[P4-discuss] Question about PI and PD

Aaron A. Glenn aaron at aagico.com
Sat May 19 12:54:17 EDT 2018


My sincere apologies. Please remove my post if possible.

On Sat, May 19, 2018, at 18:44, Antonin Bas wrote:
> Hi Aaron,
> 
> That link wasn't meant to be shared publicly. It was shared among P4 API WG
> participants only and anyone with the link was able to edit the document. I
> had to change the permissions of the doc to avoid people outside of the WG
> making edits by mistake.
> 
> On Sat, May 19, 2018 at 5:50 AM, Aaron A. Glenn <aaron at aagico.com> wrote:
> 
> > Hello Douglas,
> >
> > I'm far from an authority on the subject, but was similarly confused and
> > believe I've come to understand the situation better.
> >
> > On Fri, May 18, 2018, at 15:34, Douglas Litke wrote:
> > > I am confused about what is PI and what is PD
> > > I know PI = Protocol Independent. But what does it do? How is it related
> > > to P4Runtime (if it is)?
> > > I understand PD = Protocol Dependent. I assume this is the code that
> > > runs on the switch, and controls the ASIC. Correct?
> >
> > In the context of P4Runtime specifically, the distinction between
> > architecture/platform dependence or independence is of most interest.
> > P4Runtime is completely oblivious to any underlying protocol (even the RPC
> > between controller & agent, though gRPC & protobuf definitions are
> > exclusively being used, so far).
> >
> > I've tried to follow things in the P4 world very closely over the past two
> > years, but I missed the part where PI became P4Runtime. The repo name is
> > "still" PI on githubcom/p4lang, despite everything in it being P4Runtime.
> >
> > > Is there a defined interface between the P4Runtime code that decodes the
> > > messages from the Controller, and the code generated by the P4C that
> > > controls the ASIC? Or is it all one output?
> >
> > I believe that is P4Info. I'm only a few weeks into exploring that, so
> > I'll leave my commentary there :-)
> >
> > > I have gone through several presentations on P4 and P4Runtime, and have
> > > not been able to get a clear picture of the pieces. Maybe I just did not
> > > find the correct presentation.
> >
> > I imagine and hope the evolving v1.0.0 P4Runtime draft will be as
> > enlightening to you as it was me:
> >
> > https://docs.google.com/document/d/1o5E5sGwUJkQHnUUTl9ZPnvXp7nvZS
> > Eq2TRRH3_rpAUA/
> >
> > it took a bit of effort to find, and I apologize in advance if it is not
> > meant to be publicly announced or referenced!
> >
> >
> > Best,
> >
> > --
> >   Aaron A. Glenn
> >
> > +1 (877) 926-5767
> > AAGlenn Internetworking Company
> > Cheyenne, WY 82001 | +1 (307) 316-5767
> >
> > _______________________________________________
> > P4-discuss mailing list
> > P4-discuss at lists.p4.org
> > http://lists.p4.org/mailman/listinfo/p4-discuss_lists.p4.org
> >
> 
> 
> 
> -- 
> Antonin


-- 
  Aaron A. Glenn

+1 (877) 926-5767
AAGlenn Internetworking Company
Cheyenne, WY 82001 | +1 (307) 316-5767



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