Toshio Soumiya

A traffic control method for service quality assurance in an ATM network

The authors describe an ATM traffic control method to avoid both long-term and short-term congestion. Call admission control and policing based on user-specified traffic parameters have mainly been studied as ways to avoid long-term congestion. However, these control methods are not practical since it is difficult for users to specify accurate values of traffic parameters that include the effects of cell collision controllers and multiplexers in the customer premises network. In order to solve the problem, they propose an intelligent call admission control method. This method consists of a function to determine users traffic parameters by monitoring the cell traffic flow of each service and a function to statistically predict long-term congestion by using Gaussian and Poisson distributions. They show that congestion can be predicted by deriving the peak, average, and variation. They also describe how to derive traffic parameters and determine their values. To avoid short-term congestion, we propose reactive control, which drops cells with lower cell loss priority when congestion occurs, and we show the buffer construction and buffer control algorithm used to achieve this. Computer simulations prove that their control strategy is effective for cell toss sensitive services such as VBR (variable bit rate) video service. >

The large capacity ATM backbone switch “FETEX-150 ESP”

The ATM (Asynchronous Transfer Mode) network is regarded as effective for a multimedia telecommunication environment that enables high-speed and broadband communication. This paper reports on the system architecture and design concept of the FETEX-150 ESP (Enhanced Switching Platform) which has been designed as an ATM switch in a public broadband network. To track the latest ATM standards and trends, a simple, scalable, and open architecture was set forth for the FETEX-150 ESP design target at the beginning of the system design. This paper also describes the method for traffic management to support various traffic classes.

A strategy of quality control on ATM switching network-quality control path (QCP)

In an ATM network, there are many kinds of calls which require various qualities. A method is required to control the connection and cell administration according to the required quality of service (QoS) for each connection. In this paper, we propose the quality control path (QCP) concept to control the qualities of the established connections in the ATM switch. With this method, the buffers and the capacities of the physical links in the switch are each divided into logical paths. We also described a control scheme to maintain a required QoS for each connection.

Dynamic application load balancing in distributed SDN controller

To deploy Software-Defined Networking (SDN) in a large-scale network, cluster-based distributed SDN controllers were proposed, which enable performance scaling by simply adding a new server in the cluster. However, loads caused by many control messages from many kinds of SDN applications have not been widely studied so far. In this paper, we show an architecture of a distributed SDN controller where all kinds of applications are running on all of the servers to share the loads caused by the applications. We propose a dynamic application load balancing method which calculates the weight of round robin scheduling of an external load balancer to distribute requests submitted to the applications among the servers. Experimental results show the method increases the performance of the controller by reducing inter-server messages.

Extension of OpenFlow protocol to support optical transport network, and its implementation

By having the OpenFlow protocol support Optical Transport Networks (OTN) and work as the unified control interface for multilayer (L0-L4) networks, a simple and cost-effective multilayer Software Defined Networking (SDN) controller can be created. Our aim is to propose and standardize the extended OpenFlow protocol to support OTN in Open Networking Foundation (ONF). We describe the approved specification, and the process from proposal to standard. We applied this extension to our OpenFlow controller and OpenFlow agent and succeeded in demonstrating that the extension works as desired in single- and multi-vendor environments. Future directions for OpenFlow extension and modeling of multilayer integrated nodes are also discussed.

A Scalable Resource Management Mechanism with Feedback Control for Network Systems

With the progress of large-scaled networks, a service platform should manage effectively enormous amounts of diversified information to ensure stable operations of the platform systems in a resource-constrained environment. We propose a resource control mechanism based on a feedback control law to enable effective resource management and the stable operation of platform systems. Furthermore, we introduce the application cases for a session admission control system and a packet sampling control system, and demonstrate the effectiveness of the proposed mechanism in simulations and prototype evaluations.

Performance evaluation of TCP over ATM using World Wide Web traffic

We propose a new explicit-rate (ER) available bit rate (ABR) algorithm (load-based explicit rate control, or LBERC) that can maintain high link utilization and reduce congestion in asynchronous transfer mode (ATM) networks. In order to evaluate the algorithm, we model World-Wide Web (WWW) traffic using the file transfer distribution of the SPECweb96 benchmark. We simulate Web traffic via a client-server model that consists of Web clients, Web servers, and a finite source function (FSF) to represent client (user) behavior. When network congestion occurs, users access fewer Web pages (and open fewer new transmission control protocol (TCP) sessions). The FSF simulates this user behavior by counting the number of active TCP sessions. We present TCP-over-ABR/LBERC simulation results to verify the compatibility of interactions between TCPs window-based flow control and ABRs rate-based flow control.