simple Ethernet flow switch that exposes a standardized interface for
adding and removing flow entries.
-An OpenFlow Switch consists of three parts: (1) A "flow table" in
+An OpenFlow switch consists of three parts: (1) A "flow table" in
which each flow entry is associated with an action telling the switch
how to process the flow, (2) a "secure channel" connecting the switch
to a remote process (a controller), allowing commands and packets to
protocol implementation, providing an open and standard way for a
controller to talk to the switch.
-An OpenFlow Switch can thus serve as a simple datapath element that
+An OpenFlow switch can thus serve as a simple datapath element that
forwards packets between ports according to flow actions defined by
the controller using OpenFlow commands. Example actions are:
- Drop this flow's packets
- Encapsulate and forward this flow's packets to the controller.
-The OpenFlow Switch is defined in detail in the OpenFlow Switch
+The OpenFlow switch is defined in detail in the OpenFlow switch
Specification [2].
What's here?
------------
-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:
+This distribution includes two 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, in the datapath directory.
- dpctl, a tool for configuring the kernel module.
-The second implementation is a single userspace program, named
-"switch", that integrates all three parts of an OpenFlow switch.
+The second implementation has the following components:
+
+ - udatapath, which implements the same functionality as the
+ Linux kernel module in userspace, at a cost in performance.
+
+ - secchan, a program that implements the secure channel
+ component of the reference switch (the same program used in
+ the kernel-based implementation).
This distribution includes some additional software as well:
- A patch to tcpdump that enables it to parse OpenFlow
messages.
-For installation instructions, read INSTALL. This distribution also
-includes manpages for each of its userspace programs, in the man/
-directory.
+For installation instructions, read INSTALL. Each userspace program
+is also accompanied by a manpage.
Platform support
----------------
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.
-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 Linux kernel module is, of course, Linux-specific, and the dpctl
+utility will not be useful without the kernel module. The testing of
+the kernel module has focused on Linux 2.6.26. 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
+The userspace datapath 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
+the code most likely to need changes. So far, only Linux is
supported. We welcome ports to other platforms.
GCC is the expected compiler.
Bugs/Shortcomings
-----------------
-- The flowtable does not support the "normal processing" action.
+- The flow table does not support the "normal processing" action.
References
----------