scope:

The present document specifies the interaction between the ISUP and INAP. The interaction between other signalling systems and INAP can be found by consulting the relevant interworking recommendation to the ISUP in combination with the ISUP/INAP interaction recommendation. The present document specifies procedures in order to provide interaction between ISUP and INAP, i.e. to support IN services in an ISDN environment. In addition new protocol elements for the ISUP are defined in order to satisfy IN specific requirements. Based on the protocol inherent compatibility mechanism a stepwise upgrade of the ISUP functionality is possible. However, the new function is only available for an IN call, if supported in any of the affected exchanges.