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Integrated service digital network

ISDN (Integrated Services Digital Network) is a set of communication protocols that allows digital transmission of voice, video, and data over existing telephone lines. It was developed to digitize and integrate telephone networks to allow transmission of different data types. ISDN provides bearer, tele, and supplementary services through basic rate interface (BRI) with 2 B channels of 64 kbps each and 1 D channel of 16 kbps, or primary rate interface (PRI) with 23 B channels of 64 kbps and 1 D channel of 64 kbps. While ISDN provided faster speeds than analog networks, it has been surpassed by newer technologies like DSL and cable that provide even higher speeds at lower costs.

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COMPUTER NETWORKS Presented By Rahul Kumar Karn Presented to Siddheshwari Dutt Mishra 1
Contents  ISDN INTRODUCTION  ISDN SERVICES  ISDN CHANNELS  ISDN USER INTERFACE  FUNCTIONAL GROUPING  ISDN REFERENCE POINT  ISDN ADVANTAGE  ISDN DISADVANTAGE  REFERENCES 2
ISDN INTRODUCTION  ISDN Full Form I – INTEGRATED S – SERVICE D – DIGITAL N - NETWORK  ISDN was Developed by International Telecommunications Union (ITU-T) in 1976. 3
Continued  The main purpose is to digitize the telephone network to permit the transmission of audio, video, and text data over existing telephone lines.  Definition  ISDN is a set of protocols that combines digital telephony and data transport services.  The goal is to form a WAN that provides universal End-to-End connectivity over Digital Media. 4
ISDN Services 5
ISDN Services  Bearer services – provide the means to transfer information (voice, data, video) between users without the network manipulating the content of that information. Belongs to the first 3 layers of the OSI model.  Teleservices – the network my change or process the contents of the data.  correspond to layers 4-7 of the OSI model  rely on the facilities of bearer services 6
Continued  Supplementary services – provide additional functionality to the bearer services and tele-services  Ex. : reverse charging, call waiting, and message handling 7
Continued 8
Types of ISDN Channels 9
Barrier(B) Channel  A Bearer Channel (B Channel) is defined at a rate of 64 kbps.  It is the basic user channel and can carry any type of digital information in full duplex mode as long as the required transmission rate does not exceed 64 kbps.  It can be used to carry digital data, digital voice and any other low data rate information. 10
Continued  Several transmission can be accommo- dated at once if the signals are multiplexed first.  Four kind of connections can be set up over a B channel:  Circuit Switched  Packet switched  Frame mode  Semi-permanent 11
Data(D) Channel  A data channel (D channel) carry control signal for bearer channels.  This channel does not carry data and can be either 16 or 64 kbps, depending upon the user's need.  If we are using in-band signalling, the same cable carries data as well as control signals. 12
Continued  If we are using out-of-band signaling (as in ISDN), then two different cables carry data and control information.  Can also be used for packet switching or low speed telemetry. 13
Hybrid(H) Channel  A Hybrid channel (H-channel) is provided for user information at higher bit rates.  There are three types of H-Channels depending on the data rates:  H0 with data rate of384 kbps  H11 with data rate of 1536 kbps  H12 with data rate of 1920 kbps 14
Continued  Hybrid channels are used for high data rate applications such as video, teleconferencing and so on.  Can be used as a high-speed trunk.  Can also be subdivided as per user’s own TDM scheme. 15
User Interface of ISDN User Interface BRI Basic Rate Interface PRI Primary Rate Interface B-ISDN Broadband- ISDN 16
Basic Rate Interface  Basic Rate Interface specifies a digital pipe, consisting of two 64 Kbps B channels and one 16 Kbps D channel for a total of 144 Kbps (2B+D).  In addition, the BRI service itself requires 48 Kbps operating overhead. BRI therefore requires a digital pipe of 192 Kbps. 17
Continued  Conceptually, the BRI service is like a large pipe that contains three smaller pipes, two for the B channels and one for the D channel. The remainder of the space inside the large pipe carries the overhead bits required for its operation 18
Continued  Each B channel can be used for separate applications Such as Internet and Voice.  Allows individual B channels to be aggregated together into a Multilink channel. 19
Primary Rate Interface  The usual Primary Rate Interface (PRI) specifies a digital pipe with 23 B channels and one 64 Kbps D channel for signalling purpose.  Primary Rate Interface service consists of a D channel and either 23 B Or 30 B channels (depending on the country you are in) .  In addition, the PRI service itself uses 8 kbps of overhead. 20
Continued  Twenty three B channels of 64 Kbps each, plus one D channel of 64 Kbps equals 1.536 Mbps. 21
Continued  Each B channel to be used for separate applications including voice, data and Internet.  Multiple B channels can be Multilinked together. 22
Continued  ISDN Primary Rate Interface service provides digital access via a T1 line.  ISDN PRI service is used primarily by large organizations with intensive communications needs. 23
Broadband-ISDN  Narrowband ISDN has been designed to operate over the current communications infrastructure, which is heavily dependent on the copper cable. BISDN however, relies mainly on the evolution of fiber optics. According to CCITT BISDN is best described as 'a service requiring transmission channels capable of supporting rates greater than the primary rate. 24
Functional Grouping  Terminal Adapter (TA)  Converter device that converts standard electrical signals into the form used by ISDN - allows non-ISDN devices to operate on an ISDN network.  Exchange Termination (ET)  This is the local phone company's logical connection from your telephones to "the phone network". 25
Continued  Terminal Equipment type 1  Compatible with the ISDN network.  Ex.- Digital telephones, integrated voice/data terminals, personal computers, fax machine or videoconferencing machine.  Terminal Equipment type 2  Not compatible with the ISDN network.  Ex.- Analog telephone or modem, requires a TA, Terminal workstation 26
Continued  Network Termination type 1  This is the end of the line for the local phone company, and the beginning of your house's phone network.  Network Termination type 2  In most homes, this won't exist. If you were a big company with your own private telephone system, then this would be the guts of that telephone system. 27
Continued 28  Line Termination (LT)  This is the physical connection to the phone company. Defines the functions of the connections
ISDN Reference Points  U - Two wire cable that connects the customer’s equipment to the tele- communications provider.  R - Point between non-ISDN equipment (TE2) and the TA.  S - Four-wire cable from TE1 or TA to the NT1 or NT2.  T - Point between NT1 and NT2. 29
Continued 30
ISDN Layers 31
Simplified Layers of ISDN 32 Mechanical and electrical specs of interfaces R, S, T, U Encoding Multiplexing Power supply
Advantage of ISDN  Speed  BRI ISDN, using a channel aggregation protocol such as BONDING or Multilink- PPP, supports an uncompressed data transfer speed of 128 kb/s, plus bandwidth for overhead and signalling. PRI transfers at an even higher speed of up to 1920 kb/s.  Multiple Devices  ISDN allows multiple devices to share a single line. It is possible to combine many different digital data sources and have the 33
Continued information routed to the proper destination.  Signaling/Fast Call Setup  Instead of the phone company sending a ring voltage signal to ring the bell in your phone ("In-Band signal"), it sends a digital packet on a separate channel ("Out-of- Band signal").  The Out-of-Band signal does not disturb established connections, no bandwidth is taken from the data channels, and call setup time is very fast. 34
Disadvantage of ISDN  BRI is slower than DSL and cable.  More expensive than DSL and cable.  Bottom line: ISDN, in its current form, is no longer a “first-choice” technology 35
REFERENCES  https://en.wikipedia.org/wiki/Integrated_ Services_Digital_Network  http://ecomputernotes.com/ 36
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