Network Virtualization for Large-Scale Data Centers

The growing use of cloud technology by large enterprises to support their business continuity planning (BCP) and disaster recovery planning (DRP) is leading to an increase in the scale of the systems used by data center operators. As this increase in scale progresses, it is becoming more and more difficult to build virtual and physical networks using existing technologies. For example, the number of virtual local area networks (VLANs) that can be built in a data center using VLAN technology is limited to 4094 because of the bit length limit of a VLAN ID. With physical networks, inefficiencies in network line use due to the use of Spanning Tree Protocol (STP) switching and the complexity of network design are becoming issues. In this paper, we summarize the conditions and technical requirements faced by large-scale data centers. We also discuss various approaches to meeting these requirements such as extending the number of virtual networks and building physical networks using an alternative to STP switching, compare them, and discuss their characteristics.