Abstract: Economical and dependable networking of spatially separated branches of an organization is made possible for a plurality of individual subscribers with spatially separated branches by means of an arrangement and process for the operation of layer-3 virtual private networks (VPN A, VPN B) on a common data packet.communication network (e.g. OSI L3 data packet communication network 1). A logical separation of the layer-3 VPNs (VPNA, VPNB) is accomplished by allocating disjoint partial address spaces of a given homogeneous total address space to these L3 VPNs. A virtual private network identification number VPN ID is assigned to each L3 VPN and used to identify the disjoint partial address space by forming a part of the address. The VPN ID characterizing the L3 VPN starts at a fixed bit position in the individual subscriber address of each individual subscriber of the L3 VPN and may have a variable or a fixed length.