ISUPISUP

ISUP in the SS7 protocolISUP in the SS7 protocol

MTP Layer 1

MTP Layer 2

MTP Layer 3

TCAPTUP

INAP/AIN

IS41/MAP

SCCP

ISUP

? ?

ISUP CallISUP Call

ISUP phone callISUP phone call

IAM

ACM

ANM

REL

RLC

Contains called party number

Indicates that called party is being alerted

Call has been answered

Caller has gone on hook

This circuit has been released

SSP SSP

STP

Routing label formatRouting label format

1st bit transmitted

14-bit point code format:

SIODPCOPCSLS

8 bits14 bits14 bits8 bits

CICMsg type

4 bits12 bits

4 spare bits

SIO - signalling information octet

DPC - destination point code

OPC - originating point code

SLS - signalling link selection

CIC - circuit identification code

Connect messageConnect message

IAM

CON

REL

RLC

SSP SSP

STP

Overlap sendingOverlap sending

IAM

ACM

ANM

REL

RLC

SAM

SAM

SSP SSP

STP

Suspend and resumeSuspend and resume

IAM

ACM

SUS

ANM

RES

Call is still in speech

SSP SSP

STP

ResetReset

RSC

RLC

GRS

GRA

Resets one circuit

Resets a group of

circuits

SSP SSP

STP

Reset during a callReset during a call

IAM

ACM

RSC

RLC

ANM

SSP SSP

STP

BlockingBlocking

BLO

BLA

CGB

CGBA

Maintenance blocks

one circuit

Hardware or maintenance

blocks a group of circuits

SSP SSP

STP

UnblockingUnblocking

UBL

UBA

CGU

CGUA

Maintenance unblocks

one circuit

Hardware or maintenance unblocks a group of circuits

SSP SSP

STP