Yoshihiro Ashi

ATM transport node for flexible and robust access networks

This paper describes an architecture and functions required for integrated access networks for a future multi-service telecommunication environment. A multi-service access network can be configured over a physical ATM/SDH ring-star network applying the virtual path layering as a logical networking technology. Service specific path management and fault tolerant networking technologies, such as the automatic protection switching and the traffic management are described with hardware implementation examples. An ATM add-drop-multiplexer for 2.4-Gbps transmission link and an ATM access multiplexer with 24 156-Mbps interfaces are presented to show the feasibility of the proposed integrated access networks.<<ETX>>

Architecture and Design of IP Broadcasting System Using Passive Optical Network

We propose an IP broadcasting system architecture using passive optical networks (PON) utilizing the optical broadcast links of a PON with a downstream bandwidth allocation algorithm to provide a multi-channel IP broadcasting service to home subscribers on single broadband IP network infrastructures. We introduce the design and adaptation of the optical broadcast links to effectively broadcast video contents to home subscribers. We present a performance analysis that includes the downstream bandwidth utilization efficiency of the broadcast link and the bandwidth control of the IP broadcasting and Internet data. Our analysis and simulation results show that the proposed system can provide 100 HDTV channels to every user over fiber lines. We also propose an IPTV channel selection mechanism in an ONT by selecting a broadcast stream. We developed and evaluated a prototype that can achieve a 15-msec IPTV channel selection speed.

High-Definition IPTV Broadcasting Architecture Over Gigabit-Capable Passive Optical Network

Service providers are currently seeking to offer high-quality IP video service on single broadband IP network infrastructures, including ADSL and passive optical networks (PON). One of motivation of our work is increasing the bandwidth utilization efficiency of video data delivery to home subscribers and reducing the channel zapping time. We propose a high-definition IPTV broadcasting architecture over GPON that can provide 100 HDTV channel over fiber lines in this paper consisting of a Gigabit-capable passive optical networks (GPON), IPTV terminals, an IP broadcasting server, and an IP broadcasting management server. We adapt the optical broadcast nature of a GPON to IP multicast networks to effectively broadcast video content to home subscribers. We develop IPTV channel selection mechanism in the GPON ONT by selecting a multicast stream at a subscribers home that can achieve a 10-msec IPTV channel selection speed.

A Development of Circuit Emulation System on TDM over Ethernet Comprising OAM and Protection Function

The Ethernet* network is widely used and adopted to the access portion or metro area for the reason of new applications for native Ethernet services or its economical advantage. Apart from these applications for native Ethernet, an encapsulation technology to transport legacy services over Ethernet, i.e. TDM over Ethernet, is focused on. In order to apply it to the carrier networks, it is necessary to meet Quality of Service (QoS) requirements, and the consideration of operation, administration and maintenance (OAM) aspects are indispensable. Furthermore, in order for higher reliability, it is required to apply protection function to the networks. We have studied the encapsulation method of TDM signals applied to circuit emulator accommodating TDM signals over Ethernet. In addition, the OAM mechanism and the protection function are studied. This paper shows the frame format, the detail of the OAM mechanism and the protection function, and introduces a developed circuit for adaptation of TDM over Ethernet.

A high performance switch for OC-12 SONET self-healing ring networks

The progress of ITU-T and ANSI standards on SDH/SONET is accelerating the evolution of transmission systems all over the world. The advanced operation administration and maintenance (OAM) functions it provides makes it possible to create a self healing ring network which protects against failure. This self-healing ring consists of add/drop multiplexers (ADMs). The switch in the ADM plays an important role in achieving self-healing operation. In this paper, self-healing ring architecture and operations are analyzed in order to determine the requirements for the ADM switch. On the basis of this result, new space division switching methods, which significantly reduce the amount of hardware needed, are proposed. A parallel processing architecture which makes it possible to develop a low-cost large-scale switch is also devised. Finally, a developed switch LSI chip is presented. Combining two identical chips with the proposed parallel processing architecture, a 32/spl times/32 STS-3 switch (5 Gb/s throughput) with an STS-1 time slot interchange (TSI) function is realized.