Hi,

Trema's packet parser (set_match_from_packet()) is b).
Trema also provides normalize function (normalize_match()) to absorb
implemental differences of different switches.

Trema-switch is a).

Regards,

HIDE



> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of
> Christian Esteve Rothenberg
> Sent: Tuesday, October 02, 2012 11:47 PM
> To: Eder Leão Fernandes
> Cc: [email protected]
> Subject: Re: [openflow-discuss] How masked values are stored in the Flow
> Table on OpenFlow 1.2?
> 
> Hi all,
> 
> just looking for further clarification on the issue of how to handle
> OXM wildcarded flow entries.
> 
> If the controller sends a flow mod command that includes a flow match
> as follows:
> IP 192.168.1.1 IP_mask= 255.255.0.0
> 
> How should the flow entry installed by the switch look like?
> 
> a)  IP 192.168.1.1 IP_mask= 255.255.0.0
> 
> or
> 
> b)  IP 192.168.0.0 IP_mask= 255.255.0.0
> 
> ?
> 
> While for actual packet matching purposes it does not matter, it
> matters when you want to query about statitstics or when you want to
> modify flow entries, as the field and mask values needs to be
> syntatctically equal, not functionally equal (i.e. after applying the
> mask).
> 
> Our interpretation is that the mask should not be applied by the switch
> when
> installing the entry and should be respect what was sent by the controller
> (a). However, we have encoutered 1.2 prototype implementations that
> seem to have opted for the
> second interpretation (b).
> 
> That said, it seems like a good best practice that the controller
> itself applies any widlcards to the match field before sending any
> protocol message with an OXM flow match structure.
> 
> -Christian
> 
> 
> On Fri, Sep 28, 2012 at 10:49 AM, Eder Leão Fernandes
> <[email protected]> wrote:
> > Hi,
> >
> > I have a question regarding how masked OXM values are stored in the flow
> > tables.  I would like to know if the values should be stored with the
> > respective mask applied?
> > For example:
> > If I have an IP source value 192.168.16.150 and mask 0xffffff00. The
value
> > should be stored as 192.168.16.150 or 192.168.16.0?
> >
> > I'm asking this because, when testing Ryu Controller  with CPqD
> > implementation of OpenFlow 1.2 software switch, I noticed that tests
with
> > masked fields expect values with the mask
> > applied, leading to failures, since the switch implementation doesn't
> stores
> > the values with the masks applied.
> >
> > Thanks in advance,
> > Eder.
> >
> > --
> >
> >
> > _______________________________________________
> > openflow-discuss mailing list
> > [email protected]
> > https://mailman.stanford.edu/mailman/listinfo/openflow-discuss
> >
> 
> 
> 
> --
> Christian
> _______________________________________________
> openflow-discuss mailing list
> [email protected]
> https://mailman.stanford.edu/mailman/listinfo/openflow-discuss

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