ISDN in full description ..

1. Integrated Services DigitalIntegrated Services Digital
Network (ISDN)Network (ISDN)
Prepared by:
(MADURAI KAMARAJ UNIVERSITY)
 Pawan Kumar Singh (B244033)
 Piyush Chandra (B244034)
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2. An overview of ISDNAn 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.
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3. ISDN ServicesISDN Services
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4. 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
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5. 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.
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6. 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.
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7. 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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8. IDN
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9. ISDNISDN
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10. 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
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11. 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 Kbps
128 Kbps
B (64 Kbps)
B (64 Kbps)
Inverse Multiplexers
Inverse Multiplexing of B ChannelsInverse Multiplexing of B Channels
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12. 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.
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13. 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.10/05/13 13

14. 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)
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15. 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.
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16. 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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17. User InterfaceUser Interface
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18. 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).
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19. Basic
ISDN Channel StructuresISDN 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: 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 or
telemetry, etc.
PCM voice
channels
Signaling
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20. Basic Rate Interface (BRI)Basic Rate Interface (BRI)
• 2 B Channels
• 1 D Channel
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21. 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.
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22. Primary Rate Interface (PRI)Primary Rate Interface (PRI)
• More sophisticated service compared to BRI
• PRI service offers 23 B channels and 1 D channel
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23. 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.
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24. 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.
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25.  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.
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26.  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).
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27.  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 the10/05/13 27

28. Reference PointsReference Points
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29. 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)
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30. Interfaces and Devices (2)Interfaces and Devices (2)
TE1
TE2 TA
NT1
2W4W
ISDN devices
Analog devices:
phone, Fax III,...
Rate adaptation
S/T interface
U interface
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31. 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)
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32. ISDN LayersISDN Layers
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33. Simplified Layers of ISDNSimplified Layers of ISDN
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34. ISDN and OSI modelISDN and OSI model
Layer1 - Physical
Layer2 - Data Link
Layer3 – Network
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35. 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
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36. 56 k Technology56 k Technology
Access server
Modem
Telephone
switch
Telephone
switch
Telephone
switch
?
Access server
Modem
Modem
Digital line
Analog line
<= 33,6 kbps
<= 56 kbps
ISDN, E1,..
<= 33,6 kbps
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37. 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)
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38. 56 k Considerations56 k Considerations
56 k not reached in reality
– 45 kbps practical maximum
Cost for upgrading equipment to ITU-T
standard
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39. Using ISDN forUsing ISDN for
IP Data Networks (1)IP Data Networks (1)
Characteristics
– Speed
– Fast call setup
– Bandwidth on Demand
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40. Using ISDN forUsing 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
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41. ISDN AdaptersISDN Adapters
Internal/external
Active/passive (for internal)
Integrated NT
Plug for telephone line
Integrated modem
Synchronous PPP (with CHAP/PAP
authentication)
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42. ISDN Adapters 2ISDN Adapters 2
PPP Multilink
Rate adaption (V.110, V.120,..)
CAPI
Compression (Stac,…)
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43. ISDN RoutersISDN Routers
Integrated NT
Plug for telephone line
Integrated modem
Synchronous PPP (with CHAP/PAP
authentication)
PPP Multilink
Compression (Stac,…)
Tariff management
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44. ISDN ArchitectureISDN 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
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45. National ISDN variationsNational ISDN variations
USA: 5ESS/DMS100/NI-1/NI-2
Europe: NET3
France: VN2/VN3/NET33
Germany: 1TR6/NET3
Japan
Australia
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46. Thanks
?10/05/13 46