Suggested-by: Martin Casado <[email protected]>
---
WHY-OVS | 21 +++++++++++----------
1 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/WHY-OVS b/WHY-OVS
index ac9a381..e8c6f75 100644
--- a/WHY-OVS
+++ b/WHY-OVS
@@ -1,13 +1,13 @@
Why Open vSwitch?
=================
-We love the existing network stack in Linux. It is robust, flexible,
-and feature rich. Linux already contains an in-kernel L2 switch (the
-Linux bridge) which can be used by VMs for inter-VM communication. So,
-it is reasonable to ask why there is a need for a new network switch.
+Hypervisors need the ability to bridge traffic between VMs and with the
+outside world. On Linux-based hypervisors, this used to mean using the
+built-in L2 switch (the Linux bridge), which is fast and reliable. So,
+it is reasonable to ask why Open vSwitch is used.
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
dynamic end-points, the maintenance of logical abstractions, and
(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
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
virtualized environments. If physical switches also expose the Open
@@ -92,13 +93,13 @@ vSwitch cope with the above requirements.
network control.
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
virtualization environments.
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
subsystems when applicable (for example Open vSwitch uses the existing
-QoS stack). Open vSwitch limits disruption by using existing hooks into
-the kernel, so Open vSwitch can be deployed as a module without
-requiring any modification to the kernel.
+QoS stack). As of Linux 3.3, Open vSwitch is included as a part of the
+kernel and packaging for the userspace utilities are available on most
+popular distributions.
--
1.7.5.4
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