Moment matrix analysis (MMA) that can derive statistical properties of non-linear equations is presented in this paper. First, non-linear stochastic differential, or difference, equations are approximately expressed by simultaneous linear equations of moments defined at discrete events. Next, by eliminating higher order moments, the simultaneous linear equations are reduced to a linear vector equation of their coefficient matrix and a moment vector comprised of the moments of the system state. By computing the eigenvectors and eigenvalues of the coefficient matrix, we can analyze the moments, transient response, and spectrum of the system state. The behavior of Internet traffic was evaluated by using MMA and computer simulation, and it is shown that MMA is effective for evaluating simultaneous non-linear stochastic differential equations.

We propose a feedback controller to efficiently control web requests especially on overloaded networks. The controller is designed based on a feedback closed loop that prevents overload of web server and enforces target CPU utilization via controlling the amount of input web requests. The main contribution of this letter is the use of feedback control theory to design the controller that delicately regulates web requests even under the dynamic changes in processing power of web server. In contrast with many previous heuristic methods, the proposed controller uses a systematic approach to adaptively control web requests taking account of the dynamic behavior of web server. Simulation results performed in overloaded cases show that the proposed controller lets web server effectively control input web requests and reach its CPU utilization to desired levels in relatively small settling times.

In this paper, the design of a mobile satellite Internet access (MSIA) system and a mobile broadband satellite access system, called Mobile Broadband Interactive Satellite Multimedia Access Technology System (MoBISAT) are presented. MSIA system provides Internet service, broadcasting, and digital A/V service in both fixed and mobile environments using Ku-band geostationary earth orbit (GEO) satellite. A Ku-band two-way active phased array antenna installed on top of the transportation vehicles can enable the transmission of signals to satellite as well as signal tracking and reception. The forward link and return link are a high speed Time Division Multiplex (TDM) and TDMA transmission media, respectively, both of which carry signaling and user traffic. The MoBISAT, which is a next generation mobile broadband satellite access system, provides both Ku-band satellite TV and Ka-band high-speed Internet to the passengers and crews for land, maritime, and air vehicles. This paper addresses the main technological solutions adopted for the implementation and test results for the MSIA system and the main design features of the MoBISAT system.

Traditional Web cache servers based on HTTP and ICP infrastructure tend to have higher hardware and management cost, have difficulty in availability, automatic and dynamic reconfiguration, and may have slow links to some users. We find that peer-to-peer technology can help solve these problems. The peer cache service (PCS) we proposed here leverages each peer's local cache, similar access patterns, fully distributed coordination, and fast communication channels to enhance response time, scale of cacheable objects, and availability. Moreover, incorporating goals and strategies such as making the protocol lightweight and mutually compatible with existing cache infrastructure, supporting mobile devices, undertaking dynamic three-level caching, and exchanging cache meta-information further improve the effectiveness and differentiate our work from other similar-at-first-glance P2P Web cache systems.

Real-world IP networks are heterogeneous in terms of server and link capacities. A sophisticated and comprehensive load balancing method is essential if we are to avoid congestion in the servers and links of heterogeneous networks. If such a method is not available, network throughput is limited by bottleneck servers or links. This paper proposes an anycast technique that achieves load balancing under heterogeneity. The proposed method well suits implementation on active networks. By taking advantage of the processing ability provided by active nodes, the method can decide packet routes flexibly on the basis of various criteria to realize a variety of load balancing schemes. Some of these schemes can successfully prevent the congestion of heterogeneous networks by tackling bottlenecks in both server and link capacities. The method is also advantageous given its light control load even when using many mirrored servers. Computer simulations confirm the effectiveness of these features.

This paper presents a network architecture with a dual interface IP handoff technique that allows smooth node mobility without using any intermediate proxy. The proposed architecture is suitable for low bit-rate time sensitive real time applications, where payload tends to be short and packet header overhead is particularly significant. Connections are established as per permanent addresses of the nodes but are carried on by the IP layer according to the temporary addresses by address translation within the end hosts. The mapping information is maintained by database servers, which can be placed in the Internet in a distributed manner. We describe the architecture and show its mobile capabilities by prototype implementation and performance evaluation. Furthermore a dual-interface handoff suitable to the proposed architecture is also introduced. Preliminary results show that the proposed architecture has significantly low overheads. It is compatible with the existing infrastructure and works fine in both IPv4 and IPv6 environments. Analysis also shows that with dual-interface handoff it is possible to achieve seamless handoff without any packet loss by exploiting overlapping coverage area and speed of the mobile node. Handoff latency is reduced significantly as compare to MIPv6. We believe that with more powerful network interface card drivers our concept of dual interface handoff can be realized.

This paper presents QoS control enhanced architecture for VoIP networks. In this architecture we use both the probe flow delay and average loss rate measurement systems. First we apply the probability-based EMBAC scheme on our delay system. Then we propose a new probability-based EMBAC with a severe congestion consideration scheme to improve the admission control scheme in both measurement systems. We compare the performance of the enhanced systems in terms of blocking probability under the same condition of achieving average packet loss rate no greater than the certain target by setting an appropriate admission threshold in each system under each scenario. In this study, it is shown through simulations that for the same target voice average loss rate, the enhanced systems proposed in this paper outperform the conventional schemes in handling the network resources. Then we will seek to prove that, for extra traffic loads within a busy period of time and with an optimal admission threshold chosen in advance, the enhanced systems can be a powerful and reliable EMBAC tool for VoIP networks in achieving high network performance with minimum blocking probability and minimum average loss rates. Finally it is shown that the enhanced systems have reasonable scalability.

One of the key issues in the next generation Internet is end-to-end Quality of Service (QoS) provisioning for real-time applications. The Differentiated Services (DiffServ) architecture offers a scalable alternative to provide QoS in the Internet. However, within this architecture, an efficient scheduling mechanism is still needed to ensure such QoS guarantees. In this paper, scheduling mechanism for supporting QoS differentiation among multiple traffic classes in IP differentiated services networks is studied. A scheduling algorithm called Multiclass Efficient Packet Fair Queueing (MEPFQ) is proposed that enables fair bandwidth sharing while supporting better bounds on end-to-end network delay for QoS-sensitive applications such as voice over IP (VoIP) within the DiffServ framework. The mechanism allows to create service classes and assign proportional weights to such classes efficiently according to their resource requirements. Besides, MEPFQ tries to ensure that packets from low priority class will not be starved even under extreme congestion cases. The results from the simulation studies show that the mechanism is able to ensure both the required end-to-end network delay bounds and bandwidth fairness for QoS-sensitive applications based on the specified service weights under various traffic and network conditions. Another important aspect of the MEPFQ algorithm is that the scheme has lower implementation complexity, along with scalability to accommodate the growing traffic flows at the core routers of high-speed Internet backbone.

The new Internet has to provide the Quality of Services to converged multimedia services, in which each one may choose its own requirements. Managing such a dynamic network is not an easy task. A more intelligent and adaptive behavior is required from network management. We argue that agents are able to realize this task by dynamically adapting management mechanisms to the current network conditions. This article presents a Behavioral Multi-Agent-based model for QoS-enabled Internet. Based on this behavioral approach, we analyze network management mechanisms (or "elementary behaviors") in terms of performance and applicability profile. We use simulation to observe services performances when submitted to diverse QoS management elementary behaviors.

FEC (Forward Error Correction) can repair the damage to communication quality due to packet loss. The growing requirement of FEC for high-quality video transmission is inevitable on broadband networks. We have designed and implemented FEC, and integrated it to our developed video transmission system named "mpeg2ts." Our goal is to make it possible to deploy this system on the broadband Internet. However, the problem with constant redundancy of FEC is that weakness to fluctuation of network condition. To resolve this problem, in this paper, we propose and evaluate an efficient FEC method for high-quality video transmission. The proposed mechanisms can provide robustness as well as saving of processing load and optimization of bandwidth consumption. Moreover, we integrate it into a system to deploy it on the real broadband Internet. Transmission experiment demonstrates availability of developed system deployed on the network.

Photonic Internet Lab. (PIL) is shooting for the leading edge photonic-GMPLS (Generalized Multi-protocol Label Switching) that utilizes wide-band, cost-effective photonic technology to implement IP-centric managed networks. PIL is a consortium for researching the GMPLS protocol and advancing a de facto standard in this area. Members make leading edge GMPLS code modules and test them at the lab site. The experimental results, new ideas, and protocols are contributed to standardization bodies such as IETF and OIF. This paper also describes the world's first trial of GMPLS multi-region (multi-layer), multi-route, multi-vender signaling.

Software applications for the transfer of money or personal information are increasingly common on the Internet. These applications require user authentication for confirming legitimate users. One-time password authentication methods risk a stolen-verifier problem or other steal attacks because the authentication on the Internet server stores the user's verifiers and secret keys. The SAS-2 (Simple And Secure password authentication protocol, ver.2) and the ROSI (RObust and SImple password authentication protocol) are secure password authentication protocols. However, we have found attacks on SAS-2 and ROSI. Here, we propose a new method which eliminates such problems without increasing the processing load and can perform high security level same as S/Key systems without resetting the verifier.

In this paper, we propose a speech coding translation scheme by transferring coding parameters between GSM half rate and G.729 coders. Compared to the conventional decode-then-encode (DTE) scheme, the proposed parameter conversions provide speech interoperability between mobile and IP networks with reducing computational complexity and coding delay. Simulation results show that the proposed methods can reduce about 30% computational load and coding delay acquired in the target encoders and achieve almost imperceptible degradation in performance.

Rectangle search is a well-known packet classification scheme which is based on multiple hash accesses for different filter length. It shows good scalability with respect to the number of filters; however, the performance is not fast enough to fulfill the high-speed requirement of packet classification. In this paper, we propose a lookahead caching which can significantly improve the performance of hash-based algorithm. The basic idea is to filter out the un-matched probing case by using dual-hash architecture. The experimental results indicate that the proposed scheme can improve the performance by the factor of two for the 2-dimension (source prefix, destination prefix) filter database.

Mining traversal patterns on the Internet is one of critical issues for exploring the user access behaviors. In this paper, we propose a new data mining scheme for mining frequent trip traversal patterns on the Internet. First, we define a trip traversal as a historical contiguous sequence of web sites or web pages, which were surfed or visited on an information-providing system by one user. Next, we derive all of the maximal trip traversals by analyzing and filtering these collected trip traversals. For mining the large trip traversals from the maximal trip traversals, we present a data mining scheme integrated with the schemes presented in. Here, the extracted large trip traversals can be thought of as the realistic frequent browsed behaviors for most of users either on a web site or on an information-providing system, such as a proxy server. Finally, we implement and design a data mining system to explore the large trip traversal patterns in order to capture user access patterns to some proxy server.

With no doubt the Internet will achieve advantages in exploiting software agents for applications, thanks to their autonomy in carrying out tasks. In such a scenario, appropriated methodologies are needed to manage the interactions among agents. The BRAIN framework proposes an interaction model based on roles, each one composed by a set of capabilities and an expected behavior. The achieved advantages are agent-oriented features, separation of concerns and reuse of solutions and experiences. In this paper we present two interaction infrastructures, Rolesystem and RoleX, which rely on the above mentioned role-based interaction model. These infrastructures allow agents to assume roles and to interact. An application example and the comparison with other approaches show the effectiveness of our approach.

In this letter, we evaluate the performance of several adaptive and non-adaptive AQM schemes for congestion control in a dynamic network environment with variable bandwidth links. The AQM schemes examined are RED, BLUE, Adaptive RED, REM, AVQ and PI controller. We compare their queueing performance and show that none of them can derive stable queue length and low packet drop rate simultaneously in networks where both input traffic and available output bandwidth are time varying. Adaptive and efficient algorithms should be designed and applied in order to improve the adaptiveness and robustness of congestion control in dynamic networks such as Internet.

High-speed streaming services are considered to be among the most promising services for the broadband Internet of the next generation. A contents delivery network (CDN) that allows effective and scalable content delivery will be required in this role. However, the actual requirements for the CDN, such as quality of service (QoS), the service deployment strategy and technical issues are not yet to be defined. In this paper, the bandwidth requirement of the CDN is derived through QoS evaluation. On the basis of this requirement, we propose two feasible CDN configurations: an IP technology based configuration and an optical video distribution technology based configuration. Finally, we make lists of technical issues for the configurations and discuss some of the possible solutions.

Burst switched WDM optical networks are coming up as suitable network architectures for future Optical Internet backbones. However, the lack of optical processing capabilities results in increased burst blocking probability, which in turn lead to very limited network performance. Efficient contention resolution algorithm is therefore necessary. In this paper, we propose a distributed wavelength assignment algorithm named Priority-based Wavelength Assignment (PWA) for such networks. Each node selectively assigns wavelengths based on the wavelength priority information "learned" from its wavelength utilization history in a distributed manner. As the learning process progresses, nodes in the same part of the network tend to assign different wavelengths to avoid contentions. Simulation results show that the PWA can effectively reduce the blocking probability and increase the performance of burst optical networks compared to previous algorithms such as random assignment.

In this paper, we present an Internet personal live-broadcasting server system. Our solution is not only for experts but also for amateur users who want to broadcast using simple multimedia equipment. For scalable broadcasting services, we developed multiple-channel establishment and channel expansion. Concurrent services for a large number of broadcasting channels are effectively provided. Also, the capacity of channels can be expanded as the number of participants increases. Furthermore, for the sake of complete live broadcasting with high-quality transmission, the system supports both TCP (transmission control protocol) and UDP (user datagram protocol) according to the status of network environments as well as the received packet loss in the user system. The performance of the system is effectively evaluated at such practical commercial sites as well-known community and E-business sites.