Biblio

Caching query results is an efficient technique for Web search engines. A state-of-the-art approach named Static-Dynamic Cache (SDC) is widely used in practice. Replacement policy is the key factor on the performance of cache system, and has been widely studied such as LIRS, ARC, CLOCK, SKLRU and RANDOM in different research areas. In this paper, we discussed replacement policies for static-dynamic cache and conducted the experiments on real large scale query logs from two famous commercial Web search engine companies. The experimental results show that ARC replacement policy could work well with static-dynamic cache, especially for large scale query results cache.

One of the recent focuses in Cloud Computing networks is Software Defined Clouds (SDC), where the Software-Defined Networking (SDN) technology is combined with the traditional Cloud network. SDC is aimed to create an effective Cloud environment by extending the virtualization concept to all resources. In that, the control plane is decoupled from the data plane in a network device and controlled by the centralized controller using the OpenFlow Protocol (OFP). As the centralized controller performs all control functions in a network, it requires strong security. Already, Cloud Computing faces many security challenges. Most vulnerable attacks in SDC is Denial-of-Service (DoS) and Distributed DoS (DDoS) attacks. To overcome the DoS attacks, we propose a distributed Firewall with Intrusion Prevention System (IPS) for SDC. The proposed distributed security mechanism is investigated for two DoS attacks, ICMP and SYN flooding attacks for different network scenarios. From the simulation results and discussion, we showed that the distributed Firewall with IPS security detects and prevents the DoS attack effectively.