[ovs-discuss] ErrorMsg after requesting flow stats using OpenFlow 15

Ben Pfaff blp at ovn.org
Sun Nov 11 23:47:04 UTC 2018


OK, I took a look.  OVS just doesn't support that request in OF1.5 yet.
No one has implemented it.  As I've said, OF1.5 support is incomplete.

On Sun, Nov 11, 2018 at 11:34:11PM +0100, Jozef Valko wrote:
> Thanks a lot!
> OVS version 2.9.0 was installed along with Mininet emulator. I've already
> tried to update OVS to v2.10.1, but Mininet then met some issues in
> creating the emulation. Anyway, there was the same error with the newest
> OVS version.
> I have created a PCAP file for you. Kindly please have a look at the
> packets no. 89 and 90, these are the request and error reply packets.
> 
> Thank you for your time.
> Regards,
>  Jozef Valko.
> 
> 
> ne 11. 11. 2018 o 21:35 Ben Pfaff <blp at ovn.org> napísal(a):
> 
> > On Sun, Nov 11, 2018 at 09:12:03PM +0100, Jozef Valko wrote:
> > > Hello all,
> > > I am developing an SDN application using Ryu and Mininet. My goal is to
> > > develop security module on the top of Ryu controller. Therefore, I need a
> > > regular statistics update from the forwarders which are OVS bridges. For
> > > this purpose I am using OFPFlowStatsRequest function provided by Ryu
> > > parser. Below is the function which I am using:
> > > [image: image.png]
> > > This function runs in separate thread and sends the request every 10
> > > seconds.
> > > When I use this function with OpenFlow14 everything is fine, the
> > controller
> > > receives flow stats from the forwarder. But when I try to trigger this
> > > function using OpenFlow15, the following error shows in the controller
> > > window:
> > > [image: image.png]
> > > I tried to google this issue, searched in the specification and Ryubook
> > but
> > > I did not find any solution. Because Ryu doesn't crash, I suppose that
> > this
> > > is OVS-related issue.
> > > The only difference between requests in OF14 and OF15 is the value of the
> > > field 'type'. In case of OF14 it is 1 and in case of OF15 it is 17. Here
> > is
> > > the request before sending (OF15):
> > > [image: image.png]
> > > What can be an issue? How to properly request flow statistics from the
> > OVS
> > > forwarders using Ryu and OpenFlow15?
> > > Versions of the applications:
> > > Mininet - 2.3.0d4
> > > Ryu - ryu-manager 4.29
> > > OVS - ovs_version: "2.9.0"
> > >
> > > PortStatsRequest function is working nicely in both OF14 and OF15.
> >
> > OVS doesn't fully support OpenFlow 1.5 and does not enable it by
> > default, so I suppose that you turned it on yourself.  That is fine--we
> > are pleased to hear about problems with protocol versions that are not
> > yet complete.  Also, I don't see any problems with OF1.5 flow stats and
> > it seems to work OK in my own simple test case with ovs-ofctl.
> >
> > However, for testing incomplete protocol versions, one should use the
> > latest version of Open vSwitch.  Please try the latest release v2.10.1
> > or what one can find on master.
> >
> > Alternatively, if you can provide a hex dump of the message that Ryu is
> > sending OVS (or otherwise some kind of exact representation), I can test
> > that for you.
> >




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