+ OpenFlow Reference Release v0.1.5 <http://openflowswitch.org>
+
+What is OpenFlow?
+-----------------
+
+OpenFlow is a flow-based switch specification designed to enable
+researchers to run experiments in live networks. OpenFlow is based on a
+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 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 be sent between
+the controller and the switch, and (3) An OpenFlow 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
+forwards packets between ports according to flow actions defined by
+the controller using OpenFlow commands. Example actions are:
+
+ - Forward this flow's packets to the given port(s)
+ - 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
+Specification [2].
+
+What's here?
+------------
+
+This software is a reference implementation of an OpenFlow Switch kernel
+module for the Linux operating system, a secure channel implementation,
+and an example controller that performs switching with MAC learning.
+
+The rest of this file contains the following sections:
+
+ - Description of the directory hierarchy
+ - Platform support
+ - Quickstart build and install instructions
+ - Shortcomings
+ - References
+
+Directory Hierarchy
+-------------------
+
+ Source:
+
+ datapath/ Linux kernel module implementing an OpenFlow Flow Table
+ that incoming packets are checked against. The
+ kernel module uses netlink (a socket protocol for
+ user-kernel communication, described in RFC 3549) to
+ pass OpenFlow messages with the secure channel to be
+ relayed to the controller.
+
+ secchan/ A Secure Channel that connects to a kernel datapath
+ via netlink and a remote controller via TCP,
+ relaying OpenFlow packets received on one end to the
+ other. (The current implementation does not
+ support SSL, but this will be added in future releases.)
+
+ controller/ A simple controller that connects to a datapath via
+ a Secure Channel, commanding the datapath to act as
+ a regular MAC learning switch.
+
+ utilities/ Contains the sorce for "dpctl", a command-line utility
+ for controlling the OpenFlow datapath kernel module.
+ With it, you can add physical ports to the datapath,
+ add flows, monitor received packets, and query the
+ datapath state.
+
+ include/ Header files common to the datapath, secure channel,
+ and controller components.
+
+ lib/ Implementation files common to the datapath, secure
+ channel, and controller components.
+
+ third-party/ Contains third-party software that may be useful for
+ debugging. Currently, it only contains a patch to
+ allow tcpdump to parse OpenFlow messages.
+
+ Documentation:
+
+ README Text file describing this OpenFlow implementation,
+ aka this document.
+
+ INSTALLATION Detailed configure, build, and installation
+ instructions
+
+ man/ Man pages describing how to administer datapath,
+ secure channel, and controller.
+
+Platform support
+----------------
+
+ The datapath kernel module supports Linux 2.6.15 and above, however,
+ testing has focused on Linux 2.6.23. Support for Linux 2.4.20 and
+ above is also in place, although testing has focused on Linux 2.6.
+
+ Components have been built and tested on Debian and Ubuntu.
+
+ If you are able to build/run the code on platforms not mentioned
+ here, or have problems with supported system, please report your
+ experiences to:
+
+ <info@openflowswitch.org>
+
+ GCC is required for compilation.
+
+
+Building and Installing (Quick Start)
+-------------------------------------
+
+ Building the datapath module requires that the source for the
+ currently running Linux kernel be installed on the machine and
+ been configured.
+
+ The following instructions assume the Linux 2.6 source is located in
+ /usr/src/linux-2.6.23 and Linux 2.4 in /usr/src/linux-2.4.35
+
+ 1. ./configure the package, passing the location of one or more
+ kernel source trees on the command line:
+
+ For example, if compiling for Linux 2.6:
+ % ./configure --with-l26=/usr/src/linux-2.6.23
+
+ Or compiling for Linux 2.4:
+ % ./configure --with-l24=/usr/src/linux-2.4.35
+
+ 2. Run make:
+
+ % make
+
+ The following binaries should be built.
+
+ Datapath kernel module:
+ ./datapath/linux-2.6/openflow_mod.ko (If compiling for Linux 2.6)
+ ./datapath/linux-2.4/openflow_mod.o (If compiling for Linux 2.4)
+
+ Secure channel executable:
+ ./secchan/secchan
+
+ Controller executable:
+ ./controller/controller
+
+ dpctl utility:
+ ./utility/dpctl
+
+ 3. Optionally you can "make install" to install binaries and the
+ man pages (/usr/local/ is the default prefix). If you just want
+ access to the man pages without installing, set your MANPATH to
+ include the openflow/ source root.
+
+ 4. Insert the datapath kernel module into the running Linux instance.
+
+ (Linux 2.6)
+ % insmod datapath/linux-2.6/openflow_mod.ko
+
+ (Linux 2.4)
+ % insmod datapath/linux-2.4/openflow_mod.o
+
+ 5. Create datapaths by running dpctl on the Linux host (see man
+ dpctl(8)). Start the controller on a remote host with
+ controller (see man controller(8)). Start the Secure Channel
+ on the datapath host to connect the datapath to the controller
+ with secchan(see man secchan(8)).
+
+ For more detailed installation instructions, refer to [3].
+
+
+Bugs/Shortcomings
+-----------------
+
+- The current flowtable does not support all statistics messages
+ mentioned in the Type 0 OpenFlow spec
+- The secure channel and sample controller don't support SSL
+- The flowtable does not support the "normal processing" action
+- Configure/build system does not support separate build directory for
+ the datapath. ./configure must be run from the source root.
+- dpctl dump-flows may freeze when large numbers of flows are in the
+ flow table. This has no affect on the datapath
+
+References
+----------
+
+ [1] OpenFlow: Enabling Innovation in College Networks. Whitepaper.
+ <http://openflowswitch.org/alpha/openflow-wp-v0.1.pdf>
+
+ [2] OpenFlow Switch Specification.
+ <http://openflowswitch.org/alpha/openflow-spec-v0.2.pdf>
+
+ [3] Installation Instructions: INSTALL
+
+Contact
+-------
+
+e-mail: info@openflowswitch.org
+www: http://openflowswitch.org/alpha/