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NTC – INTERNSHIP REPORT
Submitted to:National Telecommunication Corporation
14/10/2014
By:Saifullah Khan
Usman Institute of Technology – Hamdard University, Karachi
Table of Contents
1. EWSD (Eidal Widal Switch Digital).....................................................1A. Parts of EWSD Switch........................................................................1B. DLU (Digital line unit):.......................................................................1
i. Functions Of DLU..................................................................2ii. Modules of Digital Line Unit.............................................3
iii. Physical Rack Diagram Of DLU (IBA 1-A):..................4C. Line Trunk Group (LTG)....................................................................5
i. Physical Rack Diagram:......................................................5ii. Functions of LTG...................................................................7
D. Switching Network (SN)....................................................................8i. Functions OF Switching Network:.................................8
ii. Structure:.................................................................................9iii. Physical Rack Diagram:......................................................9
E. Coordination Processor:..................................................................10i. Coordination Processor Modules..................................10
ii. Functionality of CP.............................................................112. Functional Units of EWSD exchange:..............................................12
F. Control....................................................................................................12i. Message Buffer.....................................................................12
ii. Central Clock Generator..................................................13iii. Control System Panel.........................................................13
G. Switching...............................................................................................14H. Signaling................................................................................................14I. Access......................................................................................................15
3. ZTE Exchange............................................................................................16J. Functions of Modules.......................................................................19
4. PRI Exchange.............................................................................................215. MSAG (Multi-Service Access Gateway)........................................................236. UMG (Universal Media Gateway)......................................................297. Soft Switch..................................................................................................31
1
EWSD (Eidal Widal Switch Digital)
EWSD is the digital exchange made by German Company Siemens. This is the very reliable exchange which is mostly used in Pakistan.This type of digital exchange is used as local, tandem, transit as well as international gate way exchange.The most common switch is used as main exchange. This can operate as PSTN, ISDN (BRI), PRI, CMMERCIAL Subscriber (Pay phones).
Parts of EWSD SwitchEWSD switch can be divided into following parts.
Digital line unit (DLU). Line trunk group (LTG). Switching network (SN). Coordination processor (CP).
DLU (Digital line unit)
DLU provides the gateway to the EWSD exchange. The data of home and commercial subscribers are stored in specific
modules in DLU. The telephone ring is generated in DLU. The metering of voltage is done in DLU. Provides contact with DIU (digital interface unit).
2
Functions Of DLU
Digital Line Unit
Processor and
Controller
Interface
Subscriber line circuit
(SLC)
Power
BDCGRGMGDLUC
DCC-CRDIUBDBBDE
Testing
SLMACOSSLMACMRLSLMAITFSLMD
FMTU
LCMM
3
Modules of Digital Line Unit
1- Subscriber Line Module (SLM)SLM modules store the data of all types of subscribers that includes PSTN, ISDN, PRI, home users and commercial users. In IBA1-A there are two types of SLM modules
SLMA COS. SLMA CMRL.The SLMA COS module supports 8 subscriber telephone lines and connects them to the exchange.The SLMA CMRL module supports 6 commercial lines i.e. public call offices and connects them to main exchange.2- Bus Distribution Base(BDB)
The BDB module controls all the buses that are running throughout the DLU. The BDB modules are present in the first frame and they monitor the sub control units BDE’S that are control units of the bus in the other frames.
3- Bus Distribution Extension(BDE)The BDE modules are control units of different shelves of a single rack of the EWSD exchange. The BDE module is controlled by BDB.4- Ring Generation and Measuring Module (RGMG)
The RGMG module generates ring and it also acts as metering unit for voltage in the digital line unit. 5- Digital line Unit Control (DLUC):
The DLUC module is the main control module in the DLU .it monitors all the functionalities of different modules of the DLU.6- Bus Distribution Clock Generation (BDCG):This module generates the clock for bus distribution so that all the buses are synchronized.7- DCC:One DCC module provides the voltage to first eight modules of a shelf and the later eight modules are supported by an other DCC module at the end of the shelf.
4
Physical Rack Diagram Of DLU (IBA 1-A):
DCC
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
RGMG
BDB
BDCG
DLUC
DIU
FMTU
LCMM
SLM
DCC
DCC
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
RGMG
BDB
BDCG
DLUC
DIU
SLM
SLM
SLM
SLM
DCC
DCC
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
BDE
BDE
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
DCC
DCC
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
BDE
BDE
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
DCC
DCC
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
BDE
BDE
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
DCC
DCC
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
BDE
BDE
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
DCC
DCC
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
BDE
BDE
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
DCC
DCC
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
BDE
BDE
SLM
SLM
SLM
SLM
SLM
SLM
SLM
SLM
DCC
5
Line Trunk Group (LTG)
The line/trunk group (LTG) forms the interface between the digital environment of the node and the digital switching network (SN). The LTGs perform non-central control functions and thus relieve the coordination processor (CP) of routine work.
Functions of LTG: Following are the major functions of LTG
LTG provides direct connection of one exchange with the other
exchanges of the same city or the other cities.
LTG generates telephone tone.
LTG provides a gateway to the switching network.
LTG provides interface between DLU and PCM.
Several LTG types are available for optimal implementation of the various line types and signaling methods. The two main types of LTGs (differing in their functionality) used are:
LTG-B
LTG-C
Physical Rack Diagram:
DIU
DIU
DIU
DIU
CRP
TOG
GSL
CGSM
PMU
SILC
DCC
6
LTG-B
The LTGB is used for connecting:
Up to four digital transmission routes (PDCs) for DLUs at
transmission rates of 2048 kbit/s
Up to four primary rate accesses (PAs) for medium-sized and large
ISDN PABXs (ISDN subscribers with PA) at a transmission rate of
2048 kbit/s.
Main Components of an LTG-B
Group processor (GP) Link interface unit between line/trunk group and switching
network (LIU) Group switch (GS) Speech multiplexer (SPMXA) Signaling unit (SU) Line/trunk unit (LTU)
7
Functions of LTG
Line Trunk Group
Interfacing
Trunk
Signaling
Memory Unit
Tone Generator
Code Receiving
Sync &SwitchingModule
Power
CRP
4 x DIU’s
TOG
PMUBPMUCPMUD
GSL
DCC-DE
SILC-BSILC-C
CGSM
8
Switching Network (SN)
By virtue of its high data transmission quality, the switching network can switch connections for various types of service (for example telephony, facsimile, teletext, data transmission).
This means that switching network is also ready for the Integrated Services Digital Network (ISDN).
Functions OF Switching Network: Duplicated (full redundancy)
Highly-Integrated switching network modules
One space stage module can handle up to 1024 simultaneous calls
with full redundancy
Interfaces of 8,192 Kb/s available within
Highly compact design from space-saving point of view
An exchange of 10,000 subscribers may accommodate the SN in a
single rack
Two kinds of connections: Switched & Semi-permanent
9
Structure:In large and very large exchanges the capacity stages of the switching network (SN:504LTG, SN:252LTG and SN:126LTG) include
One time stage incoming (TSI)
Three space stages (SS)
One time stage outgoing (TSO)
Medium-sized and small exchanges (SN:63LTG and SN:15LTG) contain One time stage incoming (TSI)
One space stage (SS)
One time stage outgoing (TSO)
Physical Rack Diagram:
TSM
TSM
TSM
TSM
LIS
LIS
SGC
LIS
LIS
TSM
TSM
TSM
TSM
DCC
TSM
TSM
TSM
TSM
LIS
LIS
SGC
LIS
LIS
TSM
TSM
TSM
TSM
DCC
10
Coordination Processor:
The CP performs the following functions in a network node:
Call processing
Operation and maintenance
Safeguarding
The CP consists of the following processors:
o Base Processors
o Call Processors
o Input / Output Control
o Bus for Common Memory
o Common Memory
o Input / Output Processors
Coordination Processor Modules
1. BAP: The BAPMs and the BAPSs provide the same software functional units. 2. CAP: The CAPs mainly include software for call processing functions. 3. IOC: IOCs have only firmware for communication with the call processing,
O&M and data communication peripheries.4. BCMY: The bus for common memory (BCMY) connects all processors (BAP, CAP), including the input/output controls (IOC), with each other and with the common memory (CMY).
11
5. CMY: The common memory (CMY) includes, among other things, the common database for all processors, plus the input and output lists for the IOP. The CMY is duplicated in order to ensure a high level of availability. 6. IOP: Different types of input/output processors (IOP) connect the CP113D with other units in the network node, the external bulk memories, the operation and maintenance terminal, the operation and maintenance center (OMC, via data lines) and computer centers (also via data lines).
Functionality of CP
COORDINATION PROCESSOR
BASE PROCESSOR
CALL PROCESSOR
INPUT/OUTPUT PROCESSOR
COMMON MEMORY
BUS FOR COMMON MEMORY
INPUT/OUTPUT CONTROL
12
Functional Units of EWSD exchange:The EWSD system is divided into different functional areas called subsystems coordinated by a central system. Following are the main functional units of EWSD exchange.
1. Control
2. Switching
3. Signaling
4. Access
5. Power
ControlControl belongs to the area which is responsible for the coordination of the various subunits. Control consists of the following:
Coordination Processor (CP) Message Buffer (MB) System Panel (SYP) Central Clock Generator (CCG)
Message Buffer The task of MB is to control the exchange of messages between the following subsystems:
Coordination Processor (CP) and line/trunk groups (LTG):
Commands and Messages
CP and switch group controls (SGC) of the switching
network: Setting commands for the SN
LTGs among one another: Reports
13
LTGs and the common channel signaling network control
(CCNC):Orders
Message Buffer Group
The message buffer is divided into functional groups called Message Buffer Groups according to the expansion concept. One message buffer group consists of one message buffer unit for Switch Group Control and two message buffer units for LTG. In the least configuration, at least one message buffer group may exist with at least one MBUL and one MBUS active where as the other MBUL may be inactive.In the highest configuration, there are up to 4 message buffer groups with 4 MBUS and 8 MBUL.
Central Clock GeneratorIn order to switch and transmit digital information, the sequence of operations must be synchronous throughout the equipment involved.This requires a clock supply with a high level of reliability, precision and consistency for all the nodes in the digital network. This task is fulfilled by the central clock generator (CCG).Depending upon the accuracy required, the following two modes of operation are possible.
Control System PanelThe purpose of the system panel is to display alarms and advisories of internal and external supervisory units outside the system) both visually and acoustically. It is divided into two parts namely the System Panel Control and the System Panel Display unit. System Panel Control:This utilizes the free space in the Message Buffer Rack. It is connected with the IOP: MB in the CP113. Although itself it is not redundant, it has a redundant connection with the CP via two IOP: MBs, each belonging to a different side.
14
The system panel display unit is connected with the control (SYP) via a cable but can be placed at any suitable place within the exchange by direct connection or in an OMC using some transmission system.This unit is responsible to display alarms and advisories of internal and external supervisory units (outside the system) both visually and acoustically. It is also responsible to show the CP load (in ERL) and the current date and time of the system.
SwitchingBy virtue of its high data transmission quality, the switching network can switch connections for various types of service (for example telephony, facsimile, teletext, data transmission).
This means that switching network is also ready for the Integrated Services Digital Network (ISDN).
SignalingThe EWSD digital electronic switching system can control connections to and from other network nodes using all the common signaling systems. The signaling functions in a EWSD network-node are handled by the "common channel signaling network control (CCNC)". One system that is particularly suitable for stored-program-controlled digital nodes is signaling system no. 7. This transports signaling information separately from the user information (voice, data) on common-channel signaling links.
Advantages:-
Higher speed signaling
Very reliable signal transmission
Flexibility to adapt to future requirements
Suitable transmission Medium
Copper Wires
15
Optical Fibers
Digital Radio Links
Satellite links
AccessThis includes:
Line / Trunk Group (LTG)
Digital Line Unit (DLU)
Digital Announcement System (DAS).
DAS explained:
The digital announcement unit announces recorded messages to the subscriber relating to different matters such as reason for disconnection or the disability of a non STD phone to dial an outstation call. The necessary information for such an announcement is provided by CP and DLU.
16
ZTE Exchange
ZTE is a Chinese telecommunication company that was founded in 1985.Initially it had its network limited in different cities of China later on ZTE extended its network to different countries of Asia and Africa. Unlike EWSD, ZTE is modular based exchange and in each module we have its own control system, switching network and signaling network.
At IBA exchange a ZTE exchange named ZXJ10 is installed. It has capability of supporting 10000 lines. A detailed diagram of ZTE’s module is shown in the next page.
The main advantage of having a ZTE exchange is its low cost. The ZTE exchange costs almost eight times less than that of Siemens, Ericsson or Alcatel. That is the reason why ZTE is becoming so popular in the developing and poor countries of Asia and Africa.
The disadvantage of ZTE exchange is that it is not as reliable as EWSD, Ericsson, Alcatel or even Huawei .ZTE exchange suffers from more errors than other exchanges.
17
SCL: Subscriber line circuit.DSPU: TSLC: Test subscriber line currentDT: Digital trunksCOMA: Communication card.MPPP: COMMUNICATION CARD.NET: Switching networkCKG: Clock generation.
10
ALARM-48+5-5
ALARM-48+5
-5
DSPU
DSPU
DSPU
DSPU
PP
TSLC
TSLC
TSLC
TSLC
MasterStandbyOfflineAlarmPower
SwitchResetOn/off
MasterStandbyOfflineAlarmPower
DT
DT
DT
DT
DT
10
10
ALARM-48+5
-5
SwitchResetOn/off
ALARM-48+5-5
10
DSPU
DSPU
COMA
COMA
MPPP
MPPP
SLC
SLC
SLC
SLC
SLC
SLC
PP
PP
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
SLC
ZTE
ZXJ10 MODULE
CKG
NET
CKG
NET
18
AnalogSubscriber
DigitalSubscriber
VSX
TrunkSubscriber
Centrex
BSC
BSC
BSC
PSM(PHM)
PSM(RSM)
MSS
SNM
NT SERVER
SNM (CTL)
MSMCTL
RSU
Optic fiber4.8 Mb/s
8 M b/s Optic fiber
Terminal group
OMM
CSM
WORKING OF ZTE EXCHANGE
ZXJ10
19
OMM: Operation and maintenance module.MSM: Message switching module.PSM: Peripheral switching module.RSM: Remote switching module.DSN: Digital switching network.CSM: Central switching module.
Functions of ModulesOMM (operation and maintenance module):
1- Global traffic handling.2- Database management and modification.3- Man-machine interface.4- Billing handling centre.5- Maintenance, diagnosis and test.6- Supervising the system operation status and the remote operation
environment.CSM (centre switching module):
One is the voice channel switching control part(SNM) and the other is message switching control part(MSM)SNM:Its main task is to complete the voice channel switching . the DSN consists of several planes,each two planes of 8k form a pair of active/standby DSN switching network that can be configured with 8 such 8k planes at maximum to constitute a switching network of 64k *64k.MSMCTL:It mainly provides the message switching for each MP status (module processor), to realize the communication between OMM and each MP. While man machine commands are send to each MP via MSMCTL, such as the MP switch over command, etc.PERIPHERAL SWITCHING MODULE (PSM):Its main functions are as follows.
1- PSTN subscriber access and intra-office traffic handling.
20
2- ISDN subscriber access.3- Centrex commercial users’ access.4- Mobile subscriber’s access.
A single PSM can constitute a single module office.REMOTE SWITCHING MODULE (RSM):Its structure is similar to PSM. Its functions are:
1- Providing access to remote users.2- Realizing intra subscribers switching.3- Realizing central networking with CSM.4- Providing the same n * 64 kb/s (n<=128) dynamic time slots
switching as PSM.RSU:
1- It mainly provides access for small group of remote subscribers which are usually POTS users.
2- Realizing intra RSU traffic handling.3- Networking with CSM, realizing the whole network calling possible
located far from central office by using the low optic fiber connections.
21
PRI ExchangePRI stands for primary rate interface. The PRI exchange connects the ISP’s and the subscribers of the telephone line.C&C08 is the PRI exchange installed at IBA. It is manufactured by Chinese company Huawei.
The line provided to ISP can support data transport at the rate of 2 Mbps and cannot exceed this limit. Each card in this Huawei exchange has 16 PRIs. Each PRI has 32 channels,30 channels are allocated for 2 way communication of digital data between the server and the internet users, one channel is utilized for frame alignment (synchronization) and one is used to signal the communication data. There are CPC link cards, STP and SRC announcement cards. The interconnection between different cards and frames is through optical fiber.
USER TelephoneExchange
I N
PRI ISPTransit Exchange
Connection establishment in PRI
22
MSAG (Multi-Service Access Gateway)To be able to understand about Multi-Services Access Gateway, its
need and why it was introduced, we need to study the following points.
1.CIRCUIT & PACKET SWITCHINGThe placed between two communicating persons is a complex
field of devices and machines which is divided into two basic types Circuit Switching Packet Switching
Circuit Switching is an old and expensive method of switching while Packet Switching is a modern method comparably less expensive than Circuit Switching but Circuit Switching is more reliable than Packet Switching. When a person has a circuit dedicated to for a session; he is confident of getting all the information across.
To be able to understand packet switching, we first need to realize what a packet is. The Internet Protocol (IP) just like many other protocols breaks the data into chunks and wraps; that chunks and wraps are actually called Packets. Once they reach the destination, the packets are reassembled to make up the original data again; therefore, it is obvious that for transmitting a data in packets; the data should be a digital data.
2.VoIP (Voice over Internet Protocol)It is also referred as IP Telephony or Internet Telephony. It is
another way of making calls, with the difference of making phone calls cheaper or completely free.
The main reason for which the people are turning so massively towards VoIP Technology is the cost. It is said to be cheap but mostly people use it for free. If a person a Personal Computer and a good internet speed; he can use VoIP for free.
MSAGWith the increasing demands on telecommunication services,
including data, video, voice, and multimedia services, large-capacity access networks that provide high-speed, high-quality integrated services have become the focus of access network development.
23
To address the tendency towards this type of access network, Huawei HONET UA5000 multi-service access product integrates traditional voice, VoIP, private line, PBX, video, and multimedia services for subscribers. It provides GE, FE, ports for transmitting services upstream. UA5000 is Universal Access equipment which can support both narrowband service as well as broadband service. It provides the traditional voice access, broadband access, Voice over Internet Protocol (VoIP) and multimedia services.
MSAG Features Traditional Services are retained when evolving from a TDM
Network to an IP Network, and subscribers do not have to change terminals.
High-Speed Broadband Access: The UA5000 supports: 1) the ADSL2+ and VDSL2 technologies to achieve a maximum transmission rate of 100Mbit/s
Energy Saving: The UA5000 is the first multi-service access device in the world, which have an optimized design and low power consumption components
Flexible Installation: The UA5000 provides indoor and outdoor cabinets to meet operators' requirements for flexible deployment and rapid installation
24
PROPER APERTURES FOR EXERNAL CABLE CONNECTIONS IN MSAG
25
ENTERING OF FIBER AND PNGD CABLES WITH MSAG
DISTRIBUTION & ARRANGEMENT OF FIBER (PIGTAILS) IN ODF TRAY
26
POWER MONITORING MODULE AND RECTIFIERS
AC INPUT BATT
FAN-ALM RUNALMRUNALM
COM
B
MS
PSM-B5
Power supply unit Monitoring unit Rectifier unit
HRS850-9000C HRS850-9000CHRS850-9000C
FAN-ALM RUNALM FAN-ALM RUNALM
LOAD2 LOAD3 LOAD4LOAD1
AC-L AC-N
BATT.(-) LOAD(-) BATT.(+) LOAD(+)
B1 B2+ +
AC input switch Batterycontrol switch
Output tributary switch
ACCESS PART FRAME
0 1 FAN 16 17
PWX
PWX
IPM
IPM
PVX/RSU
PVX/RSU
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL/TSS
CABLING 0 1 FAN 16 17
27
PVX or PVM boards Broadband & narrowband service board TSS or Service board
Power Cards
16U
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
XSL
CABLING
MSAG CARDS Control Card
a) Narrowband Control Card: PVMb) Broadband Control Card: IPM
Line Carda) Narrowband: ASL, A32 …b) Broadband: ADMC, ADRB …c) Combo: CSLB, CSRI …
NARROWBAND SERVICE PSTN Voice Service
a) POTS Portsb) ISDN BRI Portsc) PRI Ports
NGN Voice Servicea) VoIP calls by POTS subscribersb) VoIP calls by ISDN BRI subscribersc) FoIP and MoIP
BROADBAND SERVICES ADSL and ADSL2+ Service SHDSL Service VDSL Service
28
The narrowband or the broadband control boards can be inserted into the thirty service slots in a mixed way
Ethernet Service of residential Communities and commercial buildings
POTS SERVICE
UMG (Universal Media Gateway)The basic function of UMG is TDM to IP conversion and compression.
TYPES AMG TMG SG
UMG BOARDS
Boards Function
Front Side Board
FOMB It is used for processing and Operation & Maintenance
SPF Signaling processing frame: used for ISUP, PRA
29
Twisted Pair
UA5000POTS
UMG POTSMSU/
E V
VPD Voice processing module: used for voice processing
HRU Hot Resource Unit: used for hot swapping
Rear Side Boards
TNC It is used for conversion of TDM signal in IP
Clock Using for clock signal
FE8 Having 8 ports of FE
E32 Having 32 ports of E1s patching
PROCESS OF CONVERSION FROM TDM SIGNAL INTO IP SIGNAL IN UMG
30
TDM SignalTDM Signal
E32E32
TNCTNC
HRUHRU
SOFT SWITCH (SOFTx3000) Basics
Basic function of Soft Switch is to Control all Type of Networks. User friendly Secure Easily accessible
Features Service Provision Capability
a) Basic Voice Servicesb) Supplementary Services
Large Capacity and high integration
NORMAL FULL CAPACITY01 FCCU Module 9000 Trunk support50,000 Subscriber Support
40 FCCU Modules 36,000 Trunks support20,00,000 Subscriber can be Support
High Securitya) Security in DATA Base (Automatic Backup)b) Security in Subscribers (IP, Password)c) Security in O&M
High reliability
Hardware Design Software Design
31
FE8FE8
IP SignalIP Signal
Distributed ProcessingAssistant Work Mode (Load Share)Optimize Fault detection
GUI(Graphical User Interface)Overload Hot BackupDouble Backup
Network Capability
32
Soft Switch Soft
Switch
SIP-T
PSTN
N2000 Server
H.323
SIGTRATCP
SIP Phone
SG
H.248
MSAG
MSU/RDLU
H.248
UMG