Kentaro Ogawa

ATCA-Based Open-Architecture Router Prototype

We have developed an open-architecture router (OAR) prototype using industrial standard hardware, software components, and interfaces. The prototype is built with Advanced Telecom Computing Architecture (ATCA)-compliant hardware. Carrier-grade Linux (CGL) is used as the operating system. A new OAR configuration method is described where industrial standard hardware and software interfaces are used. Basic forwarding functions with routing protocol processing are demonstrated for the first time.

Fault Management in Functionally Distributed Transport Networking for Large Scale Networks

We propose a fault management method in functionally distributed transport networking that separates the control-plane processing part (control element, CE) from the forwarding-plane processing part (forwarding element, FE) of the router. In this architecture, one path-control process in the CE consolidates and processes the path computations and the path settings for multiple routers. This leads to reduction in the path-control complexity and efficient operation of large scale networks. On the other hand, if faults occur in a CE and the CE become unable to serve a routing function, all of the FEs controlled by the CE will be affected. Therefore, it is absolutely critical to ensure the high reliability of the CE in this architecture. The proposed method takes the redundant configuration of N+m CEs and switches from a fault CE to a standby CE. Additionally, we describe the operation of each component in the proposed method and evaluate its feasibility by using software implementation.

Functionally distributed transport networking on Next-Generation Network

Traffic in IP networks has increased and services have diversified over the last few years. IP networks need to have scalability and high-quality data transmissions and they must be able to incorporate new functions. For good processing performance and ease of adding functions to the transport stratum on a next-generation network (NGN), we have proposed a functionally distributed transport networking architecture that separates the control-plane processing part (control element, CE) from the forwarding plane processing part (forwarding element, FE) of the router. In this architecture, the CE is mounted on a general-purpose server platform, and one path-control process in the CE consolidates and processes the path computations and the path settings for two or more routers. The functions and performance of the CE are easily upgraded. Moreover, a particular CE computes the path for an entire network by using the single network-integration path-control method that treats each sub-network as one router. This leads to efficient operation of a large-scale network. In this paper, we argue that the issues of our architecture could be bottleneck factors for the path computational performance in a large-scale network and we predict the influence of these factors by using a simulation environment.

Verification of path computational performance in functionally distributed transport networking on next-generation network

Traffic in IP networks has increased and services have diversified over the last few years. IP networks need to have scalability and high-quality data transmissions and they must be able to incorporate new functions. For good processing performance and ease of adding functions to the transport stratum on a next-generation network (NGN), we have proposed a functionally distributed transport networking architecture that separates the control-plane processing part (control element, CE) from the forwarding plane processing part (forwarding element, FE) of the router. In this architecture, the CE is mounted on a general-purpose server platform, and one path-control process in the CE consolidates and processes the path computations and the path settings for two or more routers. The functions and performance of the CE are easily upgraded. Moreover, a particular CE computes the path for an entire network by using the single network-integration path-control method that treats each sub-network as one router. This leads to efficient operation of a large-scale network. In this paper, we argue that the issues of our architecture could be bottleneck factors for the path computational performance in a large-scale network and we predict the influence of these factors by using a simulation environment.

An adaptive QoS control method in the multi-channel communication of the MPEG video data streams

We propose the new scaling and bandwidth allocation method for multistream MPEG video transmission. First, we propose hybrid scaling method which applies both re-encoding and reduction of DCT coefficient, and show that relation between SNR degradation and coded bitrate can be approximated by piecewise line. Then, we obtain the optimum bandwidth allocation algorithm for multistream video transmission, based on the strategy that the largest SNR degradation should be minimum. Furthermore, a practical bandwidth allocation method is proposed for video streams, which contain scene changes. Computer simulation shows that the proposed method can decrease largest distortion of MPEG video streams.

The method for improving TCP performance in bandwidth-guaranteed network

This paper discusses the efficiency of TCP transmission over a bandwidth-guaranteed network, where the bandwidth for each flow is guaranteed by traffic policing at edge nodes. In particular, it explores a method for improving TCP performance focusing on the size of the buffer to absorb jitter and promote a faster increase in the congestion window size. We propose a rate control method at an edge node based on controlling the advertised window for improving TCP performance in a bandwidth-guaranteed network. We also evaluate the effectiveness of the proposed method using a prototype.

Fault Recovery Performance Analysis of Functionally Distributed Transport Networking System

We propose a fault recovery method in functionally distributed transport networking that separates the control-plane processing part (control element, CE) from the forwarding-plane processing part (forwarding element, FE) of the router. In this architecture, one path-control process in the CE consolidates and processes the path computations and the path settings for multiple FEs. This leads to reduction in the path-control complexity and efficient operation of large scale networks. On the other hand, it is absolutely critical to ensure the high reliability of the CE. We analyze the performance of the proposed fault recovery method by using software implementation.

Design of the multi-channel communication system for the MPEG video data streams using adaptive QoS control

In this paper, we show a design method for a multi-channel communication system for MPEG video that is based on adaptive QoS control. The relation between the SNR degradation and the coded bitrate in each scene of a video channel is approximated by linear equation. The bitrate is allocated to each scene based on a linear equation. However, if the number of channels increases, the bitrate is not allocated appropriately because the scenes change frequently. In this paper, we divide the video channels into groups. An optimum number of groups can be obtained by considering the scene characteristics. Furthermore, we also show experimental results of applying the method to a prototype system.