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Network

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. . 7 SS . Tone or Pulse Voice Mailbox Call-waiting Tone Multi-party SMS : :

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003-3400Hz . .

Call !Im busy

Voice Trunk

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Switch AUser Traffic User Traffic

Signaling Traffic Signaling Traffic

Switch B

Switch AUser & Signaling Traffic User & Signaling Traffic

Switch B ) ( Call Setup 51 02 3 5 ) (IN ) (

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7SS 07 7 SS 5791 7 SS ITU 0891 7 SS 4891 )(Red Book Update 7 SS ITU

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7SS007.SS7 Protocols (Q (series Out-of-band ) (ISDN

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Set up and clear down a call Provide Caller ID Circuit continuity check Notification to reset a faulty circuit Indication of national, international or other subscriber Nature of circuit (satellite/terrestrial)

Call forwarding Security access calls (CUG) Call holding Charging information Indication that a called party line is free Subscriber busy signal

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Service Switching Point 1- Signaling Transfer Point 2- Service Control Point 3-

(SP)

(56Kbps or 64Kbps)

SCP SCP STP SSP STP STP STP

SCP SCP SSP SSP STP SCP

SSP

SSP

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ISDN ...

TE

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STP)(STP )(LE,TE

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Network Identifier Cluster Identifier Cluster Member

SPC

Cluster=11

Network=246STP STP

Cluster=21

2

2

3

STP

STP

3

4

4

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)User Part (UP

)Message Transfer Part (MTP OSI

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MTP1OSI Physical Layer )E-1(32*64Kbps )DS-1(24*64Kbps )V35(64Kbps )DS-0(64Kbps )DS-0A(56Kbps

Digital Signal DestinationDS0 DS1 DS1C DS2 DS3 DS3

Bandwidth64 kbps 1.544 mbps 3.152 mbps 6.312 mbps 44.736 mbps 274.176 mbps

1 channel 24 channels 48 channels 96 channels 672 channels 4032 channels

Channels (DS0s)

Carrier DesignationNone T-1 T-1c T-2 T-3 T-4

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3MTP 2MTP 1MTP M T P

2MTP

) (Data Link OSI ) (Signaling Unit )(SU 8 )01111110( .

)(Flow Control )(Sequence Validation

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FISU 57 LSSU MSU FISU ACK MSU LSSU

MTP 2 MTP

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()Flag (F 01111110)

)Backward Sequence Number (BSN .

)Backward Indicator Bit (BIB .

)Forward Sequence Number (FSN ) 0 721( . )Forward Indicator Bit (FIB . )Length Indicator (LI FCS LI

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)Signaling Information Field (SIF MSU MTP )(Routing Label )Destination point Code (DPC )Origination point Code (OPC )Signaling Link Selector (SLS 2 MTP SLS : Overload ) (Share

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SIOSub-Service Indicator Service Indicator

)Service Indicator Octet (SIO MSU : )Service Indicator (SI MTP ) (ID SI MSU 3 MTP MTP .

Sub-Service Indicator .

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)Status Indicator (SI LSSU LSSU SIO SIB SIOS...

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7SS

FCS 1 FCS 1+5^ X^16+X^12+X FCS FCS 2 MTP 1 FCS FCS FCS ) (

2 MTP : Basic method Preventive Cyclic Retransmision method

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3MTP 2MTP 1MTP M T P

3MTP

) (Network OSI ) 2 MTP (

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MTP3 Users 3MTP 2MTP

Distribution Distribution Function Function SCCP ISUP etc

Discrimination Discrimination Function Function

Routing Routing Function Function

) (DPC

SIO 3 MTP

DPC SLS ) (Overload

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:

: . : : : : MTP : :

) (

: STP STP : STP STP STP : STP STP STP

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ISUP : ) (Setup ) ( ) ( ) (Release ) ( ISUP ISDN Non ISDN

ISUP

)CIC (Circuit Identification Code

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ISUP

)IAM (Initial Address MessageCalled number, calling number, transmission requirement, type of , caller The call is through-connected to the destination A one-way-audio path is opened for ring-back tone Optional If not returned, no ring-back tone at all Optional; provide information to the calling switch Open the transmission path in both directions Instigate charging for the call

)ACM (Address Complete Message

)CPG (Call Progress

ANM, Answer Message

)REL (Release )RLC (Release Complete

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SCCP 3MTP Connectionless Connection-oriented (Global Title Translation (GTT

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Connectionless

:

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Connection-oriented

: ) ( Local Reference )SCCP (SCCP

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UsersMAPOMAP

SCCPSCCP Connection-oriented SCCP Control Control (SCOC) (SCOC) SCCP SCCP Routing Routing Control Control (SCRC) (SCRC)

MTP3

SCCP

HLR VLR MSC EIR SCCP management SCCP management (SCMC) (SCMC) SCCP Connectionless Control SCCP Connectionless Control (SCLC) (SCLC)

SCRC MTP SCCP

: :

SCOCConnection-oriented (Segmentation) (Sequencing) ( Flow control)

SCLCConnectionless

SCLC: SCCP SCCP SCCP

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Mandatory Variable Parameters

Pointers

Mandatory Fixed Parameters

Message Type

Routing Label

SCCP

) (

00 EO .

.

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SCCP)CdPA , CaPA (>2Byte : )SPC (2 Bytes )SSN (1 Byte )Global Title (> 3 Bytes

)Credit (3Bytes 1,3 ) ( Secured SCCP UnACK

)End of optional parameters (1 Byte

)Message Type (1Byte

)Protocal class (1Byte

)0 , 1 , 2 , 3(

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SCCP)Release Cause (1Byte ) (SCCP Connection 0FHex

)Refusal Cause (1Byte

)Return cause (1Byte UDTS UDTS UDT

)SLR/DLR (each 3 Bytes

23 ) (Local Reference ) (virtual connection

)Segmenting /Reassembling (1Byte 1 DT 652 652 1DT

)Sequencing /Segmenting (2 Bytes 2 DT IT (P(R) P(S SCCP Segmentation ) ( S/R. (P(R) P(S FSN BSN 2 MTP .

)Subsystem Number (1 Byte SCCP

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SSN

SSN SCCP SCCP SCCP 552 SSN

i i d ad BSC HCR CR CC CC 1DT 1DT 1DT 1DT 1DT 1DT 1DT 1DT

MSC

SCCP CR SLR ) ( CC SLR DLR 1 DT RLSD RLC

: :1DT 1DT RLSD RLSD RLC RLC

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A-Interface MAP BSSAP Q931 SCCP MTP TCAP SCCP MTP Abis-Interface Q931 LAPD Air-Interface Q921 LAPDm

HLR

VLRE1/T1

MSC

E1/T1

BSC

E1/T1

BTS

Air

EIR

AC

SS7

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GSM protocol layers for signalingUm Abis A

MSCM MM RR LAPDm m radio

BTS

BSC

MSCCM MM

RR LAPDm radio

BTSM LAPD PCM

RR BTSM LAPD PCM

BSSAP SS7 PCM

BSSAP SS7 PCM

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GSM MS

SSHLR

MM + CM

MSC VLR

1 4 7

2 5 8 0

3 6 9 #

RRBSC

BTS Radio interface

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A-InterfaceTRAULAPD TS1 OAM Uncompressed Speech TS Compressed Speech TS64 Kbps

BSC

64 KbpsCCS7 TS

Transcoding

64 Kbps 64 Kbps 64 Kbps

MSC

CCS7 TS

X.25 TS2

X.25 TS2

OMC

PCM LINK

PCM LINK

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A-InterfaceTRAULAPD TS1 OAM Uncompressed Speech TS Compressed Speech TS64 Kbps

BSC

64 KbpsCCS7 TS

Transcoding

64 Kbps 64 Kbps 64 Kbps

MSC

CCS7 TS

X.25 TS2

X.25 TS2

OMC

PCM LINK

PCM LINK

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CC/MM

DTAP

BSSAP MSC

MS

BSC

RR

BSSMAP

SCCP0 0 0 0

Data (BSSAP)

Length (8 Bits)

Header BSSMAP (1 Byte)

SCCP

DTAP (2 Bytes)

0

0

0

1

Byte-1

DLCI 0 0 0 0 0 C B SAPI A

Byte-2

0

0

0

0

0

0

0

0

0 --------->RR, MM, CC 3 --------->SMS, SS

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BSSMAP

Data (BSSAP)

Parameter N

Parameter N-1

...

Parameter A

Parameter A

Parameter A

Message Type

Optional Parameters

Mandatory Parameters

Data

Length

IEI

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DTAP

Data (BSSAP)

Parameter N

Parameter N-1

...

Parameter A

Parameter A

Parameter A

Message Type

Optional Parameters

Mandatory Parameters

Data Data

Length

IEI IEI

Optional Variable Length Optional Fixed Length Data

Data Length

Mandatory Fixed Length Mandatory Variable Length

HLR

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EIR

MSC VLR

TCAP

TCAP SCCP MTP

Connectionless SCCP )(Applications TCAP )(Queries ) (Responses SSP SCP MAP MSC TCAP ,Authentication HLR Checking, Roaming IMEI

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