Virtualization osted cloud computing has significantly lowered the barrier for creating new networked services. Likewise, experimental facilities such as the Global Environment for Network Innovations (GENI; www. geni.net) let researchers perform largescale experiments on a "slice" of shared infrastructure. By letting tenants share physical resources, virtualization is a key technology in these infrastructures. Although virtual machines are now the standard abstraction for sharing computing resources, the right abstraction for networks is a subject of ongoing debate. Existing solutions differ in the level of detail they expose to individual tenants. Amazon Elastic Compute Cloud (EC2) offers a simple abstraction in which all of a tenant's virtual machines can reach each other. Nicira extends this "one big switch" model by offering programmatic control at the network edge to enable, for example, improved access control (see http://nicira.com/ en/network-virtualization-platform). Oktopus exposes a network topology so tenants can perform customized routing and access control based on knowledge about their own applications and traffic patterns. 1 Each abstraction is most appropriate for a different class of tenants. As more companies move to the cloud, providers must go beyond network bandwidth sharing to support a wider range of abstractions. With a flexible Network virtualization gives each "tenant" in a data center its own network topology and control over its traffic flow. Software-defined networking offers a standard interface between controller applications and switch-forwarding tables, and is thus a natural platform for network virtualization. Yet, supporting numerous tenants with different topologies and controller applications raises scalability challenges. The FlowN architecture gives each tenant the illusion of its own address space, topology, and controller, and leverages database technology to efficiently store and manipulate mappings between virtual networks and physical switches.
Drutskoy et al. REF proposed an SDN-based network virtualization framework, where SDN technology is used to offer a standard interface between controller applications and switch-forwarding tables.
Scalable Network Virtualization in Software-Defined Networks
IEEE Internet Computing
IEEE Internet Computing
Computer Science