Copyright © 2012 Nicira, Inc.

Licensed under the Apache License, Version 2.0 (the ``License''); you may not use this file except in compliance with the License.  You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an ``AS IS'' BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the specific language governing permissions and limitations under the License.

TITLE
*****

This manual is for PROGRAM, version VERSION.

Introduction
************

Open vSwitch is an Ethernet switch implemented in software.  It is well suited to environments that call for basic switching features such as VLANs and bonding.  However, Open vSwitch is built as a platform to open up network forwarding to programmatic extension, so it really shines in environments that demand fast, flexible control over the network.

The most common uses of Open vSwitch today deploy it as a software-based switch, that is, on general-purpose computers without hardware specialized for switching.  Within this class of uses, Open vSwitch is most often used on virtual server hosts, to forward traffic among virtual machines and to and from a physical network. Virtualization is not a requirement: Open vSwitch can also forward traffic among physical interfaces in a ``bare metal'' environment.

Open vSwitch is designed and internally layered to be amenable for use within special-purpose switch hardware, and a number of network hardware manufacturers have used it for that purpose.  This allows Open vSwitch to control high-performance hardware switches as well as software switches, although hardware is inherently less flexible than software.

What platforms?  What hypervisors? Why OVS? What is OpenFlow?