One of the most important technical problems in reliable multicast protocols is reducing redundant NAKs (negative acknowledgements) to avoid NAK implosion. A number of NAK suppression mechanisms have been proposed to deal with this problem. In MBONE, which is a virtual multicast network and makes multi-point communication across the Internet feasible, the source link, the links directly connected to or very close to the source, contributes 5% packet loss. In the NAK suppression mechanism, in the case of such a loss, the source link loss, all receivers suffer the same packet loss and the NAK suppression mechanism does not work effectively. In this paper we propose a reliable multicast protocol applied local FEC, called the local FEC, where the source link loss is recovered with the FEC applied locally only to the source link. To investigate the performance of the local FEC, it is compared with the reliable multicast protocol with a conventional NAK suppression mechanism. Our simulation results show that the local FEC outperforms the NAK suppression protocol from the view point of scalability and wasted network bandwidth.

One of the most important technical problems in reliable multicast protocol is to reduce redundant control packets and retransmitted packets. An approach for reducing them by making use of newly-invented network architecture, the active network technology, has been proposed. In the paper we compare a network-initiated approach, i.e. a reliable multicast protocol with network support, and conventional end-to-end approaches. These are compared under more realistic situations such as part of routers are equipped with the newly-invented active network technology. Our simulation results show that the network-initiated approach with 15% active routers outperforms conventional end-to-end approaches from the viewpoint of scalability. We also investigate the desirable location of active routers with a sophisticated network topology model, Tiers model, which reflects hierarchical structure of the Internet. Our simulation results suggest that at first active routers should be implemented in WANs because delay performance can be improved with a small number of active routers. After active routers are broadly implemented in WAN, the policy for location of active routers should be switched to MAN with expecting a decrease of redundant NAK transmission inside a network.

Previous studies on traffic measurement analysis in the various networks have shown that packet traffic exhibits long range dependent properties called self-similarity. Some papers reported that self-similarity degrades the network performance, such as buffer overflow. Thus, we need new network control considering self-similar properties. Network control considering the self-similarity requires high speed calculation method of the Hurst parameter. However, such a method has not been proposed yet. In this paper, we propose high-speed calculation method of the Hurst parameter based on the variance-time plot method, and show its performance. Furthermore, we try to show the effectiveness of the network control with self-similarity.

A growing number of network applications require the use of a reliable multicast protocol to disseminate data from a source to a potentially large number of receivers. This paper presents an analytic performance analysis of the packet delay incurred under three generic sender- and receiver-initiated approaches towards reliable multicast. We focus on the host processing requirements of these protocols and derive expressions for average time between the initial arrival of a packet at a sender and its correct reception at a randomly chosen receiver. Our numerical results indicate that a NAK-based protocol that limits NAK generation by intentionally and randomly delaying NAK packets can achieve substantially higher throughput than the other two protocols examined and can do so without suffering an appreciable higher delay over a range of system parameters.

Optical switching networks to transport vast amounts of information are important for B-ISDN services. Wavelength division multiplexing (WDM) is emerging as the dominant technology for future optical networks. A large capacity photonic ATM switch architecture using WDM technology is proposed in this paper. The proposed switch is suitable for WDM optical ATM networks, that is, the input and an output of the switch are wavelength division multiplexed. The switch can provide very large ATM cell switching capacity, for instance, 10 Tbit/s, with reasonable complexity. The basic switch module of the proposed switch has a simple architecture, and reduces the amount of a buffer hardware by introducing the WDM concept.

This concise paper reports the result of a study leading to the design for a subscriber's loop signaling system in a data switching network. The data switching network is intended to have improved quality and versatility, and be less expensive than the existing data communication systems. Therefore, various requirements are imposed on the subscriber's loop signaling system. The three-level subscriber's loop signaling system described in this concise paper is considered to satisfy these requirements. In this system, signals are defined by three logical states in the subscriber's loop, i.e., +, -, andN. This system is applicable to both asynchronous and synchronous terminals. The data terminal equipment-data circuit terminating equipment (DTEDCE) interface and the subscriber's loop transmission system, suitable for this signaling system, are also described.