TAP: architecture for trusted transfers in ATM networks with active switches

Significant research efforts are currently centered on effective mechanisms of cell loss control and congestion control for ATM networks. This paper presents TAP (trusted and active PDU transfer); a new architecture and protocol for ATM networks that provide assured transfers to a set of privileged VPI/VCI. The architecture proposes a new extended AAL type 5 (EAAL-5), manages the privileged connections and offers an improvement in the performance when network connections cause some cell loss by taking advantage of the idle time in the traffic sources to do the retransmissions of CPCS-PDU-EAALS. We propose a new and trusted protocol that uses NACK mechanisms (using backward RM cells), and which is supported by active ATM switches equipped with dynamic memory to store trusted native EAAL-5 PDUs (DMTE). The active architecture presents the resource management agent (RMA) to manage the retransmissions of PDUs between active switches, and the early packet discard agent (EPDA) to recover PDUs internally within the active switches. Several simulations demonstrate the effectiveness of the mechanism that recovers the congested PDUs locally at the congested switches with better goodput in the network. Also, the senders are alleviated of negative end-to-end retransmissions. The simulations, using on/off sources, analyse point-to-point, and also point-to-multipoint connections using objects, threads, synchronizations and distributed processes implemented in the Java language.