Introduction to ISDN Prepared by: Mehdi Kereshteh Payam Kaywan University of Science & Technology of Mazandaran 21/8/1384

What is ISDN? l ISDN - Integrated Services Digital Network l Telephone services  Telecommunication services l Used for voice, image and data

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

Fundamentals l 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: l who is calling l type of call l calling what number

Fundamentals l 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 ISDN l Digital –reliable connection l Speed –128 kb/s (160 kb/s) for BRI –1920 kb/s (2048 kb/s) for PRI l Fast call setup –2 seconds

Advantages of ISDN (2) l Bandwidth on Demand –adding new channels to the bundle of channels l Multiple devices –phone, fax, PC, videoconferencing system, router, terminal adapter,.. each with its own sub-address

ISDN and OSI model ISDN and OSI model l Layer1 - Physical l Layer2 - Data Link l Layer3 – Network

Interfaces and Devices (1) l Interfaces –S/T (4w) –U (2w) l Devices –NT1 –TE1 - ISDN devices –TE2 - analog devices (need TA) –TA - Terminal Adapter (rate adaptation (V.110, V.120)

Interfaces and Devices (2) TE1 TE2TA NT1 2W4W ISDN devices Analog devices: phone, Fax III,... Rate adaptation S/T interface U interface

ISDN Access Servers (1) l Digital modems (accepting analog and ISDN calls) –software busy-out feature l 56 kbit/s technologies l Rate adaptation (V.110, V.120,..) l Compression (Stack,..) l Synchronous PPP (with CHAP/PAP authentication)

ISDN Access Servers (2) l PPP Multilink l BACP (Bandwidth Allocation Control Protocol) l Controlling the number of B-channels per user l D-channel based callback l CLIP - Caller Line Identification Presentation

56 k Technology Access server Modem Telephone switch Telephone switch Telephone switch ? Access server Modem Digital line Analog line <= 33,6 kbps <= 56 kbps ISDN, E1,.. <= 33,6 kbps

56 k Prerequisites l Only one analogue/digital conversion –less noise and faster digital lines l Digital Access Server l 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 Considerations l 56 k not reached in reality –45 kbps practical maximum l Cost for upgrading equipment to ITU-T standard

Using ISDN for IP Data Networks (1) l Characteristics –Speed –Fast call setup –Bandwidth on Demand

Using ISDN for IP Data Networks (2) l Modes of Usage –Dial Up (LAN or host) –Bandwidth on Demand –Backup lines –Permanent connections

Dial Up l Providers need: –subscribe for PRI connections or multiple BRI connections –ISDN Access Server

Dial Up l Users need for host connections: –subscribe for BRI connection –ISDN Adapter l Users need for LAN connections –subscribe for PRI or BRI connection –ISDN router (commercial, PC version with ISDN Adapter,..)

Dial Up - Private PC with internal or external ISDN adapter Internet ISDN Access server ISDN connection Telephone Network

Dial Up - LAN ISDN connection ISDN router Internet LAN ISDN Access Server Telephone Network

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

ISDN Adapters 2 l PPP Multilink l Rate adaption (V.110, V.120,..) l CAPI l Compression (Stac,…)

ISDN Routers l Integrated NT l Plug for telephone line l Integrated modem l Synchronous PPP (with CHAP/PAP authentication) l PPP Multilink l Compression (Stac,…) l Tariff management

Bandwidth on Demand l Router to router connections l ISDN call setup when leased line overloaded

Backup lines l Router to router connections l ISDN call setup when leased line fails

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

ISDN Architecture Terminal equipment (TE) Network Termination (NT) Subscriber site or service provider User-network signaling User-network signaling Subscriber interface to ISDN Digital subscriber loop to C. O. Subscriber premises >64kbps non-switched capabilities >64kbps switched capabilities 64kbps ckt non-switched capabilities >64kbps ckt switched capabilities ISDN switch ISDN switch Packet switched capabilities Frame mode capabilities Common- channel signaling capabilities Network

Transmission Structure l B Channel: 64 kbps l D Channel: 16 or 64 kbps l H Channel: 384 (H0), 1536 (H1), or 1920 (H12) kbps l Basic Rate Interface l Primary Rate Interface

Basic ISDN Channel Structures B B D Primary B B D B Basic Service: Management rate: 192 kbps Standard throughput: 144 kbps Composition: B + B + D channels, + Synch & framing Primary Service: Rate: 1.544/2.048 Mbps Composition: Mbps: 30 B at 64 kbps each 2 D at 64 kbps Mbps: 23 B at 64 kbps each 1 D at 64 kbps Information: Voice, Data Signaling: Overhead or telemetry, etc. PCM voice channels Signaling

Ordering ISDN connections l With or without NT1 l Type of NT (NT1, NT1+2ab,…) l Types of B-channels (data, voice,both) l Usage of D-channel packet data l CLIP (Calling Line Identification Presentation) l Standard or comfort services

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

References - URL’s l l for RFCs: l l networking/isdn/info/isdn-guide l