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INTRODUCTION: - This journey began with simple calling that “Watson Come Here” called by inventor of telephone Graham bell. To bridge the gap between the supply and demand, govt. has decided to revise and moderate the telecom policy. Govt. opened the sector for foreign investor. This foreign suppliers set up exchange, of more capacity

EWSD of SIEMENS (GERMANY)

AXE of ERICSSON (SWEDEN)

CHENNAI FETEX-150 OF FUJITSU (JAPAN)

OCB of ALCATEL (FRANCE)

5ESS of AT&T (USA)

SYSTEMS-X 1of GPT (UK)

NEAX of NEC (JAPAN)

We have done our training with 5-ESS digital switching system, with a capacity of 15k,it can be further extended .it has given configuration in our training site

5k at Benajhaber

RSU of 6k at Kakadev

RSU of 4k at Avas-vikas

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OVERVIEW The 5ESS-2000 switch is a digital exchange that can serve as a local (lines), toll (trunks), tandem (lines and trunks), OSPS (operator service position system) or international gateway exchange depending on the switch. It can serve a small community with fewer than 100 subscribers or a large metropolitan area serving more than 100,000 subscribers. The quality of service rendered by a telephone exchange is traditionally measured by availability criterion. In the modern digital exchanges with extremely reliable hardware and software, exchange availability is ensured to a good extent. As a result the focus of provision of service has shifted from mere availability of service to the enriched features and facilities to suit the needs of both the needs of individual subscribers and business establishment. With the coming of ISDN, the network boundaries are disappearing. The methods for activation, deactivation, utilization and charging of the subscriber services need to be standardized across the networks in order to take full advantage of the more intelligent switches and user network interfaces. In the Indian networks, the services offered to subscribers are categorized as follows—

1. Basic services 2. Supplementary services 3. Non- Supplementary services 4. Miscellaneous services 5. Switching Facilities

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1- BASIC SERVICES:- Basic services are composed of telephone lines provided singly or in groups .

2-SUPPLEMENTARY SERVICES:- Any other service that is provided specific to subscribers directory no and controlled by administration and/or the subscriber himself is termed as supplementary service.

3-NONSUPPLEMENTARY SERVICES:-

A non- Supplementary services is also provided to a subscribers directory no but is more general in nature.

4-MISCELLANEOUS SERVICES:-

Miscellaneous services are also value based services but they have different method of provisioning than the supplementary or non- supplementary services.

5-SWITCHING FACILITIES:-

Switching facilities concern only the use exchange switching facilitie2s. These are independent of individual subscribers and are controlled solely by administration. Normally these facilities are not charged.

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TETETEVEVEVVCJVS

Local Subscribers (Lines)

IN-SCP

IG

IN-SSP

TE

LE

TE

LE

LE

Local Subscribers (Lines)

Local Subscribers (Lines)

IG- International Gateway TE-Toll Exchange LE-Local Exchange

(Trunks)

(Trunks) (Trunks)

(Trunks)

(Trunks)

(Trunks)

Next Gateway

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Electronic Switching System:- 3

Fig-Modular Distributed Design

P

AM

SM

SM

SM

CM

AM

AM-Administration module SM-Switching module CM-Communication module

Lines/Trunks

Lines/ Trunks

Lines/Trunks

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ADMINISTRATIVE MODULE ~ (AM) The AM is Switch equipment module which has the overall the control of the entire 5ESS – 2000 Switch. The AM controls the CM and communicate with all the SMs (through CM). If there are any problems they are reported to maintenance personnel. AM Functions- The AM has a minimum of one cabinet and maximum of 3 cabinets. The AM functions are – *Administrative data processing *Traffic Measurement – System performance report *Memory Management *System Maintenance *Allocating trunks for call processing. AM Components-

CU-Control Unit DFC-Disk File Controller DD- Disk Drive ROP-Receive only printer TD-Type device OP-Input/output processor

CU

CC

MM

DFC

IOP

TD

DD

MCC

ROP

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There are three main units within the AM *CU (Control Unit) *IOP (I/P O/P Processor) *DFC (Disk File Controller) The CU monitor over all system operation. . CU consists of [CC (central control) &MM (Main Memory)] as subunits. CC has six major functions

*Execute program –CC contains logics circuits that execute step by step instruction to control the operation of AM processor. Execute program request –it response to request from SM and from maintenance personnel *Processes administrative data – It compiles report ,

information and prints reports periodically *Monitors system operation- it maintains a log of equipment status and a list of OOS (Out of service) equipment. *Update duplicate CU- It communicate with duplicate stand by CU to keep its memory up to date. *Manages data transfer –It control memory transfer between its own memory, its hard disk and the microprocessors that serve the peripheral units in the IOP.

DISK FILE CONTROLLER (DFC) ---The DFC is responsible for interfacing with SCSI (small computer system interface) peripheral devices, such as the tape and disk drive. TAPE DRIVE (TD)—The TD is back up for information store on disk .Data can be transferred from tape to disk or from disk to tape. IOP------It is the interface for the other peripheral devices used by the switch such as (MCC & ROP) data links and alarms signaling. MCC (Master central control) ---MCC is the main local workstation of maintenance personnel.

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Switching Module:- The primary job of the switching module is to connect subscriber lines and inter-office trunks to the 5ESS switch. A switching module is a multi-unit component. A switching module is located in a variable number of cabinets. The switching modules are available in two models, the SM or SM-2000. In addition, there are 5 applications of switching modules: the LSM, HSM, RSM, and ORM. One 5ESS-2000 Switch can support as many as 192 SMs. Each SM can handle as many as 5120 lines or 500 trunks or a combination of two. The SM-2000 can handle more than 65,000 lines and about 18,000 trunks. Switching Module Functions:- All external lines, trunks, and special services circuits are terminated at the switching module. The analog and digital signals are converted4 to the digital format used inside the 5ESS-2000 switch. The SM performs almost 95% of the call processing and maintenance functions including—

1. Line and trunk scanning 2. Tone and cadence generation 3. Digit analysis 4. Call routing 5. Circuit switching 6. Packet switching 7. Announcements 8. Call process supervision 9. Routine maintenance and self-maintenance

The SM provides many subscriber calling features including— i. Call waiting ii. Abbreviated dialing iii. Call diversion iv. Conference calls

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SM Control Units: - MP- Microprocessor SMP-switching module processor TSI- Time Slot interchange MCTU/MCTSI-Module controller and TSI unit/ Module controller and time slot interchange

Located in the SMC (switching module control) cabinets are the two SM control units, the SMP and the TSI. These two units are combined into the MCTSI which is also referred as MCTU. SMP: - Switching module processor contains the microprocessor and memory used to perform the call processing and maintenance functions within the SM. The SMP provides five major functions:-

Controls peripheral units Performs call processing Performs SM maintenance Initializes SM memory Communicates with the AM and other SMs

TSI:-

The second control unit in the SM is the time slot interchanger. The TSI performs the time portion of the time-space-time division switching. This type of switching allows multiple inputs access to a set no of outputs when processing phone calls.

The TSI also switches data from the network side to the CM where it is routed to other SMs. The TSI receives and transmits peripheral time slots to and from peripheral units.

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Types Of Switching Module: - A 5ESS-2000 switch can be equipped with the following types of SMs:

LSM (Local Switching module):- This type of SM serves local lines, trunks, and ISDN.

HSM (Host Switching Module):- This type of SM provides the normal LSM subscriber interfaces and also interfaces one or more RSMs .

RSM (Remote Switching Module ):- This type of SM is designed to meet the needs of those communities that are too small to be served by their own 5ESS switch in the remote area.

PSM (Position Switching module):- This type of SM supports operator switching position system features.

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Communication Module Hardware that provides the interface between the AM and the SM(s). In a multi-module office, the CM consists of the message switch and the TMS. Communications module 2(CM2) is an updated version of the CM that is physically smaller but has an increased call handling capacity. This has been accomplished by use of the new operationally larger TMS2 and MSG2, now housed in the CM2 cabinet instead of separate TMS and MSGS cabinets. CMCU (communications module control unit) The CMCU, a part of CM2, provides message interface and timing facilities used to synchronize the time division network in the TMS via the TMSU. The CMCU consists of a DMI, NCLK2, TMS controller and metallic interface. CNI (Common Network Interface) The CNI functions as a packet switching system in the signaling network. The CNI is not a stand-alone switching system but requires configuration to an application such as the 5ESS® switch and 5ESS®-2000 switch. The CNI consists of several peripheral processors (RPCs and LNs) serially interconnected and a central processor that performs the basic operating system duties in a distributed I/O processing architecture. Communication Module Functions: -

All versions of CM are divided into two functional units:

I) MSGS (message switch control unit) II) ONTC (office network and timing complex)

The following description is based on the most common type of communication type of CM currently in the field, the CM2. The MSGS and ONTC are each made of subunits. The four major functions are of the CM are performed by these hardware subunits: -

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MSGS: MSCU (message switch control unit)-provides control

over the MSPU. MSPU (message switch peripheral unit)- Processes

control time slot. ONTC:

CMCU (communications module control unit)- Provides timing and control.

TMSU (time multiplexed switch unit)- terminates NCT links and switches data and control time slots between them.

The major functions of the CM are call switching, message switching, network timing, and normal bump. The CM is linked to the AM with a DSCH bus (metallic), to the SM with NCT links(fiber optic cables).

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Switch Application:- The 5ESS-2000 Switch was designed with a flexible modular approach with regard to both software and hardware, allowing for digital services, and capabilities that support many applications. Current applications supported by system are as follows: -

Local Exchange Toll Exchange Gateway Exchange SSP (services switching point) ISDN MSC (Mobile Switching Center or Wireless)

Local Exchange: - A local exchange is located at the bottom of the network hierarchy and has a high percentage of subscribers connected to it and a low percentage of trunks. The local exchange switches a call from an internal subscriber to another directly or through a trunk circuit to another exchange. The local exchange performs the metering and charging for multi-metering. For AMA (Automatic Message Accounting) the call information records are send to a billing center. Toll Exchange: - To connect different geographical areas within a country, a toll exchange is used. Trunk circuit connects the local exchange to a toll exchange. The toll exchange switches calls to other toll exchanges to continue the call or to a local exchange to terminate the call. Sometimes the toll exchange performs metering and charging. The metering information is then send to local exchange to update the subscriber charging registers.

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Gateway Exchange: - All calls in the network bound for an international destination is send to an international gateway exchange and are then routed to the proper country. All calls entering the network from another country are received by the international gateway first, and then routed to the proper local/toll exchange.

FIG:GATEWAY EXCHANGE,TOLL EXCAHNGE & LOCAL EXCHANGE

GATEWAY EXCHANGE> Services Switching Point: - A call is routed to an SSP, based on the dialed number. The SSP then uses the received number to locate the appropriate translation. The number is translated into a destination number, using the translation tables available in the exchange. The treatment of the call depends on the service features the called party has subscribed to.

Local

Toll

Local

GW A

GW B

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Tandem Exchange: - A tandem exchange is located between local exchange and/or local and tandem exchange. The tandem exchange is used to consolidate the use of trunks between exchanges. Instead of installing trunks between each exchange in a local area each exchange can have trunks routed to tandem exchange. All call are then routed to the tandem and on the another exchange. OSPS (Operator Service position System) > The 5-ESS -2000 switch offers automatic operator services via the OSPS. OSPS applications are directory inquiry to supply directory numbers to calling subscribers .

FIG:5-ESS SWITCH WITH ADDITION SM

AM

CM

SM

PSM

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ISDN> ISDN offers a new voice data services and allow features such as OSPS. Two people with ISDN can make phone calls and use there computer

FIG:5-ESS SWITCH COMPATIBLE WITH ISDN CONNECTION

STP (Signaling Transfer point)> It sends signaling messages on there way to proper destination over a different path then the associated voice circuit.

Signal Transfer Point

Local/Toll

Local/Toll/ Gateway

Signal

Signal

AM

CM

ISDN SM

SM

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Call Processing The purpose of the 5ESS switch is to switch calls from originating equipment to terminating equipment and to provide the proper charging information to correctly bill the customer. This function is referred to as call processing.

Subscriber

ORIGINATION

DIGIT ANALYSIS

ROUTING / SCREENING

CHARGING TERMINATION

OUTGOING CALL

SUBSCRIBER OR INCOMING CALL

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Call Processing Stages: There are five fundamental steps of call processing, including the location of the originating and terminating equipment. These steps are as follows:

Origination Digit analysis Routing/Screening Charging Termination

There are five functional steps for call processing ORIGINATION >

It begins when the subscriber line goes of –hook or when an incoming trunk is seized.

DIGIT ANALYSIS> It interprets the digit that it receive from origination,selects a destinations for each call , and passes the dialed digits to routing .

ROUTING /SCREENING>

Routing uses the destination information from digit analysis and screening information form origination to select the termination trunk lines or groups.

CHARGING>

It uses the charging information from routing to expand the charging data into a format useable by the call accounting process.

TERMINATION >

It is the last step in the call processing .Termination process are different for call destined for lines and call destined for trunks.There are of two type Trunk and Line termination.

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CHARGING Charging is the function that accesses the costs of the usage of switching capacity and that passes these costs on to the users. These users can be

subscribers ( to national traffic/originating international calls)

other administrations( to share revenues when they share national capacity) Of time interval

CHARGING METHODS

Two methods can be used to determine the actual usage of system capacity 1. Multimetering 2. Detailed billing

These methods can be used independently or in combination. The data provided by both charging methods allows for billing that is variable and dependent on

information that is fixed for each call The type of originating subscriber. The destination of the call.

information that is related to time The duration of the call. the date and time when the call was place

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1. MULTIMETERING Charges imposed by multimetering are expressed in charging units. For each subscriber the charging units are collected in a software counter- the subscriber register or software charging register. The number of charging units is in direct relation with the billed costs that are passed on to the subscriber. The system is capable of imposing charging units on Answer of a call

- lapse of a time interval since the answer of the call

- Subscriber action to control a supplementary subscriber service.

Multimetering is capable of performing both the fixed and time dependent parts of charging. CHARGE DETERMINATION The charging method is determined on imformation on origination and destination of the call.The fixed part of charge results in the applicable charging methods and the tariff identity. Advantage of this method: 1. charging units can be used to generate charging pulses 2. simple charging methods requires only the number of

imposed charging units. Disadvantage of Multimetering: Only the charging units are accumulated to the subscriber register.The events that caused the production of the charging units are lost forever.So detailed bill cannot be generated. For ISDN ( Integrated Services Digital Network ) subscribers no home meters are used.An equivalent of the home meter service is the ISDN AOC (Advice of Charge) service.

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2-DETAILED BILLING: This charging method is based upon recording of all information relevant to billing for each call. In addition to other call data, the following billing information is usually recorded.

Information concerning origin and destruction of call iThe date and time that the call was answered The date and time that the call was disconnected

THE ADVANTAGE OF DETAILED BILLING

call events are recorded per call This is applied further to different charging

situations

National billing International Revenue Sharing Monitoring the handling of a call by tracking events

CHARGING: FUNCTIONAL DESCRIPTION

A. Determination of the charging methods and the fixed charging information

B. Determination of the time dependent charging information

C. Transport of the charging data to the AM ( Administrative Module)

D. Temporary storage of the charging data in the AM.

E. Transport of the charging data from the exchange to the external billing center.

F. Billing.

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CHARGEABLE CALL DURATION- Normally the charged a call depends on the conversation time. The conversation time for a successful call is the difference between the time of call commencement and the re-answer timeout or clear forward signal. The start time and end time of the conversation time are included in the detailed billing record. CHARGE DETERMINATION- It is started as soon as enough digits have been received to connect a call to a certain destination. In a PSTN (Public Switch Telephone Network) call, the charge index is determine by 1. The origin of call, indicated by screening index 2. The destination of the call, indicated by destination index

CHARGE REGISTRATION – The charging information is registered in the basic call record in the SM. Registration of the charges is done by MM(Multimetering ) method, AMA method or a combination of both methods . Charging of basic ISDN calls can also be done via multimetering, AMA or a combination of both methods. Charging of non – ISDN supplementary services can be done via MM, AMA or both methods. Charging of ISDN supplementary services is done via AMA only. FUNCTIONAL DESCRIPTION- AMA(Automatic Message Accounting) records or generated for billable, calls that have reached the conversation phase. For calls which can not reach the build – up complete phase or do not reach the conversation phase, no AMA records are generated . AMA records are generated for execution of some these supplementary services, irrespective of whether the calls using the supplementary services are answered or not.

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Fig: Determination of charge rate

Tariff identity date Time of Day

Day No. program identity Day Charge rate Name

no. of units in answer 5No. of units per interval Length of time interval

Exception day definition

Dayb program selection

Day program selection

Rate selection

Charge rate definition

Rate name

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DIGITAL ANALYSIS Digit Analysis is the function that collects and analyzes subscriber dialed or trunk originated digits in order to determine the requested call destination or special dialed services. Digit analysis can be split up into two functional entities. Digit Collection>

responsible for collecting dialed digits from incoming trunks or lines.

1. - supporting the signaling protocol of the origination line /trunk.

2. -performing dial timing requirements. there are of two type collection; 1. PSTN Collection 2. ISDN Collection Digit Analysis>

Responsible for: - Identification of call type (normal call, dialed service,

emergency number). - Inter digit timing requirements i.e. digit analysis determines the

minimum no. of digits required to route the call. - Generation of routing request data. - The following different dialing plans exist in an exchange

depending on the position of the exchange in the network. - *Originating - *Terminating - Regional - *National - *International - the data for each dialing plan is divided over two main tables - *preliminary table containing DAPRI and DAPRO data. - *Primary table containing DANAL data.

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DIGIT ANALYSIS SELECTOR (DASEL) ***************************

This form is used to define a set of digit analysis tables for a digit analysis selector.

A preliminary table for line originated calls A preliminary table for trunk originated calls. Main analysis tables which are used after the preliminary

analysis for line/ trunk originated calls. If there is only one DASEL form defined with pointer to the

DAPRI,DAPRO,DANAL form, then these forms have to be deleted first before this DASEL form can be deleted. If there are several DASEL forms, then these DASEL form s can be deleted , until only one DASEL form remains with those pointers.

DAPRO_(Originating Preliminary Analysis) This form is to analyze the subscriber programming digits that

control services and to specify the type of main analysis table to use for all other calls.

DAPRI____ (incoming Preliminary Analysis) This form is used for preliminary analysis of incoming trunk calls. DANAL_ _(Main Digit Analysis) This form is used to define the main analysis table for both line and trunk originated calls.

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ROUTING ******************

Routing is the exchange service which translates the destination data receives from digit analysis into the physical port which leads to the dialed destination (outgoing trunk or line).

In most cases routing starts after the collection and analysis of the minimum number of digits required to determine the destination of the call. BASIC CONCEPTS Terms used are

Screening Index- It is an arbitrary number assigned by the telephone administration to uniquely identify the source of originating line for routing and charging purposes.

Destination Index- It is also assigned by telephone administration to uniquely identify each destination reachable from the exchange for routing and charging purposes.

Line Or Trunk

Digit Analysis

Routing

Line Or Trunk

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Route— -It is defined as one possible group leaving the exchange and leading to the specified destination.

Route Chain— It is defined as an ordered set of routes used to reach a given destination It contains a primary roots and one or more alternate routes.

Route Index— It is an arbitrary number assigned by the telephone administration to uniquely identify one route out of the exchang.

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COMMON CHANNEL SIGNALING SYSTEM NO.7 CCS No.7 is a CCS system which may be used in an associated and non associated mode of operation. It has following features- 1. Based on separation of speech circuit from signaling link 2. Speech circuit has no signaling function except when a

continuity check is done 3. Result in faster call set up 4. Efficient utilization of speech circuits.

This system is to provide an internationally standardized general purpose CCS system. 1. It provides a reliable means of transfer of information in correct

sequence and without loss or duplication. 2 It is optimized for operation in digital telecommunication network in conjunction with stored program controlled exchange. The signaling system is optimized for operation over 64-Kbits/s digital channels. It is also suitable for operation over analog channels and at lower speeds. The system is suitable for use on point to point terrestrial and satellite links.