SIGNALING CONNECTION CONTROL PART (SCCP)
For connection-oriented services, a distinction has to be made between temporary
signaling connections and permanent signaling connections.
Temporary signaling connection establishment is initiated and controlled by the SCCP
user. Temporary signaling connections are comparable with dialed telephone connections.
Permanent signaling connections are established and controlled by the local or remote
O&M function or by the management function of the node and they are provided for the
SCCP user on a semipermanent basis.
They can be compared with leased telephone lines.
The SCCP protocol facilitates the exchange of information between two peers of the
SCCP. The protocol provides the means for
Setup of logical signaling connection
Release of logical signaling connections
Transfer of data with or without logical signaling connections
Connection-Oriented Functions: Temporary Signaling Connections
. The following are the principal functions
used in the connection establishment phase by the SCCP to set up a signaling connection.
Setup of a signaling connection
Establishment of the optimum size of NPDUs (network protocol data units)
Mapping network address onto signaling relations
Selecting operational functions during data-transfer phase (e.g., layer service selec-
Providing means to distinguish network connections
Transporting user data (within the request)
Data Transfer Phase
. The data transfer phase functions provide the means
of a two-way simultaneous transport of messages between two endpoints of a signaling
connection. The principal data transport phase functions are listed below. These are used
or not used in accordance with the result of the selection function performed in the
connection establishment phase.
NSDU delimiting (M-bit)
O&M stands for operations and maintenance.