Introduction to ISDNIntroduction to ISDN

Prepared by: Mehdi Kereshteh Payam Kaywan

University of Science & Technology of Mazandaran

21/8/1384

What is ISDN?What is ISDN?

ISDN - Integrated Services Digital Network Telephone services Telecommunication

services Used for voice, image and data

ISDN protocolsISDN protocols

E - series for Telephone network and ISDN I - series for ISDN concepts, aspects and

interfaces

FundamentalsFundamentals

Types of channels– Bearer channel (B-channel=64 kb/s) clear pipe for data

– Delta channel (D-channel, 16 kb/s or 64 kb/s) call signaling information:

who is calling type of call calling what number

FundamentalsFundamentals

Service types– Basic Rate Interface (2 B channels + 1 D channel (16

kb/s))

– Primary Rate Interface (30 B channels + 1 D channel (64 kb/s))

Advantages of ISDNAdvantages of ISDN

Digital– reliable connection

Speed– 128 kb/s (160 kb/s) for BRI

– 1920 kb/s (2048 kb/s) for PRI

Fast call setup– 2 seconds

Advantages of ISDN (2)Advantages of ISDN (2)

Bandwidth on Demand– adding new channels to the bundle of channels

Multiple devices– phone, fax, PC, videoconferencing system, router,

terminal adapter,.. each with its own sub-address

ISDN and OSI modelISDN and OSI model

Layer1 - Physical Layer2 - Data Link Layer3 – Network

Interfaces and Devices (1)Interfaces and Devices (1)

Interfaces– S/T (4w)– U (2w)

Devices– NT1– TE1 - ISDN devices– TE2 - analog devices (need TA)– TA - Terminal Adapter (rate adaptation (V.110, V.120)

Interfaces and Devices (2)Interfaces and Devices (2)

TE1

TE2 TA

NT12W4W

ISDN devices

Analog devices:phone, Fax III,...

Rate adaptation

S/T interface U interface

ISDN Access Servers (1)ISDN Access Servers (1)

Digital modems (accepting analog and ISDN calls)– software busy-out feature

56 kbit/s technologies Rate adaptation (V.110, V.120,..) Compression (Stack,..) Synchronous PPP (with CHAP/PAP

authentication)

ISDN Access Servers (2)ISDN Access Servers (2)

PPP Multilink BACP (Bandwidth Allocation Control

Protocol) Controlling the number of B-channels per

user D-channel based callback CLIP - Caller Line Identification

Presentation

56 k Technology56 k TechnologyAccess server

Modem

Telephone switch

Telephone switch

Telephone switch ?

Access server

Modem

Modem

Digital lineAnalog line

<= 33,6 kbps

<= 56 kbpsISDN, E1,..

<= 33,6 kbps

56 k Prerequisites56 k Prerequisites

Only one analogue/digital conversion– less noise and faster digital lines

Digital Access Server Same technology in Access Server and in

dial-up modem – 56K Flex from Lucent Technologies and Rockwell– X2 from U.S. Robotics, Texas Instruments and Cirrus

Logic– V.90 - ITU-T standard (to be confirmed in 9/98)

56 k Considerations56 k Considerations

56 k not reached in reality– 45 kbps practical maximum

Cost for upgrading equipment to ITU-T standard

Using ISDN for Using ISDN for IP Data Networks (1)IP Data Networks (1)

Characteristics– Speed

– Fast call setup

– Bandwidth on Demand

Using ISDN for Using ISDN for IP Data Networks (2)IP Data Networks (2)

Modes of Usage– Dial Up (LAN or host)

– Bandwidth on Demand

– Backup lines

– Permanent connections

Dial UpDial Up

Providers need:– subscribe for PRI connections or multiple BRI

connections

– ISDN Access Server

Dial UpDial Up

Users need for host connections:– subscribe for BRI connection

– ISDN Adapter

Users need for LAN connections– subscribe for PRI or BRI connection

– ISDN router (commercial, PC version with ISDN Adapter,..)

Dial Up - PrivateDial Up - Private

PC with internal or external ISDN adapter

Internet

ISDN Access server

ISDN connection

ISDN connection

Telephone Network

Dial Up - LANDial Up - LAN

ISDN connection

ISDN connection

ISDN router

Internet

LAN

ISDN Access Server

Telephone Network

ISDN AdaptersISDN Adapters

Internal/external Active/passive (for internal) Integrated NT Plug for telephone line Integrated modem Synchronous PPP (with CHAP/PAP

authentication)

ISDN Adapters 2ISDN Adapters 2

PPP Multilink Rate adaption (V.110, V.120,..) CAPI Compression (Stac,…)

ISDN RoutersISDN Routers

Integrated NT Plug for telephone line Integrated modem Synchronous PPP (with CHAP/PAP

authentication) PPP Multilink Compression (Stac,…) Tariff management

Bandwidth on DemandBandwidth on Demand

Router to router connections ISDN call setup when leased line

overloaded

Backup linesBackup lines

Router to router connections ISDN call setup when leased line fails

EquipmentEquipment

ALL EQUIPMENT COMPATIBLE with existing national ISDN services– Test new equipment first

ISDN ArchitectureISDN Architecture

Terminalequipment

(TE)

NetworkTermination

(NT)

Subscribersite orserviceprovider

User-networksignaling

User-networksignaling

Subscriberinterface to

ISDN

Digitalsubscriberloop toC. O.

Subscriberpremises

>64kbpsnon-switchedcapabilities

>64kbpsswitched

capabilities

64kbpsckt non-switched

capabilities

>64kbpsckt switchedcapabilities

ISDNswitch

ISDNswitch

Packet switchedcapabilities

Frame modecapabilities

Common-channel signaling

capabilities

Network

Transmission StructureTransmission Structure

B Channel: 64 kbps D Channel: 16 or 64 kbps H Channel: 384 (H0), 1536 (H1), or 1920

(H12) kbps Basic Rate Interface Primary Rate Interface

Basic

ISDN Channel StructuresISDN Channel Structures

B

B

D

Primary

BB

DB

Basic Service:Management rate: 192 kbpsStandard throughput: 144 kbpsComposition: B + B + D channels, + Synch & framing

Primary Service:Rate: 1.544/2.048 MbpsComposition: 2.048 Mbps: 30 B at 64 kbps each 2 D at 64 kbps 1.544 Mbps: 23 B at 64 kbps each 1 D at 64 kbps

Information:Voice, Data

Signaling:Overhead ortelemetry, etc.

PCM voice channels

Signaling

Ordering ISDN connectionsOrdering ISDN connections

With or without NT1 Type of NT (NT1, NT1+2ab,…) Types of B-channels (data, voice,both) Usage of D-channel packet data CLIP (Calling Line Identification

Presentation) Standard or comfort services

National ISDN variationsNational ISDN variations

USA: 5ESS/DMS100/NI-1/NI-2 Europe: NET3 France: VN2/VN3/NET33 Germany: 1TR6/NET3 Japan Australia

References - URL’sReferences - URL’s

http://www.alumni.caltech.edu/~dank/isdn/ for RFCs:

http://www.alumni.caltech.edu/~dank/isdn/isdn_ai.html#RFCS

http://www.data.com http://www.pacbell.com/products/business/

fastrak/networking/isdn/info/isdn-guide http://www.adtran.com/support/isu/mpfaq.html