This Recommendation defines the functional capabilities and the information flows needed to support the Global Virtual Network Service (GVNS) as described in the GVNS Stage 1 service description (see Recommendation F.16 [5]). This Recommendation should be used as the functional requirements to develop GVNS Stage 3 specifications. The functional model specified in this Recommendation is compatible with the functional model for Intelligent Network Capability Set 1 (CS-1) and should be used as the primary source for the functional requirements of GVNS.