The A-VPN server: a solution for ATM virtual private networks

The paper presents an architectural element to be included in an ATM cross-connect in order to provide essential features for the deployment of an ATM based virtual private network service (A-VPN service). The A-VPN server aims at a solution of the egress policing problem (bandwidth enforcement function) and incorporates a set of functionalities devoted to the support of an effective statistical multiplexing principle on the different cell streams, by means of suitable buffering, shaping and selective traffic discarding functions. The target solution allows for an improved and possibly optimal utilisation of network resources, compared to peak rate allocation, while ensuring that satisfactory quality of service requirements are matched for bursty traffic. Moreover the A-VPN server is able to grow in a modular way and its approach has no special impact on the functions of the ATM cross-connect; its introduction does not require the support of particular management protocols by the network element. The A-VPN server represents a simple, efficient and cost-effective way for a timely implementation of the A-VPN service