What are SS7 - ISUP Messages, Parameters and Indicators

a) Routing label : For each individual circuit connection, the same routing label must be used for each message that is transmistted for that connection.

b) CIC - Circuit Identification Code : With this CIC Code, exchange identifieds which call circuit refers which signal.

c) Message Type Code : Consists of one octet field and mandatory for all messages. It uniquely defines the function and format of each ISUP message. Such as IAM, ACM, ANM etc.

d) The mandatory fixed part :These are the parameters that are mandatory and of fixed length for a particular message type will be contained in the mandatory fixed part. The position, length and order of parameters is uniquely defined by the message type because of that the names of the parameters and the length of the indicators are not included in the message.

e) The mandatory variable part :Mandatory parameters of variable length will be included in the mandatory variable part. Pointers are used to indicate the beginning of each parameter. Each pointer is encoded as a single octet. The name of the parameter and the order in which the parameters are sent is implicit in the message type. The parameters names are therefore not included in the message. A pointer is also included to indicate the beginning of the optional part. All the pointers are sent consecutively at the beginning of the mandatory variable part. Each parameter contains the parameter length indicator followed by the contents of the parameter.

f) The optional part, which may contain fixed length and variable length parameter fields. : The optional part consists of parameters that may or may not occur in particular message type. Both fixed and variable length parameters may be included. Optional parameters cann be transmitted in any order. Each optional parameter will include an parameter name (one octet) and the length indicator (one octet) followed by the parameter contents. If optional parameters are present and after all parameters have been sent, an "end of optional parameters" octet containin all zeros will be transmitted. If there is no optional parameter present then there is no "end of optional parameter" octet is transmitted.

There might be situations where there is a need for national message types and parameters then the codes should be chosen from the highest code downwards i.e. starting at code 11111111. The codes reserved in the range 11111111 to 11100000 for this purpose.

SS7 - ISUP Messages and Parameters :

ISUP Message List:

You may wish to check the messages in detail including the parameters they contain.

View Messages and their parameters in detail

ISUP Messages Binary Values HEX Values

Address complete 00000110 06

Answer 00001001 09

Blocking 00010011 13

Blocking acknowledgement 00010101 15

Call progress 00101100 2C

Circuit group blocking 00011000 18

Circuit group blocking acknowledgement 00011010 1A

Circuit group query 00101010 2A

Circuit group query response 00101011 2B

Circuit group reset 00010111 17

Circuit group reset acknowledgement 00101001 29

Circuit group unblocking 00011001 19

Circuit group unblocking acknowledgement 00011011 1B

Charge information 00110001 31

Confusion 00101111 2F

Connect 00000111 07

Continuity 00000101 05

Continuity check request 00010001 11

Facility 00110011 33

Facility accepted 00100000 20

Facility reject 00100001 21

Facility request 00011111 1F

Forward transfer 00001000 08

Identification request 00110110 36

Identification response 00110111 37

Information 00000100 04

Information request 00000011 03

Initial address 00000001 01

Loop back acknowledgement 00100100 24

Network resource management 00110010 32

Overload 00110000 30

Pass-along 00101000 28

Release 00001100 0C

Release complete 00010000 10

Reset circuit 00010010 12

Resume 00001110 0E

Segmentation 00111000 38

Subsequent address 00000010 02

Suspend 00001101 0D

Unblocking 00010100 14

Unblocking acknowledgement 00010110 16

Unequipped CIC 00101110 2E

User Part available 00110101 35

User Part test 00110100 34

User-to-User information 00101101 2D

ISUP Parameter List:

View Parameters in detail

ISUP Paremeters Binary Values HEX Values

Access delivery information 00101110 2E

Access transport 00000011 03

Automatic congestion level 00100111 27

Backward call indicators 00010001 11

Call diversion information 00110110 36

Call history information 00101101 2D

Call reference 00000001 01

Called party number 00000100 04

Calling party number 00001010 0A

Calling party's category 00001001 09

Circuit state indicator 00100110 26

Cause indicators 00010010 12

Circuit group supervision message type indicator 00010101 15

Closed user group interlock code 00011010 1A

Connected number 00100001 21

Connection request 00001101 0D

Continuity indicators 00010000 10

Echo control information 00110111 37

End of optional parameters 00000000 00

Event information 00100100 24

Facility indicator 00011000 18

Forward call indicators 00000111 07

Free phone indicators 01000001 41

Generic digits 11000001 C1

Generic notification 00101100 2C

Generic number 11000000 C0

Generic reference 01000010 42

Hop counter 00111101 3D

Information indicators 00001111 0F

Information request indicators 00001110 0E

Location number 00111111 3F

MCID request indicator 00111011 3B

MCID response indicator 00111100 3C

Message compatibility information 00111000 38

MLPP precedence 00111000 38

Nature of connection indicators 00000110 06

Network specific facilities 00101111 2F

Optional backward call indicators 00101001 29

Optional forward call indicators 00001000 08

Original called number 00101000 28

Origination ISC point code 00101011 2B

Parameter compatibility information 00111001 39

Propagation delay counter 00110001 31

Range and status 00010110 16

Redirecting number 00001011 0B

Redirection information 00010011 13

Redirection number 00001100 0C

Redirection number restriction 01000000 40

Remote operations 00110010 32

Service activation 00110011 33

Signaling point code 00011110 1E

Subsequent number 00000101 05

Suspend/resume indicators 00100010 22

Transit network selection 00100011 23

Transmission medium requirement 00000010 02

Transmission medium requirement prime 00111110 3E

Transmission medium used 00110101 35

User service information 00011101 1D

User service information prime 00110000 30

User teleservice information 00110100 34

User-to-User indicators 00101010 2A

User-to-User information 00100000 20

ISUP Timers List:

Symbol Default Value Acceptable Range Signal/Event

T1 15 sec. 15-60 sec. Release/Release Complete

T2 3 min. 3 min. Suspend/Resume

T5 5 min. 5-15 min. Release/Release Complete

T6 1 min. 1-2 min. On-hook, Reanswer

T7 20 sec. 20-30 sec. Initial Address, Address Complete, Subsequent Address, Connect

T8 10 sec. 10-15 sec.

T9 3 min. 1.5 - 3 min. Address Complete, Answer

T10 4 sec. 4-6 sec. Last Digit Timer

T11 20 sec. 15-20 sec. Initial Address, Address Complete, Subsequent Address

T12 15 sec. 15-60 sec. User Part Available, UA

T13 5 min. 5-15 min. Blocking, Blocking Ack.

T14 15 sec. 15-60 sec. Unblocking, Unblocking Ack.

T15 5 min. 5-15 min. Unblocking, Unblocking Ack.

T16 15 sec. 15-60 sec. Reset Circuit, Release Complete

T17 5 min. 5-15 min. Reset Circuit, Release Complete

T18 15 sec. 15-60 sec. Circuit Group Blocking, Circuit Group Blocking Ack.

T19 5 min. 5-15 min. Circuit Group Blocking, Circuit Group Blocking Ack.

T20 15 sec. 15-60 sec.

T21 5 min. 5-15 min. Circuit Group Unblocking, Circuit Group Unblocking Ack.

T22 15 sec. 15-60 sec.

T23 5 min. 5-15 min.

T24 1.9 sec. <2 sec.

T25 5 sec. 1-10 sec.

T26 2 min. 1-3 min.

T27 4 min. 4 min.

T28 10 sec. 10 sec. SQM, SQR

T29 300 ms. 300-600 ms.

T30 5 sec. 5-10 sec.

T33 12 sec. 12-15 sec.

T34 2 sec. 2-4 sec.

T35 15 sec. 15-20 sec. Digit Collection

T36 10 sec. 10-15 sec.

T38 3 min. 2-3 min. On-hook, Reanswer

T39 12 sec. 12-15 sec. Information Request, Information