网络虚拟化-简介

What is Network Virtualization? – Definition

Network virtualization (NV) is defined by the ability to create logical, virtual networks that are decoupled from the underlying network hardware to ensure the network can better integrate with and support increasingly virtual environments. Over the past decade, organizations have been adopting virtualization technologies at an accelerated rate. Network virtualization (NV) abstracts networking connectivity and services that have traditionally been delivered via hardware into a logical virtual network that is decoupled from and runs independently on top of a physical network in a hypervisor. Beyond L2-3 services like switching and routing, NV typically incorporates virtualized L4-7 services including fireballing and server load-balancing. NV solves a lot of the networking challenges in today’s data centers, helping organizations centrally program and provision the network, on-demand, without having to physically touch the underlying infrastructure. With NV, organizations can simplify how they roll out, scale and adjust workloads and resources to meet evolving computing needs.

With virtualization, companies can take advantage of the efficiencies and agility of software-based compute and storage resources. While networks have been moving towards greater virtualization, it is only recently, with the true decoupling of the control and forwarding planes, as advocated by software-defined networking (SDN) and network functions virtualization (NFV), that network virtualization has become more of a focus.

What Exactly is the Definition of Network Virtualization?

Virtualization is the ability to simulate a hardware platform, such as a server, storage device or network resource, in software. All of the functionality is separated from the hardware and simulated as a “virtual instance,” with the ability to operate just like the traditional, hardware solution would. Of course, somewhere there is host hardware supporting the virtual instances of these resources, but this hardware can be general, off-the-shelf platforms. In addition, a single hardware platform can be used to support multiple virtual devices or machines, which are easy to spin up or down as needed. As a result, a virtualized solution is typically much more portable, scalable and cost-effective than a traditional hardware-based solution.

Applying Virtualization to the Network

When applied to a network, virtualization creates a logical software-based view of the hardware and software networking resources (switches, routers, etc.). The physical networking devices are simply responsible for the forwarding of packets, while the virtual network (software) provides an intelligent abstraction that makes it easy to deploy and manage network services and underlying network resources. As a result, NV can align the network to better support virtualized environments.

NV and White Box Switching

As it stands, the trend is toward using NV to create overlay networks on top of physical hardware. Concurrently, using network virtualization reduces costs on the physical (underlay) network by using white box switches. Referring to the use of generic, off-the-shelf switches and routers, white box networking limits expenditures by not using expensive proprietary switches. NV also contributes to decreased expenses by relying on the intelligence of the overlay to provide necessary advanced network functionality and features.

Virtual Networks

NV can be used to create virtual networks within a virtualized infrastructure. This enables NV to support the complex requirements in multi-tenancy environments. NV can deliver a virtual network within a virtual environment that is truly separate from other network resources. In these instances, NV can separate traffic into a zone or container to ensure traffic does not mix with other resources or the transfer of other data.