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ISDN in full description ..
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Integrated Services Digital Integrated Services Digital Network (ISDN)Network (ISDN)
Prepared by:
(MADURAI KAMARAJ UNIVERSITY) Pawan Kumar Singh (B244033) Piyush Chandra (B244034)
04/12/23 1
An overview of ISDN An overview of ISDN
ISDN was developed by ITU-T in 1970. It is a set of protocols that combines digital telephony and data transport services.
The goal of ISDN is to form a wide area network (WAN) that provides universal end to end connectivity over digital media.
04/12/23 2
ISDN ServicesISDN Services
04/12/23 3
Continue…Continue…
The purpose of the ISDN is to provide fully integrated digital services to users. These services fall into three categories:
Bearer Services Teleservices Supplementary Services
04/12/23 4
Bearer Services:-
. Bearer Services provide to transfer information
(voice, data, and video) between the network
manipulating the content of that information.
. Bearer services belong to the first three layers of
OSI model and are well defined in the ISDN
standard. They can be provided using circuit –
switched, packet – switched, frame – switched or
cell – switched networks.
04/12/23 5
Teleservices :-
. In teleservicing the network may change or process
the content of the data.
. These services correspond to layers 4-7 of the OSI
model.
. Teleservices include telephony, telefax, videotex,
telex and teleconferencing.
. The ISDN defines these services by name, they
have not yet become standards.04/12/23 6
Supplementary Services :-
Supplementary services are those services that
provide additional functionality to the bearer
services and teleservices.
Example:- reverse charging, call waiting, and
message handling.
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IDN
04/12/23 8
ISDNISDN
04/12/23 9
Types of channels . Bearer channels
. Data channels(Delta)
. Hybrid channels
Channel rates
Channel Data Rate(Kbps)Bearer (B) 64
Data (D) 16, 64 Hybrid (H) 384, 1536, 1920
04/12/23 10
B Channels :- 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.
128 Kbps128 Kbps
B (64 Kbps)
B (64 Kbps)
Inverse Multiplexers
Inverse Multiplexing of B ChannelsInverse Multiplexing of B Channels
04/12/23 11
D Channels :- A data channel (D channel) can be either 16 or 64
Kbps, depending on the needs of the user. The primary function of D channel is to carry
control signaling information for the B channels.
. Who is calling
. Type of call
. Calling what number Can also be used for packet switching or low speed
telemetry.
04/12/23 12
H Channels :- Carry user information at higher bit rates 384 kb/s or
1536 kb/s or 1920 kb/s. These rates suit H channels 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. Uses include high speed data, fast facsimile, video,
high-quality audio.04/12/23 13
B Channel (64 kbps)
D Channel (16/64 kbps)
H Channel (384/1536 kbps)
Digital voice Signalling (using SS#7)
High-speed trunk
High-speed data (e.g. packet and circuit switched data)
Low- speed data, (e.g. packet, terminal, videotex)
Very high speed data
Other (e.g. fax, slow video)
Other (e.g. telemetry)
Other (e.g. fast fax. Video)
04/12/23 14
Advantages of ISDNAdvantages of ISDN
ISDN also provides more bandwidth than a traditional 56 kbps dialup connection.
ISDN uses bearer channels, also called B channels, as clear data paths.
Each B channel provides 64 kbps of bandwidth. An ISDN connection with two B channels would provide a
total usable bandwidth of 128 kbps. Each ISDN B channel can make a separate serial connection
to any other site in the ISDN network. ISDN lines can be used in conjunction with PPP
encapsulation.
04/12/23 15
Disadvantages of ISDNDisadvantages 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.
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User InterfaceUser Interface
04/12/23 17
ISDN standards define two main channel types The bearer channel, or B channel, is defined as a
clear digital path of 64 kbps The second channel type is called a delta channel,
or D channel.
– There can either be 16 kbps for the Basic Rate Interface (BRI) or 64 kbps for the Primary Rate Interface (PRI).
04/12/23 18
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
04/12/23 19
Basic Rate Interface (BRI)Basic Rate Interface (BRI)
• 2 B Channels• 1 D Channel
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BRIBRI
• Two B channels of 64 Kbps each, plus 1 D channel
of 16 kbps, equal 144 kbps. • In addition, the BRI services itself requires 48 kbps
of operating overhead. • BRI therefore requires a digital pipe of 192 kbps. • Conceptually, the BRI service is like a large pipe that
contains three smaller pipes, two for the B channel and one for the D channel.
04/12/23 21
Primary Rate Interface (PRI)Primary Rate Interface (PRI)
• More sophisticated service compared to BRI• PRI service offers 23 B channels and 1 D channel
04/12/23 22
PRIPRI
The usual primary rate interface(PRI) specifies a digital pipe with 23 B channels and one 64 kbps D channel.
In addition, the PRI service itself uses 8 kbps of overhead.
The PRI services is like a large pipe containing 24 smaller pipes. 23 for B channels and 1 for D channel.
04/12/23 23
Functional GroupingFunctional Grouping The devices that enable users to access the services of the BRI or PRI are described by their functional duties and collected in func- tional groupings. Functional grouping is a model that can be implemented using devices or equipment chosen by the subscriber.
04/12/23 24
Network Termination 1(NT1) :- A network termination 1(NT1) device controls the
physical and electrical termination of the ISDN at
the user’s premises and connects the user’s internal
system to the digital subscriber loop. These functions are comparable to those define for
the OSI physical layer. An NT1 organizes the data streams from a connected
subscriber into frames that can be sent over the digital
pipe, and translate the frames received from the
network.04/12/23 25
Network Termination 2(NT2) :- A network termination 2(NT2) device performs at the
physical, data link and network layers of the OSI model(layers 1, 2, 3).
An NT2 provides multiplexing (layer 1), flow control (layer 2), and packetizing (layer 3).
NT2 can be implemented by a veriety of equipment
types. For example, a private branch exchange
(digital PBX).
04/12/23 26
Terminal Equipment 1(TE1) :- Terminal equipment 1(TE1) is any device that
supports the ISDN standards. Example of TE1 are digital telephones, integrated
voice/data terminals, and digital facsimiles. Terminal Equipment 2(TE2) :- TE2 equipment is any non ISDN device, such as a
terminal, workstation, host computer, or regular
telephone. Terminal Adapter(TA) :- TA converts information received in non-ISDN Format
from a TE2 into a format capable of being carried by the
ISDN .
04/12/23 27
Reference PointsReference Points
04/12/23 28
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)
04/12/23 29
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
04/12/23 30
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)
04/12/23 31
ISDN LayersISDN Layers
04/12/23 32
Simplified Layers of ISDNSimplified Layers of ISDN
04/12/23 33
ISDN and OSI modelISDN and OSI model
Layer1 - Physical Layer2 - Data Link Layer3 – Network
04/12/23 34
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
04/12/23 35
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
04/12/23 36
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)
04/12/23 37
56 k Considerations56 k Considerations
56 k not reached in reality– 45 kbps practical maximum
Cost for upgrading equipment to ITU-T standard
04/12/23 38
Using ISDN for Using ISDN for IP Data Networks (1)IP Data Networks (1)
Characteristics– Speed
– Fast call setup
– Bandwidth on Demand
04/12/23 39
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
04/12/23 40
ISDN AdaptersISDN Adapters
Internal/external Active/passive (for internal) Integrated NT Plug for telephone line Integrated modem Synchronous PPP (with CHAP/PAP
authentication)
04/12/23 41
ISDN Adapters 2ISDN Adapters 2
PPP Multilink Rate adaption (V.110, V.120,..) CAPI Compression (Stac,…)
04/12/23 42
ISDN RoutersISDN Routers
Integrated NT Plug for telephone line Integrated modem Synchronous PPP (with CHAP/PAP
authentication) PPP Multilink Compression (Stac,…) Tariff management
04/12/23 43
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
04/12/23 44
National ISDN variationsNational ISDN variations
USA: 5ESS/DMS100/NI-1/NI-2 Europe: NET3 France: VN2/VN3/NET33 Germany: 1TR6/NET3 Japan Australia
04/12/23 45
Thanks
?04/12/23 46