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WHY-OVS: Update to reflect OVS's inclusion in Linux 3.3.

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Signed-off-by: Justin Pettit <jpettit@nicira.com>
Suggested-by: Martin Casado <casado@nicira.com>
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Justin Pettit
2012-03-20 23:23:00 -07:00
parent 012f5c4bd9
commit 81f9a03982
1 changed files with 11 additions and 10 deletions
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WHY-OVS
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@@ -1,13 +1,13 @@
Why Open vSwitch? Why Open vSwitch?
================= =================
We love the existing network stack in Linux. It is robust, flexible, Hypervisors need the ability to bridge traffic between VMs and with the
and feature rich. Linux already contains an in-kernel L2 switch (the outside world. On Linux-based hypervisors, this used to mean using the
Linux bridge) which can be used by VMs for inter-VM communication. So, built-in L2 switch (the Linux bridge), which is fast and reliable. So,
it is reasonable to ask why there is a need for a new network switch. it is reasonable to ask why Open vSwitch is used.
The answer is that Open vSwitch is targeted at multi-server The answer is that Open vSwitch is targeted at multi-server
virtualization deployments, a landscape for which the existing stack is virtualization deployments, a landscape for which the previous stack is
not well suited. These environments are often characterized by highly not well suited. These environments are often characterized by highly
dynamic end-points, the maintenance of logical abstractions, and dynamic end-points, the maintenance of logical abstractions, and
(sometimes) integration with or offloading to special purpose switching (sometimes) integration with or offloading to special purpose switching
@@ -83,7 +83,8 @@ vSwitch cope with the above requirements.
There are many ongoing efforts to port Open vSwitch to hardware There are many ongoing efforts to port Open vSwitch to hardware
chipsets. These include multiple merchant silicon chipsets (Broadcom chipsets. These include multiple merchant silicon chipsets (Broadcom
and Marvell), as well as a number of vendor-specific platforms. and Marvell), as well as a number of vendor-specific platforms. (The
PORTING file discusses how one would go about making such a port.)
The advantage of hardware integration is not only performance within The advantage of hardware integration is not only performance within
virtualized environments. If physical switches also expose the Open virtualized environments. If physical switches also expose the Open
@@ -92,13 +93,13 @@ vSwitch cope with the above requirements.
network control. network control.
In many ways, Open vSwitch targets a different point in the design space In many ways, Open vSwitch targets a different point in the design space
than the existing Linux networking stack, focusing on the need for than previous hypervisor networking stacks, focusing on the need for
automated and dynamic network control in large-scale Linux-based automated and dynamic network control in large-scale Linux-based
virtualization environments. virtualization environments.
The goal with Open vSwitch is to keep the in-kernel code as small as The goal with Open vSwitch is to keep the in-kernel code as small as
possible (as is necessary for performance) and to re-use existing possible (as is necessary for performance) and to re-use existing
subsystems when applicable (for example Open vSwitch uses the existing subsystems when applicable (for example Open vSwitch uses the existing
QoS stack). Open vSwitch limits disruption by using existing hooks into QoS stack). As of Linux 3.3, Open vSwitch is included as a part of the
the kernel, so Open vSwitch can be deployed as a module without kernel and packaging for the userspace utilities are available on most
requiring any modification to the kernel. popular distributions.