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OpenFlow 1.0 release candidate available

December 19th, 2009, Glen Gibb in OpenFlow Blog

We are pleased to announce the availability of release candidates for the OpenFlow 1.0 specification and reference switch.

The release candidates are being made available to provide the community with an opportunity to provide feedback prior to the official release. We plan on making the release official by the end of year (12/31) so please provide feedback before this date. Bugs reported in the reference software may not be corrected prior to the official release depending upon their severity; we plan to make a bug fix release in the new year that will address as many bugs as possible.

New features

New features added to the 1.0 specification include:

  • Slicing support (multiple queues per port with minimum bandwidth guarantees)
  • Matching on IP fields inside ARP packets
  • Matching on IP ToS bits
  • Improved flow duration resolution in stats/expiry
  • Opaque flow cookies added to flows
  • Ability to retrieve port stats for individual ports
  • User-specifiable datapath description added to desc stats

The updated specification also includes numerous clarifications. For a more detailed list of changes please see the release notes ( and the development wiki (

Reference switch changes

The reference switch is 1.0-RC compliant.

Kernel-mode support (comprising the datapath kernel module) has been dropped from the reference implementation. We plan a separate kernel module release some time in 1H2010.


This is the best-tested release that we’ve ever made available. The reference switch has been run in a production network for a period of two weeks to test the new features and general stability of the code base.

The test network was run under the control of two different controllers: the reference controller (distributed as part of the reference) and a 1.0-compatible version of NOX 0.6. Each controller was run for a period of about a week. Special testing modules were used with NOX to exercise each of the new features.

The reference switch has also successfully passed the regression tests on the following Linux distributions:

  • Ubuntu 9.10 (32-bit and 64-bit)
  • Debian unstable (32-bit)
  • Fedora Core 12 (32-bit)
  • CentOS 5.4 (32-bit)

Known issues

The current implementation of slicing has been observed to provide poor isolation between queues on the same port when run on systems with low-performance embedded CPUs. These problems have not been observed on systems with higher-performance CPUs.

Please see the release notes for other known issues.

Feedback and bug reporting

One important way to improve OpenFlow is to provide feedback and report bugs. Two mailing lists exist for discussing issues related to the spec and reference implementation. These lists are:

Please visit to subscribe to these lists.

Please report bugs using the OpenFlow Trac system:
Please provide as much information as possible when submitting bugs to aid the process of reproducing and diagnosing the bug.


The specification and reference switch can be downloaded from:

The specification and reference switch can also be obtained via git:

git clone git://
cd openflow
git checkout -b devel/1.0-rc origin/devel/1.0-rc


We would like to thank everyone who contributed to OpenFlow to help make this release possible.

2 Responses to “OpenFlow 1.0 release candidate available”

  1. Steve F. Says:

    This is a piece of junk. None of the links on this page works. This OPENFLOW is dead on arrival !!!

  2. grg Says:

    Thanks for reporting the issue — all links have been fixed.