Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol - Generic functional protocol for the support of supplementary services at the "b" service entry point for Virtual Private Network (VPN) applications - Part 5: Test Suite Structure and Test Purposes (TSS&TP) specification for the network (Endorsement of the English version EN 301061-5 V 1.1.3 (1998-10) as German standard)