This talk presents NTT's approach for realizing a Human-Centered Network. Last November, we announced the NTT Group's Medium-Term Management Strategy, which consists of three management objectives: (1) building the ubiquitous broadband market and helping achieve the e-Japan Strategy and the u-Japan Initiative; (2) building a safe, secure, and convenient communications network environment and broadband access infrastructure, while achieving a seamless migration from the legacy telephone network to the next generation network; and (3) striving to increase corporate value and achieve sustainable growth. Since the management strategy takes account of Japan's future social issues such as declining birthrate and aging population, the need to reduce the environmental load, etc, we believe that the R&D activities directed towards accomplishing these objectives consequently lead to the realization of a Human-Centered Network.

Undoubtedly, users' requirements and engineering constraints will influence the future information environment. The authors have started a project named CUE (Coordinating Users' requirements and Engineering constraints). The project uses an efficient ultra-multiprocessing capability with overload tolerance and maintainability/expandability, incorporating run-time reconfiguration as essential requirements to realize distributed networking systems such as TINA, which is aimed at the interoperability, reusability and transparency of application software. To satisfy these requirements from engineering viewpoints, the CUE project proposes applying to the network systems an autonomous decentralized data-driven processor which adopts an autonomous execution control scheme in which data packets passing through the pipeline achieve all data transfer, processing and storing/buffering functions in a completely decentralized manner. The processor can therefore perform high flow-rate multimedia streams with considerable flow fluctuations and act as a functional module flexibly adding to/removing from the system at run-time without any overheads. The essential requirements to realize a distributed networking environment such as TINA are first discussed. The applicability of our data-driven processor is shown through actual performance evaluations by the latest VLSI systems. An autonomous run-time reconfiguration scheme in a multiprocessor system is proposed to demonstrate the potential of the data-driven processor. Finally, the current status and future directions of the CUE project are briefly addressed.

A granulated broadband network (GBN) is proposed as an intermediate asynchronous transfer mode (ATM) based platform to be part of an evolution scenario toward B-ISDN. The GBN enables various types of services to be provided including 64-kb/s-based services and broadband services. In the GBN, information is transformed into ATM cells at subscriber line terminals or at customer premises and is transferred through ATM networks; consequently, the cost feasibility of a single-channel cell assembly/deassembly device is a significant factor in economically providing ATM-based conventional services and interworking between STM and ATM networks. Various virtual path capacities with a fine degree of granularity can be provided in a mesh structure between transit modes in the GBN. Economic feasibility studies of the GBN, by simulating on certain large-size real networks in the greater Tokyo area, indicate the possibility of a more than 50% cost reduction in transit networks.>

A new polyphase phase-locked oscillator (P-PLO) is proposed which overcomes one of the greatest difficulties in the passive bus configuration: timing extraction from signals in multiplexed channels with different mean phases. The proposed oscillator generates appropriate retiming clock pulses for each channel independent of other channels. Moreover, since pulse overlaps between channels may appear at the first and last bits of each channel, the oscillator shifts retiming clock phases of these bits to avoid sampling overlaps. A performance analysis method extended from the conventional Markov chain model is also proposed. The theoretically obtained jitter and retiming margin characteristics correspond closely to experimental results. This circuit is also shown to be adaptable to point-to-point configurations which, like passive bus, will be used in the ISDN basic interface recommended as one of the 1-series interfaces by CCITT. This allows easy rearrangement of interface wiring, e.g., changing from the passive bus to point-to-point configuration, without any adjustment of the network terminator.

Adopting digital techniques in the local network area will enhance the possibility of extending digital operation capability to the subscriber's equipment. The problem is to convey digital signals at a bit rate of at least 64 kbits/s in both directions over existing two-wire subscriber loops. This paper describes a time-shared two-wire digital subscriber transmission system in which the directional separation of two signals (GO and RETURN) is accomplished by the time division bidirectional transmission method in burst-mode, and also reports results of investigations on the feasibility of an all digital telephone subscriber loop system.