A Survey of Cloud Network Overlay Protocols

Cloud computing is model for sharing of computing and storage resources over Internet. Virtualization is the key technique behind Cloud. It enables provisioning of various kinds of services to the Cloud users on one hand; on the other it increases utilization of computing resources and bandwidth. Virtualization of server and network puts pressure on existing hardware features and protocols by arousing issues of scalability, limitation of number of ports, under utilized resources and bandwidth. MAC address table of Network Interface Card has a limited size, VLANs are not enough scalable to cater demands of Cloud, and Spanning Tree Protocol results in idle or under utilization of resources. Cloud network overlay protocols are the intricacies devised to resolve these issues. It resolves the issues of scalability, mobility, better resources and bandwidth utilization and workload migration. This paper presents comparative overview of different overlay protocols namely Shortest Path Bridging (SPB), Transparent Interconnection of Lots of Link (TRILL), Locator/ID Separation Protocol (LISP), Virtual Extensible LANs (VXLANs), Network Virtualization using Generic Routing Encapsulation (NVGRE), and Stateless Transport Tunnelling (STT) followed by conclusions and future recommendations.