The SS7 User Part
The SS7 user part provides call control and management functions and call set-up capabilities to the network. These are the higher layers in the SS7 reference model, and utilize the transport facilities provided by the MTP and the SCCP.
User Part in SS7:
- ISDN user part (ISUP),
- Transaction capabilities application pan (TCAP)
- Operations maintenance and administration part (OMAP).
- Telephone User part (TUP) and.
- Data user part (DUP)
- TUP and DUP are included in the ISUP.
Integrated Services Digital Network User Part (ISUP):
- The ISUP provides the signaling functions for carrier and supplementary services for voice, data, and video in an ISDN environment
- ISUP uses the MTP for transfer of messages between different exchanges.
- ISUP message includes a routing label that indicates the source and destination of the message, a circuit identification code (CIC), and a message code that serves to define the format and function of each message
- They have variable lengths with a maximum of 272 octets that includes MTP level headers
Transaction Capabilities Application Pad (TCAP):
- The transaction capabilities application part in SS7 refers to the application layer which invokes the services of the SCCP and the MTP in a hierarchical format
- TCAP is concerned with remote operations.
- TCAP messages are used by 18-41.
Operation Maintenance and Administration Part (OMAP):
- The OMAP functions include monitoring, coordination, and control functions.
- It ensure trouble free communications
- OMAP supports diagnostics are known throughout the global network to determine loading and specific sub network behaviors.