Re: [DMM] Call for adoption of draft-hmm-dmm-5g-uplane-analysis-02 as DMM WG document

[Behcet Sarikaya <[e-mail]>]

On Thu, Nov 15, 2018 at 2:03 PM David Allan I <[e-mail]>
wrote:

> Hi Shunsuke:
>
> First off I think there is a charter problem in that there are no
> milestones that are not 18 months out of date.  That is independent of
> draft-hmm.
>
> If I look at the list of topics that the charter suggests the WG could
> produce draft on I don't see a fit with any of them. The closest being:
>         Distributed mobility management deployment models and scenarios:
>          describe the target high-level network architectures and
>         deployment models where distributed mobility management
>         protocol solutions would apply
>
> However the charter describes a DMM solution as one being:
>         "The IETF Distributed Mobility Management (DMM) working group
>         (WG) specifies solutions for IP networks so that traffic between
> mobile
>         and correspondent nodes can take an optimal route."
>
> I cannot connect the content of draft-hmm with these objectives.  At the
> moment it appears clear that the draft has been written for the purpose of
> advocacy explicitly to 3GPP of user plane protocols.  I suppose it could be
> claimed to describe parts of the 5G architecture and that is useful, but a
> lot would need to be expunged from the draft before that part of it was
> useful to capture for archival or educational purposes.
>
> The draft's primary



> claim to fame


Wow! Claim to fame. I like that, very classy  :-)

Behcet

> from what I can tell is the conclusion that support for SSC mode 3  would
> benefit from a UP change to permit mp2p tunneling. Now I will certainly not
> claim to be an expert, and was not in the room when any of this was
> discussed in 3GPP or codified (full disclaimer, never attended a meeting).
> But my understanding of SSC mode 3 and branching is that this is a
> mechanism to support a network initiated change of UPF in a make before
> break fashion and is likely only a temporary situation.  The actual
> practice being to set up the branch point and new UPF, and the UE lets all
> old prefix correspondent sessions quiesce, while initiating all new
> sessions with the new prefix, at which point connectivity to the old UPF
> can be torn down .   As such I would consider suggesting this is a serious
> problem that requires a complete UP change from RAN to DN is a questionable
> and possibly dangerous conclusion.  I would also observe that any sort of
> solution to mp2p tunneling for the 5GC does not appear to be part of DMM's
> objectives as described in the charter; it claims to reduce state for a
> rare operational procedure, and is not a solution to optimal routing of UE
> traffic.
>
> I hope this helps
> Dave
>
>
> -----Original Message-----
> From: Shunsuke Homma <[e-mail]>
> Sent: Thursday, November 15, 2018 1:19 AM
> To: [e-mail]; David Allan I <[e-mail]>
> Cc: [e-mail]
> Subject: Re: [DMM] Call for adoption of
> draft-hmm-dmm-5g-uplane-analysis-02 as DMM WG document
>
> Hi Dave,
>
> Thank you for reviewing our draft and sending your thought for the
> adoption.
>
> When I reviewed the charter I couldn't find any text to make the draft to
> be out of scope. Could you please elaborate it with the text in the charter?
>
> Best regards,
>
> Shunsuke
>
>
> On 2018/11/15 6:52, David Allan I wrote:
> > HI
> >
> > AFAIK 3GPP CT4 is looking for work it can adopt, and has indicated
> > that it wishes to perform the analysis itself. When they were directed
> > to this document in the recent IETF DMM liaison, it  resulted in a
> > liaison reply clearly indicated they would define their own criteria.
> >
> > https://datatracker.ietf.org/liaison/1590/
> >
> > However in the draft it states in the introduction: "However we
> > believe that to provide adequate information for 3GPP, we need to
> > clearly understand what the current user plane protocol is in Release
> > 15, and architectural requirements for the user plane." And in the
> > conclusion "Our conclusion here is that we suggest the UP protocol
> > study work in 3GPP takes into account the evaluation aspects described
> > in Section 5.", there is more, but I do not feel a need to be pedantic
> about it.
> >
> > So the purpose of this draft seems to explicitly be to do work for
> > 3GPP that they have explicitly said they DO NOT WANT.
> >
> > At the same time I do not see anything in the charter that suggests we
> > should be doing this work either.  It would appear to have little to
> > do with DMM's chartered direction.
> >
> > As such I am opposed to adoption of the draft.
> >
> > Cheers
> >
> > Dave
> >
> >
> >
> > _______________________________________________
> > dmm mailing list
> > [e-mail]
> > https://www.ietf.org/mailman/listinfo/dmm
> >
>
>
> --
> ----------------------------------
> Shunsuke Homma
> <[e-mail]>
> TEL: [phone]
> FAX: [phone]
>
> NTT Network Service Systems Labs.
> Musashino city, Tokyo, Japan
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