User-programmable flexible ATM network architecture. Active-ATM-experimental results

Proposes active-ATM, a flexible, simple and cost-effective ATM-WAN architecture that can handle multiple user-customized ATM-layer protocols, such as ABR and ABT, by using a simple universal ATM transit network. The architecture enables the construction of flexible networks that can evolve easily. With active-ATM and the ATM multi-protocol emulation network architecture called ALPEN, it is easy to implement new ATM-layer protocols by using user-created programs called active-program capsules that modify only the edge nodes. Because these user-sent program capsules can be used to quickly customize the edge nodes, there is no waiting for standardization and implementation of new services. The ATM-layer protocols are emulated only at the edge nodes, making the transit network independent of customer ATM-layer protocols. The active-ATM edge node is based on the flexible programmable node architecture called PUN (programmable unified node). PUN is a platform for user-programmable ATM-layer services. A prototype system has demonstrated the flexibility of the resulting ATM network. The simple and high-speed universal ATM transit network periodically reports to the edge nodes the performance of the its routes by using periodical route performance check sequences, which are independent of the ATM-layer protocols. The information is used by the edge nodes to manage user cell rates in real time. Flexible, adaptive, and sophisticated protocols that efficiently utilize network resources can be easily supported by the network's edge nodes.