This Recommendation describes the extensions required for the support of VPN applications over the public Network Node Interface ("I). This application makes use of the Application Transport Mechanism described in Recommendation Q.765 for bearer related signalling, and the Transaction Capability (TCAP) for signalling involving no bearer. This Recommendation specifies the respective users (Le. APM-user, TC-user) to support the PSS1 information flows continuity in VPN applications (Transparent transfer of PSS 1 information flows between PINX entities). The public NNI provides transparency to the services of the private network.