Telecommunication

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Chapter 5 ????????

• Telecommunication
• Signaling Protocol

2
????

• ?????????????--????????(PSTN)??,???????????????,??
  ????????
• ??????,???????????????????(signaling
  system),?????????????????(Signaling System Number
  7,SS7),??????????????????,????????????????????????
  
• ???????SS7????????????????????????

3
????

• ??????????
• ???????
• ????????????
• ??????????
• ?????????????
• ????????????????????
• ??
• ??

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Section 5.1??????????PSTN Overview
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PSTN ??

• PSTN???????????????????
• ???????????????,?????????(circuit-switched)????
• ????64kbps?????????,???PSTN????????????
• ?????????,?????????(signal)????????,?????????????
  

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? 5-1 ???????
7
????(signaling system)

• ???????????????????,??????????
• ??????(Common Channel Signaling,CCS)?????????
• ???????????????
• ????????????(timeslot)?,????????????
• ???????????,????????????????,????????
• ??SS7?

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? 5-2 CCS???
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Section 5.2???????Signaling System Number 7, SS7
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SS7 ??? (1/2)

• 1970???,CCITT????????????,?????????(Signaling
  System Number 6,SS6)?
• ????????????????
• ?1980?????SS7?
• ???????(Intelligent Network,IN)???,?????????????,?
  ???0800?????(toll-free calling)????
• ??SS7????????????,??????????????

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SS7 ??? (2/2)

• SS7???
• ???????(packet-switched network)?????????(message-
  based)????
• ??????????
• ?????????????????(network topology)???SS7???
• ????????,SS7????? ??ANSI?Bellcore?SS7??ITU?SS7????
  ?
• ??PSTN?PCS??????SS7?
• ? ITU ???????????

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? 5-3 ??SS7????????
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SS7 ????

• SS7??????????
• MTP,Message Transfer Part ?????
• ISUP,ISDN User Part ???????????
• SCCP,Signaling Connection Control Part ???????
• TCAP,Transaction Capability Application Part
  ???????
• MAP,Mobile Application Part ???????
• OMAP,Operation Maintenance Administration Part
  ???????

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? 5-4 SS7 ????
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MTP (1/2)

• MTP?SS7?????????????,??MTP1?MTP2?MPT3?
• MTP???????????,?SS7????????????????
• MTP1??????????????????(bearer)???,?????????,??????
  (bit rate)??

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MTP (2/2)

• MTP2??MTP1???????,????????????(link)?????,????????
  ?????
• ?????????????(signal unit)?
• MTP3??????????????
• ?????????????(Message Signal Unit,MSU)
• MTP3??????????????????????????????????,???????????
  ?,?????????????????(signaling link),???????????

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ISUP

• ISUP??????????????????????????
• ??????????(circuit-related signaling)
• ISUP ?????????????????,??????(call
  setup)?????(teardown)?
• ??????,???????????,??ISUP?????????????????????
• ?5.4?????????

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SCCP

• SCCP??????????????,???????????????
• ??????????(non-circuit-related signaling)?
• ??????????,??????????????????PCS?????????????,????
  ?????????
• ??MTP3???????????????,?????????????????,??SCCP???M
  TP????????

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GTT(Global Title Translation)

• ??SCCP???????????????,??????????,?????????,???????
  ???????GTT)?
• ???PSTN????????????,?????????????????????????????,
  ?????GTT?????????(???????)????????????,???????????
  ??????

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TCAP

• TCAP?????????????,?????(transaction)?????(procedur
  e)?????
• TCAP???????????????,?????????????
• ????0800?????????????????????,????????????????????
  ??,????TCAP???

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MAP

• MAP?TCAP??????,???????????????
• ??IS-41? GSM MAP?????????????

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OMAP

• OMAP?TCAP??????,????????

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Section 5.3????????????Components and Links of
SS7
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SS7??

• ????SS7???,????SS7???????,??????SS7??
• SS7????????????(signaling point,SP)????SS7????????
  ????????????????,????(point code)?
• ????????????????????????????????????(Signaling
  Link Code,SLC)?

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SS7????? (1/2)

• ?????(Service Switching Point,SSP)
• SSP?????????,?????tandem?end office,??????????,???
  ????trunk,??????????????
• SSP??SS7???????,????????????????SS7????,??SS7?????
  ??????

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SS7????? (2/2)

• ?????(Signal Transfer Point,STP)
• STP?????????,????SS7??,???????(router)?
• ??????????,STP??????,??STP pair?
• ?????(Service Control Point,SCP)
• SCP?????????????,?????????

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0800 ????????

• SSP?????????????????,SSP?????????,??SS7???????????
  ???
• SSP???????????STP,?STP??????????SCP??
• SCP????????????(????????),?????????SSP,???????????
  ??

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??? SS7 ?????

• ??SSP???????????????,?????STP pair?
• 2?STP pairs?,???full connected????,???SS7??????(ro
  bustness)?
• ?????????????,??????45???,?????????????????????

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? 5-5 SS7 ?????????
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?????? (1/2)

• ?5-6?????????SS7???, ??????????????
• ??????????
• ????????SSP?????
• ??SSP??Class 5?????Class 4?????
• Class 4????????????
• Class 5??????????????

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?????? (2/2)

• ??????????SS7???
• ?????????SS7 ISUP??,????SS7????STP
  pair,??????????????????,???SSP?????????trunk?
• ???????SCP?,????INAP???SS7??????,??IN????
• ?????????????,SCP?????????????(Intelligent
  Peripheral,IP)?????SSP?????????,????????????,?????
  ????SCP,????????????

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? 5-6 ???????
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Section 5.4??????????SS7 Messages
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????

• ?SS7??????????????(signal unit,SU),??????
• ?MTP2?????LSSU(Link Status Signal Unit)
• LSSU???????????????????
• ?MTP2???????FISU(Fill-In Signal Unit)
• FISU????????????????????,????????????????
• ????MTP3??MSU(Message Signal Unit)
• MSU???????????????????????

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? 5-7 MTP??
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? 5-8 ??SCCP???MSU(ITU)
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? 5-9 MTP3 ????,ANSI ? ITU-T MSU ???
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ISUP ?? (1/2)

• ?MSU?SI5,??ISUP????
• ???ISUP??
• IAM(Initial Address Message)???????????????????
• ACM(Address Complete)????????????,????(alert),????
  ???trunk????
• ANM(Answer Message)???????????
• REL(Release)??????????

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ISUP ?? (2/2)

• ???ISUP??
• RLC(Release Complete)??trunk?????(idle)???
• COT(Continuity Message)??trunk???????????
• EXM(Exit Message)???????????????????????IAM?,??EXM
  ???????????????????????????????????
• SUS(Suspend Message)?????????,????????

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? 5-10 ?????????
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? 5-11 ???????
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Section 5.5?????????????Signaling Protocol of
PCS Network
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PCS ?????

• PCS?????????????(?MS?BSC?MSC?VLR?HLR??)???
• ????????,??HLR?VLR????????
• GSM????????????,???SS7???,??????GSM
  MAP,???????????????
• AMPS?IS-136?IS-95????????SS7??????IS-41?

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Section 5.6????????????????????Interworking
between PSTN and PCS Network
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PCS ? PSTN ?????

• ???PCS???????SS7??
• HLR??SCP???
• STP????????????,??STP?????SSP??
• ?PCS????SSP????????,??MSC?
• ???????
• PSTN????PCS??
• PCS????????PSTN????

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? 5-12 PCS ? PSTN ????
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? 5-13 PSTN ????? PCS Network ??
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? 5-14 PCS Network????? PSTN ??
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Section 5.7??Summary
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Summary

• SS7???????????????????????????SS7??????,???????,??
  ?PCS???PSTN?????,?????????
• SS7?????????????????????????????,???PSTN??,????HLR
  ?VLR?????????????,??????????

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Homework

• Problems