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1
DECLARATION
I hereby declare that the project entitled “Installation, Commissioning & Operation
of SDH equipment; STM-1(Siemens)” submitted for the B.Tech Degree is my
original work and the project has not formed the basis for the award of any degree,
associateship, fellowship or any other similar titles.
Signature of the Student:
Place:
Date:
2
CERTIFICATE
This is to certify that the project entitled “Installation, Commissioning & Operation
of SDH equipment; STM-1(Siemens)” is the bonafide work carried out by Sameer
Kumar Jawa student of B.Tech, Punjab Technical University, Jalandhar, during
the year June-November 2012, in partial fulfillment of the requirements for the
award of the Degree of Bachelor of Technology and that the project has not
formed the basis for the award previously of any degree, diploma, associateship,
fellowship or any other similar title.
Signature of the Guide:
Place:
Date:
3
ACKNOWLEDGEMENT
I acknowledge my gratitude and thank to all the well knowledge persons for giving me
opportunity to avail all the best facilities available at this telecom centre through which I have
gained knowledge thinking so as too just in the environment suitable for harmonic adjustment. I
am grateful to the following persons for various help rendered by them during the training
period.
Mr. R.S Sandhu (D.E) who transferred to me his innumerable knowledge of Transmission. He
was always there to address our queries and give his advice. His kind and teaching behavior is
really appreciative.
Mr. Rajesh Kumar He gives me his precious time even he was too busies but never denial me at
any cost. He empathizes on basic concept and built my basis for SDH technology. He is available
to me at any time for any kind of problem.
Mrs. Seema Aggarwal From whom I learnt tips of the SDH and PDH technology. I complete this
project under their unforgettable guidance. His way of conduct is really appreciative.
And all other faculties and other trainees who help me to complete this project and without their
help this may not be possible.
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PREFACE
We cannot achieve anything worthwhile in the field of technical education until or unless
theoretical education acquired in classroom is effectively wedded to its practical approach that is
taking place in the modern industries and other means of technical application, the technical
education is of equal proportions of practical and theoretical study. The six month training taken
at the RTTC Rajpura as a part of my practical study was a wonderful learning experience for me.
I was fortunate enough to see the infrastructure built by BSNL for the service of trainee. In the
period of training I was able to interact with many trainees which enhance my communication
skill as a part of whole.
I also observed fiber splicing and STM -1 operation and maintenance in transmission, in the
RTTC during project session of my training. Further the experience of working in a competitive
environment was also a major boon.
This report is a brief of learning experience at RTTC in transmission. In transmission section
STM-1 (SDH based equipment) installation & maintenance gives provide basis for
understanding of higher order multiplexing equipments.
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Company profile
Regional telecom training centre
(An ISO Certified Institute)
PUNJAB TELECOM CIRCLE
INTRODUCTION
RTTC Rajpura was established on 01.12.75 in a rented building belonging to Kasturba Sewa
Mandir Trust in Rajpura. It has been shifted at New RTTC Complex, Neelpur Village, Rajpura
town w.e.f. 26.7.2004. It is situated on Patiala bye pass road near Liberty Chowk. Rajpura is
situated on the main line from Delhi to Amritsar at a distance of 230 Kilometers from Amritsar
as well as Delhi and 30 Kilometers from Ambala. The RTTC Complex includes Academic &
Administrative block, staff quarters, Inspection Quarters, Student Centre and Three Hostels. The
total Trainee capacity of these Hostels is 220. The entire campus is spread over 20 acres of land.
The built up area of RTTC Complex is 9700 Sq.Mtrs. The campus is situated away from the
town and is well suited for educational institution. The campus is extremely beautiful and the
ambience rejuvenating.
Batch Capacity - The training centre started with a batch capacity of 2 SBC in December
1975 which was increased to 6 SBC in Feb 1984 by diversion of 4 SBC from RTTC
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Ghaziabad. With the recent merger of RTTC & CTTC, the SBC has now been enhanced to
9.The Training Centre is organizing regular JTO, JAO & TTA induction batches & In-service
courses/workshops on all relevant topics of modern times.
Infrastructure - There are 10 Lecture Halls , 1 Conference Hall and 1 Seminar Hall for lecture
sessions and all equipped with white boards, overhead/DLP projectors and white screens. Fully
equipped OFC/Tx lab, SDH lab , RPR lab ,3 Computer labs, Broadband/ Multiplay lab, CDOT
SBM lab, MLLN lab exits.
Supporting Facilities -
A well maintained library.
Internet facilities in hostel / IQ.
One Bus and one small vehicle.
Canteen.
Excellent student centre & other sports facilities.
Staff - At present the RTTC family comprises of 64 members.
QUALITY POLICY
RTTC Rajpura fraternity consisting of officers and staff avows to provide quality training to all
its customers and to ensure optimum utilization of its training resources. For this every faculty
and individual of RTTC will adhere to ISO 90012008 standards and will demonstrate its
compliance in all spheres of activities with a commitment to continual improvement.
QUALITY OBJECTIVES
To work hard to deliver all our courses as Quality courses i.e. defined as having acquired 85%
rating as per evaluation by the customer. To endeavor to provide excellent course content,
quality presentations, handouts and congenial classroom environment.
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TABLE OF CONTENTS
LIST OF FIGURE………………………………………………………………………...9
LIST OF ABBREVIATION USED……………………………...………………………11
1 INTRODUCTION TO OPTICAL FIBER CABLE…………………………….…..…...13
1.1 PRINCIPLE OF FIBER OPTICS………………………………………………16
1.2 PROPAGATION OF LIGHT THROUGH FIBER ........................................... 14
1.3 TRANSMISSION SEQUENCE ...................................................................... 15
1.4 ADVANTAGES OF OPTICAL FIBER............................................................ 13
1.5 APPLICATIONS OF OPTICAL FIBER........................................................... 14
1.6 LOSES OCCURE IN FIBER ............................................................................ 17
1.7 OFC SPLICING ................................................................................................ 18
1.8 FIBER SPLICING ............................................................................................ 20
2 INTRODUCTION TO TRANSMISSION SYSTEM…………………….……………..22
2.1 MULTIPLEXING TECHNIQUES ................................................................... 22
2.2 BASIC REQUIREMENTS FOR PCM SYSTEM ............................................. 23
2.3 OVERVIEW OF SDH ...................................................................................... 27
2.4 SDH HIERARCHY ......................................................................................... 30
2.5 THE STM-1 FRAME FORMAT ...................................................................... 32
3 INSTALLATION AND COMISSIONING OF STM-1 (SIEMEN)………….…………35
3.1 BLOCK DIAGRAM OF TRANSMISSION SYSTEM ..................................... 35
3.2 STM-1 .............................................................................................................. 36
3.3 STM-1 EQUIPMENT (SIEMEN) ..................................................................... 37
3.4 MOTHERBOARD CARD ............................................................................... 37
3.5 IC1.1-2G CARD .............................................................................................. 39
3.6 4E/FE ............................................................................................................... 39
3.7 E3DS3 .............................................................................................................. 40
4 CONFIGURATION APPLICATION AND PERFORMANCE………………………...45
4.1 NETWORK TOPOLOGIES ............................................................................. 45
4.2 CROSS-CONNECTION .................................................................................. 46
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4.3 VARIOUS TEST PERFORMED AT TRANSMISSION LAB ......................... 49
5 ETHERNET ON SDH…………………………………………………………………...53
5.1 VARIOUS FEATURES OF THE NEXT GENERATION SDH ....................... 53
5.2 4E/FE CARD ................................................................................................... 56
5.3 IP DATA TRANSMISSION WITH NG SDH FUNCTIONALITY. ................. 57
6 RESULT AND CONCLUSION…. ……………………………………………………60
7 FUTURE TREND………………………………………………………………………..61
8 REFERENCES…………………………………………………………………………..62
9
LIST OF FIGURES
Figure 1.1 light travelling through a fiber
Figure 1.2 Information being transmitted after converting into light form
Figure 2.1 Plesiochronous Digital Hierarchies (PDH)
Figure 2.2 Schematic diagram of hybrid communications networks
Figure 2.3 Synchronous Digital Hierarchy
Figure 2.4 STM-1 frame format
Figure 2.5 Section overheads
Figure 2.6 Multiplex section overhead
Figure 3.1 Block Diagram Of Transmission System
Figure 3.2 Shelf View of STM-1 System
Figure 3.3 Mother Board
Figure 3.4 IC1.1-2G Card
Figure 3.5 4E/FE CARD
Figure 3.6 ES3DS3 CARD
Figure 3.7 Setting the IP Properties
Figure 3.8 Shelf View
Figure 3.9 Setting of date and time
Figure 3.10 Global Parameters
Figure 4.1 Point to point topology
Figure 4.2 Ring topology
Figure 4.3 Establishment of STM-1 ring (Main Path)
Figure 4.4 Establishment of STM-1 ring (Protection Path)
Figure 4.5 Transmission and reception at same end using loop back
Figure 4.6 Transmission and Reception at Same End Using Loop Back With Protection
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Figure 5.1 Functional model of NG-SDH
Figure 5.2 4E/FE Ethernet Card
Figure 5.3 Making the Ethernet connection
Figure 5.4 Block Diagram To Transmit data from One PC to Other PC Through Ethernet Card
Figure 5.5 Pinging the System
Figure 5.6 Result of pinging
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LIST OF ABBREVIATION USED
STM Standard Transport Module
SDH Synchronous Digital Hierarchy
PDH Plesiochronous Digital Hierarchy
ISDN Integrated Subscriber Digital Network
POTS Plain Old Telephone Service
LAN Local Area Network
WAN Wide Area Network
SONET SDH over Optical Network
ADM Add Drop Multiplexer
DXC Digital Cross Connector
TM Terminal Multiplexer
LOS Loss of Synchronization
MPLS Multiprotocol Level Switching
RPR Resilient Packet Ring
ETSI European Telecommunications Standards Institute
ES Error Second
EFS Error Free Second
SES Several Error Second
AS Available Second
DM Degraded Minute
MBM Main Base Module
SPC Signaling Controller Card
BHCR Busy Hour Call Rate
CCR Call Collision Rate
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CAS Channel Associated Signaling
CCS Common Channel Signaling
RAX Rural Auto Exchange
MAX Main Automatic Exchange
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1 INTRODUCTION TO OPTICAL FIBER CABLE
Optical fiber
An optical fiber (or fiber) is a glass or plastic fiber that carries light along its length.
Fiber optics is the overlap of applied science and engineering concerned with the design and
application of optical fibers. Optical fibers are widely used in fiber-optic communications, which
permits transmission over longer distances and at higher data rates (bandwidth) than other forms
of communications. Fibers are used instead of metal wires because signals travel along them
with less loss, and they are also immune to electromagnetic interference. Fibers are also used for
illumination, and are wrapped in bundles so they can be used to carry images, thus allowing
viewing in tight spaces. Specially designed fibers are used for a variety of other applications,
including sensors and fiber lasers.
OFC Cable
An optical fiber cable is a cable containing one or more optical fibers. The optical fiber
elements are typically individually coated with plastic layers and contained in a protective tube
suitable for the environment where the cable will be deployed.
In practical fibers, the cladding is usually coated with a tough resin buffer layer, which may be
further surrounded by a jacket layer, usually plastic. These layers add strength to the fiber but do
not contribute to its optical wave guide properties. Rigid fiber assemblies sometimes put light-
absorbing ("dark") glass between the fibers, to prevent light that leaks out of one fiber from
entering another. This reduces cross-talk between the fibers, or reduces flare in fiber bundle
imaging applications.
1.1 PRINCIPLE OF FIBER OPTICS
Total Internal Reflection - The Reflection that Occurs when a Ligh Ray Travelling in One
Material Hits a Different Material and Reflects Back into the Original Material without any Loss
of Light.
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Speed of light is actually the velocity of electromagnetic energy in vacuum such as space.
Light travels at slower velocities in other materials such as glass. Light travelling from one
material to another changes speed, which results in light changing its direction of travel. This
deflection of light is called Refraction.
The amount that a ray of light passing from a lower refractive index to a higher one is
bent towards the normal. But light going from a higher index to a lower one refracting away
from the normal,
1.2 PROPAGATION OF LIGHT THROUGH FIBER
The optical fiber has two concentric layers called the core and the cladding. The inner
core is the light carrying part. The surrounding cladding provides the difference refractive index
that allows total internal reflection of light through the core. The index of the cladding is less
than 1%, lower than that of the core. Typical values for example are a core refractive index of
1.47 and a cladding index of 1.46. Fiber manufacturers control this difference to obtain desired
optical fiber characteristics.
Figure1.1 light travelling through a fiber
Light injected into the fiber and striking core to cladding interface at greater than the
critical angle, reflects back into core, since the angle of incidence and reflection are equal, the
reflected light will again be reflected. The light will continue zigzagging down the length of the
fiber.
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Light striking the interface at less than the critical angle passes into the cladding, where it
is lost over distance. The cladding is usually inefficient as a light carrier, and light in the
cladding becomes attenuated fairly. Propagation of light through fiber is governed by the indices
of the core and cladding by Snell's law.
Such total internal reflection forms the basis of light propagation through a optical fiber.
This analysis consider only meridional rays- those that pass through the fiber axis each time, they
are reflected. Other rays called Skew rays travel down the fiber without passing through the axis.
The path of a skew ray is typically helical wrapping around and around the central axis.
Fortunately skew rays are ignored in most fiber optics analysis.
The specific characteristics of light propagation through a fiber depends on many factors,
including
The size of the fiber.
The composition of the fiber.
The light injected into the fiber.
1.3 TRANSMISSION SEQUENCE
(1) Information is Encoded into Electrical Signals.
(2) Electrical Signals are Converted into light Signals.
(3) Light Travels Down the Fiber.
(4) A Detector Changes the Light Signals into Electrical Signals.
(5) Electrical Signals are Decoded into Information.
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Figure 1.2 Information being transmitted after converting into light form
1.4 ADVANTAGES OF FIBER OPTICS
Optical Fibers are non conductive (Dielectrics)
Electromagnetic Immunity
Large Bandwidth (> 5.0 GHz for 1 km length)
Low Loss (5 dB/km to < 0.25 dB/km typical)
Small, Light weight cables.
Available in Long lengths (> 12 kms)
Security
Security - Being a dielectric
Universal medium
1.5 APPLICATION OF FIBER OPTICS IN COMMUNICATIONS
Common carrier nationwide networks.
Telephone Inter-office Trunk lines.
Customer premise communication networks.
Undersea cables.
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High EMI areas (Power lines, Rails, Roads).
Factory communication/ Automation.
Control systems.
Expensive environments.
High lightening areas.
1.6 LOSES OCCURE IN FIBER
1.6.1 ATTENUATION
Attenuation is defined as the loss of optical power over a set distance, a fiber with lower
attenuation will allow more power to reach a receiver than fiber with higher attenuation.
Attenuation may be categorized as intrinsic or extrinsic.
INTRINSIC ATTENUATION
It is loss due to inherent or within the fiber. Intrinsic attenuation may occur as
Absorption - Natural Impurities in the glass absorb light energy.
Scattering - Light rays travelling in the core reflect from small imperfections into a new
pathway that may be lost through the cladding.
EXTRINSIC ATTENUATION
It is loss due to external sources. Extrinsic attenuation may occur as –
Macro bending - The fiber is sharply bent so that the light travelling down the fiber cannot
make the turn & is lost in the cladding.
Micro bending - Micro bending or small bends in the fiber caused by crushing contraction
etc. These bends may not be visible with the naked eye.
Attenuation is measured in decibels (dB). A dB represents the comparison between the
transmitted and received power in a system.
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1.6.2 DISPERSION
Dispersion is the spreading of light pulse as its travels down the length of an optical fiber.
Dispersion limits the bandwidth or information carrying capacity of a fiber. The bit-rates must be
low enough to ensure that pulses are farther apart and therefore the greater dispersion can be
tolerated.
There are three main types of dispersion in a fiber -
a) Modal Dispersion
b) Material dispersion
c) Waveguide dispersion
1.7 OFC SPLICING
Splices
Splices are permanent connection between two fibers. The splicing involves cutting of the edges
of the two fibers to be spliced.
Splicing Methods
The following three types are widely used
1) Adhesive bonding or Glue splicing.
2) Mechanical splicing.
3) Fusion splicing.
1. Adhesive Bonding or Glue Splicing
This is the oldest splicing technique used in fiber splicing. Cylindrical rods or another kind of
reference surfaces are used for alignment. During the alignment of fiber end, a small amount of
adhesive or glue of same refractive index as the core material is set between and around the fiber
ends. A two component epoxy or an UV curable adhesive is used as the bonding agent. The
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splice loss of this type of joint is same or less than fusion splices. But fusion splicing technique is
more reliable, so at present this technique is very rarely used.
2. Mechanical Splicing
This technique is mainly used for temporary splicing in case of emergency repairing. This
method is also convenient to connect measuring instruments to bare fibers for taking various
measurements. A very good mechanical splice for M.M. fibers can have an optical performance
as good as fusion spliced fiber or glue spliced. But in case of single mode fiber, this type of
splice cannot have stability of loss.
3. Fusion Splicing
The fusion splicing technique is the most popular technique used for achieving very low splice
losses. The fusion can be achieved either through electrical arc or through gas flame. The process
involves cutting of the fibers and fixing them in micro–positioners on the fusion splicing
machine. The fibers are then aligned either manually or automatically core aligning process.
Afterwards the operation that takes place involve withdrawal of the fibers to a specified distance,
preheating of the fiber ends through electric arc and bringing together of the fiber ends in a
position and splicing through high temperature fusion.
If proper care taken and splicing is done strictly as per schedule, then the splicing loss can be
minimized as low as 0.01 dB/joint. After fusion splicing, the splicing joint should be provided
with a proper protector to have following protections
Mechanical protection
Protection from moisture.
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1.8 FIBER SPLICING
Splicer Operation
It is awkward at first to hold, strip, cleave and place the fiber in the clamps. Practice makes
perfect. Here are five general steps to complete a fusion splice
Strip, Clean, & Cleave
a. Strip
Strip fiber to appropriate length per your splicer's instruction manual
b. Cleaning
Clean the fiber with Fiber-Clean towelettes or a lint-free wipe and isopropyl alcohol so that the
fiber squeaks
c. Cleaving
Place fiber (after stripping and cleaning it) in cleaver using the fiber guide to position. It align the
fiber in the cleave area to cleave at the proper length Depress the cleaver arm gently. Remove
and safely discard the fiber scrap.
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2. Load Splicer
Position tip of fiber near electrodes. Do not bump tips into anything. Ease placement by bowing
fibers in groove
3. Splice Fibers
Read The Manual. Place first cleaved fiber in v-groove with fiber tip near the electrodes
Close the fiber clamps Repeat on opposite side for second fiber. Select program on fusion
splicer. Initiate fuse cycle (can be manual or automatic)
4. Remove and Protect Splice
Remove completed splice from splice area .Use Heat-Shrink oven (or mechanical protection) to
protect the splice Place splice tray in adjustable tray holder and insert protected splice into splice
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2 INTRODUCTION TO TRANSMISSION SYSTEM
A long distance or local telephone conversation between two persons could be provided
by using a pair of open wire lines or underground cable as early as early as mid of 19th century.
However, due to fast industrial development and an increased telephone awareness,
demand for trunk and local traffic went on increasing at a rapid rate. To cater to the increased
demand of traffic between two stations or between two subscribers at the same station we
resorted to the use of an increased number of pairs on either the open wire alignment, or in
underground cable. This could solve the problem for some time only as there is a limit to the
number of open wire pairs that can be installed on one alignment due to headway
consideration and maintenance problems.
Similarly increasing the number of open wire pairs that can be installed on one alignment
due to headway consideration and maintenance problems. Similarly increasing the number of
pairs to the underground cable is uneconomical and leads to maintenance problems.
It, therefore, became imperative to think of new technical innovations which could exploit
the available bandwidth of transmission media such as open wire lines or underground cables to
provide more number of circuits on one pair. The techniques used to provide a number of
circuits using a single transmission link is called Multiplexing.
2.1 MULTIPLEXING TECHNIQUES
There are basically two types of multiplexing techniques
Frequency Division Multiplexing (FDM)
Time Division Multiplexing (TDM)
Frequency Division Multiplexing Techniques (FDM)
The FDM techniques is the process of translating individual speech circuits (300-3400
Hz) into pre-assigned frequency slots within the bandwidth of the transmission medium. The
frequency translation is done by amplitude modulation of the audio frequency with an
appropriate carrier frequency. At the output of the modulator a filter network is connected to
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select either a lower or an upper side band. Since the intelligence is carried in either side band,
single side band suppressed carrier mode of AM is used. This results in substantial saving of
bandwidth mid also permits the use of low power amplifiers.
Time Division Multiplexing (TDM)
Time division multiplexing involves nothing more than sharing a transmission medium
by a number of circuits in time domain by establishing a sequence of time slots during which
individual channels (circuits) can be transmitted. Thus the entire bandwidth is periodically
available to each channel. Normally all time slots1 are equal in length. Each channel is assigned
a time slot with a specific common repetition period called a frame interval.
2.2 BASIC REQUIREMENTS FOR PCM SYSTEM
To develop a PCM signal from several analogue signals, the following processing steps are
required
Filtering
Sampling
Quantization
Encoding
Line Coding
FILTERING
Filters are used to limit the speech signal to the frequency band 300-3400 Hz.
SAMPLING
It is the most basic requirement for TDM. Suppose we have an analogue signal.
The amplitude of the sample is depending upon the amplitude of the input signal at the instant of
sampling. The duration of these sampled pulses is equal to the duration for which the switch S is
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closed. Minimum number of samples are to be sent for any band limited signal to get a good
approximation of the original analogue signal and the same is defined by the sampling Theorem.
i.e. Fs>2Fh.
QUANTISATION
The process of measuring the numerical values of the samples and giving them a table value
in a suitable scale is called "Quantizing". Of course, the scales and the number of points should
be so chosen that the signal could be effectively reconstructed after demodulation.
Quantizing, in other words, can be defined as a process of breaking down a continuous
amplitude range into a finite number of amplitude values or steps.
ENCODING
Conversion of quantized analogue levels to binary signal is called encoding. To represent 256
steps, 8 level codes are required. The eight bit code is also called an eight bit "word".
The 8 bit word appears in the form
P ABC WXYZ
Polarity bit „1‟ Segment Code Linear encoding
for + ve 'O' for - ve. In the segment
The first bit gives the sign of the voltage to be coded. Next 3 bits gives the segment number.
There are 8 segments for the positive voltages and 8 for negative voltages. Last 4 bits give the
position in the segment. Each segment contains 16 positions.
LINE CODING
Line codec chips converts the encoded signal into HDB code which is compatible for transmit
over channel.
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2.3 OVERVIEW OF PDH AND SDH
With the introduction of PCM technology in the 1960s, communications networks were
gradually converted to digital technology over the next few years. To cope with the demand for
ever higher bit rates, a multiplex hierarchy called the plesiochronous digital hierarchy (PDH)
evolved. The bit rates start with the basic multiplex rate of 2 Mbit/s with further stages of 8, 34
and 140 Mbit/s. In North America and Japan, the primary rate is 1.5 Mbit/s. Hierarchy stages of
6 and 44 Mbit/s developed from this. Because of these very different developments, gateways
between one network and another were very difficult and expensive to realize. PCM allows
multiple use of a single line by means of digital time-domain multiplexing. The analog telephone
signal is sampled at a bandwidth of 3.1 kHz, quantized and encoded and then transmitted at a bit
rate of 64 kbit/s. A transmission rate of 2048 kbit/s results when 30 such coded channels are
collected together into a frame along with the necessary signaling information. This so-called
primary rate is used throughout the world. Only the USA, Canada and Japan use a primary rate
of 1544 kbit/s, formed by combining 24 channels instead of 30. The growing demand for more
bandwidth meant that more stages of multiplexing were needed throughout the world. A
practically synchronous (or, to give it its proper name plesiochronous) digital hierarchy is the
result. Slight differences in timing signals mean that justification or stuffing is necessary when
forming the multiplexed signals. Inserting or dropping an individual 64 kbit/s channel to or from
a higher digital hierarchy requires a considerable amount of complex multiplexer equipment.
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Fig.2.1 Plesiochronous Digital Hierarchies (PDH)
Traditionally, digital transmission systems and hierarchies have been based on multiplexing
signals which are plesiochronous (running at almost the same speed). Also, various parts of the
world use different hierarchies which lead to problems of international interworking; for
example, between those countries using 1.544 Mbit/s systems (U.S.A. and Japan) and those
using the 2.048 Mbit/s systems. To recover a 64 kbit/s channel from a 140 Mbit/s PDH signal,
it‟s necessary to demultiplex the signal all the way down to the 2 Mbit/s level before the location
of the 64 kbit/s channel can be identified. PDH requires “steps” (140-34, 34-8, 8-2 demultiplex;
2-8, 8-34, 34-140 multiplex) to drop out or add an individual speech or data channel (see Figure
1).
The main problems of PDH systems are
1. Homogeneity of equipment
2. Problem of Channel segregation
3. The problem cross connection of channels
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4. Inability to identify individual channels in a higher-order bit stream.
5. Insufficient capacity for network management;
6. Most PDH network management is proprietary.
7. There‟s no standardised definition of PDH bit rates greater than 140 Mbit/s.
8. There are different hierarchies in use around the world. Specialized interface equipment
is required to interwork the two hierarchies.
1988 SDH standard introduced with three major goals
– Avoid the problems of PDH
– Achieve higher bit rates (Gbit/s)
– Better means for Operation, Administration, and Maintenance (OA&M)
SDH is an ITU-T standard for a high capacity telecom network. SDH is a synchronous
digital transport system, aim to provide a simple, economical and flexible telecom infrastructure.
The basis of Synchronous Digital Hierarchy (SDH) is synchronous multiplexing - data from
multiple tributary sources is byte interleaved.
SDH brings the following advantages to network providers
High transmission rates
Transmission rates of up to 40 Gbit/s can be achieved in modern SDH systems. SDH is therefore
the most suitable technology for backbones, which can be considered as being the super
highways in today's telecommunications networks.
Simplified add & drop function
Compared with the older PDH system, it is much easier to extract and insert low-bit rate
channels from or into the high-speed bit streams in SDH. It is no longer necessary to demultiplex
and then remultiplex the plesiochronous structure.
High availability and capacity matching
With SDH, network providers can react quickly and easily to the requirements of their
customers. For example, leased lines can be switched in a matter of minutes. The network
28
provider can use standardized network elements that can be controlled and monitored from a
central location by means of a telecommunications network management (TMN) system.
Reliability
Modern SDH networks include various automatic back-up and repair mechanisms to cope with
system faults. Failure of a link or a network element does not lead to failure of the entire network
which could be a financial disaster for the network provider. These back-up circuits are also
monitored by a management system.
Future-proof platform for new services
Right now, SDH is the ideal platform for services ranging from POTS, ISDN and mobile radio
through to data communications (LAN, WAN, etc.), and it is able to handle the very latest
services, such as video on demand and digital video broadcasting via ATM that are gradually
becoming established.
Interconnection
SDH makes it much easier to set up gateways between different network providers and to
SONET systems. The SDH interfaces are globally standardized, making it possible to combine
network elements from different manufacturers into a network. The result is a reduction in
equipment costs as compared with PDH.
Network Elements of SDH
Figure 2 is a schematic diagram of a SDH ring structure with various tributaries. The mixture of
different applications is typical of the data transported by SDH. Synchronous networks must be
able to transmit plesiochronous signals and at the same time be capable of handling future
services such as ATM.
Current SDH networks are basically made up from four different types of network element. The
topology (i.e. ring or mesh structure) is governed by the requirements of the network provider.
Regenerators
Regenerators as the name implies, have the job of regenerating the clock and amplitude
relationships of the incoming data signals that have been attenuated and distorted by dispersion.
29
They derive their clock signals from the incoming data stream. Messages are received by
extracting various 64 kbit/s channels (e.g. service channels E1, F1) in the RSOH (regenerator
section overhead). Messages can also be output using these channels.
Terminal Multiplexer
Terminal multiplexers are used to combine plesiochronous and synchronous input signals into
higher bit rate STM-N signals.
Fig.2.2 Schematic diagram of hybrid communications networks
Add/drop Multiplexers (ADM)
Add/drop multiplexers (ADM) Plesiochronous and lower bit rate synchronous signals can be
extracted from or inserted into high speed SDH bit streams by means of ADMs. This feature
makes it possible to set up ring structures, which have the advantage that automatic back-up path
switching is possible using elements in the ring in the event of a fault.
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Digital Cross-connect
Digital cross-connects (DXC) This network element has the widest range of functions. It allows
mapping of PDH tributary signals into virtual containers as well as switching of various
containers up to and including VC-4.
Network Element Manager
Network element management The telecommunications management network (TMN) is
considered as a further element in the synchronous network. All the SDH network elements
mentioned so far are software-controlled. This means that they can be monitored and remotely
controlled, one of the most important features of SDH. Network management is described in
more detail in the section “TMN in the SDH network”
SDH Rates
SDH is a transport hierarchy based on multiples of 155.52 Mbit/s. The basic unit of SDH is
STM-1. Different SDH rates are given below
STM-1 = 155.52 Mbit/s
STM-4 = 622.08 Mbit/s
STM-16 = 2588.32 Mbit/s
STM-64 = 9953.28 Mbit/s
Each rate is an exact multiple of the lower rate therefore the hierarchy is synchronous.
2.4 SDH HIERARCHY
SDH defines a multiplexing hierarchy that allows all existing PDH rates to be transported
synchronously.
The following diagram shows these multiplexing paths.
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Fig.2.3 Synchronous Digital Hierarchy
Multiplex unit A basic SDH multiplex unit includes multiple containers (C-n), virtual containers
(VC-n), tributary units (TU-n), tributary unit groups (TUG-n), administrative units (AUn) and
administrative unit groups (AUG-n), where n is the hierarchical sequence number of unit level.
Container Information structure unit that carries service signals at different rates. G.709 defines
the criteria for five standard containers C-11, C-12, C-2, C-3 and C-4.
Virtual container (VC) Information structure unit supporting channel layer connection of SDH.
It terminates an SDH channel. VC is divided into lower-order and higher-order VCs. VC-4 and
VC-3 in AU-3 are higher-order virtual containers.
Tributary unit (TU) and tributary unit group (TUG) TU is the information structure that
provides adaptation between higher-order and lower-order channel layers. TUG is a set of one or
more TUs whose location is fixed in higher-order VC payload.
Administrative unit (AU) and administrative unit group (AUG) AU is the information structure
that provides adaptation between higher-order channel layer and multiplex section layer. AUG is
a set of one or more AUs whose locations are fixed in the payload of STM-N.
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2.5 THE STM-1 FRAME FORMAT
The standardized SDH transmission frames, called Synchronous Transport Modules of Nth
hierarchical level (STM-N).
A frame with a bit rate of 155.52 Mbit/s is defined in ITU-T Recommendation
G.707. This frame is called the synchronous transport module (STM). Since the frame is the first
level of the synchronous digital hierarchy, it is known as STM-1. Figure 2 shows the format of
this frame. It is made up from a byte matrix of 9 rows and 270 columns. Transmission is row by
row, starting with the byte in the upper left corner and ending with the byte in the lower right
corner. The frame repetition rate is 125 ms., each byte in the payload represents a 64 kbit/s
channel. The STM-1 frame is capable of transporting any PDH tributary signal.
The first 9 bytes in each of the 9 rows are called the overhead. G.707 makes a distinction
between the regenerator section overhead (RSOH) and the multiplex section overhead (MSOH).
The reason for this is to be able to couple the functions of certain overhead bytes to the network
architecture. The table below describes the individual functions of the bytes.
Figure 2.4 STM-1 frame format
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SECTION OVERHEADS
RSOH (regenerator section overhead) The Regenerator Section OverHead uses the first three
rows & nine columns in the STM-1 frame
Figure 2.5 Section overheads
A1, A2 The Frame Alignment Word is used to recognize the beginning of an STM-N frame
J0 Path Trace. It is used to give a path through an SDH Network a "Name". This message
(Name) enables the receiver to check the continuity of its connection with the desired transmitter
B1 Bit Error Monitoring. The B1 Byte contains the result of the parity check of the previous
STM frame, before scrambling of the actual STM frame. This check is carried out with a Bit
Interleaved Parity check.
E1 Engineering Order wire (EOW). It can be used to transmit speech signals beyond a
Regenerator Section for operating and maintenance purposes
F1 User Channel. It is used to transmit data and speech for service and maintenance
D1 to D3 Data Communication Channel at 192 Kbit/s (DCCR). This channel is used to transmit
management information via the STM-1 frames
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MSOH (multiplex section overhead)
Figure 2.6 Multiplex section overhead
The Multiplex Section Overhead uses the 5th through 9th rows, and first 9 columns in the STM-
1 frame.
B2 Bit Error Monitoring. The B2 Bytes contains the result of the parity check of the previous
STM frame, except the RSOH, before scrambling of the actual STM frame. This check is carried
out with a Bit Interleaved Parity check (BIP24)
K1, K2 Automatic Protection Switching (APS). In case of a failure, the STM frames can be
routed new with the help of the K1, K2 Bytes through the SDH Network. Assigned to the
multiplexing section protection (MSP) protocol
K2 (Bit6,7,8) MS_RDI Multiplex Section Remote Defect Indication (former MS_FERF
Multiplex Section Far End Receive Failure)
D4 to D12 Data Communication Channel at 576 Kbit/s (DCCM). (See also D1-D3 in RSOH
above)
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3 INSTALLATION AND COMISSIONING OF STM-1 (SIEMEN)
3.1 BLOCK DIAGRAM OF TRANSMISSION SYSTEM
Figure 3.1Block Diagram Of Transmission System
DDF(Digital Distribution Frame) DDF (at transmitter side) receive PCMs from exchange or
station which are to be transmitted to another station or exchange. DDF have different modules
which connects PCM to STM-1 System. PCM connected to DDF from station through copper
cable and from DDF to STM-1 through PCM cable.
Transmitter It is basically STM-1 system which helps to transmit PCMs through optical fiber
cable.STM-1 plays an important role in transmission system. STM-1 also helps in cross connect
the PCMs. This block contains MUX card and OLT cards.
E/O Converter It is simply OLT card which converts electrical signal to optical signal
FDF(Fiber Distribution frame) This frame (at transmitter end) distribute fiber to different
station. FDF connect to system through patch card.
FDF(Fiber Distribution frame) This frame (at receiver end) collect fiber from different station.
FDF connect to system through pigtails cable.
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O/E Converter This block converts optical signal to electrical signal.
Receiver This block will collect all PCMs received at OLT card. It will connect all the PCM to
MUX card. Here they are connected to different station through DDF.
3.2 STM-1
The STM-1 is an optical STM-1/STM-4 add-drop multiplexer used to build STM-
1/STM-4 point-to-point links, STM-1 or STM-4 rings, or STM-1 line protection, so performing
the conveyance of 2 Mbit/s, 34 or 45 Mbit/s PDH links, of 155 Mbit/s STM-1 SDH links, of
10/100 Mbit/s Ethernet links. STM-1 is product of AC-1 family.. STM-1 can be configured
either as an add/drop multiplexer or a terminal multiplexer depending upon the number of
aggregate interfaces. These interfaces can be either optical or electrical resulting in five different
types of NEs It support 2Mbps data for transmit and receive on 1-PCM. STM-1 can transmit data
up to 155.52Mbps.
KEY FEATURES OF STM-1 .
Extensive support of SDH management features.
Performance monitoring.
Synchronization management.
Fast protection switching
Sub–network connection protection (SNC–1)
Full VC–12 connectivity
Full ATM integration
NM2100 management.
Protection Function in the ADM
Cross Connection Function
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3.3 STM-1 EQUIPMENT (SIEMEN)
Figure 3.2 Shelf View of STM-1 System
3.4 MOTHERBOARD CARD
Figure 3.3 Mother Board
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Management and administrative ports
COMM Interface This isRS232 Port which is used to connecting system to computer standard .
This part has Bit rate 19200 bauds (8 data bits, no parity and 1 stop bit).
ETH Interface This interface is commonly called as Ethernet interface. It is used for network
management purpose (NMS). In practical session we have used this interface for
STM1configuration. This port can be operated at 10Mbps in either full duplex or half duplex
mode. We use shielded type RJ-45 connector to connect this port with PC. 2Mbit/s or 2MHz
synchronization port
Synchronization port interface In sync port we have provision of two external synchronization
inputs, these are T3_1 and T3_2 along with two clock outputs at 2MHz at pins named as T4_1
and T4_2. All these input and output clock are compliant with ITU-T G.703 Recommendations.
2M Port These are PCM ports carrying 2 Mbit/s data . These ports has 21 PCM carrying
capacity. These data port function block is composed of the following functions
HPA High order Path Adaptation (Tributary Unit order 12 management)
LPT Lower order Path Termination (Virtual Container order 12 management)
PPI PDH Physical Interface of G.703 port
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3.5 IC1.1-2G CARD
Figure3.4- IC1.1-2G Card
IC1.1-2G Card is OLT card. Two optical fiber cables are connected to this card. One cable for
transmit the signal and another one is used for receiving the signal
EOW/AUX Configuration
The EOW/AUX interface provides a 64 Kbit/s data channel ; this channel may be carried by a
Byte of the SDH frame.
3.6 4E/FE
Figure 3.54E/FE CARD
Each 4E/FE provides connection for
Traffic Ethernet interface either in 10Mbit//s or 100Mbit/s in full or half duplex mode.
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3.7 E3DS3
Figure 3.6 ES3DS3 CARD
Each E3DS3 provides connection for
75Ω 34/45Mbps interface complaint with ITU-T G.703 and ETS 300 166 allowing 34/45 Mbps
PDH streams.
3.8 COMMISSIONING OF STM-1(SIEMEN)
IP Addresses To operate the STM -1 Equipment with NMS, we must set the IP address of
NMS. First three bytes of IP address of NMS must be same as that of STM-1 Equipment.
To change the IP address of NMS following point
My Network Places---Properties---Local Area Network---Properties
IP Address ---Properties
Now change the IP addresses of NMS and STM-1 Equipment As shown..
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Figure 3.7 Setting the IP Properties
IP address 135.10.110.7 is address of NMS and 135.10.110.11 IP address of STM-1
Equipment. One thing must be noted that first three bytes of IP address must be same. Subnet
mask remain same i.e. 255.255.255.0
Now NMS can operate STM-1 Equipment.
Go to internet explorer.
Enter address of STM-1 Equipment (135.10.110.11)
Now we can operate the STM-1 equipment through NMS.
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EQUIPMENT
Figure 3.8 Shelf View
Name: This menu item displays the "Equipment Name" dialog box.
Date and Time: When clicked, this menu item displays the "Date and Time" dialog box. Apply
button supplies the Equipment Date and Time with the PC Date and Time.
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Figure 3.9 Setting of date and time
SECURITY
Supervisor All rights
Operator May set configuration and maintenance operations
Observer Not authorized to make any modifications (Read only access)
Passwords modification needs Supervisor access rights
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GLOBAL PARAMETERS
Figure 3.10 Global Parameters
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4 CONFIGURATION APPLICATION AND PERFORMANCE
4.-3 NETWORK TOPOLOGIES
Topology is the layout pattern of interconnections of the various elements (links, nodes,
etc.) of a computer network. Network topologies may be physical or logical. Physical topology
means the physical design of a network including the devices, location and cable installation.
Logical topology refers to how data is actually transferred in a network as opposed to its physical
design.
STM-1 can work with any topology given below
Point to point topology.
Star topology.
Bus topology.
Ring topology.
But point to point and ring topology is commonly used in STM networks. Few of above
topologies are explained below.
POINT TO POINT TOPOLOGY
Figure4.1 Point to point topology
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Point to point topology is used between the two systems in which both are connected to each
other. It is used at the edge of network.
RING TOPOLOGY
Ring topology is used at the core of the communication network. In present days we are using
this topology in our core networks. Figure 4.2 shows ring of three systems
Figure 4.2 Ring topology
CROSS-CONNECTION
Cross Connection is important function of STM-1 Equipment. By using this function we can
connect PCMs of one station to PCMs of another station. For example 1st PCM of Patiala station
can be connect to 7th PCM of Rajpura station.
To perform these function we must following.
Shelf View---Cross-Connection---Select Output Port---Configure---Select Input Port---
Apply
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Now connections are established.
Figure 4.3 Establishment of STM-1 ring (Main Path)
We can also give the protection path, if working path has been failed.
Goto Configure---Protection---Protection Input Port---Apply
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Figure 4.4 Establishment of STM-1 ring (Protection Path)
Another important function in cross connection is multiple connections. By using this function
we can connect more than 1 PCM to another station‟s PCM. For established multiple
connections we must following.
Cross-Connection--- Multiple Connection---Select OLT Card---Select N-PCM Output Port-
--Select Starting Input Port---Apply
Now multiple connections are established. We can also give them protective path by using
protection function of cross connection.
Each cross-connection is defined by its parameters
Output port Connection Destination End (Slot name and port number of selected card)
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Mode Unidirectional or Bi-directional
Input port Connection Origin End (Slot name and port number)
VC-n type Either VC4, VC3 or VC12
Protection Connection Origin End (Slot name and port number), if SNC protection is used.
Status Working or protection according to channel which is carrying traffic.
Similarly after completing the connection at one station, the same type of connections are made
at another station and the third station is just bye passed in order to provide the protection path
and complete the ring.
4.-2 TEST PERFORMED AT TRANSMISSION LAB
Transmission and reception at same end using loop back.
Transmission and reception at same end using loop back with protection.
4.-2.1 TRANSMISSION AND RECEPTION AT SAME END USING LOOP BACK
Figure4.5 Transmission and reception at same end using loop back
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Here the problem statement is that I have to send my data using PCM M4 at system A to the
system B and resent back same data using loop to system A.
Solution various step involved are given below
First choose the cross-connection on welcome page of STM-1.
Choose the slot M to select one of required PCM.
Choose PCM no. M4# and click on configure.
Here select the OLT to transmit. I choose D OLT to transmit my PCM to next station.
I cross-connect M4# with D4# on system A.
Now, as D OLT of system A is connected to B OLT of System B via optical media.
I will receive the data of D4 as B4 on B OLT.
Now, I am in need to connect my B4 to M4 on system B.
Connect the transmitter and receiver terminal in DDF of system B to create a loop.
Connect the receiver and transmitter of M4 at system A.
Results Data was received error free. When we disconnect any optical fiber, data transmitted is
lost during fiber disconnects.
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4.-2.2 TRANSMISSION AND RECEPTION AT SAME END USING LOOP BACK
WITH PROTECTION
Figure4.6 Transmission and Reception at Same End Using Loop Back With Protection
Here the problem statement is that I have to send my data using PCM M4 at system A
(135.10.110.14) to the system B (135.10.110.12) and resent back same data using loop to system
A with protection.
Solution various step involved are given below
1. First choose the cross-connection on welcome page of STM-1.
2. Choose the slot M to select one of required PCM.
3. Choose PCM no. M4# and click on configure.
4. Here select the OLT to transmit. I choose D OLT to transmit my PCM to next
station.
5. I cross-connect M4# with D4# on system A.
6. Now, as D OLT of system A is connected to B OLT of System B via optical media.
7. I will receive the data of D4 as B4 on B OLT.
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4.-1 Digital transmission analyzer observations
Test parameters
Value (in seconds)
Available Seconds 267
Unavailable Seconds 0
Error Free Seconds 253
Error Seconds 14
Severely Error Seconds 14
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5 ETHERNET ON SDH
Next Generation SDH enables operators to provide more data transport services while increasing
the efficiency of installed SDH/SONET base, by adding just the new edge nodes, sometime
known as Multi Service Provisioning Platforms (MSPP) / Multi Service Switching Platforms
(MSSP), can offer a Combination of data interfaces such as Ethernet, 8B/10B, MPLS (Multi
Protocol Label Switching) or RPR (Resilient Packet Ring), without removing those for
SDH/PDH. This means that it will not be necessary to install an overlap network or migrating all
the nodes or fiber optics. This reduces the cost per bit delivered, and will attract new customers
while keeping legacy services. In addition, in order to make data transport more efficient,
SDH/SONET has adopted a new set of protocols that are being installed on the MSPP/MSPP
nodes. These nodes can be interconnected with the old equipment that is still running.
5.1 VARIOUS FEATURES OF THE NEXT GENERATION SDH
5.1.1 GENERIC FRAMING PROCEDURE (GFP)
Generic Framing Procedure (GFP), an all-purpose protocol for encapsulating packet over
SONET (POS), ATM, and other Layer 2 traffic on to SONET/SDH networks. GFP is defined in
ITU-T G.7041 along with virtual concatenation and link capacity adjustment scheme (LCAS)
transforms legacy SDH networks to Next generation SDH networks.
There are actually two types of GFP mechanisms ;-
1. PDU-oriented known as Frame mapped GFP (GFP-F)
2. Block-code-oriented known as Transparent GFP (GFP-T)
1. GFP-F -
GFP-F(Framed) is a layer 2 encapsulation in variable sized frames. Optimised for data packet
protocols such as DVD, PPP and Ethernet, MPLS etc Frame mode supports rate adaptation and
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multiplexing at the packet/frame level for traffic engineering. This mode maps entire client frame
into one GFP frames of constant length but gaps are discarded. The frame is stored first in buffer
prior to encapsulation to determine its length. This introduces delay and latency.
Figure 5.1Functional model of NG-SDH
2. GFP-T
GFP-T is useful for delay sensitive services. GFP-T(Transparent) is a layer 1
encapsulation in constant sized frames. Optimized for traffic based on 8B/10B codification such
as VoIP, DVB-ASI, 1000BASE-T, SAN, Fiber Channel, and ESCON.
5.1.1 CONCATENATION (V-CAT & C-CAT)
SDH concatenation consists of linking more than one VCs to each other to obtain a rate that does
not form part of standard rates. Concatenation is used to transport pay loads that do not fit
efficiently into standard set of VCs.
Two concatenation schemes are
Contiguous concatenation
Virtual concatenation
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i. Contiguous concatenation
The traditional method of concatenation is termed as contiguous. This means that adjacent
containers are combined and transported across the SDH network as one container. Contiguous
concatenation is a pointer based concatenation. It consists of linking N number of VCs to each
other in a logical manner within the higher order entity i.e. VC4 and above. The concatenated
VCs remain in phase at any point of network. The disadvantage is that it requires functionality at
every N/E adding cost and complexity. Lower order VCs (VC-12, VC3) concatenation is not
possible in contiguous concatenation .
ii. Virtual Concatenation
Virtual concatenation maps individual containers in to a virtually concatenated link. Any number
of containers can be grouped together, which provides better bandwidth granularity than using a
contiguous method. It combines a number of lower/higher order VCs (VC-12, VC3 & VC4
payload) that form a larger concatenation Group, and each VC is treated as a member. 10 Mb
Ethernet would be made up of five VC-12s, creating these finely tuned SDH pipes of variable
capacities improve both, scalability and data handling/controlling ability as per SLA (service
level agreement).
5.1.2 LINK CAPACITY ADJUSTMENT SCHEME (LCAS)
Link Capacity Adjustment Scheme (LCAS) is an emerging SONET/SDH standard and is defined
in ITU-T G.7042 having capability to dynamically change the amount of bandwidth used in a
virtually concatenated channel i.e. bandwidth management flexibility. LCAS is bi-directional
signaling protocol exchanged over the overhead bytes, between Network Elements that
continually monitors the link. LCAS can dynamically change VCAT path sizes, as well as
automatically recover from path failures. LCAS is the key to provide “bandwidth on demand”.
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Benefits of LCAS-
Call by call bandwidth (Bandwidth on demand)
Bandwidth on Schedule
5.2 4E/FE CARD
The SDH bandwidth can be divided among separate connections to match fine requirements with
great flexibility and with optimal usage of the STM1 link.
The 4E/FE can terminate a combination of VC3 and VC12 connections up to an aggregated
bandwidth of 1 STM1. Multiple VC3 or VC12 connections are grouped together in a VC Group
(VCG) with Virtual Concatenation. The VC members of a given VCG do not need to be
contiguous. They do not need to take the same path across the SDH core network either. The
bandwidth of a VCG VC3-nV is n times the bandwidth of 1 VC3. The bandwidth of a VCG
VC12-nV is n times the bandwidth of 1 VC12.
Figure- 5.2 4E/FE Ethernet Card
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5.2.1 4E/FE'S FUNCTIONAL GROUPS
The 4E/FE's functional groups are composed of the following functions
ETH Ethernet
VCG Virtual Container Group
XCN Cross-Connection
HPA High order Path Adaptation
LPT Lower order Path Termination
5.3 IP DATA TRANSMISSION WITH NG SDH FUNCTIONALITY.
Statement To transmit the 2 Mbps data from one PC to another PC using Ethernet port of STM-
1 Equipment.
Solution the various step involved are given below
1. Configure the IP of PC to system 11.
2. Configure the Ethernet port of system 11. Put C1 onto the B1 with protection as D1
Choose the required Vcg‟s and apply the changes as shown in figure
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Figure 5.3 Making the Ethernet connection
1. Open system 15 using global IP.
2. Configure the Ethernet port with required settings. Put A1 onto the D1 and B1 as
protection.
3. Open System 13 with global IP.
4. Configure the system with required settings. Bypass the D1 to B1 on the system.
5. This completes the Ethernet configuration.
6. Now connect LAN wire to System 11.
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5.4 Block Diagram to Transmit data from One PC to Other PC through Ethernet Card
Figure 5.4 Ethernet Connection
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5.5 Testing of the Ethernet ring
Figure 5.5 Pinging the System
The Rajpura station is connected with the NMS system in order to test the Ethernet ring. The
Patiala station is connected to the Host from where there transmits some random data and this
data will be transmitted through the Ethernet ring and thus the ring can be tested.
5.6 RESULT
Figure 5.6 Result of pinging
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6 RESULT AND CONCLUSION
Although Hi-tech techniques like SDH making the world smaller these days, but these are not
going to fulfill the requirements of future generation. These techniques are lack of speed,
intelligence and efficiency which wouldn‟t be tolerable in the future. Future generation would
require more data rates and error less transmission which wouldn‟t be fulfilled by the present
technologies. In future every technology will be going to be IP based with introduction of IPv6
which offers us with huge number of IP addresses so that these present technologies has to either
modified or completely eliminated to make it compatible with IP based system demand. In case
of wireless technologies 2G i.e. GSM support only 9.6Kbps which we very small which does not
support essential VAS related to data services. In switching, circuit switching is not going to
support high switch rates and high traffic rates in future.
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7 FUTURE TRENDS
In future huge data rates will require in transmission media, of course media as optical fiber will
not change but technology like SDH has to modify. A modified version of the SDH as DWDM,
RPR, MLLN technology which consist of the optical multiplexing offer us huge data rates of the
order of giga bits. In case of wireless technologies by changing modulation techniques can
enhance the data rates and security. Upcoming technologies like 3G supports data rates in mega
bits which are pretty much better as compared to the existing 2G. In switching the entire circuit
switching network are to be modified to packet switched networks and will be IP based. In
nutshell future technologies will be more efficient, precise and faster as compression to present
technologies and thus these are helpful in meeting the demands of the users in order of high
speed, large bandwidth etc.
8 REFERENCES:
www.bsnl.co.in
en.wikipedia.org
www.google.com/images
STM-1 Equipment PDFs
BSNL Class Notes and PPTs