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OpenFlow News

Archive for April, 2009

liboftrace – openflow debugging tool released

April 14th, 2009, capveg in OpenFlow Blog

Yesterday, I announced a new OpenFlow debugging tool: liboftrace.  oftrace is a library for parsing and analyzing openflow messages (as defined in openflow.h) from a network dump, i.e., from tcpdump or wireshark.  I imagine (hope? ;-) that people will find their own uses for this, but the two initial motivating applications for this library are:

ofstats: a program which calculates the controller processing delay, i.e., the difference in time between a packet_in message and the corresponding packet_out or flow_mod message.


ofdump: a program that simply lists openflow message types with timestamps by switch/controller pair.

liboftrace is a C library with a swig ( wrapper that allows it to be used from your favorite scripting language.  Both ofstats and ofdump applications have been ported to python ( and and are included in the tarball as examples.

More description and the actual code are available at:

If (when) you find bugs, please post them to our bug tracking system at :

Welcome Dan Talayco

April 8th, 2009, Guido Appenzeller in OpenFlow Blog
Dan Talayco

Dan Talayco

Up to now, the OpenFlow group at Stanford has provided reference implementations of OpenFlow for two different platforms, the software switch (which runs on any PC with several network interfaces) and the NetFPGA implementation. The challenge with this is that both of these implementations have a low total bandwidht (< 10 Gb/s) and typically low fan out (< 10 ports). With these limitations, some future OpenFlow features such as QoS are hard to test in a realistic way.

To address this problem, we have recently started an effort to develop an OpenFlow reference implementation that runs on a hardware switch. Our goal here is not to compete with the production quality implementations from NEC and HP, but to create a research platform for ourselves and other universities to test out experimental features.

The person spearheading this effort is our newest team member, Dan Talayco. Dan has a background in developing software for switches from his work at Broadcom, and in an earlier life was a faculty at Franklin and Marshall college. Expect to see more from him on this blog in the next few months.

Welcome Dan!