Subject: Re: [sfc] Next Protocol = "None"

From: Greg Mirsky <[email-masked]>
Date: Sat, 1 Jul 2017 12:46:38 -0700

Hi Adrian,
predictably, I'll ask about OAM section.
The document states:

   Since OAM information will be carried in packets that also include
   payload data, that information must be carried in metadata.

I agree, that if we want to interleave or piggy-back OAM with payload
placing OAM information as metadata may be the right option in SFC.

But what about active OAM, e.g. Echo Request/Reply or proactive
monitoring? Should OAM be carried as metadata in these cases as well?

It is possible but I'm concerned that too flexible TLV format may
prove to be costly for HW-based implementation of SFC OAM.

Regards,

Greg

On Thu, Jun 29, 2017 at 3:44 PM, Adrian Farrel <[email-masked]> wrote:

> All,
>
> I refreshed this draft with a little polish.
>
> Recall, it describes how, by setting the NSH "next protocol" field to
> "None" it
> is possible to send an NSH packet without user data but with metadata.
>
> Also recall that this document contains a description of how to handle an
> NSH
> packet with an unknown/unsupported "next protocol" field value.
>
> We previously discussed whether to move some or all of this material to
> the NSH
> document.
> The feeling that I recorded was that the description of handling unknown
> next
> protocols needs to be in the NSH spec, but that it might be wise to leave
> the
> meaning and use of "none" to a separate document to avoid delaying the NSH
> spec.
> I would note that the lack of rapid advancement of the NSH spec might
> suggest
> that we should roll all of this in together.
>
> Along the way, I found I needed to write text about the security
> implications of
> metadata and the way that metadata should be secured. In theory, this
> should all
> be covered in the NSH spec, but it isn't.
>
> Cheers,
> Adrian
>
> > -----Original Message-----
> > From: I-D-Announce [mailto:[email-masked]] On Behalf Of
> > [email-masked]
> > Sent: 29 June 2017 23:28
> > To: [email-masked]
> > Subject: I-D Action: draft-farrel-sfc-convent-02.txt
> >
> >
> > A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
> >
> >
> >         Title           : Operating the Network Service Header (NSH)
> with Next
> Protocol
> > "None"
> >         Authors         : Adrian Farrel
> >                           John Drake
> >       Filename        : draft-farrel-sfc-convent-02.txt
> >       Pages           : 10
> >       Date            : 2017-06-29
> >
> > Abstract:
> >    This document describes the use of the Network Service Header (NSH)
> >    in a Service Function Chaining (SFC) enabled network with no payload
> >    data and carrying only metadata.  This is achieved by defining a new
> >    NSH "Next Protocol" type value of "None".
> >
> >    This document illustrates some of the functions that may be achieved
> >    or enhanced by this mechanism, but it does not provide an exhaustive
> >    list of use cases, nor is it intended to be definitive about the
> >    functions it describes.  It is expected that other documents will
> >    describe specific use cases in more detail and will define the
> >    protocol mechanics for each use case.
> >
> >
> >
> > The IETF datatracker status page for this draft is:
> > https://datatracker.ietf.org/doc/draft-farrel-sfc-convent/
> >
> > There are also htmlized versions available at:
> > https://tools.ietf.org/html/draft-farrel-sfc-convent-02
> > https://datatracker.ietf.org/doc/html/draft-farrel-sfc-convent-02
> >
> > A diff from the previous version is available at:
> > https://www.ietf.org/rfcdiff?url2=draft-farrel-sfc-convent-02
> >
> >
> > Please note that it may take a couple of minutes from the time of
> submission
> > until the htmlized version and diff are available at tools.ietf.org.
> >
> > Internet-Drafts are also available by anonymous FTP at:
> > ftp://ftp.ietf.org/internet-drafts/
> >
> > _______________________________________________
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>
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