulator/ demodulator

RTSCTS

TxD RxD

Flow control

Compress

Decompress

Checksum

RetransmitPacketizer

(error control)Packetizer

(error control)

DTE-to-DTE Wiring

Datatransfer

Hardwareflow control

Modemcontrol

TxD

RxD

GND

RTS

CTS

DTR

DSR

TxD

RxD

GND

RTS

CTS

DTR

DSR

Null modem cable(with DB-25 connectors)

2

3

7

4

5

20

6

2

3

7

4

5

20

6

Error Control and Data Compression Standards

• Error detection/correction— Microcom Networking Protocol (MNP)

• MNP 2–4 in public domain

• MNP 10 for cellular

— CCITT V.42• LAP-M

• MNP 4

• Data compression— MNP 5: 2:1 ratio

— V.42bis: 4:1 ratio

Data

Modem Modulation Standards

• ITU standards:– V.22: 1200 bps

– V.22bis: 2400 bps

– V.32: 9600 bps

– V.32bis: 14.4 kbps

– V.34: 28.8 kbps

– V.34 annex 1201H: 33.6 kbps

– V.90: 56 kbps

• Proprietary methods:– V.32 terbo: 19.2 kbps

– V.fast: 28.8 kbps

– V.FC: 28.8 kbps

– K56Flex: 56 kbps

– X2: 56 kbps

DCEDCE

Modem Speeds and Compression

4:1Compression

ratio

DTE DTEDCEDCE

115.2 kbps

28.8 kbps

• The speeds and compression ratios shown assume ideal conditions

4:1Compression

ratio

115.2 kbps

Theoretical Speeds

V.32

V.32bis

V.32 turbo

V.34

Maximum speed with 4:1 V.42bis compressionSpeed

38400

57600

76800

1152002880028800

1920019200

1440014400

96009600

bps

V.90 5600056000 224000

Maximum Capacity/Data Rate

Shannon Capacity:

)/1(log2 NSBC Bandwidth of link Signal-to-Noise ratio

For example: Bandwidth of telephone link from telephone to a typical home is approx 3300Hz – 300Hz = 3kHz Signal-to-noise ratio is approx 30dB = 10log10(S/N) Therefore, C = 3000*log2(1001) ~= 30kb/s

Connecting to the Modem

Forward connection to a router to login

Reverse connectionto a modem to configure it

Asynchronous line

Basictelephone

service

Configuring PPP and Controlling Network Access

with PAP and CHAP

Objectives

Upon completion of this chapter, youwill be able to perform the followingtasks:• Configure PPP between a central site and a remote site

• Configure PAP or CHAP authentication

• Verify and troubleshoot a PPP link

Chapter Activities

Windows 95 PC

Cisco 700

Modem

Branch office

ISDN/analog

Cisco 3640

PPP, CHAP

Analog host-LAN dialup

Small office

Cisco 1600

Central site

Frame Relay

Frame Relay

service

PRI

BRI

BRI

Frame Relay

Async

PP

P, C

HA

P

AAA server

Async

Remote Node Connections

Novell IPXTCP/IP

AppleTalk

TCP/IPPPP

SLIPARAP

AppleTalk

PPP Architecture

Physical Layer(such as EIA/TIA-232, V.24, V.35, ISDN)

High-Level Data Link Control (HDLC)

Link Control Protocol (LCP)

Network Control Protocol (NCP) (specific to each network-layer protocol)

Upper-layer protocols

OSI layer

2

1

(such as IP, IPX, AppleTalk)3

Autoselect

User dials in

Autoselect on?

Start PPP

Start SLIP

Start ARAP

(Start as if run from EXEC)

Start EXEC (or dedicated

mode)

Parse start sequence for each enabled protocol

CR PPP frame

SLIP frame

ARAP frame

No

Yes

Enabling PPP and Async Interface Commands

Router(config-if)#encapsulation {ppp | slip}Router(config-if)#encapsulation {ppp | slip}

Router(config-if)#async mode interactiveRouter(config-if)#async mode interactive

Router(config-if)#async mode dedicatedRouter(config-if)#async mode dedicated

• Defines encapsulation type

• Places the line in dedicated PPP/SLIP mode

• Places the interface in interactive mode (allows an EXEC process)

OR

Async Interface Commands for Addressing

Router(config-if)#peer default ip address {address | pool pool-name | dhcp}

Router(config-if)#peer default ip address {address | pool pool-name | dhcp}

Router(config-if)#ip unnumbered type number Router(config-if)#ip unnumbered type number

Router(config-if)#async dynamic addressRouter(config-if)#async dynamic address

• Assigns an IP address to a remote node

• Allows a remote user to specify the IP address

• Configures the asynchronous interface to be unnumbered

PAP or CHAP

Authentication PSTN/ISDN

PPP LCP Options

PSTN/ISDNCallback

Compression

Multilink

Bundle

Data

PPP AuthenticationChecklocal

database

Querysecurityserver

database

Incoming PPPnegotiation

Determineauthentication

method

Local

Fail

Pass

Noauthentication

Disconnect Start PPP

Pass

Security

server

PPP Negotiating PAP Authentication

Inputs name andpassword when prompted

username johnpassword urbiz

Remote user John

Access server Cisco1

Run PPP

Use PAP

“john, urbiz”

Accept or reject

Local userdatabase

• One-way PAP

Configuring PAP Example

hostname right

int async 0

encapsulation ppp

ppp authentication PAP

ip add 10.0.0.2 255.255.255.0

dialer-map ip 10.0.0.1 name left 555-4321

ppp pap sent-username rightpassword right1

hostname right

int async 0

encapsulation ppp


ip add 10.0.0.2 255.255.255.0

dialer-map ip 10.0.0.1 name left 555-4321

ppp pap sent-username rightpassword right1

hostname left

int async 0

encapsulation ppp


ip add 10.0.0.1 255.255.255.0

dialer-map ip 10.0.0.2 name right 555-2345

ppp pap sent-username leftpassword left1

hostname left

int async 0

encapsulation ppp


ip add 10.0.0.1 255.255.255.0

dialer-map ip 10.0.0.2 name right 555-2345

ppp pap sent-username leftpassword left1

Leftrouter

Rightrouter

PSTN/ISDN

• Two-way PAP

PPP Using CHAP Authentication

username johnpassword urbiz

Remote userJohn

Access serverCisco1 Run PPP

Use CHAP

Response

Accept or reject

Challenge

Request for challenge

Local userdatabase

Name: johnPassword: urbiz

• One-way CHAP

CHAP in Action—Call

766-13640-1

User dials in

CHAP in Action—Challenge

01 random 3640-1id

User dials in766-1

3640-1

CHAP in Action—Response

MD5

hash

01 random 3640-1iduser pass3640-1 pc1

User dials in766-1

3640-1

CHAP in Action—Response (cont.)

01

02

random 3640-1id

id hash 766-1

user pass3640-1 pc1

User dials in766-1

3640-1

MD5

hash

CHAP in Action—Verification

01

02

random 3640-1id

id hash 766-1

user pass766-1 pc1

user pass3640-1 pc1

=?

User dials in766-1

3640-1

MD5

hash

MD5

hash

CHAP in Action—Result

01

02

03

random 3640-1id

id hash 766-1

id “Welcome in”

user pass766-1 pc1

user pass3640-1 pc1

User dials in766-1

3640-1

MD5

hash

MD5

hash

Configuring CHAP Example

hostname left

username right password sameone

int async 0

encapsulation ppp

ppp authentication CHAP

hostname left

username right password sameone

int async 0

encapsulation ppp


hostname right

username left password sameone

int async 0

encapsulation ppp


hostname right

username left password sameone

int async 0

encapsulation ppp


Leftrouter

Rightrouter

PSTN/ISDN

PPP Callback Implementation Considerations

Return call is not made if:• The last interface is in use when callback is attempted• A DDR interesting packet used last available interface

Initiating call

Hold-queue started

Rotary group (all busy)

Callbackserver

Callbackclient

Callbackclient

Callbackserver

Client called X

Yes

Asynchronous Callback Operation Flowchart

CHAPCHAPAutoselectprotocol

Call

Authenticate

Callback

No

End

Authen.OK?

Hangup

PPP Callback Operation

Call initiation

Call acknowledgment

User authentication

Callback client Callback server

Initiating call disconnected

Server-to-client dial string identified

Client called

Authentication

Connection proceeds

1

2

3

4

5

6

7

8

Asynchronous Callback Global Commands

Router(config)#username username [password password][callback-dialstring phone-number][callback-line line-number][callback-rotary rotary-group-number]

Router(config)#username username [password password][callback-dialstring phone-number][callback-line line-number][callback-rotary rotary-group-number]

• On the callback server

Asynchronous Callback Line/Interface Commands

Router(config)#line line-number

Router(config-line)#callback forced-wait seconds

Router(config-line)#script callback script-name

Router(config)#line line-number

Router(config-line)#callback forced-wait seconds

Router(config-line)#script callback script-name

Router(config-if)#ppp callback acceptRouter(config-if)#ppp callback accept

Router(config-if)#ppp callback initiateRouter(config-if)#ppp callback initiate

• On the callback server

7

Configuring a PPP Callback Server

Plano(config)#interface s2Plano(config-if)#ip address 10.1.1.7 255.255.255.0Plano(config-if)#encapsulation pppPlano(config-if)#dialer callback-securePlano(config-if)#dialer map ip 10.1.1.8 name Dallas class dial1 5555678 Plano(config-if)#dialer-group1

Plano(config-if)#ppp authentication chap!Plano(config)#map-class dialer dial1Plano(config-map-class)#dialer callback-server usernamePlano(config-map-class)#dialer hold-queue timeout 60

Plano(config)#interface s2Plano(config-if)#ip address 10.1.1.7 255.255.255.0Plano(config-if)#encapsulation pppPlano(config-if)#dialer callback-securePlano(config-if)#dialer map ip 10.1.1.8 name Dallas class dial1 5555678 Plano(config-if)#dialer-group1

Plano(config-if)#ppp authentication chap!Plano(config)#map-class dialer dial1Plano(config-map-class)#dialer callback-server usernamePlano(config-map-class)#dialer hold-queue timeout 60

1

23

45

6

Plano(config-if)#ppp callback accept


Dallas 10.1.1.8 5555678Plano 10.1.1.7 5551234

Configuring a PPP Callback Client

Dallas(config)#interface s0Dallas(config-if)#ip address 10.1.1.8 255.255.255.0Dallas(config-if)#encapsulation pppDallas(config-if)#dialer map ip 10.1.1.7 name Plano 5551234Dallas(config-if)#dialer-group 1

Dallas(config-if)#ppp authentication chap

Dallas(config)#interface s0Dallas(config-if)#ip address 10.1.1.8 255.255.255.0Dallas(config-if)#encapsulation pppDallas(config-if)#dialer map ip 10.1.1.7 name Plano 5551234Dallas(config-if)#dialer-group 1

Dallas(config-if)#ppp authentication chap

12

34

Dallas(config-if)#ppp callback request


Dallas 10.1.1.8 5555678Plano 10.1.1.7 5551234

Supported Compression Algorithms

128–384 kbps

2:1 to 3:1Compression

ratios

Compresseddata

Data

128–384 kbps

Compression Decompression

• Predictor

• Stacker

• MPPC

• TCP header

128 kbps

Configuring Compression

• Interface compression algorithms

Router(config)#int s2Router(config-if)#compress {predictor | stac | mppc}Router(config)#int s2Router(config-if)#compress {predictor | stac | mppc}

• TCP header

Router(config)#int async 2Router(config-int)#ip tcp header-compressionRouter(config)#int async 2Router(config-int)#ip tcp header-compression

Router(config)#int async 2Router(config-int)#ip tcp header-compression passiveRouter(config)#int async 2Router(config-int)#ip tcp header-compression passive

Why Use Multilink PPP?Not Cisco

Ciscoaccessserver

Bundle

Bundle

Ciscoaccessserver

BrandX

Multilink PPP Operation

LCP option negotiation

Bundle

MRRU

• Synchronize multiple PPP data streams

Summary

After completing this chapter, you shouldbe able to perform the following tasks:• Configure PPP between a central site and a remote site

• Configure PAP or CHAP authentication

• Verify and troubleshoot a PPP link

Review Questions

• What are the LCP options for PPP?

• Describe why PPP callback is important.

• Describe how CHAP provides security.

• IP• AppleTalk• Novell IPX• Banyan VINES• XNS

• DECnet• ISO-CLNS• Compressed TCP• Bridging

X.25 cloud

X.25

Virtualcircuit

X.25

An Introduction to X.25

LANprotocol

LANprotocol

OSI Reference Model X.25 Protocol

Application

Presentation

Session

Transport

Network

Data Link

Physical1

2

3

4

5

6

7 •

•

•

•

X.25

LAPB

Physical 1

2

3

X.25 Protocol Stack

– X.25 DTE—Usually a subscriber's router or PAD – X.25 DCE—Usually a PDN's switch or concentrator

Public data network (PDN)

X.25 DTE X.25 DTEX.25DCE

X.25DCE

X.25 DTE and DCE

– PAD collects data and outputs it into X.25 packets

DTEDTE host

Identifying the PAD

DCEDCE

X.25 X.25

PAD

Asynchronousterminals

Public data network (PDN)

Data network ID code Network terminal number

4 decimal digits Up to 10 or 11 decimal digits

X.25 (X.121) Addressing Format

– Addressing set by service provider

X.25

ARP X.25 map

ETH DestinationMAC

SourceMAC

IP IPX.25 Source DestinationX.121X.121

TokenRing

X.25 Address Resolution

X.25

IP network IP network

IP datagram (L3)X.25 header (L3)

Data-linkframe(LAPB) (L2)

X.25 Encapsulation

– Protocol datagrams are reliably carried inside LAPB frames and X.25 packets

Switched virtual circuits(SVCs)

Permanent virtual circuits(PVCs)

X.25 Virtual Circuits

– Numbering for up to 4095 VCs per X.25 interface

IPX

Host

– SVCs may be combined to improve throughput for a particular protocol

SVC Usage

TCP/IP

AppleTalk

– Each network-layer protocol is associated with its own virtual circuit

Single-Protocol Virtual Circuits

IPX

Host

Multiprotocol Virtual Circuits

– Multiple protocols are carried within a virtual circuit to a single destination

– A maximum of nine protocols may be mapped to a host

TCP/IP

AppleTalk

IPX

Host

– Interface configuration– Select X.25 DTE or DCE encapsulation

– Configure parameters for X.25 network attachment

–Map protocol address to X.121 address

– Additional configuration steps

X.25 Configuration Tasks

– Defines encapsulation type

– Establishes interface address

Router(config-if)#encapsulation x25 [dte | dce]

Router(config-if)#x25 address x.121-address

Configuring X.25 SVCs—Steps 1 and 2Step 1

Step 2

– Specifies how a single protocol reaches a destination

– Specifies how multiple protocols reach a single destination using one SVC

Router(config-if)#x25 map protocol address x.121-address [options]

Router(config-if)#x25 map protocol address [protocol2 address2]*x.121-address [options]

Configuring X.25 SVCs—Step 3

or

Configuring X.25 SVC Example

IP address: 10.60.8.2

X.121 address: 311082191234

S1

X.25IP address: 10.60.8.1

X.121 address: 311082194567

Central siteS0Token

Ring

Central(config)#interface serial 1

Central(config-if)#encapsulation x25

Central(config-if)#x25 address 311082194567

Central(config-if)#ip address 10.60.8.1 255.255.248.0

Central(config-if)#x25 map ip 10.60.8.2 311082191234 broadcast

Central site

Branch(config)#interface serial 0

Branch(config-if)#encapsulation x25

Branch(config-if)#x25 address 311082191234

Branch(config-if)#ip address 10.60.8.2 255.255.248.0

Branch(config-if)#x25 map ip 10.60.8.1 311082194567 broadcast

Branch office

Branch office

S0

Configuring X.25 SVC Example Central(config)#interface serial 1






Central site

IP address: 10.60.8.3X.121 address: 311082198901


S1

X.25IP address: 10.60.8.1X.121 address: 311082194567

Central siteS0Token

Ring

Branch office

Branch office

– Specifies how protocols reach a destination using a PVC

Router(config-if)#x25 pvc circuit protocol address [protocol2 address2]* x.121-address [options]

Configuring X.25 PVCs—Steps 1 to 3

– Defines encapsulation type

– Establishes interface address

Router(config-if)#encapsulation x25 [dte | dce]

Router(config-if)#x25 address x.121-address

Step 1

Step 2

Step 3



Central(config)#interface serial 1




Central(config-if)#x25 pvc 4 ip 10.60.8.2 311082191234 broadcast

Central site

Branch(config)#interface serial 0

Branch(config-if)#encapsulation x25

Branch(config-if)#x25 address 311082191234

Branch(config-if)#ip address 10.60.8.2 255.255.248.0

Branch(config-if)#x25 pvc 3 ip 10.60.8.1 311082194567 broadcast

Branch office

Configuring X.25 PVC Example

PVC 4

S1

X.25

Central siteS0Token

Ring

Branch office

Additional X.25 Configuration Tasks

– Configure interface for X.25 Layer 3 parameters– Virtual circuits

– Packet size

– Window size

– Window modulus

PVCs

Incoming only

Two-way

Outgoing only

SVC

SVC

SVC

1–4095

1–40951–4095

1–40951–4095

1–40951–4095

00

11024

00

x25 pvc circuit

x25 lic circuitx25 hic circuit

x25 ltc circuitx25 htc circuit

x25 loc circuitx25 hoc circuit

Range Default Command

Configuring X.25 VC Ranges

– Specifies default incoming packet size

– Specifies default outgoing packet size

Router(config-if)#x25 ips bytes

Router(config-if)#x25 ops bytes

Configuring X.25 Packet Sizes

– Specifies default unacknowledged packet limits

– Defines packet-level window counter limit

Configuring Window Parameters

Router(config-if)#x25 win packets Router(config-if)#x25 wout packets

Router(config-if)#x25 modulo modulus

Additional X.25 Configuration Options Example

Router(config)#interface serial 0Router(config-if)#encapsulation x25

Router(config-if)#x25 address 311082198756Router(config-if)#x25 ips 1024Router(config-if)#x25 ops 1024Router(config-if)#x25 win 7Router(config-if)#x25 wout 7

S0

X.25 network

Verifying X.25 ConfigurationCentralA#sh int s 3/1Serial3/1 is up, line protocol is upHardware is CD2430 in sync modeInternet address is 10.140.1.1/24MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec, rely 255/255, load 1/255Encapsulation X25, loopback not setX.25 DTE, address 311010100101, state R1, modulo 8, timer 0Defaults: idle VC timeout 0cisco encapsulationinput/output window sizes 2/2, packet sizes 128/128Timers: T20 180, T21 200, T22 180, T23 180Channels: Incoming-only none, Two-way 1-1024, Outgoing-only noneRESTARTs 1/0 CALLs 0+0/0+0/0+0 DIAGs 0/0LAPB DTE, state CONNECT, modulo 8, k 7, N1 12056, N2 20T1 3000, T2 0, interface outage (partial T3) 0, T4 0VS 5, VR 3, tx NR 3, Remote VR 5, Retransmissions 0Queues: U/S frames 0, I frames 0, unack. 0, reTx 0IFRAMEs 5/3 RNRs 0/0 REJs 0/0 SABM/Es 0/1 FRMRs 0/0 DISCs 0/0Last input 00:00:29, output 00:00:29, output hang neverLast clearing of "show interface" counters neverQueueing strategy: fifoOutput queue 0/40, 0 drops; input queue 0/75, 0 drops5 minute input rate 0 bits/sec, 0 packets/sec5 minute output rate 0 bits/sec, 0 packets/sec<Output Omitted>

Laboratory Exercise: Visual Objective

Branch office

Cisco 3640

Cisco 1600

Central site

X.25

X.25service

X.25

S3/1X.121 address: 31101010XXX1

S0 X.121 address: 31101010XXX2

Summary

•After completing this chapter, you should be able to perform the following tasks:• Configure an X.25 WAN connection

• Assign X.121 addresses to router interfaces and map higher-level addresses to X.25 addresses

• Verify X.25 configuration in the router

Review Questions

• Explain the difference between an X.25 DTE and DCE.

• Assume you want an IP connection over an X.25 link. What must you do to map the network layer address to the X.121 address?

• How can you limit traffic by lowering the amount of acknowledgements sent across the X.25 link?

Using ISDN and DDR Technologies to Enhance Remote

Connectivity

Objectives

• Upon completion of this chapter, you will be able to complete the following tasks:– Select BRI or PRI service for a particular

application– Identify Q.921 and Q.931 signaling and call

sequences– Configure ISDN BRI– Configure ISDN PRI– Configure ISDN DDR

Chapter Activities

Windows 95 PC Modem

Branch office

ISDN/analog

Small office

Central site

Frame Relay

Frame Relay

service

PRI

BRI

BRI

Frame Relay

Async

ISD

N, P

PP

, CH

AP

, DD

R

AAA server

Async

Asynchronous Versus ISDN

• Analog converted to digital and back

Channelbank

Channelbank

SWSW SWSW

• Digital end-to-end

Channelbank

Channelbank

SWSW SWSW

ISDN Services and Channelized E1 and T1

56/64 kbps56/64 kbps

16 kbps

144 kbps

2B

D }{BRI

T1 1.544 Mbps

or

E1 2.048 Mbps (includes sync)

23B (T1) or30B (E1)

D

64 kbpseach

64 kbps}PRI

2.048 Mbps(includes sync)

31 64 kbpschannels }E1

1.544 Mbps(includes sync)

24DS0s }T1

31

BRI Call Processing

ISDNservice provider

4

B channel

D channel/SS7 signaling

2 SS7

Q.931 signaling Q.931 signaling

TE1 NT1 LE

Local loop terminator

ISDN local exchange

ISDN terminal equipment

NT2

Customer premises switching equipment

TE2 TA

Non-ISDN terminal

equipment

Terminal adapter

Non-U.S. demarcations

U.S. demarcation

S U

R

T

BRI Functional Groups and Reference Points

Physical Representation of BRI Reference Points

Cisco ISDNrouter

To ISDNservice

Walljack

4-wirecircuit

2-wirecircuit

S/T UTA NT1NT1

S/T bus

S/T bus

S/T interface as a multipoint connection

To non-ISDNdevice (TE2)

R

ISDNphone

PRI—Layer 1 Standards and Reference Points

LE

U

ITU-T I.431ANSI

T1.601

TE CSU/DSU

S/T

ITU-TI.430

ISDN Protocol Layers

Layer 3

LAPD (Q.921)

D Channel B Channel

I.430/I.431/ANSI T1.601I.430/I.431/ANSI T1.601

HDLC/PPP/FR/LAPB

Layer 1

Layer 2

DSS1 (Q.931) IP/IPX

BRI Layer 1—I.430 FramingNT TE Frame

1 111111111111111 8 8 8 8

F FDL L L L L L L L LD D DB2B1B2B1L

1 111111111111111 8 8 8 8

F FDE A F E S E S E SD D DB2B1B2B1L

TE NT Frame

ISDN

NT1

Daisy-chainS/T bus

TEI/SAPI

TEI/SAPI LE

ISDN Layer 2

– ITU-T Q.920 and Q.921– Defines logical link between TE/TA and NT2/LE– Carries Layer 3 D-channel messages

ISDN Layer 3—D Channel Q.931

• Q.931 defines call control between the TE and local switch

TE ETNT1 LTQ.931

ISDN switch (LE)

Q.931 Messaging—Call Setup ExampleCalling

partyCalled

party

Setup

Connect acknowledge Connect

acknowledge

Setup

Setup acknowledge

Call proceeding

Alerting

Connect

Alerting

Connect

Call proceeding

Tim

e

ISDN service provider

ISDNswitch

ISDNswitch

Q.931 Messaging—Call Teardown Example

Released

Disconnect

Calling party Called partyDisconnect

Released

Release complete

Release complete

Release

Tim

e


ISDNswitch

ISDNswitch

DDR OperationInteresting

?

Connected?

Phone #?

Connected?

Dial

No

Yes

Yes

No

No

Send

Incoming packet

ResetIdle

TimerYes

NoInterface

up?

Yes

Yes

No

Using DDR with ISDN


BRI or

PRI

1.

2. Remoterouter

1. Packet arrives2. Switch packet to DDR interface, determine if interesting 3. If interesting, dial DDR destination via ISDN 4. Connect to remote router

3.

4.

ISDN Configuration Tasks

–Global configuration–Select switch type–Specify traffic to trigger DDR call

–Interface configuration–Select interface specifications–Configure ISDN addressing

–Optional feature configuration

ISDN

ISDN Configuration Commands

– Set global parameters with this command:• isdn switch-type

– Set interface parameters with these commands:• encapsulation ppp (CHAP and Multilink PPP)

• ip address

• isdn spid1

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

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

Selecting the ISDN Switch Type

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

– Global or interface command

Setting Interface Protocols

Router(config-if)#encapsulation {ppp | hdlc}Router(config-if)#encapsulation {ppp | hdlc}

• Selects framing for that ISDN BRI

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

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

• Selects PPP authentication type

Setting SPIDs if Necessary

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

• Sets a B channel SPID required by many service providers

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

• Sets an SPID for the second B channel

DDR Configuration Tasks

1. Define interesting traffic2. Assign interesting traffic definition

to ISDN interface 3. Define destination 4. Define call parameters

ISDNserviceprovider

BRI or

PRIRemoterouter

Interesting traffic arrives

Dial destination

Defining Interesting Traffic Router(config)#dialer-list dialer-group-number

protocol protocol-name {permit | deny} list access-list-number

Router(config)#dialer-list dialer-group-numberprotocol protocol-name {permit | deny} list access-list-number

• Defines interesting packets for DDR • Associated with the dialer group assigned to the interface

Router(config-if)#dialer-group group-number Router(config-if)#dialer-group group-number

• Assigns an interface to the dialer access group specified in the dialer-list command

Using Access Lists for DDR Router(config)#access-list access-list-number {permit|deny} {protocol | protocol-keyword } {source source-wildcard | any} {destination destination-wildcard | any} [protocol-specific-options] [log]

Router(config)#access-list access-list-number {permit|deny} {protocol | protocol-keyword } {source source-wildcard | any} {destination destination-wildcard | any} [protocol-specific-options] [log]

• Gives tighter control over “interesting” traffic and uses standard or extended access lists

• Associates an access list with a dialer access group

Router(config)#dialer-list dialer-group list access-list-number

Router(config)#dialer-list dialer-group list access-list-number

Defining Destination Parameters

Router(config-if)#dialer map protocol next-hop-address [name hostname] [broadcast] dial-string Router(config-if)#dialer map protocol next-hop-address [name hostname] [broadcast] dial-string

• Defines how to reach a remote ISDN destination

Setting Default/Static Routes

Default route istoward cloud

Static route is towardthe remote site

TCP/IP

Setting Static Routes

Router(config)#ip route 172.108.0.0 255.255.0.0 192.254.35.2 Router(config)#ip route 172.108.0.0 255.255.0.0 192.254.35.2

172.108.0.0

192.254.35.2

BRI 0

Setting Default Routes

172.254.50.0

172.254.30.0

172.254.45.2 172.254.45.1

Router(config)#ip route 172.254.50.0 255.255.255.0 172.254.45.1

Router(config)#ip default-network 172.254.50.0



Router(config)#ip default-network 172.254.50.0


Setting Route Redistribution

• This router advertises static routes to other routers

192.150.42.0

Router(config)#router igrp 109Router(config-router)#network 172.108.0.0Router(config-router)#redistribute staticRouter(config)#ip route 192.150.42.0

255.255.255.0 10.0.0.2

Router(config)#router igrp 109Router(config-router)#network 172.108.0.0Router(config-router)#redistribute staticRouter(config)#ip route 192.150.42.0

255.255.255.0 10.0.0.2

10.0.0.1

10.0.0.2

172.108.0.0

Deactivating Routing Updates on an Interface

• Does not broadcast routes on that interface

Router(config)#router igrp 100Router(config-router)#passive-interface bri0Router(config)#router igrp 100Router(config-router)#passive-interface bri0

BRI 0

Configuring a Simple ISDN Call

– Use PPP encapsulation– All IP traffic to destination triggers ISDN call– Carrier uses a 5ESS basic rate switch– Service provider assigns connection parameters

192.168.1.1

NT1

E0

BRI 0E0

10.170.0.1

Cisco-a

Cisco-bISDN

NT1

10.170.0.2

BRI 0

192.168.2.1

51055512344085554000

Configuration Example, Cisco-a

192.168.1.1

BRI 0

10.170.0.1

Cisco-aCisco-b

ISDN10.170.0.2

4085554000

hostname Cisco-aisdn switch-type basic-5essusername Cisco-b password samepassinterface bri 0 ip address 10.170.0.1 255.255.0.0 encapsulation ppp dialer idle-timeout 300 dialer map ip 10.170.0.2 name Cisco-b 4085554000 dialer-group 1 ppp authentication chap!ip route 192.168.1.0 255.255.255.0 10.170.0.2dialer-list 1 protocol ip permit

hostname Cisco-aisdn switch-type basic-5essusername Cisco-b password samepassinterface bri 0 ip address 10.170.0.1 255.255.0.0 encapsulation ppp dialer idle-timeout 300 dialer map ip 10.170.0.2 name Cisco-b 4085554000 dialer-group 1 ppp authentication chap!ip route 192.168.1.0 255.255.255.0 10.170.0.2dialer-list 1 protocol ip permit

Configuration Example, Cisco-b

BRI 0

10.170.0.1 10.170.0.2

5105551234

192.168.2.1

hostname Cisco-bisdn switch-type basic-5essusername Cisco-a password samepass interface bri 0 ip address 10.170.0.2 255.255.0.0 encapsulation ppp dialer idle-timeout 300 dialer map ip 10.170.0.1 name Cisco-a 5105551234 dialer-group 1 ppp authentication chap!ip route 192.168.2.0 255.255.255.0 10.170.0.1dialer-list 1 protocol ip permit

hostname Cisco-bisdn switch-type basic-5essusername Cisco-a password samepass interface bri 0 ip address 10.170.0.2 255.255.0.0 encapsulation ppp dialer idle-timeout 300 dialer map ip 10.170.0.1 name Cisco-a 5105551234 dialer-group 1 ppp authentication chap!ip route 192.168.2.0 255.255.255.0 10.170.0.1dialer-list 1 protocol ip permit

ISDN

Cisco-aCisco-b

BRI 0

Access Lists and DDR for ISDN

– Cisco-a allows all IP traffic except Telnet and FTP to trigger ISDN calls to Cisco-b, and access subnet 192.168.1.0

10.170.0.3NT1

ISDN ServiceProvider

NT1

NT1

10.170.0.1

10.170.0.2

192.168.1.1

Cisco-c192.168.3.1

4085554000

4085551234

Cisco-a

Cisco-b

Access List Configuration Example, Cisco-a

hostname Cisco-aisdn switch-type basic-dms100username Cisco-b password samepassusername Cisco-c password samepassinterface bri 0 ip address 10.170.0.1 255.255.0.0 encapsulation pppdialer idle-timeout 300dialer map ip 10.170.0.2 name Cisco-b 4085554000dialer map ip 10.170.0.3 name Cisco-c 4085551234dialer-group 2 ppp authentication chap(continued on next figure)

hostname Cisco-aisdn switch-type basic-dms100username Cisco-b password samepassusername Cisco-c password samepassinterface bri 0 ip address 10.170.0.1 255.255.0.0 encapsulation pppdialer idle-timeout 300dialer map ip 10.170.0.2 name Cisco-b 4085554000dialer map ip 10.170.0.3 name Cisco-c 4085551234dialer-group 2 ppp authentication chap(continued on next figure)

10.170.0.3

ISDN Service Provider

BRI 0

10.170.0.1 10.170.0.2192.168.1.1Cisco-a

Cisco-b

Cisco-c

192.168.3.1

4085554000

4085551234

Access List Configuration Example, Cisco-a (cont.)

ip route 192.168.1.0 255.255.255.0 10.170.0.2ip route 192.168.3.0 255.255.255.0 10.170.0.3access-list 101 deny tcp any any eq ftpaccess-list 101 deny tcp any any eq telnet access-list 101 permit ip any anydialer-list 2 protocol ip list 101

ip route 192.168.1.0 255.255.255.0 10.170.0.2ip route 192.168.3.0 255.255.255.0 10.170.0.3access-list 101 deny tcp any any eq ftpaccess-list 101 deny tcp any any eq telnet access-list 101 permit ip any anydialer-list 2 protocol ip list 101

10.170.0.3

ISDN Service Provider

BRI 0

10.170.0.1 10.170.0.2192.168.1.1Cisco-a

Cisco-b

Cisco-c

192.168.3.1

4085554000

4085551234


Optional ISDN Configurations

– Specify Multilink PPP or BOD– Enable caller ID screening– Configure rate adaptation– Called number answer

SpeedLimit128

kbpsB2

B1With BODor MP64 kbps

64 kbps

B Channel Aggregation

– Available on all Cisco IOS platforms with ISDN– Accomplished via Cisco proprietary BOD or

Multilink PPP

Cisco Proprietary BOD

Traffic Buffer

B1

Router(config)#int bri0

Router(config-if)#dialer load—threshold load


Router(config-if)#dialer load—threshold load

B2

ISDNRouter

B Channel Aggregation Using Multilink PPP

Data in

BB AAB1B1

B2B2

Sequencing andfragmentation

Data out

Sequencing andreassembly


A1A1

A2A2


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

Router(config-if)#ppp multilink


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


B1B1

B2B2

A1A1

A2A2BB AA

Configuring Multilink PPP

– MLP can be configured on:• Asynchronous serial interfaces

• Synchronous serial interfaces

• Basic Rate Interfaces (BRI)

• Primary Rate Interfaces (PRI)

Configuring Multilink PPP (cont.)Rotary group

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


• Enables Multilink PPP on a dialer rotary group

• Defines the threshold to bring up another link

ISDN

Configuring Multilink PPP (cont.)

Router(config)#interface bri0Router(config-if)#no ip addressRouter(config-if)#encapsulation pppRouter(config-if)#ppp multilinkRouter(config-if)#dialer idle-timeout 30

Router(config)#interface bri0Router(config-if)#no ip addressRouter(config-if)#encapsulation pppRouter(config-if)#ppp multilinkRouter(config-if)#dialer idle-timeout 30Router(config-if)#dialer load-threshold 128 either

ISDN

Configuring Multilink PPP (cont.)

Router(config)#interface dialer1Router(config-if)#ip address 10.10.10.7 255.255.255.0Router(config-if)#encapsulation pppRouter(config-if)#dialer idle-timeout 30Router(config-if)#dialer map ip 10.10.10.8 name Router 81012345678901

Router(config-if)#dialer-group 1Router(config-if)#ppp authentication chap

Router(config)#interface dialer1Router(config-if)#ip address 10.10.10.7 255.255.255.0Router(config-if)#encapsulation pppRouter(config-if)#dialer idle-timeout 30Router(config-if)#dialer map ip 10.10.10.8 name Router 81012345678901

Router(config-if)#dialer-group 1Router(config-if)#ppp authentication chap

Router(config-if)#dialer load-threshold 128 either


ISDN

Rotary group

Caller Identification Screening

Call setup message with local ISDN

numbers

5551234

Router A Router B

RouterISDN

number

A 5551234

Compare with allowed numbers

Accept call

– Extra level of call management– Call not set up (or charged) until acceptance– An alternative: PPP encapsulation and CHAP

ISDN

Configuring Caller ID Screening

Router(config-if)#isdn caller number Router(config-if)#isdn caller number

• Enables caller ID screening

56 kbps

Selecting ISDN Rate Adaptation

– Configured for outgoing calls– Requested lower speed from call is honored– Assigned on a per-destination basis

56 kbps

BRI 0BRI 0

BRI 1

64 kbps64 kbps

ISDN

Configuring Rate Adaptation

Router(config-if)#dialer map protocol next-hop-address [name name] [speed speed] [broadcast] [dial-string]

• Negotiates speed for calls to a destination

Configuring Called-Number Answer

• Sets the number to allow the interface to respond/answer

Router(config-if)#isdn answer1 [called-party-number] Router(config-if)#isdn answer1 [called-party-number]

Router(config-if)#isdn answer2 [called-party-number] Router(config-if)#isdn answer2 [called-party-number]

or

Monitoring PPP on BRIBranchF#sh int bri 0 1BRI0:1 is up, line protocol is up Hardware is BRI MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, rely 255/255, load 1/255 Encapsulation PPP, loopback not set, keepalive set (10 sec) LCP Open Open: IPCP, CDPCP Last input 00:00:02, output 00:00:02, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0 (size/max/drops); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 45 packets input, 1448 bytes, 0 no buffer Received 45 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 45 packets output, 1444 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out 3 carrier transitions

Monitoring ISDN BRI D Channel

•BranchF#sh int bri 0•BRI0 is up, line protocol is up (spoofing)• Hardware is BRI• Internet address is 10.155.0.1/24• MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, rely 255/255, load 1/255• Encapsulation PPP, loopback not set• Last input 00:00:04, output never, output hang never• Last clearing of "show interface" counters never• Input queue: 0/75/0 (size/max/drops); Total output drops: 0• Queueing strategy: weighted fair• Output queue: 0/1000/64/0 (size/max total/threshold/drops)• Conversations 0/1/256 (active/max active/max total)• Reserved Conversations 0/0 (allocated/max allocated)• 5 minute input rate 0 bits/sec, 0 packets/sec• 5 minute output rate 0 bits/sec, 0 packets/sec• 680 packets input, 3651 bytes, 0 no buffer• Received 223 broadcasts, 0 runts, 0 giants, 0 throttles• 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort• 680 packets output, 3697 bytes, 0 underruns• 0 output errors, 0 collisions, 5 interface resets• 0 output buffer failures, 0 output buffers swapped out• 3 carrier transitions

Monitoring ISDN BRI B ChannelsBranchF#sh int bri 0 1 2BRI0:1 is up, line protocol is up Hardware is BRI MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, rely 255/255, load 1/255 Encapsulation PPP, loopback not set, keepalive set (10 sec) LCP Open Open: IPCP, CDPCP Last input 00:00:01, output 00:00:01, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0 (size/max/drops); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 82 packets input, 2844 bytes, 0 no buffer Received 82 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 82 packets output, 2838 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out 5 carrier transitions(output omitted)

Monitoring ISDN BRIRouter#show isdn status

The current ISDN Switchtype = basic-5essISDN BRI0 interface Layer 1 Status: ACTIVE Layer 2 Status: TEI = 65, State = MULTIPLE_FRAME_ESTABLISHED Layer 3 Status: 1 Active Layer 3 Call(s) Activated dsl 0 CCBs = 1 CCB:callid=2, sapi=0, ces=1, B-chan=1 Total Allocated ISDN CCBs = 1

Router#show isdn status

The current ISDN Switchtype = basic-5essISDN BRI0 interface Layer 1 Status: ACTIVE Layer 2 Status: TEI = 65, State = MULTIPLE_FRAME_ESTABLISHED Layer 3 Status: 1 Active Layer 3 Call(s) Activated dsl 0 CCBs = 1 CCB:callid=2, sapi=0, ces=1, B-chan=1 Total Allocated ISDN CCBs = 1

Verifying Multilink PPPRouter#show ppp multilinkBundle rudder, 3 members, first link is BRI0: B-Channel 10 lost fragments, 8 reordered, 0 unassigned, sequence 0x1E/0x1E rcvd/sentBundle dallas, 4 members, first link is BRI2: B-Channel 10 lost fragments, 28 reordered, 0 unassigned, sequence 0x12E/0x12E rcvd/sent

Router#show ppp multilinkBundle rudder, 3 members, first link is BRI0: B-Channel 10 lost fragments, 8 reordered, 0 unassigned, sequence 0x1E/0x1E rcvd/sentBundle dallas, 4 members, first link is BRI2: B-Channel 10 lost fragments, 28 reordered, 0 unassigned, sequence 0x12E/0x12E rcvd/sent

Verifying Multilink PPP (cont.)Router# show interface bri0 1 BRI0: B-Channel 1 is up, line protocol is up Hardware is BRI MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, rely 255/255, load 1/255 Encapsulation PPP, loopback not set, keepalive not set lcp = OPEN multilink = OPEN ipcp = OPEN Last input 0:05:51, output 0:05:52, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0 (size/max/drops); Total output drops: 0 Output queue: 0/64/0 (size/threshold/drops) Conversations 0/1 (active/max active) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 15 packets input, 804 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 14 packets output, 806 bytes, 0 underruns 0 output errors, 0 collisions, 19 interface resets, 0 restarts 0 output buffer failures, 0 output buffers swapped out 1 carrier transitions

Troubleshooting Multilink PPP

BranchF#debug dialerBranchF#ping 10.115.0.135

Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.115.0.135, timeout is 2 seconds:

BRI0: Dialing cause ip (s=10.155.0.1, d=10.115.0.135)BRI0: Attempting to dial 6000%LINK-3-UPDOWN: Interface BRI0:2, changed state to updialer Protocol up for BR0:2.%LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:2, changed state to up!!!!Success rate is 80 percent (4/5), round-trip min/avg/max = 32/34/36 msBranchF#BRI0: rotary group to 6000 overloaded (1)BRI0: Attempting to dial 6000%ISDN-6-CONNECT: Interface BRI0:2 is now connected to 6000 CentralF

BranchF#debug dialerBranchF#ping 10.115.0.135

Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.115.0.135, timeout is 2 seconds:

BRI0: Dialing cause ip (s=10.155.0.1, d=10.115.0.135)BRI0: Attempting to dial 6000%LINK-3-UPDOWN: Interface BRI0:2, changed state to updialer Protocol up for BR0:2.%LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:2, changed state to up!!!!Success rate is 80 percent (4/5), round-trip min/avg/max = 32/34/36 msBranchF#BRI0: rotary group to 6000 overloaded (1)BRI0: Attempting to dial 6000%ISDN-6-CONNECT: Interface BRI0:2 is now connected to 6000 CentralF

Troubleshooting Multilink PPP (cont.)

• CHAP/PAP/caller ID on answering router?• Dialer load threshold on one router?• Fair queuing turned on?

Bundle

Router#debug isdn q921Router#debug isdn q921

Router#debug isdn q931Router#debug isdn q931

• Shows call setup and teardown of ISDN network connections (Layer 3) between the access router and the ISDN switch

ISDN debug Commands

– Shows data link layer messages (Layer 2) on the D channel between the access router and the ISDN switch

Configuration Tasks for PRI

– Select the PRI switch type

– Specify T1/E1 controller, framing, and line coding for the facility

– Set PRI group timeslots for T1/E1 and indicate the speed used

– Specify the interface on the router that you will configure for DDR

T1/E1 PRI23B (T1) or30B (E1)

D

ISDN PRI Configuration

Router(config)#controller {t1 | e1} {slot/port | unit-number}

Router(config)#controller {t1 | e1} {slot/port | unit-number}

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

• Configures the ISDN PRI switch type

• Configures the ISDN PRI controller

T1/E1 Controller Parameters

Router(config-controller)#framing {sf | | crc4 | no-crc4}

• Selects the line-code type on the controller

Router(config-controller)#linecode {ami | | hdb3}

• Selects the framing type on the controller

• Specifies the T1 clock source

Router(config-controller)#clock source {line [primary | secondary] | internal} Router(config-controller)#clock source {line [primary | secondary] | internal}

esf

b8zs

Additional ISDN PRI Configuration Parameters

• Specifies ISDN PRI on the T1 or E1 controller

• Specifies the serial port for the PRI D channel

Router(config)#interface serial {slot/port: | unit:}{23 | 15} Router(config)#interface serial {slot/port: | unit:}{23 | 15}

Router(config-controller)#pri-group [timeslots range] Router(config-controller)#pri-group [timeslots range]

• Switches incoming analog calls to internal modems

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

PRI Configuration ExampleCisco 3600

T1 PRI

isdn switch-type primary-5ess!controller t1 0/0pri-group timeslots 1-24framing esflinecode b8zsclock source line!interface serial 0/0:23ip address 192.168.11.2 255.255.255.0isdn incoming-voice modem

ISDN5ESS


Branch office

Central site

PRI

BRI

ISDN

ISDN, PPP,CHAP, DDR

Summary

• After completing this chapter, you should be able to perform the following tasks:– Select BRI or PRI service for a particular

application

– Identify Q.921 and Q.931 signaling and call sequences

– Configure ISDN BRI

– Configure ISDN PRI

– Configure ISDN DDR

Review Questions

– Compare ISDN BRI with ISDN PRI.

– If you are not sure what your ISDN switch type is, where would you obtain this information?

– What are Q.921 and Q.931?

Establishing a Dedicated Frame

Relay Connection and Controlling Traffic

Flow

Objectives• Upon completion of this chapter, you will be able to p

erform the following tasks:– Configure Frame Relay– Configure Frame Relay subinterfaces– Configure Frame Relay traffic shaping– Verify Frame Relay operation

261

Chapter Activities

Windows 95 PC Modem

Branch office

ISDN/analog

Small office

Central site

Frame Relay

Frame Relay

service

PRI

BRI

BRI

Frame Relay

Async

AAA server

Async

Frame Relay Overview

– Virtual circuits make connections

– Connection-oriented service

DTE or CPE

routers

Frame Relayworks here

TokenRing

CSU/DSU

DCE or FrameRelay switches

Frame Relay Operation

– Get locally significant DLCIs from your Frame Relay provider

– Map your network addresses to DLCIs

CSU/DSU

DLCI=500

PVC

10.1.1.1

ARPInverse ARP or

Frame Relay map

ETH DestinationMAC

SourceMAC

IP IP(10.1.1.1)

FrameRelay

DestinationDLCI (500)

CSU/DSU

Frame Relay Signaling

•Cisco supports three LMI standards:– ANSI T1.617 Annex D

– ITU-T Q.933 Annex A

– “The gang of four”

DLCI=500 PVC

LMI500=Active400=Inactive

DLCI=400PVC

Keepalive

Configuring Basic Frame Relay

Central Branch

Central(config)#interface Serial1Central(config-if)#ip address 10.16.0.1 255.255.255.0Central(config-if)#encapsulation frame-relay

Configuring Address Mapping

Branch

Non-Cisco

Central(config)#interface Serial1Central(config-if)#ip address 10.16.0.1 255.255.255.0Central(config-if)#encapsulation frame-relayCentral(config-if)#bandwidth 56Central(config-if)#frame-relay map ip 10.16.0.2 110 broadcastCentral(config-if)#frame-relay map ip 10.16.0.3 120 broadcast ietf

Central Branch

DLCI to Branch=110DLCI to Non-Cisco=12010.16.0.1/24

10.16.0.2/24

Central siteVC

VC

10.16.0.3/24

Verifying Frame Relay Operation

– Displays line, protocol, DLCI, and LMI information

Router#show interface serial 0Serial0 is up, line protocol is up Hardware is CD2430 in sync mode MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec, rely 255/255, load 1/255 Encapsulation FRAME-RELAY, loopback not set, keepalive set (10 sec) LMI enq sent 112971, LMI stat recvd 112971, LMI upd recvd 0, DTE LMI up LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0 LMI DLCI 1023 LMI type is CISCO frame relay DTE FR SVC disabled, LAPF state down Broadcast queue 0/64, broadcasts sent/dropped 32776/0, interface broadcasts 14 Last input 00:00:00, output 00:00:03, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0 (size/max/drops); Total output drops: 0 Queueing strategy: weighted fair <Output Omitted>

Verifying Frame Relay Operation (cont.)

– Displays PVC traffic statistics

Router#show frame-relay pvc 110 PVC Statistics for interface Serial0 (Frame Relay DTE) DLCI = 110, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0 input pkts 14055 output pkts 32795 in bytes 1096228 out bytes 6216155 dropped pkts 0 in FECN pkts 0 in BECN pkts 0 out FECN pkts 0 out BECN pkts 0 in DE pkts 0 out DE pkts 0 out bcast pkts 32795 out bcast bytes 6216155

<Output Omitted>


– Displays the route maps, either static or dynamic

Router#show frame-relay mapSerial0 (up): ip 10.140.2.1 dlci 120(0x78,0x1C80), dynamic, broadcast,, status defined, active


– Displays LMI information

Router#show frame-relay lmi LMI Statistics for interface Serial0 (Frame Relay DTE) LMI TYPE = CISCO Invalid Unnumbered info 0 Invalid Prot Disc 0 Invalid dummy Call Ref 0 Invalid Msg Type 0 Invalid Status Message 0 Invalid Lock Shift 0 Invalid Information ID 0 Invalid Report IE Len 0 Invalid Report Request 0 Invalid Keep IE Len 0 Num Status Enq. Sent 113100 Num Status msgs Rcvd 113100 Num Update Status Rcvd 0 Num Status Timeouts 0


– Displays LMI debug information

Router#debug frame-relay lmiSerial3/1(in): Status, myseq 214RT IE 1, length 1, type 0KA IE 3, length 2, yourseq 214, myseq 214PVC IE 0x7 , length 0x6 , dlci 130, status 0x2 , bw 0Serial3/1(out): StEnq, myseq 215, yourseen 214, DTE updatagramstart = 0x1959DF4, datagramsize = 13FR encap = 0xFCF1030900 75 01 01 01 03 02 D7 D6 Serial3/1(in): Status, myseq 215RT IE 1, length 1, type 1KA IE 3, length 2, yourseq 215, myseq 215Serial3/1(out): StEnq, myseq 216, yourseen 215, DTE updatagramstart = 0x1959DF4, datagramsize = 13FR encap = 0xFCF1030900 75 01 01 01 03 02 D8 D7


– Clears dynamically created Frame Relay maps

Router#sh frame mapSerial0 (up): ip 10.140.2.1 dlci 120(0x78,0x1C80), dynamic, broadcast,, status defined, activeRouter#clear frame-relay-inarpRouter#sh frame mapRouter#

Selecting a Frame Relay Topology

Star (hub and spoke)

Full mesh

Partial mesh

– Broadcast traffic must be replicated for each active connection

Reachability Issues with Routing Updates

Routingupdate

A

Circuit #21

Circuit #22

Circuit #23

D

C

B

B

C

D

2

3

1

Resolving Reachability Issues

– Split horizon can cause problems in NBMA environments

– A single physical interface simulates multiple logical interfaces

– Subinterfaces can resolve split horizon issues

Subnet A

Subnet B

Subnet C

S0

PhysicalinterfaceLogical interface

S0.1S0.2S0.3

Configuring Subinterfaces–Multipoint– Subinterfaces act as default NBMA network

–Can save subnets because uses single subnet

–Good for full-mesh topology

–Point-to-point– Subinterfaces act as leased line

–Each point-to-point connection requires its own subnet

–Good for star or partial-mesh topologies

Central(config)#<Output Omitted>Central(config-if)#interface Serial0Central(config-if)#no ip addressCentral(config-if)#encapsulation frame-relay!Central(config)#interface Serial0.2 point-to-pointCentral(config-subif)#ip address 10.17.0.1 255.255.255.0Central(config-subif)#frame-relay interface-dlci 110!Central(config)#interface Serial0.3 multipointCentral(config-subif)#ip address 10.18.0.1 255.255.255.0Central(config-subif)#frame-relay interface-dlci 120Central(config-subif)#frame-relay interface-dlci 130!<Output Omitted>

Configuring Subinterfaces Example10.17.0.1S0.2-DLCI=110

10.18.0.2S0

Branch

Central

Branch

10.18.0.1S0.3-DLCI=120S0.3-DLCI=130

10.18.0.3S0

120

130

10.17.0.2S0

Branch110

56 kbpsT1

Branch office Central site

Frame Relay cloud

Frame Relay Traffic Shaping Overview

CIR=32 kbps

Frame Relay Traffic Flow Terminology

I am congested.

T1

Bc=64 kbps

Local accessloop=T1

Local accessloop=64 kbps

Traffic flow

FECN

BECN

Frame Relay Traffic Flow Terminology (cont.)

Time (T=Bc/CIR)

Discard

Bc

Bc + Be

Access rate

Discard frame

DE=1

DE=0CIR

Frame 1 Frame 2 Frame 3 Frame 4

Bit

s

56 kbps T1

Branchoffice

Frame Relaycloud

Bottleneck Centralsite

I need to reduce the pace at which

I send packets.

Why Use Traffic Shaping over Frame Relay?

56 kbps T1

Frame Relay cloud

Why use Traffic Shaping over Frame Relay? (cont.)

Branchoffice

Centralsite

BECN

– Enters map class configuration mode so you can define a map class

Router(config)#map-class frame-relay map-class-name

Configuring Frame Relay Traffic Shaping—Steps 1 and 2

Configuring Frame Relay Traffic Shaping—Step 2 (cont.)

– Defines the average and peak rates

or

Router(config-map-class)#frame-relay traffic-rate average [peak]

– Specifies that the router fluctuates the sending rate based on the BECNs received

Router(config-map-class)#frame-relay adaptive-shaping becn

– Specifies a custom queue list

or

Router(config-map-class)#frame-relay custom-queue-list number

– Specifies a priority group

Router(config-map-class)#frame-relay priority-group number

or

Configuring Frame Relay Traffic Shaping—Step 2 (cont.)

– Enables Frame Relay on an interface

Router(config-if)#encapsulation frame-relay

Router(config-if)#frame-relay traffic-shaping

– Enables Frame Relay traffic shaping on an interface

Router(config-if)#frame-relay class map-class-name

– Maps the map class to virtual circuits on the interface

Step 3

Step 4

Step 5

Configuring Frame Relay Traffic Shaping—Steps 3 to 5

Traffic Shaping Rate Enforcement Example

T1

Frame Relay cloud

9.6 kbps

9.6 kbpsBranch office

Central site

I need to send packets at the CIR

for each VC.

CIR=9.6 kbps

CIR=9.6 kbps

Branch office

Egress point

Configuring Traffic Shaping Rate Enforcement Example

Central(config)#interface Serial2Central(config-if)#no ip address Central(config-if)#encapsulation frame-relayCentral(config-if)#frame-relay traffic-shapingCentral(config-if)#frame-relay class branch!…!Central(config)#map-class frame-relay branchCentral(config-map-class)#frame-relay traffic-rate 9600 18000

T1

Frame Relay cloud

Branch office

Central site

Branch office

I need to adjust my transmit speed

because of BECNs.

Traffic Shaping BECN Support Example

56 kbps T1

Frame Relay cloud

Branchoffice

Centralsite

BECNBECN

BECN

Configuring Traffic Shaping BECN Support Example

Central(config)#interface serial 0Central(config-if)#no ip address Central(config-if)#encapsulation frame-relayCentral(config-if)#frame-relay traffic-shapingCentral(config-if)#frame-relay class becnnotify!…!Central(config)#map-class frame-relay becnnotifyCentral(config-map-class)#frame-relay adaptive-shaping becn

56 kbps T1

Frame Relay cloud

Branchoffice

Centralsite

BECN

BECN

interface Serial0 no ip address encapsulation frame-relay frame-relay lmi-type ansi frame-relay traffic-shaping frame-relay class slow_vcs!interface Serial0.1 point-to-point ip address 10.128.30.1 255.255.255.248 ip ospf cost 200 bandwidth 10 frame-relay interface-dlci 101!interface Serial0.2 point-to-point ip address 10.128.30.9 255.255.255.248 ip ospf cost 400 bandwidth 10 frame-relay interface-dlci 102 class fast_vcs! interface Serial0.3 point-to-point ip address 10.128.30.17 255.255.255.248 ip ospf cost 200 bandwidth 10 frame-relay interface-dlci 103

!map-class frame-relay slow_vcs frame-relay traffic-rate 4800 9600 frame-relay custom-queue-list 1!map-class frame-relay fast_vcs frame-relay traffic-rate 16000 64000 frame-relay priority-group 2!access-list 100 permit tcp any any eq 2065access-list 115 permit tcp any any eq 256!priority-list 2 protocol decnet highpriority-list 2 protocol ip normalpriority-list 2 default medium!queue-list 1 protocol ip 1 list 100queue-list 1 protocol ip 2 list 115queue-list 1 default 3queue-list 1 queue 1 byte-count 1600 limit 200queue-list 1 queue 2 byte-count 600 limit 200queue-list 1 queue 3 byte-count 500 limit 200

Configuring Traffic Shaping Queuing Example

Verifying Frame Relay Traffic Shaping

CentralA#sh frame-relay pvc

PVC Statistics for interface Serial3/1 (Frame Relay DTE)

DLCI = 110, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial3/1.1

input pkts 35 output pkts 40 in bytes 4324 out bytes 6684 dropped pkts 0 in FECN pkts 0 in BECN pkts 0 out FECN pkts 0 out BECN pkts 0 in DE pkts 0 out DE pkts 0 out bcast pkts 25 out bcast bytes 5124 Shaping adapts to BECN pvc create time 00:12:55, last time pvc status changed 00:12:55


Cisco 3640Central site

Frame Relay

Frame Relay

S3/1

BE

CN

Branch officeCisco 1600

S0 Frame Relayservice

Summary

– Configure Frame Relay

– Configure Frame Relay subinterfaces

– Configure Frame Relay traffic shaping

– Verify Frame Relay operation

After completing this chapter, you shouldbe able to perform the following tasks:

– What is a DLCI and how is it used to route Frame Relay traffic?

– Why would you use Frame Relay subinterfaces?

– List and describe three Frame Relay traffic shaping features.

Review Questions

wide area network(wan)

Documents