# Server Operation and Virtualization to Save Energy and Cost in Future Sustainable Computing
## 3 Server Operation and Virtualization to Save Energy and Cost
### Test Bed in Large Scale  
It goes from the 1 st layer at the bottom to the 7 th layer. The 1 st layer is a Physical Layer that defines the mechanical, electric, and physical dimensions to connect the system. The 2 nd layer is the Data Link Layer that sends a data link reliably through the physical link. The 3 rd layer, the Network Layer, sends data to the destination safely and quickly by dividing into packets. The 4 th layer is the Transport Layer, which performs transparent data transfer between the two systems related to TCP or UDP protocol. The 5 th layer is the Session Layer, which provides dimension to manage the telecommunication by the application process at both ends. The 6 th layer is the Presentation Layer, which has a conversion function if the data expression method between sender and receiver is different or provides a common format. Lastly, the 7 th layer is the Application Layer, which enables accessing the network for data exchange between application programs in the language of the application layer. This was applied to vEPC through NFV virtualization in this study. First, the network was configured using HP DL380 as hardware. Network construction by operating server is relevant to the Physical and Data Link Layers. Likewise, the Network and Transport Layers serve to send data packets from vEPC to the destination using TCP/IP and UDP on the network. In the Session Layer, the Application area provides actual services while being closest to the telecommunication service provider that uses the system with software of vEPC realized as virtualization. Figure 5 shows a design for the cost reduction of network server from the center of hardware. Specifically, it shows the change of use from the hardware depending on a specific manufacturer to the compatible hardware using NFV technology. In the legacy hardware on the left, the place of use is defined per board. Thus, it divides its role including a board for call processing and a board for system management and for processing incoming call, demonstrating that it is equipment for call processing. Since the role is clearly divided, it is impossible to secure compatibility between different boards that are difficult to manage. Providing spare items of each board in case of failure poses a disadvantage for the telecommunication service provider. Meanwhile, such phenomenon has been resolved to some degree as it goes to NFV on the right. After separating between hardware and software of VMware  
Figure 5: Cost Reduction of Network Server from the Center of hardware. and KVM with Hyperwise on the compatible HP DL380 or BL460 server, call processing was realized at the manufacturer's hardware with application. HP (Palo Alto, CA, USA) and Dell (Round Rock, TX, USA) servers are easy to buy in the market, thereby enabling flexible and efficient network operation in the same pool with virtual resources. Table 1 shows the hardware configured in this study. Table 2 presents the software configured in this study. Figure 6 presents a design for cost reduction in this network server operation focusing on software. It is for a general-format NFV product. The basic hardware of NFV uses a compatible server by HP and Dell that can be bought easily in the market where Intel's x86 chip is used. In this hardware, hardware and software were divided with Hypervisor such as KVM and VMware to realize application in the form of VM. To realize the product in VM format, the service provider can freely adjust VM according to the demand of customers. For example, if the data traffic increases rapidly, it can be dealt with by installing additional VM without the purchase or installation of separate hardware. In addition, since VM transfer is possible between servers when there is any server or VM failure, VM can be moved to another server. Cost reduction is also enabled since it can be purchased easily; hence the CAPEX/OPEX reduction effect.