Implement userspace switch.

[sliver-openvswitch.git] / README

diff --git a/README b/README
index 36f9187..cb0a9fc 100644 (file)
--- a/README
+++ b/README
@@ -30,17 +30,22 @@ Specification [2].
 What's here?
 ------------
 
-This distribution includes a Linux-specific reference implementation
-of an OpenFlow switch, comprising:
+This distribution includes two different reference implementations of
+an OpenFlow switch.  The first implementation, which is closely tied
+to Linux because it is partially implemented in the Linux kernel, has
+the following components:
 
        - A Linux kernel module that implements the flow table and
-          OpenFlow protocol.
+          OpenFlow protocol, in the datapath directory.
 
        - secchan, a program that implements the secure channel
           component of the reference switch.
 
        - dpctl, a tool for configuring the kernel module.
 
+The second implementation is a single user-space program, named
+"switch", that integrates all three parts of an OpenFlow switch.
+
 This distribution includes some additional software as well:
 
        - controller, a simple program that connects to any number of
@@ -63,11 +68,11 @@ directory.
 Platform support
 ----------------
 
-Other than the Linux kernel module, the software in the OpenFlow
-distribution should compile under Unix-like environments such as
-Linux, FreeBSD, Mac OS X, and Solaris.  Our primary test environment
-is Debian GNU/Linux.  Please contact us with portability-related bug
-reports or patches.
+Other than the Linux kernel module and userspace switch
+implementation, the software in the OpenFlow distribution should
+compile under Unix-like environments such as Linux, FreeBSD, Mac OS X,
+and Solaris.  Our primary test environment is Debian GNU/Linux.
+Please contact us with portability-related bug reports or patches.
 
 The Linux kernel module is, of course, Linux-specific, and the secchan
 and dpctl utilities will not be as useful without the kernel module.
@@ -75,6 +80,11 @@ The testing of the kernel module has focused on Linux 2.6.23.  Linux
 2.6 releases from 2.6.15 onward and Linux 2.4 releases from 2.4.20
 onward should also work.
 
+The userspace switch implementation should be easy to port to
+Unix-like systems.  The interface to network devices, in netdev.c, is
+the only code that should need to change.  So far, only Linux is
+supported.  We welcome ports to other platforms.
+
 GCC is the expected compiler.
 
 Bugs/Shortcomings