Re: Alia Atlas' Discuss on draft-ietf-bfd-seamless-ip-04: (with DISCUSS)

[Alia Atlas <[e-mail]>]

Hi Carlos,

On Mon, May 2, 2016 at 7:22 PM, Carlos Pignataro (cpignata) <
[e-mail]> wrote:

> Hi Alia,
>
> Thanks for the review and for these! Please see inline.
>
> > On May 2, 2016, at 6:26 PM, Alia Atlas <[e-mail]> wrote:
> >
> > Alia Atlas has entered the following ballot position for
> > draft-ietf-bfd-seamless-ip-04: Discuss
> >
> > When responding, please keep the subject line intact and reply to all
> > email addresses included in the To and CC lines. (Feel free to cut this
> > introductory paragraph, however.)
> >
> >
> > Please refer to
> https://www.ietf.org/iesg/statement/discuss-criteria.html
> > for more information about IESG DISCUSS and COMMENT positions.
> >
> >
> > The document, along with other ballot positions, can be found here:
> > https://datatracker.ietf.org/doc/draft-ietf-bfd-seamless-ip/
> >
> >
> >
> > ----------------------------------------------------------------------
> > DISCUSS:
> > ----------------------------------------------------------------------
> >
> > I think that these are both simple fast issues to resolve.
> >
> > 1) Sec 3: "This document defines only the UDP port value
> >   for the S-BFD Echo function.  The source port and the procedures for
> >   the S-BFD Echo function are outside the scope of this document."
> > Please add a reference to the S-BFD base document for defining where the
> > procedures are found.
> >
> > Where, precisely, is the source port defined?  It wasn't in the S-BFD
> > base
> > document.  This seems like a hole.  Can you please clarify?
>
> This is done exactly as in RFC 5881, purposefully. I can add a clarifying
> sentence like:
>
> OLD:
>    This document defines only the UDP port value
>    for the S-BFD Echo function.  The source port and the procedures for
>    the S-BFD Echo function are outside the scope of this document.
>
> NEW:
>    S-BFD echo follows the BFD echo definitions of [RFC 5881].
>    Consequently, this document defines only the UDP port value
>    for the S-BFD Echo function; the source port and the procedures for
>    the S-BFD Echo function are outside the scope of this document.
>

How about a reference by the source port to [RFC 5881] and a reference
for the procedures for the S-BFD Echo function
[draft-ietf-bfd-seamless-base]?

What wasn't clear to me - not having recently read RFC 5881 in detail - was
that the UDP source port was defined in RFC 5881.  I knew the procedures
were
in draft-ietf-bfd-seamless-base.


> >
> > 2) Sec 4:  " If the port is not 7784, then the packet MUST be looked up
> > to locate
> >   a corresponding SBFDInitiator session or classical BFD session based
> >   on the value from the "your discriminator" field in the table
> >   describing BFD discriminators. "
> >
> > I assume that you mean that UDP source port is used to look up the
> > appropriate receiver.
> > If that receiver handles BFD and S-BFD packets, then the "your
> > discriminator" field is used
> > to identify the BFD session.   PLEASE clarify that because this reads as
> > if BFD is the only
> > application that uses UDP.
> >
>
> Indeed, very much so. I suggest:
>
> OLD:
>    If the port is not 7784, then the packet MUST be looked up to locate
>    a corresponding SBFDInitiator session or classical BFD session based
>    on the value from the "your discriminator" field in the table
>    describing BFD discriminators.  If the located session is an
>    SBFDInitiator, then the destination IP address of the packet SHOULD
>    be validated to be for self.  If the packet is a classical BFD
>    session, then the procedures from [RFC5880] apply.
>
> NEW:
>    If the port is not 7784, but the packet is demultiplexed to be for an
>    SBFDInitiator, then the packet MUST be looked up to locate
>    a corresponding SBFDInitiator session based
>    on the value from the "your discriminator" field in the table
>    describing BFD discriminators.  In that case,
>    then the destination IP address of the packet SHOULD
>    be validated to be for itself.  If the packet demultiplexes to a
> classical BFD
>    session, then the procedures from [RFC5880] apply.
>
> Would that work?
>

Sure - sounds good.  Thanks,
Alia


> Thanks,
>
> — Carlos.
>
> >
> >
> >
>
>