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C-DOT DSS MAX-VE - C

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2. MESSAGE NETWORK FIGURE 4 3 INTER PROCESS COMMUNICATION THROUGH CDOS LOTUS VOL1 DESIGN MAX2315 MX2315GD MXISGDOI 48 C DOT DSS MAX VE 4 3 1 4 3 2 SOFTWARE ARCHITECTURE Peripheral Processor Subsystem The telephony software for handling lines trunks and service circuits is controlled by the Peripheral Processors These are 16 bit microprocessors programmed assembly level language The main activity of the telephony software is to detect events and communicate them to the Base Processor where logical call handling is done The Peripheral Processors also carry out the commands given by the Base Processor for generating suitable telephony events on the outgoing lines and trunks Events like line seizure answer disconnection and signalling information between exchanges etc are examples of telephony events which are processed by the Peripheral Processors These events are converted into a set of pre defined messages which are sent to the Base Processor for subsequent processing Transmission of ringing current outpulsing of decadic digits on a junction and sending MF signals on junctions are some of the examples of the events which are created by the Peripheral Processors under the control of the Base Processor and sent on the outgoing external lines and trunks Another important function of Peripheral Processors is to carry out all the maintenance related test functions on hardwar
3. TWNINYAL 8702 sna 9 8 9 5 4 HSS HS3 HS3 8 wn 2089 i gi HS3 v 60689 I dq L L 5 5 1 215 ns 055 24 3 2 1 4 HARDWARE ARCHITECTURE including initial alignment and error correction by retransmission level 2 terminal it can handle both the Basic Error Correction BEC and the Preventive Cyclic Retransmission PCR methods This can be soft configured at the time of link activation or switchover of a terminal It also handles level 2 flow control functions Two PHC terminals are configured as C 85 terminal at the time of SUM initialisation in order to enable code and data downloading from the Input Output Module The number of C 85 is however variable and depends upon the switch configuration The SS7 protocol software is distributed over the following cards Signalling Handler Module ESH and CPU HPX cards of SUM Base
4. NIT 1239 ANN WOd WNINYAL 213 Lt 9 z L oaj sl z JINX SLA S 51 u3 9105 ASV 8 SANIT 8 055 34 HARDWARE ARCHITECTURE CM CO LOCATED REMOTE BM 050 BUS 51215 34Mbps 2 1 2 3 4 BM1 BM CM CABLES T Gi BUS1 CSW 512ts 34Mbps BM3 BM4 lt 51 BUS1 TEA BUS BM 1 2 3 4 16 LINKS AO 4 BM2 BM CM CABLES C C1 BUS1 CRS 16 E1 LINKS NOTE FOR CONNECTION OF RBM THROUGH 2 LINKS CRS CARD WILL USED BM END AND EMC CARD AT CM END CS CENTRAL SWITCH CSW CENTRAL SWITCH CARD VBI VEBM INTERFACE VCI VECM INTERFACE VECM VALUE ENGINEERED CENTRAL MODULE FIGURE 3 10 INTERCONNECTION BETWEEN COLOCATED REMOTE BM AND CENTRAL MODULE LOTUS VOL1 DESIGN MAX231 5 MX2315GD MXISGDIB GENERAL DESCRIPTION 35 Chapter 3 3 3 3 3 1 36 VALUE ENGINEERED CENTRAL MODULE Value Engineered Central Module VE CM is responsible for switching of inter Base Module calls communication between Base Modules and
5. P U TIG CG 72 amp C G IG P U Gy U NOTE 1 TC MAY BE ECL EDT TWT OR E amp M NOTE 2 IN CASE TU2 4 6 OR 8 AS ETT BE EQUIPPED IN SLOT 24 FIG 7 2A ENHANCED TERMINAL UNIT ETU 123 4 5 6 7 8 9 1011 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 P P P s s TITID IB T T D Bi T Ti Bi Di T T D S S U U VIT T T CCIT T T 0 II II II DIGITAL UNIT CDU DESIGN MXGDISDN MXISGDCC GENERAL DESCRIPTION 79 Chapter 7 1234 5 6 7 8 9 1011 1213 14 15 16 17 18 19 2021 22 23 24 25 26 P P L L k Lk E LE L b I LE Lo Ld L s s T G l G U U 1284 5 6 7 C 9 1011 12 13 14 15 16 1 2 1 LC BRL OR PRL CARDS NOTE IIC CARDS ARE REQUIRED ONLY IN CASE OF CONCENTRATION OF ISTU FIG 720 ISTU CONFIGURATION 12 3 4 5 6 7 8 81011 12 13 14 15 16 17 18 19 2021 22 23 24 25 26 P P s s M 555 S P U UJU U P 5 S S S
6. for use local integrated local cum transit switch in non air conditioned rural environment Single Base Module RAX Based on XL Hardware SBM XL for application as local transit or local cum transit switch upto 1536 lines Single Base Module based on VE hardware SBM VE for application as local transit or local cum transit switch upto 4K lines with 480 trunks The line to trunk ratio can be configured as needed Multi Base Module exchange based on XL hardware MAX XL for application as local transit or local cum transit switch with 56000 lines including Access Network subscribers working on V5 2 interface and 8100 trunks The line to trunk ratio can be configured as needed This is possible with 14 line BMs and 18 trunk BMs Multi base Module exchange based on VE hardware for application as local transit or local cum transit switch with 1 00 000 lines and 15000 trunks The line to trunk ratio can be configured as needed This is possible with 17 line BMs and 15 trunk BMs The design of these products follows a family concept The advantages of family concept include standardised components commonality hardware documentation training installation and field support for all products and minimization of inventory of spares The modular design of these products has been consciously achieved by employing appropriate hardware software and equipment practices SALIENT FEATURE
7. 1 Tvu1N32 asya wa 6L LL 370 lt 65 8 91 420 IHL 3H1 OL k 315 1 V 7 Z 9 2 Nad Z LW1 auns 7 Z Wa Wa V 2 2 J cow ornagy 2 LOLIT 4 42 ans 4 gt ut Wa 1 2 2 Z 2 2 d7 ans Z Z Wa MNNYL 1 Z ysm 2 9 s nay zsm Ege 9 47 auns gt gt 1 AVM 6 17 01 Wa 1 puz 22 eng ew znad zen L 2 auns Z 3 1 4 90 1 Y 3NI1 WAL 181 87 GENERAL DESCRIPTION Chapter 7 7 3 2 88 Minimum Distance between back suite and wall 1600mm Minimum Distance between suite end and wall on the power side end 2000mm on the other side 1000mm Fire Detection The Switch Room and all other rooms should be equipped with a common fire detection system The system comprises of detectors connected to a general indicator panel
8. Layered architecture loosely coupled modules and well defined message interfaces between modules Maintainability Use of high level programming language proper documentation and modular design Increased reliability due to fault tolerant software with automatic audits and recovery Efficiency Time critical processes coded in assembly level language and very strict checks on execution times of all software modules SOFTWARE ARCHITECTURE OVERVIEW C DOT DSS MAX software is divided into a number of subsystems Each subsystem consists of a number of modules which are called processes A process consists of a number of functions which are the smallest units in the software hierarchy Processes There are two types of processes in the system Eternal processes are created at the time of system initialisation and remain alive throughout the life of the system Dynamic processes on the other hand are created whenever an event requiring the services of that particular type of process occurs After processing the input the process dies whenever the logical chain of events come to an end While only one instance of an eternal process can be active within a processor at one time multiple instances of a dynamic process may exist at a given time in a processor For example the Status Control Process SCP gets a seizure on a particular terminal and does subsequent processing After validating the origination if originating calls are a
9. Cards extract the information from time slots 0 and 1 of Bus0 1 from the Base Modules These time slots carry control message from each Base Module and these messages are sent to the Central Message Switch CMS The CMS sends these messages to the Central Switch Controller CSC to control switching based upon this information Four 512 channel buses from four BMs are multiplexed to form a 2048 channel 16 Mbps multiplexed BUS which is sent to both copies of the Central Switch CSW Card Switching of these 2048 channels is done based upon the switching information received by CSW from CMS Clock Distribution CM provides the central clock for distribution to the Base Modules The 16MHz clock may be locally generated by using high stability VCXO crystal or may be derived from an external reference clock using the Network Synchronisation Controller NSC card In the event of failure of external reference or duplex failure of the NSC cards the local clock is fed in the holdover mode synchronised to last reference value In any arrangement the local or external clock is distributed via Central Chock Extender CCK cards C DOT DSS MAX VE HARDWARE ARCHITECTURE The card provides an interface between CSC and central switch CSC 3 3 2 3 4 3 5 makes switch card access through also handles power supply errors in CSU and BTU Each CCK CBX NSC complex form a security block 1 cann
10. which receive switched data buses from all the BMs connected to CM In case of SBM exchanges the function of NSC card is achieved by external add on synchronization equipment C DOT NSE In this mode of operation the system works on external clock received from C DOT NSE instead of using its own clock However in exceptional case of failure of both the clock sources from C DOT NSE the system has provision to switch over to its own clock A brief description of implementation of Network Synchronization in C DOT DSS using NSC card along with its functional block is explained below Function of NSC Card The NSC card forms the interface between EDT Enhanced Digital Trunk card and the CCKs Central Clock Cards It receives the 2 048 MHz reference input clock from EDT and converts it into a 16 384 MHz clock using a PLL Phase Locked Loop This clock is fed to both copies of CCKs It also generates a sync signal 8 kHz and feeds it to the CCKs for further distribution to all the BMs The NSC has an On Board Micro Processor OBMP to take care of the PLL functions diagnostics communication with SSC Duplication and Security block The NSC card is duplicated and its access is similar to CBX cards The NSC and CBX form a security block as there is only one device enable for each GENERAL DESCRIPTION 43 Chapter 3 3 7 44 NSC CBX pair The 2 048 MHz clock and 8 kHz sync signal are exchanged between the two copies of NSC Clock
11. 2Mbps E 1 PCM links 57 Signalling Unit Module SUM to support 57 protocol handling in the exchange 5 unit to support V5 2 protocol for access network interface ISDN Terminal Unit to support termination of BRI PRI interfaces and implementation of lower layers of DSS1 signalling protocol Terminal Unit Refer Fig 3 1 The enhanced terminal unit is used for interfacing 256 terminations The types of terminations supported are analog subscriber lines analog trunks and digital trunks ETU can be concentrated with ISTU SUM VU CDU Various card types used in ETU are described in the following sections Controller Card The controller card in ETU is the Enhanced Terminal Controller ETC card It provides voice and signalling interface for 256 ports and gives out an 8 Mb 128 port link towards the time switch for inter TU switching It also has on board provision for 30 MF DTMF resources Termination Cards The following card types are supported in ETU a Enhanced CCM Line card ECL This is a 16 port SLIC based line card which can be used to interface ordinary CCB as well as CCM lines It provides basic BORCSHT functions as well as reversal 16KHz and CLIP on all 16 lines PCM outputs of two ECL cards form one terminal group 1 32 channel 2 Mbps link towards the ETC b Analog Trunks Two wire trunk TWT and E amp M four wire trunk EMF cards can be used in ETU to interf
12. 4 Other Units Add On Modules amp Services 15 Hardware Apebateet reou 17 17 2 2 BM ess ens 17 3 3 Value Engineered Central Module 36 3 4 Administrative Module 37 3 5 Input output Module 37 3 6 Network Synchronization C DOT 088 43 Display Panel LIL 44 Software Architecture 45 4 1 Introd Uti OM 45 4 2 Software Architecture Overview 45 4 3 C DOT Real Time Operating System CDOS 46 Subscriber and System Features cc ccsccsccssscccaeesacsccaasacsadansaccasassaccaaaasiacacaasacdadaanaaccaapavaccacaaace 56 5 1 Introduction a awana E A ae 56 5 2 PSTN Analog and ISDN Subscriber Services 56 5 3 ISDN Supplementary 60 SS Sir Mea a u u u l um acess a ener 65 Capacity inier eind aeiia Pira EA AEAEE EERE R i ER E a E
13. Centralise Billing Telecom Management Network Centre In addition one 10 Mbps Ethernet port is also implemented in the IOP VH which has AUI or Co axial interface support at physical level to allow networking of user terminals in future A SCSI 2 controller with integrated DMA and SCSI cores is used for interfacing the disk drive and cartridge tape drive Note Presently the two ports namely X 25 and ETHERNET are not supported in current UNIX release IOP VH Peripherals Input Output Processor IOP VH supports three standard SCSI 2 interfaces on VHC card one each for Winchester Drive Cartridge Tape Drive and one as spare Here it may be noted that only the peripherals with SCSI 2 interface can be used in IOP VH GENERAL DESCRIPTION 41 Chapter 3 OGQqQSSIXWWSSI CXW TOA SN LOT STVNINYSL 1304 OISV 8 AEN LOALIHOYV HA dO l LOG 9 vie 4304 3991 1SOH 3OSNOO 5 4SNYSHLS 552 SH 49 83 19 95 x 7 NOILVYNDIANOO 1 01 JALOV d8 dV OL dOl 15 A8S SNI LOV SNI LOV SNI 0 4
14. In addition to the services available for PSTN Analog as well as ISDN subscribers a number of supplementary services are offered only to ISDN subscribers Charging Related Supplementary Services The Advice Of Charge service provides charging information to the user paying for a call The option of providing the information at a predefined stage of the call is based on the type of AOC facility subscribed i ii AOC E Charging information at the end of the call The charging information is provided by the serving local exchange at the end of a call It is sent in the charge advice information element of the call clearing message AOC D Charging information during a call In this case the charging information is provided by the serving local exchange every time a quantum of charge has been added The charging information is sent in an appropriate message When the call C DOT DSS MAX VE SUBSCRIBER AND SYSTEM FEATURES is cleared the remaining number of charge units incremental case or the total charge units cumulative case is transferred to the user in the call clearing message 5 3 2 Group Line Supplementary Services i ii 111 Direct Dialling In DDI This service enables a user of ISPBX to be called without attendant intervention This service is based on ISDN number The DDI user while being a subscriber of an ISPBX is allocated an ISDN number from directory number set of the serving public exch
15. Processor HPX of Home BM The 7 is implemented using the HPX card based on Motorola 68040 microprocessor and 128 memory card in duplex mode It can support 128 PHC terminals using eight ESH cards The level 3 Message Handling MH and Signalling Network Management SNM functions reside here The incoming 57 messages meant for own point code are routed by MH to the appropriate Base Modules as per the Circuit Identification Code CIC where the circuits are terminated and addressed to the relevant software processes in the Base Module in accordance with the software architecture of C DOT DSS MAX 5 Interface Unit VU Refer Fig 3 5 V5 X capability in C DOT DSS is implemented by using a new hardware unit called V5 interface Unit VU in each BM where V5 x support is needed This unit can be equipped as a principal or concentration TU It can be concentrated with CDU but not with SUM It has hardware identical to that used in SUM and software for V5 interface It consists of CPU memory SUI Power Supply cards and protocol handler cards ESH for V5 X V5 subscribers are connected on access network which is in turn connected to the Local Exchange LE through 1 links programmed as Access Network Interfaces Als Protocol handling for calls to from these subscribers is done by the VU using Enhanced Signalling Handler ESH cards Each ESH card provides 16 terminals Existing 8 port protoc
16. UAN is available in two modes local UAN and National UAN C DOT DSS MAX VE 5 3 5 6 5 3 5 7 SUBSCRIBER SYSTEM FEATURES Local UAN dialled by 1901YYxxxx where YY is the SCP ID connects only to a number in the local network while national UAN dialled by 0901YYxxxx is used to access a number anywhere in the national network directory number with STD facility can only dial a National UAN number while the local UAN is accessible from every directory number Detail billing records of UAN are not available at SCP Local exchanges provide the detailed billing logs and call logs UAN can be used in conjunction with ODR TDR CFC and CD to make it more useful Premium Rate PRM Premium Rate customers provide value added professional services by advertising a premium rate number The service users are charged a premium for calls made to the premium rate number The per call premium rate and the revenue sharing arrangement between the customer and the service provider is agreed upon at the time of service subscription The premium rate is a multiplier over the normal call charge This service can be used in conjunction with features like ODR amp TDR It is quite a popular and useful service and is used for getting medical advice stock market quotations astrological advice etc Detailed records of all PRM calls are prepared at the SCP These contain details such as the date time destination PRM number and the user s n
17. as CAS CCS trunks Enhanced Signalling Handler Card 16 Nos protocol handler signalling links per card for 7 or V5 x SHM cards which have 8 signalling links are also supported ISDN BRI Card 8 BRI 2B D interface 16 Bearer Channels ISDN PRI Card One PRI 30B D interface ie 30 Bearer Channels 2 TERMINAL UNIT FRAME Enhanced Terminal Unit ETU ECL 16 analog subscribers or 16 CCB subscribers with all ports supporting 16 KHz metering pulse amp CLIP EDT Four E1 links per card TWT EMF 8 analog trunks per card Compact Digital Unit CDU It supports 16 PCMs with EDT cards 7 Signalling Unit Module SUM 128 CCS7 protocol handlers signalling links 1 2 1 3 1 5 1 6 PRI or combination of them Base Module Analog Digital 480 Analog 480 Digital trunks 32 Annc or any combination of analog amp digital trunks subject to maximum of 1K trunks including announcements 2 2 2 3 2 4 5 GENERAL DESCRIPTION 71 Chapter 6 6 3 6 4 6 4 1 72 EXCHANGE CONFIGURATIONS C DOT DSS MAX can be configured to support any combination of lines and trunks for different applications in the network as Local Exchange Local cum Tandem Exchange Trunk Automatic Exchange TAX or Integrated Local cum Transit ILT Exchange In its maximum configuration upto 1 00 000 lines and 15 000 trunks limited to 800K BHCA are supported when configured as Loc
18. can interface upto 6000 subscribers The number of Base Modules directly corresponds to the exchange size There can be various configurations of MAX VE 12 C DOT DSS MAX VE SYSTEM ARCHITECTURE VSCOSIXW GSSLECXWS LESXVIN NDISAC E IOA SNLOT WALSAS AYNDIA ALVY lHdd 1 OISV8 1 MYOMLAN S309lAH3S 1 NASI ZON 5 TANNVHO NOWWOO 2599 GALVIDOSSV 8 HOLIMS 4 NSH me TANVd 14510 dav S q O _ 1 WO aaa SAILVYLSININGY WY WHINSD N9 asya ng WOI WY dav S3OVdu31NI NASI 1 53999 u 1800 8 SVO WO SANNHL SOTVNV WaS X8Vd S3NI 5 899 13 GENERAL DESCRIPTION Chapter 2 2 3 2 14 Single Base Module SBM In this configuration Base Module acts an independent switching system and provides connections to 4K lines and 480 trunks It directly interfaces with the Input Output Module for bulk data storage operations and maintenance functions Clock synch
19. groups of four cabinets each Each such group is called a half suite Two half suites make one full suite All exchange configurations can be organised as a number of half suites or full suites SBM exchange is organised as a maximum of three cabinets put in one row Flooring Floor is generally covered with 2mm thick antistatic vinyl strips to give antistatic property to the floor which is necessary to avoid damage to the sensitive circuitry which incorporate many CMOS devices False Ceiling The false ceiling comprises of panels made of Supersil aluminum some of which have holes for fixing fire detectors and lighting fixtures The minimum floor to beam height of the Switch Room should be 3000mm A false ceiling is not mandatory and is needed only for old telecom buildings Switch Room Dimensions To allow free movement of personnel and access to equipment the following standard suite arrangement are followed Distance between two suites 1000mm Distance between front suite and wall 1000mm C DOT DSS MAX VE PACKAGING LAYOUT amp ENVIRONMENT 3IWQS SIXW SSL 8 XIWSLI84XVINNNOISHQNI TOA SNLOT HOLIMS dONVHOX3 Viva 9319001 ATALOWSY OST AVN 513 8 SOS ILON NOISNAWIC TANVd
20. of the Virtual Private Network These network accesses are all subjected to the user defined call screening and dialling plan On net locations are directory numbers located on the SSP itself On net directory numbers require subscriber data creation and on net group creation at the SSP apart from the corresponding data at SCP Off net Locations Off net locations are those locations that are not defined by the customer to be part of the VPN The data corresponding to the off net directory numbers is neither present at SSP or SCP These directory numbers emulate on net or GENERAL DESCRIPTION 63 Chapter 5 5 3 5 3 5 3 5 4 5 3 5 5 64 virtual on net locations by dialling access code group id of the VPN group and the authorisation code of the subscriber they are trying to emulate Virtual On net Locations The VPN members for which data is created at the SCP only These are not resident on the SSP but are subject to VPN defined call treatment e g call screening VPN User Group A group of on net locations and virtual on net locations defined by the customer as a closed user group Each user group can be assigned a different set of calling privilege Virtual Card Calling VCC This service is a part of the Alternate Billing Services class It allows the users to make calls from anywhere in the network and let the charges to be debited from a prepaid card For holding the card the VCC customer need not have a directory
21. selection is done before the PLL block If all the inputs to the NSCs fail it runs in the holdover mode If the inputs are not restored till the end of the holdover period duration of the holdover period is defined in the Parameteric Specifications the NSCs go into the free run mode The NSCs work in mutual synchronisation as the PLLs track each other ALARM DISPLAY PANEL Alarm Display Panel ADP is a microprocessor based hardware unit which is attached to the BP in SBM configuration or AP in MBM configuration via HDLC links for providing audio visual indication of system faults It is a three card implementation A matrix of LEDs is provided to indicate the maintenance status of the switch units and their level of initialisation A seven segment display shows the count of lines and trunks currently faulty Keys are provided for manual acknowledgment initiating self test and selective audio disable C DOT DSS MAX VE 4 1 4 2 4 2 1 Chapter 4 Software Architecture INTRODUCTION The software architecture of C DOT DSS MAX 15 distributed in nature and has been designed to map onto the distributed control architecture of the system The switch hardware is surrounded by a number of software layers each of which presents higher levels of abstractions for the successive upper layers of software The major design objectives of the C DOT DSS MAX software and the strategies employed to achieve them are Simplicity
22. smallest unit of system packaging Although the cards may be two layer four layer six layer or eight layer depending upon the packaging density required all the cards have the same size 254 mm x 304 8 mm x 1 6 mm A circuit card is equipped with a pair of 64 pin 96 pin or 128 pin female euro connectors on its rear edge Card Frames Circuit cards are packaged into a card frame Card frame is made of welded mild steel and has slots and guides on the upper and lower planes Each set of upper and lower guides provide a path for the circuit card to slide on On the rear plane of the frame a back plane PCB is fixed which is also called the motherboard The motherboard may be one piece or split type The motherboard has 24 sets of 64 pin 96 pin or 128 pin male euro connectors for the circuit cards In order to avoid wrong insertion of cards plastic padding is provided on the rear edge so as to provide polarisation Each card frame has a maximum of 24 circuit cards and a motherboard The motherboard provides interconnections between cards for signals and power supply It also provides connectors for interframe connections Depending upon the function required a card frame is equipped with appropriate set of circuit cards GENERAL DESCRIPTION 75 Chapter 7 7 2 3 7 2 5 1 76 Racks Cabinets The card frames are organised into an equipment rack rack 15 the supporting structure for six card frames On the slide rails provided in
23. the rack card frames are fixed on the rack in a specific order depending upon the function to be performed by the equipment e g Base Module Central Module or Line Module The rack also provides bus bars and power filter boxes for power distribution and runways for interframe and MDF cabling The height of a cabinet is 6 feet 1800 mm in order to facilitate removal and replacement of circuit cards and connectors without using ladders etc The cabinets are arranged side by side in suites Each suite can have a maximum of 8 or 4 cabinets i e full suite or half suite interconnected by the supporting ironwork Cable troughs carry interconnection cables and run along a suite over the cabinets Within a trough there is provision for running power cables and interconnection cables separately Cable troughs are also run between suites to carry BM CM cables and MDF cables from the cable entry point to the respective suites C DOT DSS MAX equipment is housed in three types of cabinets viz re Base Module Cabinet 2 Line Module Cabinet a Central Module Cabinet Base Module Cabinet Fig 7 1 The Base Module BM cabinet houses the following units in the frames CCS7 Signalling Unit Module SUM ISDN Terminal Unit ISTU Base Processor Unit BPU Value Engineered Time Switch Unit VSU Compact Digital Unit CDU V5 signalling unit VU Enhanced Terminal Unit ETU 055 PACKAGING LAYOUT amp
24. the Administrative Module clock distribution and network synchronisation For these functions Central Module has a Central Time Switch Central Switch Controller and a Central Message Switch VE CM provides connectivity upto 32 BMs Each BM interfaces with CM via two 34 Mbps serial links These buses carry voice information of 1024 terminations of the Base Module towards CM the reverse direction after switching has been done in the Central Switch under the control of Central Switch Controller CSC the same buses carry the switched voice information for 1024 terminations towards BM Thus in 32 Base Module configuration there are 64 links carrying the 1 information from Base Modules to the Central Module and also the switched information in the reverse direction Provision for connection of RBMs to CM through E1 links is also there Central Switch CS and Central Switch Controller CSC In order to take care of the large number of interface signals the switch portion of CM is divided into three stages viz MUX stage Switch stage and DEMUX stage The MUX DEMUX stages are implemented on single card to provide the Base Module to Central Module interface in each direction Interfacing and switching are controlled by CSC which provides control signals for the MUX DEMUX cards and the Central Switch cards Interconnection between MUX DEMUX cards and the Central Switch is shown in Figure 3 11
25. which provides man machine interface Maintenance Software Used for initializing communication protocol with C DOT DSS MAX It also provides software for synchronization of duplex Input Output Processor The functions of IOP software subsystem in C DOT DSS MAX are downloading and initialisation performance measurement of processes provision of man machine interface and handling billing traffic and maintenance reports etc C DOT DSS MAX VE SOFTWARE ARCHITECTURE Maintenance Subsystem KERNEL 2 k a a N J z Pi N Administration Command Subsystem Interpreter N N we IOP SOFTWARE ARCHITECTURE Programming 9 lt Environment 9 lt lt x SHELL Communication BASED ON UNIX MODEL GENERAL DESCRIPTION LOTUS VOL1 DESIGN MAX2315 MX2315GD MXISGDIS 55 5 1 5 2 5 2 1 56 Chapter 5 Subscriber and System Features INTRODUCTION The C DOT Digital Switching Systems offer a wide range of telephony features and supplementary services Further capabilities can be developed to meet specific customer needs Due to mandatory requirement of exchange of messages between the switching systems and user s equipment some of the services a
26. 048MHz 048MHz 2 048MHz 2 2 048MHz 2 048 2 2 048MHz 2 Y Y NSC SYNCHRONISED OUTPUT h SYNCHRONISED OUTPUT SYNCHRONISED OUTPUT k 98 1 NSC 1 lt 1 CSC 1 lt SWC SWC SWC SWC SWC SWC COPY COPY 1 Re SWP SWP 1 SWC SWITCH CARDS SWP SWITCH PLANE FIG 3 1 2 CLOCK DISTRIBUTION IN C DOT DSS MAX VE LOTUS VOL1 DESIGN MAX2315 MX2315GD MXISGDCD GENERAL DESCRIPTION Chapter 3 SOGDSIXIN COS LECXINNG LESXVININDISAC ETIOA SN LOT HOLIMS SDVSSAW 1 90 l LOIS INIL H3TIOHINOO HOLIMS TVHIN3O 959 HOLIMS 3SVSS3N TVHIN3O SWO 5 SALLVYLSININGY 29 51016216 30 snd 15 1 5 sn8 30 LS LOIS INL Sday 9 SLOTS INILZ 959 lt 4 4 N lt gt dol SIND gt OL gt lt lt L NX gt gt 90 WO 40 xnwaqxnW Wa 5 55 MAX VE 40 3 5 1 HARDWARE ARCHITECTURE link operate a duplex configuration Working as front end processor it provides initial code down load to the subsystems man machine interf
27. 59 Chapter 5 5 3 5 3 1 60 Vil ix Xi facility is used by the maintenance personnel as part of routine maintenance activities Trunk Offer This service makes it possible for the operator to interrupt a call in progress in order to allow another incoming call to be offered The choice of accepting or rejecting the new call rests with the subscriber Queuing Service This enables the subscriber to have one or more calls placed in a queue when his line group of lines are busy When the subscriber line becomes free the first caller in the queue is connected and the other callers in the queue move one place ahead Priority Subscriber During overload and network congestion priority service assures an improved service level for priority subscribers such as those responsible for maintenance of law and order or essential services The priority subscribers are served even during overload due to heavy traffic in the exchange via alternate group of trunks A few trunks may be identified for this purpose which are exclusively used by priority subscribers while normal subscribers are denied access to them The eligibility of priority subscribers for an alternate group of trunks is programmed by the exchange administrator Distinctive Ringing for Long Distance Calls The PSTN subscribers are connected different ringing cadence to inform them that this call is a long distance STD ISD call ISDN SUPPLEMENTARY SERVICES
28. A8S SNI C DOT DSS MAX VE 42 3 6 3 6 1 3 6 2 HARDWARE ARCHITECTURE NETWORK SYNCHRONIZATION IN C DOT DSS All the three modes of operation of Network Synchronization are implemented in C DOT DSS These are 1 Locked Mode When one or more primary reference clocks are available NSC NSE enters into locked mode by selecting one of the available network clocks according to fixed priority and synchronises to it 1 Holdover Mode When NSC NSE loses the network clock to which it was locked and when no other network clocks are available it enters the holdover mode in which it synchronises to the last reference value iii Free Run Mode When none of the network reference clocks are available and no locking to external reference has taken place before In this mode system works on its local clock In C DOT DSS MAX Network Synchronisation Controller NSC Card synchronises the local clock of the exchange with the network clock It gets input clocks from digital trunks connected to higher level or same level exchanges It has an on board clock source It gives a network synchronised clock and SYNC signals to the duplicated Central Clock CCK card The CCK is controlled by the CSC through CBX It generates its own clock and can be configured to select between the local clock and two copies of NSC clock Each clock card distributes 16 MHz clock and 8 kHz SYNC to self CSU and 16 MHz clock to all Bus Termination Units BTUs
29. C DOT DSS MAX VE GENERAL DESCRIPTION System Section No 415 005 0861 Draft 01 March 2003 Practices C DOT DSS MAX VE GENERAL DESCRIPTION This Document is updated as Software Release 2 3 1 6 2003 C DOT Printed in India C DOT DSS GENERAL DESCRIPTION DRAFT 01 MARCH 2003 PHALGUN 2059 SERIES 000 OVERVIEW CSP SECTION 415 005 0861 THIS C DOT SYSTEM PRACTICE REFERS TO THE C DOT DIGITAL SWITCHING SYSTEM MAIN AUTOMATIC EXCHANGE VALUE ENGINEERED ABBREVIATED AS C DOT DSS MAX VE IN THE REST OF THIS PUBLICATION THE INFORMATION IN THIS SYSTEM PRACTICE IS FOR INFORMATION PURPOSES AND IS SUBJ ECT TO CHANGE WITHOUT NOTICE A COMVENT FORM HAS BEEN INCLUDED AT THE END OF THIS PUBLICATION FOR READER S COMMENTS IF THE FORM HAS BEEN USED COMMENTS MAY BE ADDRESSED TO THE DIRECTOR SYSTEMS CENTRE FOR DEVELOPMENT OF TELEMATICS 39 MAIN PUSA ROAD NEW DELHI 110 005 2008 BY C DOT NEWDELH Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Table of Contents 7 1 1 Pur pose u u 7 12 OS 7 AP CHILE CHUTE 8 DAM General 8 2 2 Salient Features of C DOT 8 2 3 Basic Modules 12 2
30. During standalone mode of operation the local and incoming terminating calls in RSU are switched and the metering information of all the RSU subscribers is stored in the RSU It is sent to the host whenever the PCM links are available again Value Engineered Central Module VE CM The Central Module CM consists of a message switch and a Time switch to provide inter module communication and perform voice and data switching between Base Modules It provides control message communication between any two Base Modules and between Base Modules and Administrative Module for operation and maintenance functions It also provides clock and synchronisation on a centralised basis Administrative Module AM Administrative Module performs system level resource allocation and processing function on a centralised basis It performs all the memory and time intensive call processing support functions and also administration and maintenance functions and communicates with the Base Modules via the Central Module It supports the Input Output Module for providing man C DOT DSS MAX VE 2 4 2 4 1 2 4 2 2 4 3 2 4 4 SYSTEM ARCHITECTURE machine interface and also supports the Alarm Display Panel for the audio visual indication of faults in the system Input Output Module Input Output Module is a powerful duplex computer system that interfaces various secondary storage devices like disk drives cartridge tape drive and floppy
31. ENVIRONMENT TERMINAL UNIT 1 FRANE TU TERMINAL UNIT 2 2 TU2 TERMINAL UNIT 3 FRAME 3 TU3 TERMINAL UNIT 4 FRAME 4 TU4 BASE PROCESSOR UNIT 5 BPU VALUE ENGINEERED TIME SWITCH UNIT a VSU NOTE TU CDU ISTU VU SU IN LINE AND ANALOG TRUNK BMs ETT TTC CARD CAN BE EQUIPPED IN SLOT 24 OF TU2 4 6 OR 8 FIG 7 1 BASE MODULE BM CONFIGURATION LOTUS VOL1 DESIGN MAX2315 MX2315GD MXISGDC1 GENERAL DESCRIPTION 77 Chapter 7 7 2 3 2 7 2 4 78 Depending upon the application Base Module cabinet is equipped with combination of frames containing four principal Terminal Unit frames a Time Switch Unit frame and a Base Processor Unit frame The remaining four principal terminal units are housed in a line module cabinet called Auxiliary BM However in concentration mode each BM can support 4 more module line racks each of them equipped with 6 Terminal Units with lines only Equipage of cards in different types of frames are explained in Fig 7 2A 7 2B 7 2C 7 2D 7 2E amp Central Module Cabinet Central Module CM cabinet is similar in size and shape to the Base Module cabinet It however houses the circuitry of both the Central Module and the Administrative Module It houses the following units in the card frames as shown in Fig 7 3 a Bus Termination Units B
32. HB modes of charging are implemented in ISUP For ISDN traffic it is possible to charge each bearer service traffic differently i e for same interface subscriber it is possible to charge Speech with one rate and 64 Kbps Unrestricted Data with different rate Multiple bearer services on the same interface subscriber can have different level of access barring i e speech call can be restricted to Normal whereas Data call can be allowed upto international Exchange Operation Features A number of operation features are implemented in C DOT DSS for administrators with different level of control mechanisms to prevent un authorised operation Some of the features are listed below C DOT DSS MAX VE 5 4 4 SUBSCRIBER AND SYSTEM FEATURES Single Line and Group Line Administration Trunking Routing and Charging Administration Traffic and Performance Measurements Data Backups and Restoration Calendar Administration Password Administration with different level of password management along with two different level of privileges for operator terminal port as well as for the operator account the exchange operation in C DOT DSS is fully secured from unauthorised operation System Reconfiguration Expansion Software Upgradation Patch Administration The modular software architecture of C DOT DSS facilitate easy upgradation to support more value added services to meet the future requirement Also the upgradation i
33. ICES IOP LOTUS VOL1 DESIGN MAX2315 MX2315GD MXIGD SC 22 C DOT DSS MAX VE 3 2 1 3 1 HARDWARE ARCHITECTURE Control Part SCCP and Transaction Capabilities Application Part TCAP have been implemented in the C DOT MAX This enables the switch to provide communications interface between Intelligent Network Application Part INAP across the network and to function as an Integrated Service Switching Point SSP Architecture of CCS7 Fig 3 4 The SUM hardware is packaged into a standard equipment frame similar to that of a Terminal Unit It can be retrofitted in any Terminal Unit TU frame position The place of SUM in the switch architecture is similar to a Terminal Unit even though it is a module by itself and contains global resources It interfaces with the Time Switch via a Signalling Unit Interface Card SUI on a 128 channel PCM link operating at 8 Mbps SUM hardware comprises the following cards i High Power Processor Controller for XME HPX Card This is a 68040 based card which act as the central controller in SUM There are two copies of this card one remains active while the other lies in hot standby mode Some layer 3 protocol functions are also resident on this card It also handles the communication with the Base Processor of the home BM and between PHC terminals 11 Extended memory card This ca
34. IM s 5 U U l lI IXIHIHIRIHIE U U 1 2 1121314 5 6 718 4 3 ESH ENHANCED SIGNALLING HANDLER CARD FOR 7 FIG 7 2D 7SU CONFIGURATION LOTUS VOL1 DESIGN MAX2315 MX2315GD MXISGDCO 80 C DOT DSS MAX VE PACKAGING LAYOUT amp ENVIRONMENT 12 34 5 6 7 8 9 1011 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 P x H H 5 M P P M s U E x x E U I BASE PROCESSOR UNIT BPU CONFIGURATION 12 3 4 6 6 7 9 1011 1421314 15 16 17 18 19 2021 22 23 24 25 26 P P 5 s sisi ss 5 5 U st e w U II R R FIG 7 2F VALUE ENGINEERED TIME SWITCH UNIT VSU CONFIGURATION LOTUS VOL1 DESIGN MAX2315 MX2315GD MXISGDTS GENERAL DESCRIPTION 81 C DOT DSS MAX VE Chapter 7 N 8 S 5 5 gt m m lt 1 T Q
35. It detects responses from smoke detectors spread over the entire technical and non technical areas of the building which generate both audio and visual alarms indicating fire smoke and the zone affected Detectors are attached to the ceiling or the false ceiling if provided Openings for Cable Routing Openings should be provided in the walls and floors of the Switch Room for routing cables between the switching equipment and Power Plant MDF and OMC rooms All these openings are made before the commencement of exchange installation work The placement and number of the openings 15 however site dependent For an average sized exchange openings of following dimensions are required opening of size 400mm x 200mm between Switch Room and Power Plant Room opening of the size 500mm x 300mm between Switch Room and MDF Room An opening of the size 200mm x 200mm between Switch Room and OMC IOP Room Operation and Maintenance Centre OMC Room Equipment The OMC Room houses mainly the peripheral equipment such as Alarm Display Panel ADP Operator Maintenance Alarm OMA Panel Indicator Panel for fire detection Printers 2 C DOT DSS MAX VE 7 3 3 7 3 4 PACKAGING LAYOUT amp ENVIRONMENT OOD Terminals 2 CRP Terminals for exchange operators Some spare terminals are also provided for miscellaneous uses The number of terminals depends upon the exchange configuration Dimensi
36. It is also possible to know the existing status of pending faults alarms in the exchange just by dialing the monitoring number from any where in the telephone network Similarly it is possible to report the critical alarms in form of ring to one of telephone numbers which may be of the office residence number of the maintenance incharge of the exchange as explained above System Integrity The hardware and software architecture of the C DOT DSS has been designed to ensure highest level of system integrity even in case of extreme environment like switch reconfiguration due to fault overload due to spurt in traffic cleaning up the resources as time slots etc Some of the important features are listed below Established calls are maintained even in case of switch reconfiguration due to fault or switch plane interchange by the operator In built periodic audits to release the time slots that are held up due to different reasons in exceptional cases Over load control mechanism to initiate the blocking of call traffic originations Different level of call blockings based on the priority of the originations Lines or Trunks In addition different level of initialisations are also implemented which are triggered automatically by the system to overcome critical hardware or C DOT DSS MAX VE SUBSCRIBER AND SYSTEM FEATURES software faults The level of initialisation is triggered in such a way that minimum disturbance of th
37. Output Module for interfacing peripheral devices Administrative processor is responsible for global routing translation resource allocation and all other functions that are provided centrally in C DOT DSS MAX The implementation of AM is similar to Base Processor Complex of BM using the same hardware configuration INPUT OUTPUT MODULE Input Output Module IOM consists of duplicated Input Output Processor IOP The Input Output Processor IOP is a general purpose computer with UNIX Operating System It is used as the front end processor in C DOT DSS It handles all the input and output functions in C DOT DSS The IOP is connected to AP BP via HDLC links During normal operation two IOPs interconnected by a HDLC GENERAL DESCRIPTION 37 Chapter 3 LESXV NOISAC EIOA SNLOT 89 HOLIMS 9 HOLIMS 1 5 1 6 lt 555 LOIS ANIL 9 AHOWSW lt gsna N HOLIMS TVH1N3O gsna a gt xnN sna L s1 8502 i 055 38 HARDWARE ARCHITECTURE REFERENCE INPUTS REFERENCE INPUTS
38. Packaging The equipment practices provide modular packaging Common cards and advanced components have been used in the system hardware in order to reduce the number and type of cards Standard cards racks frames cabinets and distribution frames are used which facilitate flexible system growth Interconnection technology has been standardised at all levels of equipment packaging All these features together with ruggedised design make C DOT DSS MAX easy to maintain and highly reliable 2 2 7 Centralised O amp M Another important feature of the design is the provision of both local and centralised operation and maintenance Beginning with local operation and maintenance with the installation of similar digital switches in the network centralised operation and maintenance will provide maintenance and administration services very economically All these services are provided through a simple interactive man machine interface 2 3 BASIC GROWTH MODULES C DOT MAX VE architecture is based on the following four basic modules Fig 2 1 a Value Engineered Base Module VE BM b Value Engineered Central Module VE CM Administrative Module d Input Output Module 2 3 1 Value Engineered Base Module VE BM The Base Module is the basic growth unit of the system It interfaces the external world to the switch The interfaces may be subscriber lines analog and digital trunks CCM and PBX lines and access networks Each Base Module
39. S OF C DOT MAX VE C DOT MAX VE is a versatile digital switch which can be configured for various applications e g local ILT or TAX This is possible due to distributed software architecture amp modular hardware This product provides capacity expansion over MAX XL and also takes care of the hardware obsolescence in MAX Some design features of MAX VE are described in the following section C DOT DSS MAX VE 2 2 1 SYSTEM ARCHITECTURE Flexible Architecture C DOT MAX VE is a modular and flexible digital switching system which provides economical means of serving metropolitan urban and rural environments It incorporates all important features and mandatory services required by the user with the option of upgradation to provide additional capacity as well as new features and services in future The architecture for C DOT DSS is such that it is possible to upgrade a working C DOT SBM or MBM Exchange to provide ISDN CCS7 amp V5 2 service by adding minimum additional hardware modules while retaining existing hardware units Another feature of the architecture is to support PSTN ISDN and V5 subscribers through Remote Switching Unit RSU This unit can provide switching facility locally even in case of failure of the communication path to the parent exchange The system employs an open ended architecture for flexibility of configuration and growth The processor architecture is characterised by distributed control and message based communi
40. TU b Central Switch Unit CSU Central Switch Controller Unit CSCU d Administrative Processor Unit APU This Bus Termination Unit occupies the first and fourth card frames in the CM rack Each frame contains the VEBM Interface VBI Cards The number of cards depends upon the number of Base Modules equipped in the system For connection of RSUs using E1 links EMC card is used instead of VBI at CM end while CRS card replaces VCI at BM end The Central Switch Unit occupies second and third card frames in the CM rack amp houses the Central Switch CSW cards Central Switch Controller Unit CSCU occupies the fifth card frame in the CM rack and houses the circuitry for timing control and CSC complex Administrative Processor Unit APU occupies the sixth card frame in the CM rack and contains the circuitry for the Administrative Processor Controller APC complex and the Central Message Switch complexes The CM cabinet is equipped with special cooling arrangement for dissipating the heat from the high performance circuitry in various card frames Cabling A standard cabling concept has been used for providing interframe and intercabinet cabling Cables are used to carry signals and power The following types of interconnections are possible C DOT DSS MAX VE PACKAGING LAYOUT amp ENVIRONMENT 12 3 4 5 6 7 8 8 1011 12 13 15 16 17 18 18 2021 22 23 24 25 26 TIT TERE
41. TU Frame Co axial or 1 cables 8 four pair 84 C DOT DSS MAX VE PACKAGING LAYOUT amp ENVIRONMENT Cabinet Description of Type of Cable and Connectors Interconnection BTU RSU CM BTU frame to RSU Digital trunk cables 2 pairs for each BM XL connections DTK Input Output APU Copy 0 7 2 module connectors on and Processor IOP to and APU 1 25 pin D type connector on the IOP APU Terminals and Console Host Operator RS232C cables with 9 pin D type Printers of IOP terminals and Printers connectors IOP IOP HDLC link Twisted pair cable with 25 pin D type connectors 7 2 5 Power Supply and Earthing Arrangement From power supply busbars power is tapped through cables to each suite separately From the float rectifier which derives 48V DC from 440V AC power cables are terminated on the DC Distribution Panel DCDP From the DCDP power cables are run along the cable runways and ladders and terminated on the Power Distribution Panel PDP Distribution Panel consists of two busbars for 48V one each for copy 0 and copy 1 equipment Similarly there are two busbars for ground For each Base Module cabinet the power i e 48V is tapped twice one for each plane through a fuse Whenever the fuse blows off the LED which is connected in parallel glows on the FBI Card and an audio alarm is given at a centrally located point The ground cable is ru
42. UNUSED PSM CARD SLOT SHOULD EQUIPPED WITH THE DUMMY LOAD CARD CML S00 2 UNUSED PSS CARD SLOT SHOULD BE EQUIPPED WITH THE DUMMY LOAD CARD CSL S00 3 VBI CAN BE REPLACED BY EMC TO PROVIDE 16 E1 LINKS TOWARDS RBM NOTE FIG 7 3 CENTRAL MODULE VE CONFIGURATION LOTUS VOL1 DESIGN MAX2315 MX2315GD MXISGDAG 82 7 2 4 1 7 2 4 2 PACKAGING LAYOUT amp ENVIRONMENT Connections to Main Distribution Frame MDF Inter cabinet Connections Input Output Processor IOP Connections Alarm Display Panel ADP Connections Concentration Mode Connections Cabling Connections to Main Distribution Frame Base Module Cabinet On the motherboard corresponding to each Terminal Card there are three 7 2 module connectors with hoods All such connections from each Terminal Unit are combined to form of 64 pair telephone cables which terminate on a 64 connection module on the exchange side of the Main Distribution Frame Inter cabinet Connections Base Module Cabinet Central Module Cabinet Interconnections This intercabinet connection for communication between each BM and the is made via coaxial cables CXAX The connection is made between VEBM VCI cards in VEBM and VBI Cards in the CM cabinet In the case of remotely located Base Modules as RSU the connection is through E3 PCM links At the Base Module end the digital trunk cables are connected from EMC card slot to exchange
43. a aena eia 70 6 1 Introduction u Gane 70 6 2 Termination Capacity 70 63 Exchange Confie rations uu U u kaqa akaqa 72 6 4 Traffic Carrying Capacity uuu uapa 72 6 5 Systema uuu ll l S 73 6 6 System Reliability l 78 6 7 Overall Service Star Cards 74 Chapter 7 Packaging Layout 75 Well uka uapa 75 7 2 Equipment Practices for in 75 Layo ku 85 7 4 Climatic and Environmental Conditions 2 90 Annexure Technical Specifications Summary 92 H HOME MAXVE WORD MAXVEGD DOC March 25 2003 Chapter 1 Introduction 1 1 PURPOSE amp SCOPE This document gives an overview of C DOT DSS MAX VE family products The contents of the document include details of hardware software signalling interfaces subscriber services etc 12 ORGANISATION The product details are distributed over the following chapters Chapter 2 provides a brief description of C DOT DSS family products The basic building blocks of C DOT DSS have been introduced which are explained in detail in subsequent chapters Chapter describes the ha
44. a user with an established call to suspend communication by an appropriate signalling procedure and resume communication at a later time This service permits the user a To move the terminal from one socket to another within the same basic access b To suspend the call and subsequently resume it at the same terminal amp socket c To replace one terminal by another compatible terminal at the same socket d To move the call from one terminal to another compatible terminal at the same basic access This service is used only in the active phase of a call and not in the call establishment and clearing phases In addition the service shall independently apply to the calling and called user Note User shall be responsible for ensuring that compatibility of the terminals with the suspended call is retained IN Services C DOT DSS MAX offers wide range of IN services that are available to PSTN and ISDN subscribers as follows C DOT DSS MAX VE 5 3 5 1 5 3 5 2 SUBSCRIBER SYSTEM FEATURES Freephone or Tollfree FPH TLF Freephone service is one of the most popular IN service in the world It allows a subscriber accepting to receive a call to be charged for the whole or part of the cost of the call Apart from reverse charging this services also supports features like Time Dependent Routing TDR route calls to the office number during business hours and to the residence during others Origin Dependent Routin
45. ace and data storage for billing and other administrative information Refer Fig 3 14 for IOP VH architecture IOP VH Hardware Architecture The IOP VH is value engineered high performance IOP designed using a single card The IOP CPU uses MC 68040 25 MHz processor on the VHC card It has 16 MB expandable to 32 MB onboard DRAM and 512 KB EPROM All active IOP processes reside in the dynamic RAM Also the data being transferred through HDLC links secondary storage devices and terminals use the dynamic RAM The IOP as a module is duplicated to provide redundancy for cartridge and disk drives as well as serial communication terminals and printers The system has provision for 7 HDLC channels Two of these are used to connect the IOP to both the copies of AP BP The third link is for connection with mate IOP when the two are working in synchronisation i e duplex IOP configuration The rest four links are spare at present but may be used towards the four CMSs in future Eight RS 232C Serial Links through ASIO ports are also implemented for connecting operator terminals and printer to the IOP in addition to two ports as Console and Host The monitor based operations are performed only from the Console and the same is true in case of login to root account The operations like initial boot up software link loading etc could be performed only from the Console One X 25 port is implemented for 64Kbps full duplex link to communicate with
46. ace analog trunks Digital trunks Two types of trunk cards can used in this unit 1 RAX WLL controller RWC card Each card provides two 32 channel PCM 1 interfaces which may be used in CAS CCS mode Each interface occupies one terminal group in the ETU C DOT DSS MAX VE HARDWARE ARCHITECTURE LLODSIXINGDS LEZXNNS LESXVW NDISAG EIOA SN LOT LINN YATIOULNOO TVNINYSL 013 LOIS AWIL 9 WNINYSL OL TWNINYSL OL sng OL SyNnul SINN y 2 5 1 2 0 821 sng A ol 8 SINNT sdang 5126 LOL 19 GENERAL DESCRIPTION Chapter 3 23 2 1 1 5 3 2 1 1 4 3 2 1 2 8 2 1 3 20 11 Enhanced digital trunk EDT card Each card provides four 32 channel 1 interfaces and takes up four terminal groups Service Cards a Advanced service card ASV This card provides upto 14 PSTN announcements or 56 IN announcements Upto three ASV cards can be used in ETU One ASV card takes up one terminal group in ETU b Enhanced Terminal Tester ETT card This card is used to test lines analog trunks in any TU It occupies 16 time slots or ports in ETU Enhanced Power Supply Unit EPU Two EPU cards in load sharing mode provide 5V 12V amp 12V t
47. ad of CLIP receives the call with the calling line identification even if the calling C DOT DSS MAX VE 5 2 2 5 2 3 SUBSCRIBER AND SYSTEM FEATURES party has requested that his the calling party s identification should not be presented to the called user The CLIRO facility is offered at the discretion of the administration to special category subscribers like the police hospitals operator positions and other emergency centres Malicious Call Identification MCID This facility is used for ascertaining the origin of malicious calls During conversation the subscriber has to use suitable procedure to notify the exchange about the malicious call The detail of the call is recorded in the exchange which can be retrieved later on If the caller is from an exchange which does not support identification of calling line junction identity is found and an identification request may be sent to the originating exchange by the exchange personnel Call Offering Supplementary Services Call offering services permit the served user to request the network to divert the incoming calls to a specific number In call forwarding the network forwards the call to a pre registered number which can be specified by the user or exchange administrator i ii iii Call Forwarding Unconditional CFU This service permits the served user to request the exchange to forward all incoming calls to other number The served users o
48. al Local cum Tandem When configured as TAX 30 000 trunks are supported Table 6 2 Termination Capacity of Exchange Configurations Exchange Configuration Termination Capacity Description Single Base Module SBM VE 4000 lines and 480 trunks The trunks may be analog and or digital The no of trunks can be increased at the cost of reducing subscribers Multi Base Module MAX VE Ideal configuration to support 1 00 000 lines and 15000 trunks with 17 Line BMs and 15 Trunk BMs limited to 800K BHCA Remote Switching Unit RSU 6 000 Subscriber Lines Trunk interface at the cost of subscriber lines 4 Multi Base Module VE as TAX 30 000 Trunks TRAFFIC CARRYING CAPACITY The traffic carrying capacity of C DOT DSS MAX is ideally 16000 erlangs This figure is based on the ideal traffic of one erlang per switched circuit But the actual traffic carrying capacity of one switched path is always less than one in practical application Accordingly capacity is reduced to 14400 Erlangs BHCA Handling Capability The basic processing element of the exchange is the Base Processor in the Base Module Base processor has the capability of handling 25 000 Busy Hour Call Attempts The C DOT DSS MAX exchange with 32 Base Modules can handle upto 8 00 000 BHCA Various exchange configurations and their traffic capacities are summarised in Table 6 3 C DOT DSS MAX VE 6 5 6 6 SYSTEM CAPACITY Table 6 3 Traffie Capacity of Exchan
49. ange The administration allocates a range of ISDN numbers towards the ISPBX one for each DDI user Multiple Subscriber Number MSN This service provides the facility of assigning multiple ISDN numbers to more than one user on a single interface This service allows direct dialling to one of the terminals connected to an access and enables the network to determine ISDN number which is applicable for originating calls for subscriber characteristics and charging services The addressing of terminals is achieved by applying a set of ISDN numbers which need not be consecutive When a call with one of these ISDN numbers is delivered the corresponding MSN number is indicated to the MSN user Sub Addressing SUB This service is offered to the called user that expands its addressing capability beyond that provided by the ISDN number The sub address is used by the served user to identify a particular terminal on a multi drop access or a virtual terminal or process within a terminal If the calling party provides a sub address in SET UP message the network delivers this sub address unchanged and without interpretation to the called user s installation It is the called user s responsibility to interpret the significance of the sub address 5 3 3 Number Identification Service 1 Connected Line Identification Presentation COLP It is a supplementary service offered to the calling party to know the complete ISDN number of the c
50. ard are made via twisted pair cables with two 7x2 module connectors with a hood on the exchange side and a 25 pin D type connector on the ADP side Concentration Mode Interconnections between BM and LMs In 4 1 concentration mode each Terminal Unit TU Frame of BM is connected to a maximum of three other Terminal Unit Frames in the Line Module For interconnecting them two pairs of 7x2 module connectors are from each Terminal Unit in the Base Module and connected to the Terminal Unit in the Line Module by daisy chaining Table 7 1 summarises all the interconnections in C DOT DSS MAX Table 7 1 Cabinet Description of Type of Cable and Connectors Interconnection Base Module BM Terminal Cards Exchange 7x2 module connectors with hood from side MDF a TU form a 64 pair telephone cable terminated on 64 pair connection module on the MDF A 24 pair cable is used in a TU Frame having EMF trunks Base Module Line TU Frame in BM to TU in Daisy Chaining with 7x2 module Module LM connectors and twisted pair flat cable Central Module CM APU Frame IOP 11 pair twisted pair shielded cable with 7x2 module connectors for each plane BTU Frame CSU Frame Flat cables with module connectors between CSW and VBI cards on the front side of the cards ADP to APU APU Frame ADP 2 Twisted pair cable with 7x2 module HDLC link connector on the APU side and 25 pin D type connector on the ADP side VSU Frame B
51. arm Display Panel and the Input Output Module Figure 3 9 summarises the various units and sub units of the Base Module Any base module can be configured as a Remote Switch Unit RSU and connected to central module on 34 Mbps link or 2 Mbps link as shown Fig 3 10 a 34 Mbps links VBI cards are used at CM end and all the 32 BMs can be configured as Remote BMs RBMs b 2 Mbps links CRS cards at BM end and EMC cards at CM end provide sixteen 2 Mbps links between a BM amp CM GENERAL DESCRIPTION 33 Chapter 3 LESXVININDISAC ETOA SNLOT dSV8 66 LINN 55 ASV AX 5126 SAH 019 ASV 208 AN 179 WOOL J P A 51215 7 size YOL lt 5 gt ee sdawive A sz L 51821 LINN HOLIMS ANIL tH3TIOH1NOO HOLIMS qQ3t33NISN3 INTIVA 1015 AWIL HOLIMS tH3T IOH1NOO SOVSYSLNI 1 Q3ONVHN3 HO1VH3N39 3NOL 5 HOLIMS SDVSSAW 3021438
52. as Access Network interfaces AIs ISDN Terminal Unit ISTU This unit can be equipped as a terminal unit in any BM A maximum of 256 bearer channels can be provided using ISTU Out of these 256 channels any combination of Basic rate Primary rate interfaces can be configured Intelligent Network IN Services C DOT DSS MAX VE can be used as an integrated Service Switching Point SSP for IN services This capability can be added to an already working MAX exchange by upgrading the software and providing additional announcements for IN services Software upgrades add CCS7 protocol for SSP Service Control Point SCP interface the call processing software for GENERAL DESCRIPTION 15 Chapter 2 processing IN service triggers and the administration interface for creating amp modifying the additional data or generating reports for IN services 16 C DOT DSS MAX VE 3 1 3 2 3 2 1 Chapter 3 Hardware Architecture GENERAL The hardware architecture of C DOT is mapped closely on the system architecture described in the previous chapter It consists of base modules central module administrative module and Input Output module Each module is explained below in detail VALUE ENGINEERED BASE MODULE VE BM Value Engineered Base Module VE BM is the basic building block and growth unit of C DOT MAX VE It interfaces the subscribers trunks and special circuits The subscribers may be individual or grouped PBX
53. billing observation If the exchange is used as a leading TAX Centralised Automatic Message Accounting CAMA can be easily incorporated provided the signalling supports the required information flow from the originating exchanges The exchange is connected with a number of VDUs for providing the human interface Man machine communication is extremely user friendly and provides a large number of forms and menus for carrying out exchange management functions Over 200 man machine commands are provided for exchange operation administration and maintenance functions Database Subsystem The management of global data i e the data shared between various applications and processes is done by the Database subsystem The objectives of this subsystems are Easy Access Database software provides uniform and easy access to the database This access is independent of the data as well as the application to be accessed Quick Access Quick access to data is ensured by structuring the data as arrays and using indexing for accessing them This is specially required for real time sensitive application programs such as call processing processes Transparency Database software subsystem makes the application programmer transparent to the actual data structures and data organisation Thus a change in data structures or data organisation does not force a change in the application program Consistency In order to satisfy real time a
54. cation in order to achieve a loosely coupled network for a flexible system architecture Software is written in high level language C and distributed over various processors The application software is structured as a hierarchy of virtual machines The software is packaged such that depending upon the actual switch configuration it can be distributed over appropriate controllers The software features are implemented by communicating processes For inter processor communication messages are exchanged over HDLC links that are implemented either as direct links or switched network paths This approach hides the physical details of processes from each other and provides a flexible communication network between the processors New modules can be added and existing modules can be modified without affecting other modules in the system Resources are identified as global or local depending upon their distribution in the system The resources which depend upon the number of terminals are provided within the basic growth unit the Base Module Base processors are provided for handling call processing locally In a small system application these processors independently support call processing exchange operation and maintenance functions On the other hand in order to avoid replication of large data and memory intensive functions some features and facilities are provided centrally Program backup bulk data storage man machine interface an
55. ce It is possible to have 64 simultaneous four party conferences without conference card Miscellaneous Services i Hot Line Timed This service is also referred as a Fixed Destination Call with Time out This allows a subscriber to establish calls to a pre registered number After getting dial tone if the subscriber does not dial any digit for a specified minimum time he is automatically connected to the number C DOT DSS MAX VE SUBSCRIBER AND SYSTEM FEATURES already registered in the system If subscriber dials digits before the time out a normal connection is established in accordance with the dialled digits Incoming calls are not affected by this service Hot Line Without Time out This service is also referred a Fixed Destination Call Immediate This allows a subscriber to establish calls to a pre registered number by just lifting the handset In this service such a connection is set up immediately upon lifting the handset hence the subscriber cannot dial normal outgoing calls Incoming calls are not affected by this service iii Reminder Call Alarm Services When this service is activated the subscriber is offered a call initiated by the exchange at a specified time s When the alarm call matures and is answered an announcement follows to notify the alarm call This service is available in two forms i In semiautomatic form the booking is manual through exchange operator and the execution is auto
56. d operations and maintenance facilities are therefore provided centrally in order to provide a means of separating the switch from the operations and maintenance interface GENERAL DESCRIPTION 9 Chapter 2 2 2 2 2 2 3 2 2 4 10 Technology The system employs a T T T switching configuration and is based 32 channel PCM structure It uses a basic rate of 64Kbps and 2Mbps primary multiplexing rate Control is distributed over the system by using 32 bit 16 bit microprocessors All the critical control circuitry has built in redundancy System hardware utilises advanced concepts in micro electronics for a compact and optimum design Basic memory unit has been implemented as a 32 to 128 dynamic RAM board Single chip digital signal processors used for implementing DTMF and MF and tone receivers This approach reduces costs power dissipation and saves space on the PCBs Customisation based on ASICS FPGAs has been used to optimize space utilisation and reduce the number of components on various cards Redundancy To meet the stringent availability requirements C DOT DSS employs hot standby technique for all processor complexes so that in the event of the failure of any one security block the duplicate copy takes over Hardware cross links between processors have been planned in such a way that even the failure of two dissimilar processors will not affect system performance Also wherever there is no dup
57. drive It supports printer and upto 11 serial ports for video display units which are used for man machine communication interface All the bulk data processing and storage is done in this module OTHER UNITS ADD ON MODULES amp SERVICES In addition to the basic units described in the previous sections there are additional hardware units or software modules which can be added to the switch to provide various capabilities A brief description of each of these units is provided in this section CCS 7 Signalling Unit Module SUM The SUM provides 557 signalling capability in C DOT MAX VE exchanges It is housed and equipped like a terminal unit but is a module by itself with global resources for handling CCS7 protocol It contains software and hardware for level 2 amp 3 functions of ITU T CCS7 protocol Only one such unit is installed in the whole exchange to provide SS7 signalling capability in the exchange V5 X Unit VU This unit adds V5 x capabilities to C DOT MAX VE exchanges It is packaged into a standard terminal unit frame and can be equipped in any principal or concentration TU position VU hardware is same as that of SUM One VU has to be equipped in each BM where V5 x interface needs to be provided A maximum of 3072 Access Network AN or V5 subscribers can be supported per BM These subscribers are interfaced to the exchange using an Access Network connected to one or more E1 links of Compact Digital Unit CDU configured
58. e Peripheral Processors operate test functions to be used by the maintenance software resident in the Base Processor Since the firmware of the peripheral processors must be real time sensitive it is programmed in assembly level language and fused into EPROMs The firmware along with the hardware provides a higher logical view to the other software subsystems and effectively insulates the hardware details from the application programs Call Processing Subsystem The Call Processing software subsystem receives the information about telephony events that occur outside the exchange It processes this incoming information and gives commands to the Peripheral Processors for interconnecting subscribers through the switching network The Call Processing subsystem is divided into a number of eternal and dynamic processes The processing of a call is done on a half call basis i e corresponding to an originating terminal an Originating Terminal Process OTP is created Similarly corresponding to a terminating terminal a Terminating Terminal Process TTP is created To supervise these two processes a Call Manager CMR is created on a per call basis Different combinations of originating and terminating terminal processes enable the system to handle local outgoing incoming and transit calls Figure 4 4 shows the processes involved in handling a call in a Multi Base Module MBM configuration Feature handling is done at the Call Manager l
59. e This is an economical solution and meant for quick implementation and deployment of ISDN Service C DOT has implemented ETSI PHI 300 099 interface to PSPDN Network I NET which is being expanded as overlay network across the country to offer wide range of data communication services including 64 128 kbps frame relay service Both the cases of routing the packet data traffic on Bd and Bb channels are supported in C DOT DSS Architecture of ISDN Terminal Unit Figure 3 6 In C DOT DSS architecture the ISDN interfaces are terminated on an add on terminal unit called ISDN terminal unit ISTU A maximum of 256 bearer channels are provided by integrating one ISTU which can be configured to support any combination of BRI or PRI interfaces If the requirement of PRI BRI interfaces are more than 256 bearer channels one or more ISTUs can be integrated in C DOT DSS with the option of equipping them in the same BM or distributed across different BMs in the exchange The architecture also supports different level of concentration ensuring the connectivity of every subscriber for signalling and providing uniform allocation of time slots for switching of Bearer channels carrying data and voice The circuit switched traffic is separated at ISTU and routed towards Circuit Switch Time Switch Unit of C DOT DSS Similarly packet switched traffic is routed towards PSPDN on ETSI PHI interface As explained earlier the core switching element o
60. e Observation Incoming Call Barring Intrusion Barring etc Freephone VCC VPN Premium Rate Service ACC UAN Televoting Subscriber Line upto 1000 ohm loop at 30mA Leakage Resistance upto 20K ohm 5 22 pulse s Dual Tone Multifrequency DTMF as per CCITT Rec Q 23 upto 7 alternate choice for resources Progressive upto 512 can be configured as any mix of incoming outgoing or bothway trunks upto 4000 in MAX amp 1000 in SBM upto 12 digits Prefixing of four digits and replacement upto 6 digits all standard methods such as periodic pulse metering AMA CAMA LAMA 128 8 type of days are possible for different charging 16 tariff zones in multiple of 15 minutes in CP memory automatic hourly MMI programmable to duplicated magnetic disk drive AMA CAMA data more frequently in multiple of 3 records output to tape or file transfer to centralised data processing centers Traffic Measurements in conformance to ITU T E 50X Security for data base by commands classification Tracing of long duration in high revenue call 93 Annexure Junction Billing Alarm Monitoring Space requirements Dimensions Racks Height Depth Width Distance between rack rows Weight per meter of rack row Flooring Ground Surface Height for Ceiling Environmental conditions Ambient temperature Relative humidity Power Consumption Application Local Tandem Separate counters for Local STD and ISD call
61. e also routined periodically and faults are isolated through minimal human interface Human Interface Human Interface provides man machines communication between the operator and the system It supports the maintenance commands that are given by the operator Human interface also displays alarms via Output Outside Dialogue OOD terminal and the Alarm Display Panel ADP and prints maintenance reports that are generated as a result of tests audits and diagnostics Administration Subsystem Administration subsystem consists of traffic billing exchange performance measurement and human interface functions It also provides online software patching capability Administration subsystem is responsible for maintaining a large number of traffic records on the basis of the information received it through Call Event Records and a large number of traffic related commands Similarly the Traffic and Exchange Measurement Process correlates a number of these traffic records and generates reports on the overall exchange performance These reports are extremely useful in monitoring the health of the exchange and for network planning C DOT DSS MAX VE 4 3 5 SOFTWARE ARCHITECTURE Billing processes provide billing records and itemised detailed billing information for local and trunk calls Detailed Billing Records made by default for all STD and ISD calls Detailed billing records for local calls are provided for subscribers under local
62. e services are affected 5 4 5 System Applications The implementation of different features and services are generic and modular integrated into a common software link The same software link can be used for different application as Local Exchange Tandem Exchange Trunk Automatic Exchange TAX Integrated Local cum Tandem TAX Exchange ILT Support to CCS7 ISDN and V5 X through add on hardware units 57 configuration for integrated STP functions IN SSP configration 5 4 6 Local MF Resources in CDU In MAX XL only global MF DTMF resources of time switch unit were available In MAX VE local resources available on controller cards of ETU CDU can also be used for call processing Each controller card provides 30 MF DTMF resources GENERAL DESCRIPTION 69 6 1 6 2 70 Chapter 6 System Capacity INTRODUCTION The capacity of C DOT DSS is defined in terms of the following parameters The termination capacity expressed as the number of lines and trunks e The amount of traffic in erlangs that can be switched e The number of Busy Hour Call Attempts BHCA that can be processed with a given call mix while meeting the overall service quality requirements This section indicates the maximum capacity of different system elements as well as that of complete exchange equipped to its ultimate termination capacity It has been ensured that the specified parameters are valid to mee
63. eered Time Switch VTS The new value engineered time switch derives its name from its basic functionality of time switching the PCM slots Time switching is done from TU TU TU CM and CM TU It also has a facility of 64 four party conferences The card has an on board controller time switch amp communication links The time switch complex receives the following PCM links and performs time switching on them for switching within the Base Module Sixteen 128 channel multiplexed links 8Mbps from different terminal units 8 each from CO and C1 Two 128 channel multiplexed links from the service circuit Interface controller Eight 128 channel 8Mbps serial links from TUs are multiplexed into two 4 Mbps parallel bus 0 amp bus 1 outputs of 512 channels each to VCI cards VCI cards convert these into 34 Mbps E3 serial links towards CM Base Processor Unit BPU Base Processor Unit BPU is the master controller in the Base Module It is implemented as a duplicated controller with memory units These duplicated sub units are realised in the form of the following cards High Performance Controller HPX Card Memory Extender XME HPX controls time switching within the Base Module via the High Performance Message Switch HMS and the Time Switch Controller It communicates with the Administrative Processor via HMS for operations and maintenance functions In SBM configuration HPX directly interfaces with the Al
64. evel GENERAL DESCRIPTION 49 Chapter 4 GLOBAL ROUTING v4 8 GRRA RESOURCE ALLOCATION j fs y CALLMANAGER CMR ae gt T 4 Hees ge es Bee ORIGINATING TERMINATING 7 TERMINAL TERMINAL PROCESS PROCESS Z S STATUS CONTROL PROCESS x PP PERIPHERAL PROCESSORS PP ORIGINATING TERMINATING LINE LINE ETERNAL PROCESS DYNAMIC PROCESS GPC IS NOT REQUIRED IN SBM SYSTEMS GRRA DIRECTLY COMMUNICATES WITH TTP PROCESSES IN CALL PROCESSING SUBSYSTEM GLOBAL PATH y FIGURE 4 4 LOTUS VOL1 DESIGN MAX2315 MX2315GD MAX L CP 50 C DOT DSS MAX VE 4 3 3 4 3 3 1 4 3 3 2 SOFTWARE ARCHITECTURE Routing is handled by Global Routing and Resource Allocation Process GRRA and path allocation is done by Global Path Control GPC process In Single Base Module SBM configuration GPC is not present All access to the data are made through Data Base Access Routines DBARs special feature of the Call Processing software subsystem is generation of an exhaustive Call Event Record CER on every call This Call Event Record contains the complete detail of a call and is sent to the Administration Software subsystem at the termination of the call The Administrat
65. f C DOT DSS or T T T functions as CS element ISDN traffic GENERAL DESCRIPTION 27 Chapter 3 8 LINKS 7 OF 32 B CHANNELS 256 256 256 Kbps HDLC ITC1 1 Mbps SERIAL LINK LC14 FOR D CHANNEL 1 15 PS PACKET SWITCH CS CIRCUIT SWITCH PCM SIGNALLING 32 B Ch ONLY IN CASE OF CONCENTRATION FIG 3 6 __ 2Nos 128 B Ch 8Mbps PCM LINKS AS LINK AND LINK1 ICC1 ISTU ARCHITECTURE cs LOTUS VOL1 DESIGN MAX2315 MX2315GD MXIGDIA 28 C DOT DSS MAX VE 3 2 1 5 2 3 2 1 5 3 HARDWARE ARCHITECTURE Basic Rate Interface BRI is through twisted pair of copper cable conforming to G 961 standard It provides support for continuous powering up of NT and in emergency condition to support one TE for POTS service with current limiting The Primary Rate Interface PRI is standard 2 048 Mbps link driven on symmetric twisted pairs with characteristic impedance of 120 ohms conforming to CCITT 1 481 standard The ISDN terminal cards are Basic Rate Line BRL and Primary Rate Line PRL cards Basic Rate Line BRL Card Figure 3 7 The Basic Rate Line card BRL is an interface to the switching system supporting 8 U interfaces towards
66. f batteries GENERAL DESCRIPTION 89 Chapter 7 7 3 5 7 4 90 Main Distribution Frame MDF Room room houses the and one or two VDU terminals which are used test positions Two basic configurations of MDF are standardized Frame type wall mounted extendable single sided MDF is proposed for exchanges upto 2000 ports For Main Automatic Exchanges above 2000 ports an open frame type double sided extendable MDF is used MDF provides easy access to connector blocks used for terminating external cables on line side and equipment cables on exchange side Facilities for disconnection interception and testing on either side of the connector block are available for day to day maintenance Complete flexibility is available through jumper pair for interconnecting any line side cable pair to any equipment number on the exchange side of the MDF Note 1 In case of Switch Room Layout the dimensions are given for Main Exchange as per full suite configuration of its ultimate capacity In smaller configurations the half suite configurations with different layout considered 2 Dimensions for other service rooms are only a recommendation and the planner is free to re organise it to suit site specific requirement CLIMATIC AND ENVIRONMENTAL CONDITIONS The system is capable of working satisfactorily under the following environmental conditions During pre installation period Temperatu
67. g ODR all calls originating from a particular geographical area are routed to the nearest customer service location Originating Call Screening OCS disallow calls from particular geographical area Call Forwarding Conditional CFC calls forwarded to the specified locations in case of default directory number being busy or not responding Call Distribution CD calls distributed on more than one directory numbers based on the percentage defined Virtual private network VPN The Virtual Private Network VPN service provides the VPN customer all the features of a private network by using the Public Switched Telephone Network PSTN resources It allows the VPN customers with significant long distance traffic between corporate sites to configure and use switched carrier circuits as if they were dedicated private lines A VPN customer can define his own private numbering plan and class of service restrictions across closed user groups VPN service in this sense can be compared with a Centrex or a PBX The charging for a VPN call can be flexible The charges are levied to a common charge number In this way a company s travelling salesman can make STD calls while the charges are levied to the organisation s common charge number Some unique terms associated with the VPN service are defined below On net Locations These are authorised network access locations that are logically defined by the customer to be part
68. ge Configurations SL No Exchange Configuration Traffic Capacity Description SBM VE 450 Erlangs The BHCA capacity may be 25 000 Remote Switching Unit RSU 450 Erlangs The capacity may be 25 000 3 14400 Erlangs The capacity 15 8 00 000 SYSTEM RELIABILITY The C DOT DSS 15 designed to meet the reliability standards as defined in the specifications The system uses fully digital techniques for switching including the subscriber stage The system is built using a minimal number of standard units modules which allow flexible growth of the exchange and easy upgradation in technology and new features very important feature of C DOT DSS MAX architecture is the extensive duplication of units controller units are duplicated or have 1 redundancy Software design matches this high degree of redundancy provided by hardware to minimize the system down time To minimize failures caused by human and or software errors the C DOT DSS MAX has extensive software maintenance functions The design of software is such that propagation of software faults is contained and it provides sufficient checks to monitor the correct functioning of the system The facilities are in built to ensure automatic software recovery on detection of software faults Whenever a faulty condition occurs the software provides for the isolation of the faulty subsystem and automatically initiates diagnostic programs for diagnostic pur
69. ifications of the Telecom Engineering Centre TEC ISDN User Part ISUP Signalling Connection C DOT DSS MAX VE HARDWARE ARCHITECTURE 12815 8Mbps LINK 38 COSINE TIME SWITCH LINKS FROM FOUR NETWORK 32 ts 2Mbps LINKS RW s amp 4 OR 4 EDT COMPLEX COMPLEX 3 COMPACT DIGITAL UNIT FRAME NOTE 1 EACH COMPLEX CONTAINS ONE TERMINAL UNIT WITH 4 PCMs 2Mbps NOTE 2 EACH RWC CARD PROVIDES 2 PCM LINKS EACH EDT CARD PROVIDES 4 PCM LINKS FIG 3 2 COMPACT DIGITAL UNIT CDU DESIGN MAX2315 MX2315GD MxisgdCDU GENERAL DESCRIPTION 21 Chapter 3 7 24 NOTE SUBSCRIBER LINES PSTN ISDN ANALOG TRUNKS DIGITAL TRUNKS SIGNALLING LINKS DIGITAL LINKS TERMINAL INTERFACE CONTROLLER GENERIC CPU COMPLEX SIGNALLING INFORMATION VOICE INFORMATION SERVICE CIRCUITS INTERFACES ARE NOT SHOWN HOME BASE MODULE BMx CENTRAL MODULE CM 2 TIME SWITCHING Z P OF SIGNALLING SUM Q INFO TS 2 N T 2 N TIME SWITCHING OF VOICE INFO ISTU 2 N N N N 5 N TIME SWITCHING CDU TU z Z TS Z 2 TSC BASE PROCESSOR GSC BASE MODULE BMy AM APG IOM DEV
70. ion subsystem in turn processes the Call Event Records for extracting billing and traffic related information in the form of reports In case the call involves a terminal under observation a Call Detail Record CDR is also generated Maintenance Subsystem The Maintenance software subsystem 18 responsible for the following major functions Initialisation System integrity Switch maintenance Terminal maintenance Human interface Initialisation Initialisation consists of loading code and data from the IOP onto the System During initialisation the Administrative Processor AP under the control of EPROM based routines establishes communication with the Initialisation Process IOPI in the IOP IOPI reads code files from the disk and transmits them to AP Base Processor code is broadcast to all the Base Processors in the system through the Central Message Switch However since data files differ from one Base Processor to another they are loaded sequentially Five levels of initialisation are offered ranging from initialisation without the dislocation of the single call stable upto higher and higher levels till the entire system is cleared up and reloaded System Integrity When all the subsystems are performing normally they keep sending periodic sanity messages to the Base Processors All Base Processors in turn keep sending messages to the Administrative Processor Loss of sanity of a processor is detected within a
71. ir conditioning practices should be used to take into account the ambient conditions prevailing outside the Switch Room which will depend upon the part of the country for which the C DOT exchange is being planned GENERAL DESCRIPTION 91 Annexure A Technical Specifications Summary System Data Number of Subscriber lines Number of trunks TANDEM TAX Switching capacity Busy Hour Call Attempts BHCA Processors Memory capacity External Memory magnetic tape magnetic disk Common Channel Signalling links Operating voltage Transmission Performance and reliability Clock accuracy maximum relative frequency deviation Interfaces Network Trunk Signalling systems Subscriber Access Interfaces PSTN Subscribers Basic access Primary rate access PSPDN Interface ETSI PHI 300 009 V5 X Interfaces Network Interworking Supplementary Services Number Identification Service 92 upto 1 00 000 with 15000 trunks upto 30 000 upto 8 00 000 BHCA load A as per ITU T 9 504 upto 14400 E 32 Mbyte Two devices of 150 Mbyte each Two devices with storage capacity up to 9 1 G byte each with redundancy upto 128 signalling links 50V 6 VDC ITU T Rec Q 507 Q 517 32 Channel E 1 PCM ITU T Rec Q 504 Q 514 Plesiochronous 109 Synchronous 10 11 All standard signallling systems for different interfaces as Two wire physical TWT E amp M and E 1 PCM Decadic CCITTR2 CCS7 Country
72. l hardware This will be achieved by concatenating of 64 Kbps B channels and they need not be contiguous but should be progressive H channels are used for higher bandwidth requirement e g LAN high speed data communication and Video transmission GENERAL DESCRIPTION 29 Chapter 3 7 2 PCM LINKS FOR 32 B Ch 2840 46 2 U INT D Ch 2B D D Ch P S LAPD Y lt gt Y LCP LCP LINE CARD PROCESSOR P S PACKETS AND SIGNALLING LAPD LINK ACCESS PROTOCOL ON D CHANNEL 3 7 BRI LINE CARD LOTUS VOL1 DESIGN MAX2315 MX2315GD MXIGDBLC 30 C DOT DSS MAX VE 3 2 1 5 4 3 2 2 3 2 2 1 3 2 2 2 HARDWARE ARCHITECTURE ISTU Control Unit The control unit interfaces BRL PRL cards on one end TSU the other end It has a 256 x 256 switch The 256 channels are switched on to a 128 channel 8Mbps link towards Time Switch Unit The D channel data traffic is switched towards ISTU where interface has been configured Signalling data received from BRL PRL cards is forwarded to BP after LAPD to C 85 conversion The traffic on BP from an ISDN subscriber can be potentially 8 times the traffic of a non ISDN subscriber To reduce the load on BP some of the functions like ISTP terminal process overload and concentration control shifted to the control unit of ISTU The active standby status of control units is communicated to ter
73. lication of hardware units multiple units are provided to work in a load sharing mode In the event of failure of one of the units other units will share its load preventing disruption of service Common Hardware Units Various hardware units such as controller complexes and message switches have been standardised for multiple applications This interchangeability is an important feature of the system hardware that helps in reducing inventories and increasing system availability Some of these standardised units are Module Control Unit Module Control Unit is 32 bit microprocessor complex with associated memory unit The same unit can be used as the Base Processor Unit in the Base Module or as the Administrative Processor Unit in the Administrative Module or Central Switch Controller in Central Module It is also used in the CCS7 unit and the V5 X unit as the CPU C DOT DSS MAX VE SYSTEM ARCHITECTURE Interface Controller This is 16 bit microprocessor based unit with time switching network that can be used to control either terminal interface in the Terminal Unit or service circuit interface in the Time Switch Unit In both the cases its function is to assign time slots on the 128 channel link between the terminals subscribers trunks etc and the time switch Message Switch Message Switch is implemented as a 32 bit message switch controller which provides upto 39 HDLC links for message communication between con
74. lines analog or digital lines The trunks may be two wire physical E amp M Four Wire digital CAS or 5 The basic functions of a Base Module are Analog to digital conversion of all signals on analog lines and trunks e Interface to digital trunks and digital subscribers e Switching the calls between terminals connected to the same Base Module Communication with the Administrative Module via the Central Module for administrative and maintenance functions and also for majority of inter BM switching i e call processing functions e Provision of special circuits for call processing support e g digital tones announcements MF DTMF senders receivers Provision for local switching and metering in stand alone mode of Remote Switch Unit as well as in case of Single Base Module Exchange SBM For these functions the Base Module hardware is spread over the following types of units a Terminal Units b Base Processor Unit Value Engineered Time Switch Unit Each of these Units is described in the following sections Terminal Units The following terminal units can be used in MAX VE GENERAL DESCRIPTION 17 Chapter 3 3 2 1 1 3 2 1 1 1 3 2 1 1 2 18 Enhanced Terminal Unit to interface analog lines analog trunks digital trunks and to provide special circuits such as conference announcements and terminal tester Compact Digital Terminal for interfacing digital trunks i e
75. ll in waiting The call which has been put on hold is retrieved by the user as and when it is required The procedure of invocation to put the conversation on hold and its subsequent retrieval is different for ISDN and PSTN subscribers Multi Party Services i ii Three party conference The three party call service enables the served user to establish participate in and control a simultaneous communication involving the served user and two other parties The served user can request to convert two party conversation into a three party conference During the three party conversation the served user can disconnect one party disconnect the 3 way conversation or choose to communicate privately with one of the parties in which case the call to the other party is held Four party conference The CONF Add on conference service enables the served user to establish and control a conference i e a simultaneous communication involving of users max upto 4 When the CONF service is invoked the serving local exchange allocates conference resources to the served user and add any existing call indicated by the served user to the conference On successful invocation of conference the served user becomes the conference controller The conference controller may then add drop isolate reattach parties from the conference The conference controller can also hold and retrieve the conference e g to add parties and finally end the conferen
76. llowed from the terminal SCP creates an Originating Terminal Process OTP which manages the terminal till the termination of the call and then kills itself While there will be only one SCP in the GENERAL DESCRIPTION 45 Chapter 4 4 2 2 4 3 46 number of will equal to number of terminals the call set up phase at any moment Software Subsystems The main subsystems of C DOT DSS MAX software are Figure 4 1 C DOT Real Time Operating System CDOS Peripheral Processors Subsystem Call Processing Subsystem Maintenance Subsystem Administration Subsystem 9 Database Subsystem 7 Input Output Processor IOP Subsystem C DOT REAL TIME OPERATING SYSTEM CDOS The operating system is primarily responsible for the following functions and services Figure 4 2 Management of Processes e Synchronisation and Communication between Process e Time Management e Interrupt Handling e Resource Management e Memory Management e Online and Offline Debugging Facility The operating system has been designed to minimise the overheads in terms of real time Each set of primitives has a number of options through which additional information can be passed on for synchronization and mutual exclusion In the distributed architecture of C DOT DSS MAX one of the important roles played by the CDOS is to provide an effective interprocess communication between proces
77. matic In this case the operator needs to be operator connected to the system via a VDU ii In automatic form the booking is done automatically by the subscriber through a control procedure and its execution is also automatic iv Subscriber Controlled Call Restriction Services Denying all calls to a line while allowing it to originate calls as current access level Denying various level of originations from a line no ISD calls no STD and ISD calls only local calls and selected Level 1 services etc while allowing incoming calls to terminate normally on it Subscriber controlled barring offers flexibility to a subscriber to change outgoing restrictions by selecting one access level using predefined procedure through secret password To maintain the secrecy of the password the user can modify the password by using predefined procedure Intrusion Service For reasons of call security in terms of fully undisturbed call subscriber avail of intrusion barring facility This can be useful for example when data transmission is being done on the line vi Dialling by Terminal Equipment Number Sometimes a specific line trunk tone or announcement is to be accessed by its Terminal Equipment Number TEN in the exchange This is specifically required for dialling to lines which do not have a directory number or in case of directed calls via outgoing trunks This GENERAL DESCRIPTION
78. minal cards through the status information The control units themselves update the dynamic events at OS application level so that switchovers are handled properly Value Engineered Time Switch Unit VSU VSU implements three basic functions time switching within the Base Module routing of control messages within the Base Module and across Base Modules and support services like MF DTMF circuits answering circuits tones etc These functions are performed by three different functional units integrated as time switch unit in a single frame refer Fig 3 8 Service Unit SU Service unit comprises two types of cards Advanced service card ASV amp Service Circuit Interface Controller SCIC ASV provides tones answering circuits amp MF DTMF resources Upto 4 ASV cards be equipped two for tones and two for MF DTMF resources These cards form three terminal groups towards the SCIC SCIC multiplexes these with one terminal group from HMS into one 128 channel 8 Mbps link towards the VTS ETC CTC cards are used as SCIC in VSU Base Message Switch BMS Base Message Switch BMS routes the control messages within the Base Module across different Base Modules and also Administrative Module via the Central Module It is implemented on one card i e High Performance Message Switch HMS card This card provides 9 HDLC links for communication with SCIC VTS BP amp mate BMS when used as BMS and provides a message transfer poi
79. n directly from the busbar to the respective Base Module cabinets The power cables are placed on the cable troughs and terminated on the busbars of the respective Base Modules Below the busbar on the Power Distribution Panel two more busbars are placed on which the cables from chassis and logic ground of each Base Module are terminated Cables are brought out from the Service Earth Plate to these busbars 7 3 EXCHANGE LAYOUT A typical C DOT DSS MAX installation is spread over the following rooms e Switch Room Operations and Maintenance OMC Room e Input Output Processor IOP Room e Power Plant Room amp Battery Room Main Distribution Frame MDF Room Cable Chamber In SBM configuration the Switch and IOP are installed in a single room whereas in MBM configuration these are separately provided Other equipments like power GENERAL DESCRIPTION 85 Chapter 7 plant battery MDF Cable Chamber and PCM junctions are installed in separate rooms either on the same or different floors of the exchange building required The switch room layout of a sample MBM configuration is shown in Figure 7 4 For other configurations the dimensions and layout are different 7 3 1 7 3 1 1 86 Switch Room Equipment The C DOT DSS MAX Switch Room consists of BM and CM cabinets mounted in standard suites These cabinets are fastened to the Switch Room ironwork and interconnected by cables The cabinets are organised in
80. nt between BP amp these controllers When GENERAL DESCRIPTION 31 Chapter 3 NLODSIXW GOS LESXINNG NSA 5 ANIA 8 E SINH 995 9 HOLIMS INIL SLA LOTS 51 X YNA JCH 1 Y L 1 INI SdqNW 1 YITOHLNOO SLINOHIO 6 208 H3TIOH1INOO LLIN OAN HOLIMS J YSSIN H IH SAH 2 23 5126 z 019 9 9195 Z 5126 WO SIA WOd 8 51 821 VOL 2 b a WOd 5126 gt 5 SLNN INT sda ye 777 SANIT 8 1 9 C DOT DSS MAX VE 32 3 2 2 3 3 2 3 HARDWARE ARCHITECTURE used as Central Message Switch in a CM it has 39 HDLC links for communication with CSC IOPs and mate CMS Value Engin
81. number in the conventional sense Virtual Card Calling service is an access code based service All VCC calls require the dialling of the service key followed by the card number The card numbers are first defined in the SCP VCC cards of appropriate denominations and access barring levels are then printed by the service provider at the time of service subscription on secure stationery The cards can also be purchased off the shelf by the customer from a reseller With each call the charge is debited from the customer s card Account Card Calling ACC This service is also an Alternate Billing Service and allows the users to make calls from anywhere in the network and let the charges to be credited to an account Account Card Calling service is also an access code based service The service user dials the service key and the ACC account number followed by a Personal Identification Number PIN when prompted for it The PIN is modifiable by the customer The credit limit access barring level and initial PIN of the customer is decided at the time of subscription Universal Access Number UAN This service enables a person or an organisation to publish one local or national number and have incoming calls routed to different destinations based on the geographical location of the caller UAN is similar to Freephone except in the way charging is done In UAN the calling party bears the expenses of the call as defined by network Moreover
82. o initiate the corrective measures in case of a fault Some of the features are Hot stand by redundancy for all the controllers Periodic auditing of process and resources Automatic scheduling of fault control mechanism to restrict the fault propagation GENERAL DESCRIPTION 67 Chapter 5 68 Automatic system reconfiguration to ensure the best possible configuration Depending upon the system configuration and size of the pool of resources the exchange administration can decide about the thresholds to raise retire different level of alarms Extensive diagnostic features to isolate the fault at card level Multiple ETT support MAX VE upto 4 ETT cards be equipped each base module for testing of lines and analog trunks Automatic scheduled routining for Switch Units and Terminals Subscribers Trunks Resources Remote alarm reporting The health of all the switch units and terminals are continuously monitored by the system In case of un manned operation the details of all the maintenance related activities are generated in form of alarms logs which are analysed to take corrective measures Whenever any alarm non urgent urgent critical is raised in the switch room the ring will go to a pre defined telephone number to inform the concerned person On answer related tones will be heard which will indicate the presence of specific alarm in the switch room Remote alarm monitoring
83. o establish a call due to non availability of circuits service circuits internal congestion internal time outs or any other internal traffic situations other than those caused by faults e Line to Trunk Connection outgoing The loss probability on line to trunk connection should be less than 0 005 1 out of 200 Trunk to Line Connection incoming The loss probability on trunk to line connections should be less than 0 0066 1 out of 150 e Line to Line Connection intra office The loss probability averaged over all line to line combinations should be less than 0 01 1 out of 100 Trunk to Trunk Connection tandem The loss probability should be less than 005 1 out of 200 in case of trunk to trunk connections C DOT DSS MAX VE 7 1 7 2 7 2 1 7 2 2 Chapter 7 Packaging Layout amp Environment INTRODUCTION Equipment practices in C DOT DSS MAX are followed such that the equipment packaging is modular flexible and provides economy of space Standard racks frames circuit cards and back planes have been used The salient feature of C DOT DSS is that only three types of RACKS CABINETS are used irrespective of capacity or configuration of the Exchange The brief description of the equipment practices followed in C DOT DSS MAX alongwith the details of Exchange Layout Plans and Environmental Aspects are described in this chapter EQUIPMENT PRACTICES FOR PACKAGING Circuit Cards Circuit card is the
84. o the ETU Ringer voltage 75VRMS output is supplied by one of the EPUs This is a continuous voltage and the appropriate cadence for normal distinctive ring is provided by dynamic software control of ring relays on line cards Compact Digital Unit CDU Refer Fig 3 2 Each CDU can house upto four digital terminal units in one frame thus providing upto sixteen E 1 links Each terminal unit of the CDU is known as a complex thus there can be complex 0 1 2 amp 3 equipped as four principal TUs in a BM CDU can be concentrated with ETU SU and VU There are three types of cards in CDU i Compact Terminal Controller CTC These cards provide voice amp signaling interface for the digital trunks in each complex of a CDU and interface towards the time switch Each complex has two CTC cards working in hot standby mode ii Digital trunk cards RWC as well as EDT cards described in section 3 2 1 1 2 can be used in CDU 11 Power supply cards four PSU II cards provide the required voltages in the CDU CCS7 Signalling Unit Module SUM Refer Fig 3 3 SS7 capability in C DOT DSS MAX VE exchanges is implemented in the form of a SS7 Signalling Unit Module SUM frame Only one such unit is equipped in the exchange irrespective of its configuration or capacity This unit can be concentrated with ETU CDU but not with V5 X Unit CCS7 implementation in C DOT MAX exchanges is based on ITU T recommendations and the Indian National Spec
85. ol handler cards SHM are also supported A maximum of 3072 V5 subscribers can be supported in each BM through one or more AI links For more details on VU hardware amp S W please refer to V5 X User Manual GENERAL DESCRIPTION 25 Chapter 3 26 gt V5 SUBSCRIBERS E1 LINKS FROM AN TSU TO BP FIG 3 5 V5 X INTERFACE IN MAX VE 128 TS CTC IN CDU N BACK 32 TS PCM PLANE TGs BUS PHC SUI VUCPU IN VU PCM 128 TS VU DESIGN ANINTRFC VUINBM C DOT DSS MAX VE 3 2 1 5 3 2 1 5 1 HARDWARE ARCHITECTURE ISDN Terminal Unit IST U ISTU provides BRI PRI interfaces in C DOT DSS By equipping one ISTU in the exchange a maximum of 256 P lt channels are available to the administrator which can be configured as BRI PRI or any as per site requirement Depending on the requirement of number of ISDN interfaces one or ISTUs can be integrated in C DOT DSS either one BM distributed across different BMs The ISDN traffic is of two distinct types 1 Circuit switched voice amp data ii Packet switched data In case of Circuit switched voice amp data the traffic is routed through ISDN PSTN network In case of packet switched data the packet traffic is routed to PSPDN where packet processing takes plac
86. onnected party on answer It should be noted that if the called user belongs to an ISPBX the connected number shall only identify the ISPBX and not the called user s extension The extension itself can be identified only if the called user has subscribed to the DDI service and has included his DDI digits during call confirmation GENERAL DESCRIPTION 61 Chapter 5 5 3 4 5 3 5 62 ii iii Connected Line Identification Restriction COLR This is a service offered to the connected party to restrict the presentation its identity to the calling party When COLR is subscribed the destination exchange informs originating exchange with a notification that the connected party s identity is not allowed to be presented to the calling party Connected Line Identification Restriction Override COLRO Subscriber with the COLRO facility is given the connected line identification even if the connected party has requested that his the connected party s identification not to be presented to the calling user by the invocation of the COLR service Miscellaneous Services i Terminal Portability TP Terminal Portability TP is a supplementary service that allows the user to move a terminal from one socket to another within the same basic access during the active phase of the call It also allows the user to move a call from one terminal to another with the same basic access in the active phase of the call It allows
87. ons For an exchange of capacity 5000 ports or more the dimensions of the OMC Room are approx 5000mm x 7000mm Input Output Processor IOP Room Equipment The IOP Room houses the two IOPs with one or more video display terminals and printer kept for the use of system administrator Rest of the terminals and printers are kept in the OMC Room Two inverters of 1 KVA each are required for IOP OMC rooms to provide uninterrupted power to the VDUs and printers Dimensions For an exchange of 5000 ports and more the dimensions of the IOP Room are 2500mm x 3000mm while for smaller exchanges both the IOP and OMC rooms be put together room of dimensions 3000mm x 7000mm Power Plant Room amp Battery Room Power Plant Room The following equipment is provided in this room Float Rectifiers Switching Cubicle Battery Chargers LT Panels Intermediate Distribution Panel IDP Dimensions The dimensions of the Power Plant Room are 10000mm x 8000mm The cubicles for float rectifiers battery charger and the switching cubicle are situated within this room and have different dimensions Their placement however depends upon the exchange site Battery Room This room houses an 2x24 cell array of batteries working in parallel float with the rectifiers It is mandatory that the Battery Room be located next to the Power Plant Room The dimensions of the Battery Room are 7000mm x 12000mm and it houses two sets o
88. ot be used with CCK1 Thus there 15 0 complex and copy 1 complex The CBX also synchronises all CSC accesses to CSU with the 16 MHz clock as well as BTU Fig 3 12 depicts the clock distribution in C DOT MAX VE Central Message Switch CMS Central Message Switch CMS complex is the central message transfer point of the switch It is implemented as four different message switches working in load sharing mode Each message switch is a high performance message routing block implemented by using High Performance Message Switch HMS card which has high speed 32 bit microprocessor MC 68040 This card supports 39 HDLC links with flexibility of programming individual HDLC links upto 750 kbps All Central Message Switches CMS1 2 3 amp 4 are used for routing of messages across the Base Modules On the other hand only 51 and CMS2 interface with the Administrative Module for routing control message between Base Processors and Administrative Processor This communication is used to access office data for routing inter module calls and administration and maintenance functions Fig 3 13 depicts the Central Message Switch in C DOT MAX VE ADMINISTRATIVE MODULE AM Administrative Module AM consists of a duplicated 32 bit controller called the Administrative Processor Controller APC It communicates with Base Processors via the Central Message Switch for control messages and with the duplicated Input Output Processors in the Input
89. poses The diagnostic programs have a design objective of localising 95 of the faults to a single PCB level and the rest to a two PCB level Provision is also made for safety of charge records The charging information is dumped at regular intervals to non volatile duplicated back up memories automatically The software maintenance functions include data audits as well as system integrity monitors and controls An Alarm Display Panel is provided for a continuous indication of the system status Audio visual alarms are provided for monitoring power failures SYSTEM RELIABILITY STANDARDS For purpose of assessing the service reliability the period after cutover is divided into a non stabilised period and a stabilised period The non stabilised period covers a running in period followed by a six month test period The service quality figure obtained during the running in period is not used for assessing the long term reliability of the system However this period is kept as short as possible The service reliability during the stability period is shown in next section GENERAL DESCRIPTION 73 Chapter 6 6 7 74 During automatic reconfiguration only the calls in the set up stage are lost without affecting the established calls OVERALL SERVICE STANDARDS Service objectives have been defined for four types of call connections under designed load conditions The overall service standard is expressed as probability of not being able t
90. pplications the database cannot be totally non redundant Thus in order to provide quick access to duplicated data items the database software maintains consistency between these duplicated data items Security Database subsystem keeps the database locked to protect it against possible corruption Synchronisation In a multi process environment special care needs to be taken to maintain data consistency at the end of multiple updations of processes This synchronisation is provided by the database software subsystem Keeping these objectives in mind physical data is organised as global data structures and resource tables and the global data is accessed via Data Base Access Routines DBARs Global data structures are maintained on terminal related data fixed office data and extended office data and centralised routing and translation tables In addition linked lists on free GENERAL DESCRIPTION 53 Chapter 4 global and local resources and a reference memory for unprotected terminal 4 3 6 54 status data are maintained Input Output Processor Subsystem Input Output Processor IOP subsystem uses UNIX as the basic operating system IOP software subsystem is structured as a layer above UNIX and comprises of the following parts as shown in Fig 4 5 Command Interpretation Layer A topmost layer like a shell to receive validate and execute operator commands Administration Software A layer above UNIX
91. rd provides upto 128MB of memory in blocks of 32MB iii Signalling Unit Interface card SUI This card combines the functions of terminal unit interface card and terminal unit controller TUC card of MAX XL and acts as the interface between Signalling Handler Module card and the time switch iv Power Supply Cards Two PSU II cards provide the voltages required by various cards in the unit v Enhanced Signalling Handler Cards ESH Each ESH card supports upto 16 Protocol Handler terminals Existing 8 port protocol handler cards SHM are also supported Each terminal of ESH be soft configured 557 protocol terminal or as C 85 protocol C DOT proprietary protocol a variation of X 25 protocol terminal for internal control message communication Each terminal buffer validates incoming messages and lists them in a receive queue for processing by level 3 The message discrimination and routing functions of level 3 are also implemented here Similarly it can send out messages from the transmit queue with sequence control The terminal handles all the level 2 functions GENERAL DESCRIPTION 23 Chapter 3 IOA SNLOT WAS 1 HOLIMS OL Tu ANIT INS INL 9 5 WVudd ad
92. rdware architecture of the MAX VE switching system in detail The contents include the architecture of different switching modules and user network interfaces upto block level The implementation details of other features like Network Synchronisation Remote Switching Unit are also included in this chapter alongwith details of Common Channel Signalling No 7 CCS7 Integrated Services Digital Network ISDN and 5 implementation Chapter 4 explains the software architecture of C DOT MAX VE The contents include the core architecture of different software modules Chapter 5 describes the telephony features supplementary services and system features Brief description of each service with the constraints of its functioning in a few exceptional cases are included Chapter6 contains details regarding the termination and traffic handling capacity of C DOT MAX VE Chapter 7 provides details of system packaging exchange layout climatic and environmental conditions etc Annex lists down the technical specifications of C DOT MAX VE as a ready reference for network planners GENERAL DESCRIPTION 7 2 1 2 2 Chapter 2 System Architecture GENERAL C DOT Value Engineered MAX 15 a recent addition to the family of C DOT Digital Switching Systems Products in this family cater to a wide range of network requirements with respect to capacity and applications as described below 256 Port Rural Automatic Exchange
93. re 10 C to 50 C Relative Humidity Upto 100 e Switch Room and IOP room Conditions exchange in operation Temperature 17 C to 27 C Relative Humidity 45 to 80 Air Movement 3 2 air changes per hour Dust Filteration Particle size above 5 microns excluded 99 exclusion C DOT DSS MAX is capable of operating for four hours after air conditioning failure in the exchange C DOT DSS MAX VE PACKAGING LAYOUT amp ENVIRONMENT Illumination Generally fluorescent lamps for general lighting to a level of 300 lux in equipment rooms should be provided If special lighting is required for working on the equipment provision for bay fixtures for bay lighting would be made in the design Air conditioning Air conditioning does not require any upward throw of air through the bottom of cabinets Air supply grills for throwing conditioned air may be conveniently located on the sides or on the false ceiling if provided to ensure uniform distribution Heat load of the exchange due to occupancy and lighting load in the switch room and OMC room is also considered for air conditioning provisions For a typical four full suite configuration the heat load is as follows Occupancy 10 Equipment dissipation 35 KW Lighting load 1 W sq ft Air conditioning provisions are required to provide adequate temperature and relative humidity control as per the specified Switch Room conditions Standard a
94. re exclusively offered to ISDN subscribers In case of few of the services offered to PSTN and ISDN subscribers the implementation of services to PSTN subscribers may be partial and invocation procedure may also differ due to the same reason PSTN ANALOG AND ISDN SUBSCRIBER SERVICES The subscriber services provided by C DOT DSS MAX exchanges for PSTN Analog as well as ISDN subscribers are explained as per their logical grouping Number Identification Service 1 ii iii Calling Line Identification Presentation CLIP When this service is subscribed by a user as terminating facility all the incoming calls are offered to the user along with the details of calling party s identity In exceptional cases for example if the calling party has subscribed CLIR or due to interworking constraints in the network it will not be possible to provide identity Calling Line Identification Restriction CLIR This service is offered to the calling party to restrict presentation of it s number to the called party When CLIR is subscribed the originating exchange notifies the destination exchange that the calling number is not allowed to be presented to the called party The terminating local exchange may indicate to the called user that the calling user identity is unavailable due to restriction Calling Line Identification Restriction Override CLIRO Subscriber with CLIRO as terminating facility inste
95. riginating service remains unaffected The other number could be a fixed pre determined number or a number specified by the subscriber in the activation request Call Forwarding Busy CFB This service permits the served user to request the exchange to forward all incoming calls to other number if the served user s number is not free The served user s originating service is unaffected Call Forwarding No Reply CFNR This service permits the served user to request the exchange to forward all incoming calls which are not replied within ring time out period to other number The served user s originating service is unaffected Call Completion Services 1 Call Waiting A subscriber engaged in an existing call is given an indication Call Waiting tone or ZIP tone that another caller is attempting to connect to his number The caller will hear ring back tone By flashing the hook switch the called subscriber can talk with either party while GENERAL DESCRIPTION 57 Chapter 5 5 2 4 5 2 5 58 ii keeping the other on hold acceptance without clearing If the called subscriber replaces his handset in response to the tone acceptance by clearing the exchange will automatically extend ring to the subscriber and re establish the connection on answer with the party waiting Call Hold This facility is used by the user to put the existing conversation on hold for the time being and initiate a new call or receive a ca
96. ronisation is provided by an external equipment It is very useful for rural environments and small urban exchange applications Multi Base Module MBM In MBM configuration a MAX VE exchange can have upto 32 Base Modules depending upon its size and application a Central Module Administrative Module Input Output Module and Alarm Display Panel The Base Modules can be co located or remotely located as Remote Switch Units depending on the requirements Remote Switch Unit RSU is an integral part of MAX VE architecture In order to realise a RSU any normal BM can be remoted with the host exchange via 2 Mbps 34 Mbps digital links The number of 2 Mbps 34 Mbps links between the Main Exchange and RSU is primarily determined by the traffic A maximum of 16 PCMs can be provided between a RSU amp Main exchange Analog and Digital trunk interfaces are also implemented in RSU to support direct parenting of small exchanges from RSU itself instead of parenting it to the main exchange in order to save the media required from main exchange As far as call processing is concerned RSU is an autonomous exchange capable of local call completion Operation and maintenance functions are handled by the host exchange In the event of failure of PCM links RSU goes into standalone mode of operation In case it is not possible to process a call request due to unavailability of links to the host the subscriber is connected to appropriate tone or announcement
97. s for all the Trunk Groups with option of detail billing Remote alarm monitoring and reporting Main Exchange for 10 000 subscriber lines 35m2 2 450 mm 500 mm 770 mm min 1 000 mm front edge to front edge 450 kg Antistatic Flooring False flooring is not mandatory min 300 mm False ceiling 15 not mandatory Desirable to reduce in AC Load 17 27 C 10 80 MAX VE 10K lines 390 Amps MAX VE 40K lines 1050 Amps SBM VE 4K lines 8 5 24 Amps Trunk Automatic Exchange TAX Integrated Local Tandem TAX and RSU Remote Switching Unit RSU 94 C DOT DSS MAX VE System Practices COMMENTS C DOT The following comments pertain to Document pr No Month Year COMMENTS Use a separate sheet if required Please mail your comments to Your Reference Centre for Development of Telematics Name Attn Director Systems Designation 39 Main P Road r usa hoa Address New Delhi 110 005 91 11 25740374 Fax 91 11 25756378
98. s required to meet specific network requirement as well as bug fixes in exceptional cases number of features to support software patch installation through user friendly procedures are implemented Minimum disturbance No disturbance to services Easy and safe patch administration procedure Facility to install remove a software patch if required The propagation of patch through extensive documentation alongwith details of software deliverables procedures and release highlights compatibility for Exchange Operation It is possible to perform above operation even by the exchange operators with minimum skills The operation commands are coded in simple English language with in built checks to avoid destructive operations command is executed only after verification of different parameters input by the operator The operation commands are classified as per their significance usage and it is possible for the exchange administrator to allow restrict a set of commands to the specific operator history log of all the operations are maintained at system level and also for each operator separately which can be analysed to trace the details of unauthorised operation Maintenance Features set of maintenance features are implemented in C DOT DSS with objective of restricting the need of maintenance personnel to bare minimum This has been made possible by automatic scheduling of maintenance activities t
99. ses residing in the same or different processors A sender process is transparent to the fact whether the destination process resides in the same or different processor For communication between processors CDOS makes use of C 85 protocol which utilises the HDLC based message network between processors Figure 4 3 C DOT DSS MAX VE SOFTWARE ARCHITECTURE LEZXINNS LEZXVNA NSISIA FIONSNLOT 405 1 XVN SSC 1008 29 Sls WALSASENS SHOSS3OOtid 3H1 30 V SI 3HVAALdOS TWNINHAL 5 SYVMLAOS ANY 55 TIYO 40 51515 09 SYVMLIOS NOILYONddY 408 NOIl1VOI 1ddV 7 47 GENERAL DESCRIPTION Chapter 4 MESSAGE I O SEND RECEIVE DEBUGGING MONITOR READ OS TABLES PROCESS 1 PROCESS MANAGEMENT PROCESS CO ORDINATION CREATE CREATE SET RESET EVENT FLAG START START WAIT ON EVENT FLAG TERMINATE TERMINATE WAIT ON SEMAPHORE MEMORY MANAGEMENT 4 N ALLOCATE CDOS DEALLOCATE PERIPHERAL TIME MANAGEMENT READ SET CANCEL ALARM WRITE PAUSE CANCEL PAUSE GET SET TIME 1 PROCESS 2 PROCESS 3 2 df 6008 CDOS C 85 0 85 PROTOCOL PROTOCOL
100. side MDF from where it is connected to the transmission equipment In case 2 Mbps links are to be used VCI card is replaced by CRS card at VEBM end and VBI card replaced by EMC card at CM end Input Output Processor Connections From each of the Input Output Processors 0 and IOP 1 the following interconnections are made HDLC Cables RS422 interface 0 to IOP 1 25 pin D type connectors with twisted pairs Administrative Processor Unit copy 0 IOP 0 1 Twisted pairs with 7x2 module connector on the APU and 25 pin D type connector on the IOP 0 1 Administrative Processor Unit copy 1 IOP 0 1 Twisted pairs with 7x2 module connector on the APU and 25 pin D type connector on the IOP 0 1 GENERAL DESCRIPTION 83 Chapter 7 Terminals and Printer Cables RS232C interface These connections are provided for flexible access to any serial port using 8 pair telephone cables with 9 pin D type connectors are used Note In standalone configuration IOP directly links with the processor card the Base Processor Unit The connectors and cables are same as above Alarm Display Panel Connections In SBM configuration Alarm Display Panel ADP communicates with the Base Processor Unit via an HDLC link However in MBM configurations it communicates with the Administrative Processor Unit via an HDLC link In both the cases interconnections to the duplicated copies of the Processor C
101. specific MF Signalling Ordinary subscribers CCB subscribers with reversal 16 kHZ subscribers with or without reversal 144 kbit s 2B 1D B 64 kbit s D 16 kbit s 2 048 kbit s 30B 1D B D 64 kbit s Will be made available V5 2 interfaces to support Access Networks ISDN lt gt ISDN ISDN gt PSTN and ISDN lt gt PSPDN interworking functions are integrated and no external interface mediation device is required CLIP CLIR CLIRO COLP COLR COLRO MCID C DOT DSS MAX VE Group Line Service Charging Service Call Completion Service Call Transfer Service Multi Party Service Other Service IN Services Line characteristics Subscriber Lines Rotary Dialling Pushbutton Dialling Routing Alternative Routing Path selection for trunks within a trunk group Number of trunk groups per exchange Number of Routes Depth of digit analysis Prefixing Digit Replacement Charge registration Methods Total Charge Rate Number Types of Days Tariff switching Local charge storage Charge saving Charge data processing Administration Features Traffic features Password amp Security Call GENERAL DESCRIPTION TECHNICAL SPECIFICATIONS SUMMARY SUB MSN LH DDI AOC E AOC D CH CW Hot Line Timed Hotline No delay Terminal Portability CFU CFB CFNR 3 PTY Dynamic Locking Access Level for O G Calls Morning Alarm Reminder Service Lin
102. t overall reliability objectives for the C DOT DSS as specified in ITU T recommendations TERMINATION CAPACITY A Terminal Card is the basic system element It interfaces terminates the lines and trunks The next higher element is a Terminal Unit The types of terminal card and terminal unit used in C DOT DSS along with its functions are already explained in chapters 3 and 4 A BM can be concentrated to provide maximum termination capacity of 6000 lines Each Base Module has eight principal Terminal Units equipped in two BM racks The rack containing BPU amp VSU is known as Principal BM PBM while the additional rack which houses remaining Principal TUs is known as Auxiliary BM rack ABM Each line module has 6 Terminal Units Line module containing concentration TUs of Principal BM TUs is known as principal line module whereas the line module containing concentration TUs of auxiliary BM TUs is known as Auxiliary Line Module ALM A maximum of 32 BMs can be connected in MAX VE configurations Table 6 1 summarises the termination capacities of the various system elements of C DOT DSS MAX C DOT DSS MAX VE SYSTEM CAPACITY Table 6 1 Termination Capacity of System Elements 51 System Element Termination Capacity Description 1 TERMINATION CARD 11 CCM Line ECL 16 analog subscribers or 16 CCB subscribers with all ports supporting 16 KHz metering pulse amp CLIP EDT Card Four 2 Mbps E1 links
103. tenance Features System Applications Numbering Plan MAX VE supports a local numbering plan of up to 8 digits Signalling Routing and Charging C DOT MAX VE implements standard network interfaces and signalling schemes to avoid add on equipments e g multiplexers The analog network interfaces i e Two Wire Physical Trunk and Four Wire E amp M are implemented The digital E 1 PCM interface is supported with all the three types of CAS signalling Register signalling can be configured as Decadic Indian R2 and CCITT R2 signalling with provision to use R2 Signalling in semi compelled or fully compelled mode The E 1 links can also be configured as CCS7 links Trunks are also supported in Remote Switch Unit RSU To meet routing requirement for transit applications 4000 routes in MBM and 1000 routes in SBM exchanges are implemented with depth of analysis upto 12 digits Each route can have a maximum of seven alternate choice of grouped resources for routing and a max of 64 categories for routing and charging of the calls With additional features like time zone based routing CLI based routing priority based routing filtering of calls for selected emergency special service routes it is possible to meet routing charging requirements of complex networks Pre selection and dynamic selection of National Long Distance Operator NLDO is available for MAX VE subscribers For 57 traffic Charge Unit CHU and Charge Band C
104. the user It interfaces with the ISDN Terminal Controller ITC Switching Network for signalling and switching of voice and packet information Primary Rate Interface Line Card PRL The PRL Card is an interface to terminate a 2 048 Mbps link using symmetric twisted pair cable with characteristic impedance of 120 Ohms It conforms to ITU T recommendations 1 431 1 604 703 G 704 and G 706 for functional requirements The interface can be configured for applications as 30 0 ISDN PRI Interface towards ISDN PBX as well as ETSI PHI Interface towards PSPDN Each PRL card forms a terminal group TG and a maximum of 8 PRL cards can be accommodated in each ISTU The PRL Card interfaces to ITC to route signalling and voice information The B channels of PRI interface are mapped 2 048 Mbps link towards However the procedure to handle signalling information is different for each type of interface In case of 30B D interface the D channel signalling information is extracted from 16 time slot and converted to HDLC format before sending it to ITC card on 1 024 Mbps signalling link shared by all the termination cards of the ISTU It is possible to configure PRI interface as PRI 16 i e 16B D interface so that each terminal group TG consists of one PRL card and one BRL card The basic design of PRL Card and also the implementation of ISDN services in C DOT DSS supports HO and H1 channels in future without adding any additiona
105. trollers It is used in base modules as well as the central module of an MBM system 2 2 5 Optimisation In C DOT DSS distribution of functions has been optimised There are local functions which are entrusted to the growth units i e the Base Modules for local switching and interfacing The resources required by these functions are directly linked with the number of lines and trunks equipped These functions are Terminal Interfacing interfacing analog ISDN lines analog and digital trunks CCM amp PBX lines Circuit Switching switching within the Base Module Call Processing majority of call processing functions Concentration for providing upto 4046 subscribers on 1024 time slots On the other hand the functions that are shared globally over the switch are provided by a central facility which may either be the Central Module or the Administrative Module These functions are Inter module Communication Inter BM and BM AM communication via the Central Module Message Switching Inter BM and BM AM control message communication via the Central Message Switch in the Central Module Resource Allocation Done by the Administrative Module GENERAL DESCRIPTION 11 Chapter 2 Operations and Maintenance Bulk data storage by the Input Output Module and man machine interface provided by the Administrative Module via the Input Output Module Services Announcements and conference circuits 2 2 6 Modular
106. umber Televoting VOT Televoting is a very powerful mass calling service used by organisations engaged in psephology and other opinion poll related services The power of this service lies in the instant availability of the results of voting The users call one or more televoting number s advertised by the customer The last two digits of the televoting number are the choice digits The caller is acknowledged by an announcement The televoting period is pre decided between the customer and the service provider and is advertised before polling At the end of the specified period the network provider hands over poll results televoting counters maintained at the SCP to the customer Televoting is available in two flavours One in which for each call the called party is charged and the second in which the calling party is charged for each call For picking out lucky callers etc there is a provision for connecting every nth call to a special number or announcement 5 4 SYSTEM FEATURES C DOT DSS family exchanges support a number of networking features to meet the expectations of Network Planners as well as a set of operation and maintenance GENERAL DESCRIPTION 65 Chapter 5 5 4 1 5 4 2 5 4 3 66 features for the convenience of O amp M personnel Some of the system features explained in this chapter are listed below Numbering Plan Signalling Routing and Charging Exchange Operation Features Exchange Main
107. very short period of time and corrective action e g reconfiguration is taken immediately The most important activity under System Integrity is to keep a check on the general integrity of the system and to keep the system sane by resorting to the appropriate level of initialisation The integrity is checked by periodic and idle time audits and also by the numerous defensive checks built into the application processes themselves GENERAL DESCRIPTION 51 Chapter 4 4 3 3 3 4 3 3 4 4 3 3 5 4 3 4 52 Switch Maintenance Switch Maintenance is five tiered activity consisting of fault detection confirmation isolation reconfiguration and diagnostics The diagnostic procedure pinpoints the faulty element down to the level of one card in most of the cases After fault repair validation of the newly replaced card is carried out before it is brought back in service High degree of redundancy provided by the architecture is fully exploited to keep the down time to a minimum Reconfiguration is done with minimal disturbance to the subscriber Switch maintenance also ensures periodic automatic tests on all the switch units Terminal Maintenance Terminal Maintenance involves fault detection fault reporting and testing of all the subscriber lines and trunks Terminal Test Controller TTC performs tests on the external lines and trunks as well as on the line and trunk interface circuits within the exchange Service circuits ar

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