1. Configuration Guide
  2. SIP Signaling Services
  3. SIP SIP-I Interworking
  4. ISUP Version Interworking

ISUP Version Interworking

ISUP messages can be carried in SIP messages through either a standard body or through a multipart MIME encoded body. While ANSI and ITU are the two major ISUP format types, each contains many specific variants. To facilitate instances where two sides of an ISUP-to-ISUP call use different ISUP versions, the Oracle Communications Session Border Controller (SBC) supports interworking between the following ISUP formats: ANSI, ITU, ETSI-356 (an ITU variant), GR-317 (an ANSI variant) and (Signalisation Pour l'Interconnexion des Réseaux Ouverts/Signaling for the Interconnection of Open Networks) SPIROU. To do so, the SBC can move, delete, and add parameters to various sections of the message.

The ISUP message version is determine by one of two things:

  • The content type of the SIP message
  • The MIME content-type

When the base and version parameters do not match, the SBC first uses the base parameter value to determine the format. If there is no base, the SBC then checks the version parameter. If there is neither, the SBC uses the isup-version configured in the sip-isup-profile configuration from the inbound realm, session agent, or SIP interface. Available values for that parameter are ansi-2000, itu-99, gr-317, etsi-356, or spirou. The SBC considers unknown any value for the version that fails to match one of these or is missing.

An example of the base and version information set to SPIROU is as follows: 

application/ISUP;base=spirou;version=spirou

Messages that contain an unknown ISUP format pass through the SBC untouched. If there are operations to be performed on them, however, SIP-SIPI interworking takes place. After the body has been converted, the SBC updates both the base and version parameters of the content-type.

Custom formats are not supported.