This paper describes the adaptability of communication software through a biologically-inspired policy coordination. Many research efforts have developed adaptable systems that allow various users or applications to meet their specific requirements by configuring different design and optimization policies. Navigating through many policies manually, however, is tedious and error-prone. Developers face the significant manual and ad-hoc work of engineering an system. In contrast, we propose to provide autonomous adaptability in communication endsystem with OpenWebServer/iNexus, which is both a web server and an object-oriented framework to tailer various web services and applications. The OpenWebServer's modular architecture allows to abstract and maintain a wide range of aspects in a HTTP server, and reconfigure the system by adding, deleting, changing, or replacing their policies. iNexus is a tool for automated policy-based management of OpenWebServer. Its design is inspired by the natural immune system, particularly immune network, a truly autonomous decentralized system. iNexus inspects the current system condition of OpenWebServer periodically, measures the delivered quality of service, and selects suitable set of policies to reconfigure the system dynamically by relaxing constraints between them. The policy coordination process is performed through decentralized interactions among policies without a single point of control, as the natural immune system does. This paper discusses communication software can evolve continuously in the piecemeal way with biological concepts and mechanisms, adapting itself to ever-changing environment.

In recent years, the concept of Quality of Service (QoS) has gained attention in the network research community and its extension towards delivering QoS level assurance to sensitive applications has generally been agreed to be crucial for the longevity and usability of the Internet. On the Internet, the Differentiated Services (DiffServ) architecture is a general framework for the differentiated treatment of traffic aggregates in the core network. However, DiffServ does not extend to end-to-end QoS assurance. In this paper, we propose a simple resource-brokering scheme operating over a hierarchically connected internetwork of administratively-independent DiffServ-capable domains that is a simplified model of the Internet. The proposed asynchronous, multi-agent resource-brokering scheme operates locally but avoids conflicts globally. In this way, the traffic control reflects the underlying structure of the internetwork, introduces only a localized complexity thus scaling up well, and permits independent policies between the interconnected domains.

Telepresentations will be popular in the future of ubiquitous digital media. To realize a telepresentation easily over the Internet, we design a communication protocol to control a remote material (digital media) used in a telepresentation. We describe our proposed protocol; RMOP (Remote Material Operation Protocol) in this paper. This protocol specifies commands for material operations such as synchronization of slides, drawing, and pointing. Since this protocol just specifies the common formats through IP networks independent of special functions of presentation tools, it can be applied to various presentation tools. To design the protocol, we consider the trade-off between reliability of IP multicast and practical availability in the actual Internet. We adopt the reliable multicast mechanism to improve reliability but not to lose practicality in the protocol. Also, we describe an implementation of our prototype system using RMOP for a telepresentation. Then we show some evaluations such as the protocol overhead and comparisons with the other existing systems. Last, we show a case study of a telepresentation over the Internet using our system.

This paper describes agent technology and the various ways in which it can be applied to command, control, communications and intelligence in general, and to network-centric warfare in particular. The paper provides a brief overview of agents, their properties, and their advantages. It covers the concept of the current military trend, network-centric warfare. Problems associated with agents are described, including the conflict between security and autonomy, in a distributed environment. The paper concludes with a discussion of research trends in mobile agents, particularly with regard to applications in the Department of Defense.

It has been reported that IP packet traffic exhibits the self-similar nature and causes the degradation of network performance. Therefore it is crucial for the appropriate buffer design of routers and switches to predict the queueing behavior with self-similar input. It is well known that the fitting methods based on the second-order statistics of counts for the arrival process are not sufficient for predicting the performance of the queueing system with self-similar input. However recent studies have revealed that the loss probability of finite queuing system can be well approximated by the Markovian input models. This paper studies the time-scale impact on the loss probability of MMPP/D/1/K system where the MMPP is generated so as to match the variance of the self-similar process over specified time-scales. We investigate the loss probability in terms of system size, Hurst parameters and time-scales. We also compare the loss probability of resulting MMPP/D/1/K with simulation. Numerical results show that the loss probability of MMPP/D/1/K are not significantly affected by time-scale and that the loss probability is well approximated with resulting MMPP/D/1/K.

We propose the Geographical Location Information (GLI) system that maps a mobile entity on the Internet to a geographical position. Users can look up the latest geographical location information of registered mobile entities (forward-lookup) and can also search for mobile entities within a specified area (reverse-lookup). The GLI system consists of home and area servers. The home server maintains latest geographical location information of the mobile entities and processes forward-lookup requests. The area server maintains the latest geographical location information of the mobile entities in the area that it manages and processes reverse-lookup requests. To provide a highly scalable system, home and area servers are managed in a distributed manner based on a hierarchical server structure and delegation of authority to servers that manage lower layers. To reduce the amount of traffic due to distributed management, the delegation information of authority is cached by the servers. In our performance evaluation of the GLI system, the prototype implementation can handle 4,500-8,000 requests/sec for location lookup and location registration. We found that 52 home servers and 33 area servers are enough to handle all cars in Japan under some assumed parameters through the performance evaluation.

A mechanism of dual stack-hosts using a technique called "Bump-in-the-Stack" (DSH-BIS) has been developed to enable transition from IPv4 to IPv6. DHS-BIS allows hosts to communicate with other IPv6 hosts by using existing IPv4 applications regardless of their IP versions. We successfully demonstrated "DSH-BIS" at an IETF meeting and WIDE camps.

A lot of efforts have been made to develop the international Internet environment. In order to achieve a better and efficient information infrastructure around the globe, there are very strong urgent demands in the area of Asia and Pacific for a practical working environment where engineers and researchers in related fields work cooperatively. Our AI3 Project was started in 1995 by WIDE Project and JSAT. It has been operating a satellite based testbed network in Southeast Asia and conducting a series of research activities using the testbed. In this paper, we explain AI3 satellite Internet infrastructure and describe our efforts of the deployment in Asia using our developed technology. Furthermore, we evaluate our testbed network from the aspect of sustainable international collaboration.

The authors have been in charge of the operation of one of the root DNS servers for more than three years. In this paper, the overview of our system to provide high availability is introduced. In the following sections, a traffic analysis system to analyze the characteristics of the DNS queries and the brief summary which may help future DNS system deployment is described.

In this article, we survey current and next generation IX (Internet eXchange) technologies. An IX is a mechanism to interconnect many networks to each other. In other words, an ISP can establish 'peerings' with other ISPs by connecting their routers into IXes. First, we describe the basic IX model, including a policy model, called the 'bilateral' model, which allows participating ISPs to control routing policy and traffic on a 'peer' basis. Next, we classify current IX architectures from a technical point of view and discuss issues of current IXes. In the latter potion of this article, we describe next generation IX technologies, which achieve new features for IXes, such as: enabling larger volume traffic exchange with optical technology, providing virtual private peerings, migrating data-link media to participate into an IX, and exchanging traffic over widely distributed areas. We survey cutting-edge technologies for next generation IXes, and discuss the future of IX technology.

In this paper we study the scalability issue in the design of a centralized bandwidth broker model for dynamic control and management of QoS provisioning. We propose and develop a path-oriented, quota-based dynamic bandwidth allocation mechanism for efficient admission control operations under the centralized bandwidth broker model. We demonstrate that this dynamic bandwidth allocation mechanism can significantly reduce the overall number of QoS state accesses/updates, thereby increasing the overall call processing capability of the bandwidth broker. Based on the proposed dynamic bandwidth allocation mechanism, we also extend the centralized architecture with a single bandwidth broker to a hierarchically distributed architecture with multiple bandwidth brokers to further improve its scalability. Our study demonstrates that the bandwidth broker architecture can be designed in such a manner that it scales with the increase in the network capacity.

The unidirectional transmission links such as broadcast satellite links and cable links are strongly demanding type of link to provide high bandwidth and ubiquitous Internet connectivity with lower cost. In order to provide an internet connectivity, the UDLs, unidirectional links, should be available for the IP service. However, since the current Internet routing and upper layer protocols assume the bi-directional link, the UDLs have been considered as unavailable links for the IP service. This paper proposes an architecture and a mechanism for the IP service over the UDL. The proposed system emulates the bi-directional connectivity between all nodes on the UDL, in order to use the dynamic routing protocol, the TCP/IP protocol, on the UDL system. Receiver uses a link layer tunneling mechanism to forward the IP datagrams to the Feed over an IP cloud, that is not directly connected to the UDL. This proposed architecture enables the dynamic routing capability for UDLs, as well as user applications, without any software modification.

In the future Internet, various kinds of services will rapidly increase its volume and require different qualities. Thus, it is main technical problem to guarantee various QoS to each connection. However, in the current IP networks where most applications use TCP as transport protocol, most typical packet discarding scheme, RED (Random Early Detection), causes unfairness such as the difference of bandwidth sharing among flows traversing the same router. To dissolve this problem, we consider that two viewpoints are important associated with flow-base fairness. One is instantaneous flow condition and the other is historical flow condition. In this paper, we propose the packet discarding scheme considering both instantaneous and historical use of network resources for the purpose of dissolving unfairness of each flow and improving the flow-base QoS. We call this proposal method "Random Early Drop with Dual-fairness metrics (DRED). " DRED can improve whole throughput and transfer completion time of information such as a file, etc.

This paper investigates the stochastic property of the packet destinations and proposes an address generation algorithm which is applicable for describing various Internet access patterns. We assume that a stochastic process of Internet access satisfies the stationary condition and derive the fundamental structure of the address generation algorithm. Pseudo IP-address sequence generated from our algorithm gives dependable cache performance and reproduces the results obtained from trace-driven simulation. The proposed algorithm is applicable not only to the destination IP address but also to the destination URLs of packets, and is useful for simulation studies of Internet performance, Web caching, DNS, and so on.

The design and implementation of a novel English writing environment is described. The system integrates modern computer and networking technologies with analytical tools from linguistics and language pedagogy to construct an advanced English writing environment. The system is not only suitable for students in learning English, but also of benefit to teachers in making comments and detecting learners' common difficulties. Furthermore, the collected essays from students and comments from teachers constitute a useful learner corpus. This is also of benefit to researchers in analyzing learners' persistent errors. In order to allow global access from the Internet, the system is web-based. Users, for example, students, teachers, and researchers, may access the system through web browsers. The system was developed in a cooperative effort of Computers And Networking (CAN) laboratory and the Research in English Acquisition and Pedagogy (REAP) Group at Tamkang University. The system has been piloted by six English faculty members at Tamkang University and is currently being used in five high schools in Taiwan. The learner corpus currently consists of over 800,000 word tokens of learners' writing.

Recently, traffic of real-time communication such as video or IP telephony is increasing in Internet. Low delay and low jitter communication is required to perform these kinds of services smoothly. CoS (Class of Services) scheme which controls traffic by the class unit such as application is currently being paid attention. It is considered to be efficient control mechanism which utilizes characteristics of Internet traffic. One of effective methods for queueing control to realize CoS is CBQ (Class Based Queueing). Efficient and dynamic bandwidth allocation can be realized by using CBQ. However, CBQ mechanism is not necessarily efficient for real-time communication. In this paper, We clarify the effect of dynamic CBQ control scheme on real-time communication by experiment. In addition, we show that low delay and low jitter communication is possible by reducing unnecessary control overhead which is caused by traffic change. We propose new mechanism which changes bandwidth allocation of CBQ dynamically suppressing non real-time traffic and giving priority to real-time traffic on using bandwidth. We also show its efficiency by using real system.

By the growth of the Internet, the client's access to the Internet have been increasing. In order to meet those demands, asymmetric networks have become a great attraction. However, asymmetric networks composed of satellite and terrestrial links have not been enough investigated. Therefore, this paper proposes a new formula for TCP performance evaluation for the asymmetric networks. Using this evaluation formula, we calculate the throughput of TCP Reno over the asymmetric networks taking Slow Start into account. The calculation results are compared with the following: (1) the value based on an existing theoretical formula, (2) the outputs of simulation by NS (Network Simulator), and (3) the experimental results using VSAT (Very Small Aperture Terminal) satellite communication system for satellite links and the Internet for terrestrial links. As a result, it is shown that the new formula is more precise than the one already proposed.

We have developed a new scheme to provide Diffserv-based QoS over ATM access networks. Well-known Diffserv over ATM scheme requires some extension for conventional routers with ATM interfaces. The routers must map their Diffserv classes of services into ATM QoS classes and forward IP packets into prioritized VCs based on DSCP (DiffServ Code Point). The purpose of this work is to provide Diffserv-based QoS over ATM network using conventional IP over ATM interfaces on routers. We propose DSCP snooping at ATM edge nodes, which differentiates services over a single VC between two IP domains. A prototype circuit was used to evaluate this scheme.

A new algorithm called core-stateless random-early-detection (CS-RED) is described. This algorithm can improve the fairness characteristics under a wide range of network conditions and is robust in terms of the setting of its control parameters. It can be used in a distributed architecture, as can the core-stateless fair-queuing (CSFQ) algorithm, so it is applicable to large-capacity backbone routers. Through a detailed evaluation, we have identified and clarified the fairness degradation problem in the CSFQ algorithm. We solved this problem by incorporating the congestion notification proposed in the RED algorithm into CSFQ; we call this hybrid CS-RED. Comparison of the fairness characteristics in a computer-simulated network using either the CS-RED or CSFQ algorithm showed that a higher level of fairness is achieved with the CS-RED algorithm under a wide variety of network conditions without degrading link utilization. Furthermore, the CS-RED algorithm uses a treatment that is more general than the penalty box mechanism to penalize unresponsive flows in best-effort networks.

The problems caused by misbehaving flows are becoming important issues in high-speed best effort networks. In this paper, we propose the MXQ (MaXimal Queuing) mechanism which correctly identifies and adequately penalizes misbehaving flows. Identification and penalization are the keys to controlling misbehaving flows, which is believed to be crucial for providing best effort services to a large number of residential customers at reasonable cost. The proposed mechanism consists of estimating incoming traffic at network edges and selective packet discard at network nodes. This combination realizes the identification and penalization in a correct, adequate and easy to understand way, thus maintaining the stability and efficiency of best effort networks. A number of experiments are performed on a prototype system to examine the unfairness caused by different TCP implementations, which is one type of misbehavior. The results show that the MXQ mechanism can adequately penalize the misbehaving flows, and can improve fairness, even when differently implemented TCP flows are present.