Hi,
what Keith says makes sense. I believe mandating support for multipart
in SIP is a SIP-specific problem. Mandating suppport for
multipart/alternative is also a SIP-specific problem, since a
SIP-specific problem such as the transition to new session description
formats depends on that.
However, specifying if an implementation that supports multipart should
support nested body parts or not is something more general on which the
email folks have a lot of experience.
Cheers,
Gonzalo
DRAGE, Keith (Keith) wrote:
Well, at the moment, what I am trying to do is get some understanding of
what we should scope as valid SIP work.
We need to be able to understand why something that is clearly a generic
problem for specification of nested MIME bodies merits a SIP specific
solution.
So:
- is a generic solution already documented elsewhere?
- if a generic solution is not documented elsewhere, should one be
documented, rather than a specific SIP solution?
Regards
Keith
> -----Original Message-----
> From: Christer Holmberg (JO/LMF)
> [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, May 30, 2007 8:52 AM
> To: DRAGE, Keith (Keith); Gonzalo Camarillo (JO/LMF); Paul Kyzivat
> Cc: [email protected]
> Subject: RE: [Sip] MIME: Nested bodies with option-tag?
>
>
> Hi Keith,
>
> >Once we get down to a decision of supporting nested versus not
> >supporting nesting, presumably we are then entirely in the
> realm of the
> >multipart coding itself.
> >
> >Could I ask someone to elaborate on what generic
> requirements already
> >exist within multipart/mime in this respect, before we start
> looking at
> >defining SIP specific rules or indications?
>
> I am very sure that I have seen text related to the support
> of nested multiparts, and what nodes are expected to support,
> somewhere, but I yet have not found it.
>
> Regards,
>
> Christer
>
>
> >
> > Regards
> >
> > Keith
> >
> > > -----Original Message-----
> > > From: Christer Holmberg (JO/LMF)
> > > [mailto:[EMAIL PROTECTED]
> > > Sent: Tuesday, May 29, 2007 2:47 PM
> > > To: Gonzalo Camarillo (JO/LMF); Paul Kyzivat
> > > Cc: [email protected]
> > > Subject: RE: [Sip] MIME: Nested bodies with option-tag?
> > >
> > >
> > > Hi,
> > >
> > > My main concern is not what wording (SHALL, MUST, etc) we use.
> > >
> > > The issue is that I think we need text saying what
> implementations
> > > that DO NOT support alternative and/or nested shall do. If
> > we say that
> > > they shall reject the message I believe that many of the existing
> > > implementations will be compliant with the spec.
> > >
> > > And, if we give the possibility to simply reject the message, I
> > > believe it will be easier to get people to change their
> > > implementations, if they currently simply discard
> > alternative and/or
> > > nested today.
> > >
> > > Regards,
> > >
> > > Christer
> > >
> > >
> > > > -----Original Message-----
> > > > From: Gonzalo Camarillo [mailto:[EMAIL PROTECTED]
> > > > Sent: 29. toukokuuta 2007 16:06
> > > > To: Paul Kyzivat
> > > > Cc: Christer Holmberg (JO/LMF); [email protected]
> > > > Subject: Re: [Sip] MIME: Nested bodies with option-tag?
> > > >
> > > > Hi,
> > > >
> > > > what I am hearing is that there are implementations out
> > there that
> > > > support multipart but not nested. Therefore, we need to
> decide two
> > > > things:
> > > >
> > > > 1) do we want to have a MUST for multipart and a SHOULD for
> > > nested? I
> > > > would say that we should have the same level (e.g., MUST, if we
> > > > decided that MUST is appropriate) for both.
> > > >
> > > > 2) do we need a way for implementations that support
> > > multipart but not
> > > > nested to be quickly updated to, at least, report that
> > fact with an
> > > > error response? This may make sense.
> > > >
> > > > Cheers,
> > > >
> > > > Gonzalo
> > > >
> > > > Paul Kyzivat wrote:
> > > > > More or less repeating what I said before:
> > > > >
> > > > > I expect we do have to account in some way for
> > > implementations that
> > > > > have already been deployed, in absence of a
> clarifying document.
> > > > > Exactly how we deal with that is still TBD.
> > > > >
> > > > > But as we define what is required to support this in the
> > > future, I
> > > > > think there is *no* benefit to defining two levels of
> > > > support - full
> > > > > and partial. Anybody that sets out to provide support
> for this
> > > > > document should be expected to do it all - its not that
> > > much harder.
> > > > >
> > > > > Paul
> > > > >
> > > > > Christer Holmberg (JO/LMF) wrote:
> > > > >> Hi,
> > > > >>> I wonder whether we should define an option-tag for the
> > > > support of
> > > > >>> nested bodies.
> > > > >>>
> > > > >>> I don't think there's a lot to be gained from
> > defining such an
> > > > >>> option-tag. The sender should already be aware that
> > > > there is a risk
> > > > >>> the recipient can't understand nested bodies, and have
> > > > arranged for
> > > > >>> suitable fallbacks. Conversely, the recipient should (at
> > > > least) be
> > > > >>> able to skip the nested multipart body part in the proper
> > > > "I don't
> > > > >>> understand this body part" way. All an option-tag would
> > > > do is allow
> > > > >>> the sender to not add a fallback.
> > > > >>
> > > > >> In that case we need some specific text saying that if the
> > > > receiver
> > > > >> does not support nested multiparts it MUST
> do-this-and-do-that.
> > > > >>
> > > > >> Because, as I said earlier, I don't think we will
> > > achieve what we
> > > > >> want by saying that one MUST be able to parse nested
> > > > multiparts. It
> > > > >> can be rather tricky to implement (depending on how the
> > > parser is
> > > > >> implemented, though), and since there aren't really any
> > > > use-cases out
> > > > >> there yet I am pretty sure some people will choose not to
> > > > implement
> > > > >> it (and saying that people are not compliant in that
> > > case will not
> > > > >> really help from an interop perspective). So, because of
> > > > that I think
> > > > >> it would be good not to mandate the support of nested
> > > > multiparts, but
> > > > >> to mandate appropriate behavior if not supported - just
> > > > like in any
> > > > >> other case when a MIME body contains an unsupported but
> > > > required content type.
> > > > >>
> > > > >> Regards,
> > > > >>
> > > > >> Christer
> > > > >>
> > > > >>
> > > > >>
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> > > > >>
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