This fifth part of EN 301 061 specifies the Test Suite Structure and Test Purposes (TSS&TP) for the network side of the
T reference point (as defined in ITU-T Recommendation I.411 [9]) of implementations conforming to the stage three
standard for the generic functional protocol for the support of supplementary services for Virtual Private Network
(VPN) applications for the pan-European Integrated Services Digital Network (ISDN) by means of the Digital
Subscriber Signalling System No. one (DSS1) protocol, EN 301 061-1 [2].