CONTENTS

1 General
1.1 Message type code
1.2 Formatting principles
1.3 Mandatory fixed part
1.4 Mandatory variable part
1.5 Optional part
1.6 End of optional parameters octet
1.7 Order of transmission
1.8 Coding of spare bits
1.9 National message types and parameters
1.10 International message types and parameters
2 Coding of the general parts
2.1 Coding of the message type
2.2 Coding of the length indicator
2.3 Coding of the pointers
3 SCCP parameters
3.1 End of optional parameters
3.2 Destination local reference
3.3 Source local reference
3.4 Called party address
3.4.1 Address indicator
3.4.2 Address
3.5 Calling party address
3.6 Protocol class
3.7 Segmenting/reassembling
3.8 Receive sequence number
3.9 Sequencing/segmenting
3.10 Credit
3.11 Release cause
3.12 Return cause
3.13 Reset cause
3.14 Error cause
3.15 Refusal cause
3.16 Data
3.17 Segmentation
3.18 Hop counter
3.19 Importance
3.20 Long data
4 SCCP messages and codes
4.1 General
4.2 Connection request (CR)
4.3 Connection confirm (CC)
4.4 Connection refused (CREF)
4.5 Released (RLSD)
4.6 Release complete (RLC)
4.7 Data form 1 (DT1)
4.8 Data form 2 (DT2)
4.9 Data acknowledgement (AK)
4.10 Unitdata (UDT)
4.11 Unitdata service (UDTS)
4.12 Expedited data (ED)
4.13 Expedited data acknowledgement (EA)
4.14 Reset request (RSR)
4.15 Reset confirmation (RSC)
4.16 Protocol data unit error (ERR)
4.17 Inactivity test (IT)
4.18 Extended unitdata (XUDT)
4.19 Extended unitdata service (XUDTS)
4.20 Long unitdata (LUDT)
4.21 Long unitdata service (LUDTS)
5 SCCP Management messages and codes
5.1 General
5.1.1 SCMG format identifier
5.1.2 Formatting principles
5.2 SCMG message parameters
5.2.1 Affected SSN
5.2.2 Affected PC
5.2.3 Subsystem multiplicity indicator
5.2.4 SCCP congestion level
5.3 SCMG Messages
6 References
6.1 Normative references
6.2 Informative references
Annex A Mapping for cause parameter values
A.1 Introduction
A.2 Connection refusal
A.3 Connection release
A.4 Connection reset
A.5 Return cause
Annex B International SCCP addressing and format specification
B.1 Introduction
B.2 Guidelines on using SCCP addressing information elements in the international network
B.3 GT routing specification of international services
B.4 International GT routing specification
B.4.1 Translation selector: TT = 17, NP = 1, NAI = 4
B.4.2 Translation selector: TT = 1, NP = 0, NAI = 4
B.4.3 Translation selector: TT = 2, NP = 2, NAI = 4
B.4.4 Translation selector: TT = 0, NP = 1, NAI = 4
B.4.5 Translation selector: TT = 3, NP = 1, NAI = 4