This Recommendation specifies the SCCP messages formats and codes for the support of
connection-oriented services, connectionless services and the management of SCCP.
The SCCP messages are passed between SCCP and MTP across the MTP-SAP by means of the user
data parameter of the MTP-TRANSFER request or indication primitives as appropriate
(see Table l/Q.701).
NOTE - The MTP-TRANSFER primitive, in addition to the user data parameter, contains four parameters
with the contents as follows (see Table UQ.701):
o the contents of the OPC consisting of information equivalent to 14 bits, to be conveyed in the
the contents of the DPC consisting of information equivalent to 14 bits, to be conveyed in the
the contents of the SLS consisting of information equivalent to 4 bits. If the MTP service
standard routing label of the MTP;
standard routing label of the MTP;
"in-sequence delivery" of SDUs is a requirement, SCCP shall use the same SLS value for all SDUs
with the same sequence control and called address parameters;
001 1 binary (see 14.2.UQ.704).
o
o
o information equivalent to the contents of the SIO. For SCCP, the encoding for the service indicator is
A SCCP message consists of the following parts (see Figure 1):
- the message type code;
- the mandatory fixed part;
- the mandatory variable part;
-
The description of the various parts is contained in the following clauses. SCCP management
messages and codes are provided in clause 5.
ITU-T Q.713-2001 history
2001ITU-T Q.713-2001 Signalling connection control part formats and codes Study Group 11