EWSD Overview

BSNLALT C T ALT CENTRE EWSD Overview H.S.Jakhar D.G.M. (SW-II) ALTTC Ghaziabad 7/10/2013 SW-II/EWSD_Overview/HSJ 1 BSNL System Features ALT C T ALT CENTRE • EWSD Digital switching system has been designed and manufactured by M/s Siemens, Germany. • The name is the abbreviated form of German equivalent of Electronic Switching System Digital (Electronische Wheler Systeme Digitale). • EWSD switch can support maximum 2,50,000 subscribers or 60,000 incoming, outgoing or both way trunks, when working as a pure tandem exchange. 7/10/2013 SW-II/EWSD_Overview/HSJ 2 BSNL System Features • It can carry 25,200 Erlang traffic and can withstand 1.4 million BHCA. • It can work as local cum transit exchange • Can support – – – – CCS No.7 ISDN IN V5.X features. ALT C T ALT CENTRE 7/10/2013 SW-II/EWSD_Overview/HSJ 3 • (3) Switching Network (SN) All the LTGs are connected to the SN which inter connects the line and trunks connected to the exchange in accordance with the call requirement of the subscribers. CCNC and CP are also connected to SN.System Architecture BSNL ALT C T ALT CENTRE The main HW units of an EWSD switch are as under: • (1) Digital line unit (DLU) . • (2) Line/Trunk Group (LTG) . 7/10/2013 SW-II/EWSD_Overview/HSJ 4 .functional unit on which subscriber lines are terminated.Digital Trunks and DLUs are connected to LTGs. routing.It is used for system-wide coordination functions. such as. • (5) Common Channel Signaling Network Control (CCNC) Unit . etc. zoning. The User Part (UP) is incorporated in the respective LTGs.This unit functions as the Message Transfer Part (MTP) of CCS#7. However each subsystem in EWSD carryout practically all the tasks arising in their area independently.BSNL System Architecture ALT C T ALT CENTRE • (4) Coordination Processor (CP) . 7/10/2013 SW-II/EWSD_Overview/HSJ 5 . BSNL ACCESS DLU DLUC LTG GP SWITCHING NETWORK ALT C T ALT CENTRE LTG GP COMMON CHANNEL SIGNALING CCNC CCNP COORDINATION SYPC SYP MB CCG SGC EM OMT CP MBC DISTRIBUTED CONTROLS IN EWSD 7/10/2013 SW-II/EWSD_Overview/HSJ 6 . e. PBX lines or V5. • One DLU is connected to two different LTGs for the reasons of security. i. in the vicinity of the groups of subscribers.. A subset of CCS# 7 is used for CCS on the PDCs.Digital Line Unit (DLU) BSNL ALT C T ALT CENTRE • Analog or Digital (ISDN) subscribers. • DLUs are connected to EWSD sub-systems via a uniform interface standardized by CCITT. 7/10/2013 SW-II/EWSD_Overview/HSJ 7 .1 interface are terminated on DLU • DLUs can be used locally within the exchange or remotely as remote switch unit . Primary Digital Carrier (PDC) to facilitate Local or Remote installation. BSNL SUBSCRIBER LINES AND PBX LINES LOCAL APPLICATION ALT C LTG SN T ALT CENTRE DLU 4 Mbps 4Mbps SUBSCRIBER LINES AND PBX LINES REMOTE APPLICATION DLU PDC0 WITH CCS PDC1 W/O CCS PDC2 WITH CCS PDC3 W/o CCS LTG CP APPLICATIONS AND CONNECTION OF DIGITAL LINE UNIT 7/10/2013 SW-II/EWSD_Overview/HSJ 8 . • In case of remote DLUs. In case of a local DLU interface. each towards a different LTG. TS32 carries CCS. two towards each LTG. • 120 channels are used for user information (speech or data) and signaling information is carried in TS16 of PDC0 and PDC2.BSNL Digital Line Unit (DLU) ALT C T ALT CENTRE • A local DLU is connected to two LTGs via two 4 Mbps (64 TSs) links. maximum 4 PDCs of 2 Mbps (32 TSs) are used per DLU. 7/10/2013 SW-II/EWSD_Overview/HSJ 9 . • In case the link between a remote DLU and the main exchange is broken. • Each module can support 16 subscribers. • Digital (ISDN) subscribers are terminated on the SLMD modules. the subscribers connected to the remote DLU can still dial each other. the analog subscribers are terminated on SLMA (Subscriber Line Module Analog) cards (module). • One DLU can carry traffic of 100 Erlangs.BSNL Digital Line Unit (DLU) ALT C T ALT CENTRE • Within the DLU. • A standard rack of DLU (local ) can accommodate two DLUs of 992 subscribers each. 7/10/2013 SW-II/EWSD_Overview/HSJ 10 . subscribers lines and telephones. • This card is also used for interconnecting a number of remotely situated DLUs (maximum 6). • An ALEX (ALarm Externals) module is used for forwarding external alarms. called a Remote Control Unit (RCU) • All DLUs are provided with a Test Unit (TU) for performing tests and measurements on SLCAs. 7/10/2013 SW-II/EWSD_Overview/HSJ 11 . in a cluster.Digital Line Unit (DLU) BSNL ALT C T ALT CENTRE • For emergency service DLU-controller (DLUC) always contain up-to-date subscribers data. • Numbers of SLMAs are accordingly reduced to accommodate these modules. • Stand Alone Service Cr. card (SASCE) is provided in each R-DLU for switching calls in such cases. BSNL ALT C DLU SLMA DIUD0 PDC0 PDC1 T ALT CENTRE ANALOG AND ISDN SUBSCRIBER LINES. PBX LINES Test line DLUC0 TO TWO LTGS PDC2 SLMD DIUD1 PDC3 DLUC1 TU 4096 KBPS NETWORK 0 4096 KBPS NETWORK 1 CONTROL NETWORK 0 CONTROL NETWORK 1 MAIN COMPONENTS OF A DLU 7/10/2013 SW-II/EWSD_Overview/HSJ 12 . Announcements Trunks. They are connected in any of the following ways : -(i) Via 2/4 Mb/s PDCs with remote/local DLUs to which analogue or ISDN subscribers are connected. CCS#7 Trunks).Line/Trunk Groups(LTG) BSNL ALT C T ALT CENTRE LTG forms the interface between the digital environment of an EWSD exchange and the SN. 7/10/2013 SW-II/EWSD_Overview/HSJ 13 .2 Trunks. OCANEQ. -(iii) Via Primary rate Access lines to ISDN PBXs (ISDN subscribers with PA). -(iv) V5. IP (SSP). -(ii) Via 2 Mbps digital access lines to other digital exchanges in the network ( MF R2 Trunks. 7/10/2013 . switching user channels from and to the switching network. injecting audible tones. carrying out quality-of-service measurements.e. acquiring traffic data. i. • Operation i. etc.. • Safeguarding functions. i.e. receiving and analyzing line and register signals.Line/Trunk Groups(LTG) BSNL ALT C T ALT CENTRE • Functions • Call processing functions. detecting errors in the LTG and on transmission paths within the LTG.. etc. etc.. SW-II/EWSD_Overview/HSJ 14 and maintenance functions.e. analyzing the extent of errors and initiating countermeasures such as disabling channels or lines. ERLANG CAPACITY PER LTG IS 100 ERL.OCANEQ.CHLS) ALT C T ALT CENTRE FRAME TYPE of LTGN F:LTGN(A) (FOR DLUS[L&R].2). OCE:N) ONE LTG SUPPORTS 128 TS (I/P & O/P) MAX. ATE:N. 7/10/2013 SW-II/EWSD_Overview/HSJ 15 . FUNCTIONS LIKE COUC. COU) C FUNCTION (FOR TRUNKS ON CAS & CCS AND CCS#7 SIGN. PRI. TRUNKS) LTG LTG F: LTGN(B) (FOR SPL. PHMA ( V5. PRI.BSNL DIFFERENT Functional TYPES IN LTG FUNCTIONAL TYPE B FUNCTION (FOR DLUS[L&R].2.V5. the LTGs present signaling independent interface to the switching network. • The bit rate on all highways linking the line/trunk groups and the switching network is 8192 kbps ( 8 Mbps ). • Each LTG is connected to both planes of the duplicated switching network. 7/10/2013 SW-II/EWSD_Overview/HSJ 16 .Line/Trunk Groups(LTG) BSNL ALT C T ALT CENTRE • Although the subscriber lines and trunks employ different signaling systems. • Each 8 Mbps highway contains 128 channels at 64 kbps each. Digital Interface unit ( DIU30 ) for connection of 2 Mbps digital trunks and either DLU or PA. 7/10/2013 SW-II/EWSD_Overview/HSJ 17 - - - . One LTG can comprise four DIU30.Line/Trunk Groups(LTG) BSNL ALT C T ALT CENTRE The functional units of the line/trunk group are: • Line / Trunk Unit (LTU) is a logical unit that comprises a number of different functional units. Code Receivers (CR) are Multi-frequency code receivers for trunks or DTMF subscribers. module B or module C (COUB or COUC) for conference calls. i. Conference Unit.e. Automatic Test Equipment for Trunks (ATE:N) checks trunks and Tone Generators (TOG) during routine tests. Code Receivers (CR) for MFC signaling and push-button dialing and Receiver Module for Continuity Check (RM:CTC)  Group Switch (GS) which functions as non-blocking time stage switch ( 512 TS) controlled by the GP.BSNL Line/Trunk Groups(LTG) ALT C T ALT CENTRE  Signaling Unit (SU) comprises Tone Generator (TOG) for audible tones.  Link Interface Unit (LIU) connects LTG to SN via two parallel 8 Mbps SDCs. The received signals from LTU.  Group Processor (GP) controls the functional units of the LTG. SU. 7/10/2013 SW-II/EWSD_Overview/HSJ 18 . GS & LIU are processed with help of GP SW. signals 8Mb/s SN0 to/from SN(8Mbps) SN1 GP (PU. SMX and GCG) SILC INTERNAL STRUCTURE OF LTG 7/10/2013 SW-II/EWSD_Overview/HSJ 19 . MU.LTU BSNL DIU:LDIB DIU30 or LTU COUC COUB or LTU CR or LTU OCANEQ PHMA ATE:T SU CR TOG CTC GS LIU ALT C T ALT CENTRE SPHI SPHO SIHI SIHO Addr. • LTGN is the latest release of LTG. One LTG rack can accommodate 40 PCMs in five LTGG frames. Upto 16 LTGN can be installed in one frame and a rack can contain 64 LTGN. Only one module makes up a complete LTGN for the basic tasks.BSNL Line/Trunk Groups(LTG) ALT C T ALT CENTRE • In LTGG. Upto 30 LTGM can be installed in one rack with each frame containing 5 LTGM. 7/10/2013 SW-II/EWSD_Overview/HSJ 20 . Only three modules are necessary for a complete LTGM namely DIU120A or DIU:LDIM. • LTGM was the next standard type of LTG. each containing two LTGGs. GPL and GSM. GS and LIU have been combined into GSL module. in accordance with the switching information from the coordination processor (CP). 7/10/2013 SW-II/EWSD_Overview/HSJ 21 ALT CENTRE ..Switching Network BSNL ALT C T • Different peripheral units of EWSD.e. MB are connected to the Switching Network (SN) via 8192 kbps highways called SDCs (Secondary Digital Carriers). • Connection paths through the TSGs and SSGs are switched by the Switch Group Controls (SGC) provided in each TSG and SSG. • The SGCs also independently generate the setting data and set the message channels for exchange of data between the distributed controls. LTGs. which have 128 channels each. CCNC. i. • The SN consists of several duplicated Time Stage Groups (TSG) and Space Stage Groups (SSG) housed in separate racks. BSNL ALT C SN SDC:LTG TIME STAGE GROUP T ALT CENTRE LTG 1 SDC:SSG LTG n SDC:LTG SDC:SSG SPACE STAGE GROUP CCNC SDC:CCNC CP MB SDC:TSG SDC:SGC SGC SDC:SGC SGC Switching Network 7/10/2013 SW-II/EWSD_Overview/HSJ 22 . One SDC is extended from SGC of each TSG and SSG towards MB. • Each TSG can accommodate 63 SDCs from LTGs and one SDC to MB. • The switching network can be expanded in small stages by adding plug-in modules and cables and if necessary by assigning extra racks.Switching Network BSNL ALT C T ALT CENTRE • The switching network is always duplicated (planes 0 &1). so that a standby connection is always immediately available in the event of a failure. • Each connection is switched simultaneously through both planes. 7/10/2013 SW-II/EWSD_Overview/HSJ 23 . 000 subscriber lines or 7.500 trunks when fully equipped is installed in a single rack and can handle 3150 erlangs traffic. ALT CENTRE 7/10/2013 SW-II/EWSD_Overview/HSJ 24 . • SN has 7 type of modules.200 erlangs. • In its maximum configuration.Switching Network BSNL ALT C T • The smallest duplicated SN:63 LTG configuration which can handle 30. the EWSD switching network has 8 TSGs and 4 SSGs ks) to connect 504 LTGs and has a traffic handling capacity of 25. • SNs for 126 LTGs and 252 LTGs are also available which can handle 6300 and 12600 erlangs traffic respectively. Each TSG & SSG is accommodated in only two shelves of the respective racks.BSNL Switching Network ALT C T ALT CENTRE • SN(B) has only 5 types of modules.Speech Path Switching .CCS#7 signalling channels connection (NUC) 7/10/2013 SW-II/EWSD_Overview/HSJ 25 .Message Path Switching . Remaining shelves accommodate LTGs. • Main Functions: . receipt of error messages. error detection. zoning. alarm treatment. • Processing of received information for routing. • Handling of the man-machine interface. charges. path selection.BSNL Coordination Area ALT C T ALT CENTRE •Coordination Processor (CP) handles the data base as well as configuration and coordination functions. • Supervision of all subsystems. e.: • Storage and administration of all programs. exchange and subscriber data. 7/10/2013 SW-II/EWSD_Overview/HSJ 26 . error location and error neutralization and configuration functions.g. operation can continue without restriction (redundancy mode with n+1 processors).BSNL Coordination Processor (CP) ALT C T •The CP113C is multiprocessor and can be expanded in stages.400. •The rated load of n processors is distributed among n+1 processors. ALT CENTRE 7/10/2013 SW-II/EWSD_Overview/HSJ 27 .000 BHCA. •It has a maximum call handling capacity of over 1. •This means that if one processor fails. OF CP 113C .BSNL BASIC CONFIG. 0 B:IOC IOP IOP 11 . 0 B:IOC IOP IOP ALT C T ALT CENTRE IOP IOP IOP IOP CAP0 . 11 . . . . CAP5 BAPM BAPS IOC0 IOC1 IOC2 IOC3 BCMY0 BCMY1 CMY1 CMY0 HARDWARE STRUCTURE OF THE CP113C 7/10/2013 SW-II/EWSD_Overview/HSJ 28 . • The other functional units of CP 113C are call processors (CAPs) which are similar to BAPs 7/10/2013 SW-II/EWSD_Overview/HSJ 29 Coordination Processor (CP) T .2 to 4 IOCs coordinate and supervise accessing of CMY by IOPs.e. MOD). • Common Memory (CMY). • Input / Output Controller (IOC) . • Input/output processors (IOP) -Various types of IOPs to connect the CP113C to other subsystems & to the external mass storage devices (EM i. Maximum 12 IOPs can be connected to one IOC. MTD..ALT C BSNL ALT The Basic functional units of CP 113C are as follows : CENTRE • Base Processor (BAP) for operation & maintenance and call processing. the two O&M terminals (OMT/ BCT). MDD.256 to 1024 MB in 4 memory banks consisting of 4 Mb DRAM chips. 24/V. V. BSNL MBG CCG IOP:MB IOP:MB IOP:MB IOP:MB MDD MOD C MTD ALT CENTRE OMT/ BCT Data line.g.28 X. MDD MOD MTD OMT/ BCT Data line.BIOC0 CCNP IOP:MB IOP:MB IOP:UN1 BIOC1 Number depends on SN size. CT or billing centre ALT T IOP:UN1 Alarm function : monitors fans of CP racks SYPC IOP:TA IOP:TA IOP:MB IOP:MB IOP: SCDP LCUB LCUB (IOP:LAU) IOC0 IOC1 BCMY0 BCMY1 Structure of the CP113C input/output system with 2 IOCs 7/10/2013 SW-II/EWSD_Overview/HSJ 30 . OMC.21/V35 LAUB LCUB (LAU) X.25 links to e. be synchronized even more accurately by an external master clock (10-11). It is installed in the Equipment Room or in the Exploitation Room. where necessary. • Central Clock Generator (CCG) for the synchronization of the exchange and. The SYP also displays external alarms such as fire and air-conditioning system failure . the SN & the LTGs. • System Panel Display (SYPD) to display system internal alarms and the CP load. the network. 7/10/2013 SW-II/EWSD_Overview/HSJ 31 .BSNL Coordination Area ALT C T ALT CENTRE Other units assigned to CP are: • Message Buffer (MB) for coordinating internal message traffic between the CP. It can. The CCG is extremely accurate (10-9). however. • External memory (EM).Programs & data that dont always have to be resident in CP . for . 7/10/2013 SW-II/EWSD_Overview/HSJ 32 . .BSNL Coordination Area ALT C T ALT CENTRE Some more units assigned to CP are: • Operation and Maintenance Terminals/ Basic Craft Terminal for Input/output. • To ensure that these programs and data are safeguarded under all circumstances. for input and output. The EM also has a magneto optical disk ( MOD) and/or magnetic tape device (MTD). Two OMTs/ BCTs are provided for O&M functions.Call charge and traffic measurement data. the EM is duplicated (two MDDs).An image of all resident programs and data for automatic recovery. a distinction is made between a message transfer part (MTP) and the user parts (UP). TUP: telephone user part. • For flexibility. • The UP is incorporated in the software of the relevant LTG. • The common MTP functions in an EWSD exchange are handled by the common channel signalling network control (CCNC). 7/10/2013 SW-II/EWSD_Overview/HSJ 33 .CCS#7 is one of the systems that is used for inter-exchange signalling in EWSD.g.BSNL ALT C T Common Channel Signaling Network Control (CCNC) ALT CENTRE • The CCITT. ISUP: ISDN user part. • The user parts vary according to the specific application (e. Equipments handling upto 96 signaling links can be equipped in additional racks. each with 8 signaling links & one duplicated CCNP. • The CCNC is connected to SN via two 8 Mbps highways. 7/10/2013 SW-II/EWSD_Overview/HSJ 34 .BSNL ALT C T ALT CENTRE Common Channel Signaling Network Control: • A maximum of 254 common signaling channels can be connected to the CCNC . equipped in one rack can handle upto 48 signaling links. The CCNC. • The digital links are extended from the LTGs over both planes of the duplicated SN and multiplexers to the CCNC. • CCNC consists of upto 32 signaling link terminal (SILT) groups. • Analog signaling links are linked to the CCNC via modems. BSNLCCS via analog data links Modem Multiplexer CCS via digital data links ALT C T ALT CENTRE 0 7 0 7 SILT group 0 SILT group 31 0 31 0 31 CCNP 0 CCNP 1 CP bus system COMMON CHANNEL SIGNALLING NETWORK CONTROL 7/10/2013 SW-II/EWSD_Overview/HSJ 35 . of Subscriber lines max. • Clock accuracy: Maximum relative frequency deviation : Plesiochronous 10-9. 7/10/2013 SW-II/EWSD_Overview/HSJ 36 .7 etc. 60 000 Switchable traffic max. of Trunks max. 250 000 No. • Supply voltage: -48 V nominal D. Synchronous 10-11 • Signaling systems All conventional signaling systems:MF R2. 25 200 E. No.System Data BSNL ALT C T ALT CENTRE • Call-handling capacity No.C. 1000 bothway • Call charge reg. Periodic pulse metering.BSNL System Data ALT C T ALT CENTRE • Traffic routing or random group Per destination one primary route & max. 1000 incoming and Max. AMA Billing (CAMA. LAMA) IACHASTA 7/10/2013 SW-II/EWSD_Overview/HSJ 37 . 1000 outgoing and Max. 15 alternate routes. Sequential selection of idle trunks of a trunk • Number of trunk groups per exchange: Max. Max. 6 tariffs per zone ALT C T ALT CENTRE Tariff switchover possible in 15m intervals • Space requirements: Example: Exchange for 24000 lines 2 units approx. 100m • Environmental conditions Ambient temperature: 5°C to 40°C Relative humidity: 10% to 80% 7/10/2013 SW-II/EWSD_Overview/HSJ 38 .System Data BSNL • Call Charge reg. 511 zones Max. BSNL ALT C T EWSD Overview ALT CENTRE THANK YOU 7/10/2013 SW-II/EWSD_Overview/HSJ 39 .