No abstract

No abstract

Nowadays, many people are devoting attention to Virtual Private Network (VPN), which is a method for private network construction on an open network like the Internet. To enhance security in the private network, IT managers design internal VPNs for sections. Therefore, the IT managers and users of network applications need to assume environments that have multiple firewalls on the communication path. In this paper, we propose a VPN construction method suited to a multiple firewall environment. In our proposed method, each firewall has an end-toend encryption function and a relay control function. The user does not need to be conscious of multiple firewalls with this environment, and by means of this method, we can make a VPN that provides for communication performance under these functions.

No abstract

Optimally placing virtual machines on numerous physical servers saves clouds' hardware resources. In the case of the virtual desktop cloud, the placement task becomes more difficult because the workload of virtual desktop changes quickly over time.In this paper, we first study the workload of CPU, memory, and hard disks of 172 machines that provide virtual desktops to remote users. We also thoroughly analyze CPU usage metric and show that office users' desktops often repeat a certain pattern every workday. We then evaluate the virtual machine placement algorithms including PBA, which utilizes the correlation between the CPU usage patterns to find the suitable server for a virtual desktop, and First Fit, a widely used placement algorithm in cloud infrastructure.