Schematic showing TCAP in the OSI model.

The TCAP layer provides communication capabilities for interactive applications in a distributed environment. TCAP originated from ITU Recommendations X.219 and X.229 (ROSE, Remote Operation Service Element). TCAP layer uses transport services provided by SCCP to implement transaction capabilities application services. TCAP defines the end-to-end protocol between TCAP users, which may be located in a SS7 network or in another network supporting TCAP protocol.

The graphic on the right show how TCAP fits into the OSI model.


TCAP supports the following features:

  • Single transaction/dialogue identifier specified by service user
  • Simultaneous dialogues per application/subsystem number
  • Components (operations and their replies) and parameters assembly into TCAP messages
  • Dialogue and user information assembly into TCAP messages
  • Association of operations and their replies
  • Abnormal situations handling
  • Optional operations/replies timers (ITU)
  • Unstructured dialogue to send one or more components that do not expect replies
  • Structured dialogue to send one or more components that expect replies
  • Structured dialogue supporting the following transaction message types: begin, continuation, end, query with/without permission, conversation with/without permission, response, abort and exception reporting
  • All classes of structured dialogue operation (class 1: both success and failure are reported, class 2: Only failure is reported, class 3: Only success is reported and class 4: Neither success nor failure is reported)
  • Statistics information to determine traffic loads and quality-of-service
  • Point code/subsystem number and/or global title addressing capabilities while using SCCP transport services
  • Point code/subsystem states change indications while using SCCP transport services

TelcoBridges and TCAP

TCAP support is provided via the Toolpack web portal. It is also available via the original Toolpack API as the TCAP Control Library.

Related actions

Refer to the appropriate Toolpack release: