Distributed Denial of Service (DDoS) attacks are a pressing problem on the Internet as demonstrated by recent attacks on major e-commerce servers and ISPs. Since the attack is highly distributed, an effective solution must be formulated with a distributed approach. Recently, some solutions, in which intermediate network nodes filter or shape congested traffic, have been proposed. These solutions may decrease the congested traffic, but they still cause "collateral victims problem," that is, legitimate packets may be discarded mistakenly. In this paper, we propose Active Countermeasure Platform to minimize traffic congestion and to address the collateral victim problem using the Active Networks paradigm, which incorporates programmability into intermediate network nodes. Our platform can prevent overloading of the target and consuming the network bandwidth of both the backbone and the protected site autonomously. In addition, it can improve the collateral victim problem based on user policy. This paper shows the concept of our platform, system design and evaluation of the effectiveness using a prototype.

The roadside network system for ITS services uses microcells in its access infrastructure. For the roadside network that provides the uninterrupted communication using microcells such as DSRC, an effective communication control scheme must be established so as to manage the communication passes to vehicles in the network. One of the fundamental requirements for the communication control scheme for the roadside network is to assure fault-tolerance, which means in this system that the communication control mechanism needs to be managed even in part of the base stations in the network might be in fault. On the other hand, for the communication control in the roadside network using microcells, issues to be solved are the handover mechanism for taking over connection information to provide uninterrupted communication environment, which causes the degradation of the end-to-end throughput. In order to solve those problems, the authors developed a communication control scheme. We implemented the scheme as the specific 'ADS algorism' to control the communication zone dynamically, which works effectively on the Autonomous Decentralized System (ADS) communication platform. Furthermore, we also developed the specific ADS algorism to assure fault-tolerance for the communication zone control, which can reconfigure the communication zone in case the BSs in the roadside network are in fault and can keep the operations by the reconfigured communication zone. We evaluated the ADS algorism for the communication zone control by computer simulation. The results show the effectiveness of the ADS algorism for the dynamic communication zone control mechanism and for the fault-tolerant mechanism for communication zone reconfiguration on fault.

In order to realize universal service access of mobile users on the global telecommunication environment, we have to consider the scalable networking architecute based on the distributed object computing technologies. In this paper, we apply TINA to the promising networking architecture, and propose TINA-based scalable model for realizing personal mobility service, which especially focuses on making access to telecommunication services from any legacy systems that do not support such the new environment, using a downloadable module in an end terminal, as well as considering load balance of a whole system. Our proposed model also focuses on exchanging personal infomation of mobile users between different administrative domains, by separating the already-specified user profile information objects into two parts, which are the domain-common part and domain-specific part, and propose secure exchange procedure.