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AXE10 - Overview • M/s Ericsson Telecom , Sweden • BHCA – busy hour call attempts capacity 8,00,000 • CCS-7 & ISDN support • 26,000 Erlang • Blocking factor 10 power -6 ie one call in 10,00,000 may fail due to blocking in group switch. • Hardware redundancy – duplicated hardware – built in check functions – automatic block and switch over

Eric Ssion 10

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Page 1: Eric Ssion 10

AXE10 - Overview

• M/s Ericsson Telecom , Sweden• BHCA – busy hour call attempts capacity 8,00,000• CCS-7 & ISDN support• 26,000 Erlang• Blocking factor 10 power -6 ie one call in

10,00,000 may fail due to blocking in group switch.

• Hardware redundancy – duplicated hardware – built in check functions – automatic block and switch over

Page 2: Eric Ssion 10

Salient features- Design• SPC stored programme control• PCM principles• TST time space time principle.• Duplicated CP central processor• RPs – regional processors• Functional modularity – smoother, quicker

hardware extension, system upgradation is easier, new functions easily incorporated

• Highest degree of backward compatibility• One system for all applications – local, transit,

Mobile switching centre, hybrid

Page 3: Eric Ssion 10

Functional hierarchy

Page 4: Eric Ssion 10

AXE – Subsystems in APTBoth software and hardware• SSS – subscriber switching subsystem• GSS – group switching subsystem• TSS – trunk and signalling subsystem• CCS- common channelling subsystem• OMS – operation and maintenance subsystemOnly software• SUS – subscriber services subsystem• CHS – charging subsystem• TCS – traffic control subsystem

Page 5: Eric Ssion 10

AXE – Subsystems in APZ

• CPS – central processor subsystem• RPS – Regional processor subsystem• IOG – input output group

- FMS File management subsystem- MCS Man machine communication- SPS Support processor subsystem- DCS Data communication subsystem

Page 6: Eric Ssion 10

Functional blocks

• Each subsystem will have functional blocks.• Eg BT both way trunk is a functional block in

TSS . Software in RP is BTR, Software in CP is BTU.

• Interworking between function blocks is only through CP

• Data of a function block is accessed by its own program only.

Page 7: Eric Ssion 10

SSS – subscriber switching subsystem

Functions• BORSHCT function• Battery feed- (-48V DC)• Overvoltage protection• Ringing current• Subscriber line signalling• Hybrid – 2 wire to 4 wire conversion• Concentration/expansion• Testing of subscriber lines

Page 8: Eric Ssion 10

SSS functions

• Analogue to digital / D to A conversion• Switching • Scanning for off/on hook• Digit / tones receiving• Control tones

• CJ - combines junctor– a coordinating function block – coordinated all functions in the SSS subsystem – only software

Page 9: Eric Ssion 10

SSS functions

• Switching within SSS

Switching ( time slot change)Calls within same EMG switched without using

GSS

A/D

A/D

Internal PCM Lines (pmt access for every subs

EMTS

Extl PCMGSS

Page 10: Eric Ssion 10

SSS – concentration/expansion

• EMG = 2048 subscribers• PCM lines – 32 pcms 2048:1000 = 2:1 8 pcms 2048: 256 = 8:1• Max 32 pcms, min 2 pcms• PCMs between SSS and GSS are called system

lines

Page 11: Eric Ssion 10

Subsciber line signalling

• On/off hook – scanning• Dial pulses• Tones• Control tones• Ringing signals

Page 12: Eric Ssion 10

MSU and RSU

• Local subscriber switches – MSU – LSS normally called Local EMG – Extension module group• Remote subscriber switches – RSU – RSS - normally called Remote EMG• MSU and RSU can be differentiated by some

hardware units

Page 13: Eric Ssion 10

SSS - Hardware• EMG Extension module group - LSM –A (Line switch magazine – analogue)

- LSM –BA ( ISDN BRA)- LSM – PRA ( ISDN PRA)

• SEPRM – special equipment for private meters• SULTACCS subs line testing and feeding howler

tone – one for every 4 LSS• RPBC – pair – interfacing between LSS andCPs• IOSULT –in RSU only – testing of subs lines,

howler tone, V.24 I/O for man-machine communication

Page 14: Eric Ssion 10

SSS - hardware

• 1 EMG = 2048 customers• 1 LSM A = 128 subscribers

• RSU to GSS = max 32 pcms, each pcm chl-0 for synch and chl-16 for signalling

• MSU to GSS = 32 pcms always – synch and signalling separate bus

Page 15: Eric Ssion 10

SSS – Hardware units

• POU – power unit• REU – ringing current eqpt unit ie ring generator (

1 per EMG)• EMTS – Extension module time switch• KRC – keyset receiver circuit• LIB – line interface board LIBA, LIPA• SLCT – subs line and circuit tester• ETB/JTC – exch terminal board (RSU) /junctor

terminal circuit (MSU)

Page 16: Eric Ssion 10

SSS HardwareHardware Function

LIB Detection of on/off hook, Ring trip

Digit reception pulse, A/D conversion

Power feed, Ringing relayKRC Digit reception tone

EMTS Control tone generator, switchingREU Ringing signal generator

ETB/JTC Concentration/expansion

Page 17: Eric Ssion 10

SSS – important points

• No traffice balancing is requirred – ie any subs to any LIB

• Call meter associated with subs telephone number

• Each EMG need not have dedicated PCM with GS

• Each EMG need not have a KRC board – common pool – all subs .

Page 18: Eric Ssion 10

GSS – group switch subsystem• Both software and hardwareFunctional blocks• GS – group switch – Time switch module and space

module. Performs path selection and release of the established connections.

• GSM1 and GSM2 – group switch operation and maintenance function

• CCD – conference call device – upto 32 participants• CLT – clock generation and timing – 3 clock modules,

supplies clock pulses to TSMs and SPMs• NS – Network synchronisation with other digital

exchanges.• Routine tests – SNEFI, SNEFD, SNETR, SNEAL

Page 19: Eric Ssion 10

GSS – contd….• GSS is a central part of the system• Almost all calls and signalling systems use GSS

to connect hardware to various channels.• Other subsystems that interwork with GSS• For traffic handling

TCS, TSS, SSS• For O & M

OMS –call set up and release of test calls• Others SUS – subscriber services

Page 20: Eric Ssion 10

GSS - Hardware

• ETC – exchange terminal circuits• CCD – conference call devices• PCD – pulse code devices – for analogue

devices

• SNT – SNTP switching network terminal point• 128 TSMs with 4x4 SPMs – 65536 cross point• This is called 64K Group switch

Page 21: Eric Ssion 10

GSS

• CLM clock module - Three clocks CLM0, CLM1 and CLM2– one is master – VCXO voltage control crystal oscillator.

• TSM uses two clock rates – 4096 MHz for internal speed of the switch, 8kHz for synchronisation of the switch.

Page 22: Eric Ssion 10

TSS – Trunk & signalling subsystem• Both hardware and softwareFunctions• To handle trunk lines• handle signalling to & from other exchanges• Supervising the digital lines DIP• Synchronisation

• DIP – digital path – E1 terminations in ETC cards

Page 23: Eric Ssion 10

Functional blocks• BT – bothway trunk – responsible for the traffic

handling functions of the trunk lines• BTM – Both way trunk maintenance – responsible for

O & M functions related to trunk lines• CSR – code sender/received – functions for signalling• ET – handles ETC and synch of DIPs – owns and

supervises the exchanges’s ETCs.• DIPST – Dip supervision & test – handles errors

detected on the DIP. Alarms are generated if limit values set by command are exceeded.

• C7BTC – C7 BT coordination• C7CMNT – C7 circuit maintenance

Page 24: Eric Ssion 10

TSS - Hardware

• ETC – exchange terminal circuit EI• CSR – code sender receiver----------------------------------------R – routeRouting analysis – sending program 3 digits1 digit – when to seize an outgoing device2 digit – when to send seiqure signal to other exchange3 digit – which digit to send as the first digit to the next

exchangeEg. SP = 664

Page 25: Eric Ssion 10

TSS - signalling

• CSR – code sender / receiver• CIU – CSR interface unit• CTU – CSR tone sending unit• CCC – CSR control unit

Page 26: Eric Ssion 10

CCS – common channel signalling subsystem

Software and HardwareFunctions• Implements C7 signalling in AXE-10• Delivers signalling packages between two

signalling points• Error detection/correction – order of the

signals.• MTP message transfer part in implemented in

CCS.Note: User part is implemented in TSS

Page 27: Eric Ssion 10

Functional blocks in CCS• C7ST2 – signalling terminals – terminations.• C7DR2 – discrimination, distribution and routing.

This block reads the destination information in the signalling units and routes it to the correct user or reroute

• C7DP2 – destination point mangement – this block administers the destination points in the network

• C7LS2 – link set management – handles link sets • C7SL2 – signalling link management – handles

signalling links

Page 28: Eric Ssion 10

CCS - Hardware

• ST – signalling terminals• PCDD – pulse coding device , digital – rate

adaption – ie 64 kpbs that come from the signalling terminals are put together into one 2 Mbps pcm line.

Page 29: Eric Ssion 10

C7 – important points

• MTP is the transport service of C7• Different user parts utilize the services offered

by the message transfer part• The telephone user part TUP for plain old

telephony service POTS• Signalling points and signalling transfer points

are components in the signalling network• A signalling link is a 64 Kbit link with one

signalling terminal ST at each end.

Page 30: Eric Ssion 10

TCS – Traffic control subsystem• Only software• TCS occupies a central position in the AXE• TCS’s tasks include controlling the set-up and

clearing phases• Stores subscriber data, circuit data

TCS

GSS TSS SSS CCS MTS

Page 31: Eric Ssion 10

TCS – Function blocks• RE – register function – this block stores the

incoming digits and handles the set-up of calls• CL – call supervision – this block supervises calls

in progress and clears them.• DA – digit analysis – this block contains tables for

digit analysis• RA – Route analysis – this block contains tables

for selecting outgoing routes • SC – subscriber categories – this block stores

subscriber categories for all subscribers connected to the exchange

Page 32: Eric Ssion 10

TCS – Function blocks• TOM – Trunk offering management – this

block takes over the functions of RE or CL when a busy subscriber is to be supervised by an operator

• COF – Coordination of flash services – this block takes over the functions of CL when more than two subscribers are to take part in one and the same speech connection

Page 33: Eric Ssion 10

SUS – subscriber services subsystem

• Only software• Provides subscriber services like call transfer, call waiting,

dynamic STD barring, etc.Some important parameters• LIC – line interface circuit – • Hundred groups – level of exchange• SULII – subs line interface initiate• SULIE – subs line interface end• SUSCP – subs category print• SUSCC – subs category adding/changing/deleting a

category• SCL – parameter for subs category Eg. Scl = HLI -1 hotline

Page 34: Eric Ssion 10

SUS – subscriber services subsystem

• PABX – PABX and PABX with indialling • Hunting facility – HNB=1 rotary hunting,

HNB=0 sequential hunting• Abbreviated dialing – ADI-1 operator

controlled, ADI-2 subs controlled• STD barring CBA-1, provisioning CBA-0.• Subs controlled barring – CCB-2 & KWC-1• DNP – TBO-2 & BIC-1

Page 35: Eric Ssion 10

SUS• Outgoing only – BIC-1• Incoming only – BOC-1• Call forwarding

Unconditional CFUV-1Busy CFBV-1No Reply CFNRV-1

• Call waiting CAW-1 & FLA-2• Printing of call meter value – CHSIP• Testing of LICs – SLOCI:DEV = LI-xx&&yy; 4

numbers

Page 36: Eric Ssion 10

CHS – Charging subsystem

• Software only• Charging functions

1. Charging method2. Charging analysis

• CHS has external and internal interfaces • External

CHS-TCS information regarding subscriber services, normal calls and accounting

Page 37: Eric Ssion 10

CHS – Charging subsystem

• CHS-SSS – special equiment like SEPRM• CHS-TSS – incoming and outgoing calls

charging• CHS –CP – reading system information like

date, time, day, etc

Page 38: Eric Ssion 10

CHS – charging method

• Pulse metering PM – Pure Karlsson method ( no start pulse)Modified Karlsson methodIndividual periodic methodPre-emptive metering method ( start pulse)

• Toll ticketing TT – Ttfilexx CDR

Page 39: Eric Ssion 10

CHS – charging analysis

• End of selection• Charging case• Type of A-subscriber• Call tye

Page 40: Eric Ssion 10

Yet to cover

• Call handling• APZ subsystems• System maintenance philosophy

• ISDN