Minutes IETF99: detnet
minutes-99-detnet-00

 DetNet Minutes IETF99 (Prague)
>
> Session 1:
> THURSDAY, July 20, 2017
> 0930-1200  Morning Session I
> Congress Hall I
>
> Slides:       https://datatracker.ietf.org/meeting/99/session/detnet
> Etherpad:    
http://etherpad.tools.ietf.org:9000/p/notes-ietf-99-detnet?useMonospaceFont=true
> Meetecho:     http://www.meetecho.com/ietf99/detnet > Audio stream 
http://ietf99streaming.dnsalias.net/ietf/ietf993.m3u > Jabber: 
xmpp:detnet@jabber.ietf.org?join > > Available post session: > Recording: 
https://www.ietf.org/audio/ietf99/ > YouTube:   
https://www.youtube.com/watch?v=rrqVLyJCfvk > > Num Start #Min Information > 0 
 9:30   10  Title:  Intro, WG Status, Draft Status >                Presenter: 
Chairs Question for discussion by WG, ready for last call on Arch draft? Use
Cases mature but no rush to close door, new use cases coming in, old ones still
under discussion. At some point need to ship it. Not critical for near term.
Once not rev'd for a while will call it done. Will do last call on (which one?)
Completing dataplane alternatives is not too critical. It was helpful coming up
with the dataplane solutions draft. Security draft on the agenda, would like to
ask if ready for adoption.

> 1   9:40   15  Title:  DetNet Architecture
>                Presenter:  Norm Finn
>                Draft: 
https://tools.ietf.org/html/draft-ietf-detnet-architecture-02

No substantial change since March'17. Just clarifications etc.
Arch doc - remove sec 5 on ideas that didn't make it. Then ask for WG last call.
Everyone should look over it, meanwhile do removal as planned. If removed text
is a problem, please propose text on how to resolve. Pascal Thubert: Wireless
is experimental, too early to put in this draft, so not working on it Lou
Berger: (poll)   How many have read this version: a good number
        How many have read other versions: also a good number
How many think ready for LC: also a reasonable number
Lou Berger: Once planned update is publish will move towards last call, so
please read and send comments and proposed text to the list.

> 2   9:55   30  Title:  DetNet Data Plane Encapsulation
>                Presenter:  Jouni Korhonen
>                Draft:  https://tools.ietf.org/html/draft-dt-detnet-dp-sol-01
<slide 10>
Stewart Bryant: Would be good if had a unified approach that could then be
adapted to the underlay only once. Jouni Korhonen: Last time got feedback that
encapsulation was nogo due to not being done that way before. Stewart Bryant:
Will need more discussion, particularly if need new HW Lou Berger: Tradeoffs -
I personally agree that it's unfortunate to not have a single encapsulation,
but the elimination of PWs on end stations makes their stack support of DetNet
easier.  I also agree that it needs to be consider further once WG document.
Stewart Bryant: Look forward to have the discussion around adoption. Norm Finn:
Much of the focus on the data plane docs has been on sequence number defined
needed for PREF. Not necessary for hard partitioning (zero congestion, fix
latency) doesn't need serialization. Maybe thus more flexible in terms of
encapsulation? Some applications that don't need serialization might be easier.
Stewart Bryant: Is simpler design that works for "most" applications better?
Lou Berger: Separable between flow ID and encapsulation. Two building blocks.
Greg Mirskey: Is PW an Ethernet PW? There are different types of PWs. Jouni
Korhonen: Yes, typical Ethernet PW. Greg Mirskey: Usually no seq number in
Ethernet PW? And many implementations don't even implement control word. Jouni
Korhonen: Assume we always have a control word, if HW doesn't support it, too
bad. If want PW device to be DetNet capable won't be available off the shelf,
will need to adapt it. Thus we are brave enough to take this step. Lou Berger:
Said another way if hardware doesn't support the protection function,
serialization isn't need. Pat Thaler: Old HW won't support DetNet timing
requirements, so probably can't do DetNet over old HW.  Also, it is important
to support control work in general - w/o it can't distinguish bet IPv4 vs v6.
Stewart Bryant: Old HW didn't support control word (CW) so would be new
implementation. Encouraging people to put CW in for reasons suggested by Pat.
Expect all new hardware to support the control work.  Sequence number is an
option, but don't think any have implemented it. Pat Thaler: Packet Replication
and Elimination Function (PREF) has been part of DetNet since the start.  It is
necessary for some of the use cases and requires serial numbers. Norm Finn: The
detnet goal is to do PREF, need serial #. The goal of DetNet is not PWs. PW was
handy place to find serial numbers. IF some don't do Lou Berger: This is a good
point.  We have a requirement to define a function, not use PWs.  If WG decides
on a different path, e.g., EPVN-based encapsulation, than this is a fine
direction if this is WG consensus. Jeff Tantsura: Must reference different
draft (EVPN VPWS). Also control word not mandatory, used if not entropy label
(?). May consider making it required. Lou Berger: this is good feedback for WG
adoption. Deborah Brungard: Speaking as AD, use of control word is fine for
this new functionality. PALS will have strong statement about bad things if no
control word, so can expect to have control word.  There is concern on the
design team work, it's time to being this work to the WG and consider it or
individual drafts. Need to go forward. Lou Berger:  This is a good point, there
are no other contributions for DetNet data plane.  If hashing out solutions, we
should do this in the context of a WG document. Jouni Korhonen:  DT doesn't
want to continue as DT, ready to move to adoption and see if serves as solid
base for further work. Lou Berger: Remember, adoption doesn't say this will be
RFC, says this is what WG will start with. Greg Mirsky: Doesn't adoption mean
that we've agreed with the technical solution. If don't feel e.g. PW is correct
technical solution, do we adopt?  What does adoption say? Lou Berger: It says
this is the starting point for the documented WG solution. Again, we don't have
alternative documents to start so there is no choice. Stewart Bryant:
Invitation for alternative proposals Lou Berger: Yes, this invitation has
always been open. Stewart Bryant: Need open discussion not closed meetings with
reporting. Lou Berger: DT archives open. Can discuss any document on mailing
list. Eric Gray: In most WGs once DT has been appointed, worthless effort to do
alternative designs. Lou Berger: But individuals can always produce individual
draft, will be considered/integrated. Eric Gray: This isn't the case in many
WG. <multiple people>: we've seen this happen in other WGs Jouni Korhonen:  can
we move forward? Shahram Davari: If objection for PW is that CW not used. The
RFC has control word. Objective is minimum change in standards. Don't need to
create new standard. <slide 11> Lou Berger: Do you need control word if don't
care about protection function? Jouni Korhonen: No. But less options the
better, would prefer it to be required. Stewart Bryant: Get a lot of things if
keep control word. Legacy HW is the only argument against. But think should
always be there. Andy Malis: As PALS co-chair, we're making CW mandatory in
PALS WG, should be mandatory here also. Greg Mirsky: Need CW since transit
nodes doing caching, without CW might be incorrectly parsed. Must have CW.
First label critical. <slide 15> Lou Berger: Keep in mind whether data plane
functions are captured in Arch doc. For example, is resource
hierarchy/aggregation covered? Jeff Tantsura: EVPN active-active could be used
to provide resiliency Greg Mirsky: Confused by IPv6 using underlying v6
structure. Lou Berger: Both V6 over detent and detnet over v6 are supported.
Flat TSN domain is single Ethernet domain. Greg Mirsky: in detnet v6 over TSN
there is nothing to be done Lou Berger: there still is service mapping Norm
Finn: Is laid out in Arch and data plane drafts. Use cases: one use case is
interconnecting TSN domains w/L2 connectivity. To make large, need routers. Is
in the documents. Alexander Patrescu: IPv6 - need to connect TSN link to 802.11
link. Can flows be guaranteed for WiFi? Lou Berger: Would be interesting to see
how to do this in a future draft. Please contribute! Norm Finn: As Pascal
pointed out, wireless (particularly WiFi) is less deterministic. We don't know
how to do that - if you do, let us know. <slide-19> Jouni Korhonen: Time for WG
adoption! A good basis, not complete, sufficient to go forward. The DT feels
the document is a solid foundation to move forward. Lou Berger: As there are no
other alternative proposals and that this is a product of a DT, we would like
to start a WG adoption poll on the list. As part of this call, we would also
like to collect issues that will be addressed in post-adoption versions (i.e.,
post -00) of a WG document.  Are there objections to this approach. Stewart
Bryant: We should follow classic call for adoption and expect alternatives to
appear soon. Greg Mirsky: Often see humms then adoption on list.  Agree w/
Stewart - just on the merit of this draft, and if there will be other documents
there will be other documents. Deborah Brungard: Could state in various
sections that it is a proposal not a final decision, and to make clear that the
content is under discussion. This would allow others to provide input to merge
in later. Lou Berger: We put multiple proposals in a single draft. Rev draft
-00 to identify issues in a -01 draft sounds like a good way to capture issues
identified during adoption. Stewart Bryant: Not just sequence numbers that are
a concern. Adoption usually implies buy-in of technologies, there are areas
that I have reservations on and have not been debated in the WG. Lou Berger:
Such concerns can be included in the draft, section by section, then addressed
as part of WG process.  Anyone who looks at the draft will immediately see
which sections have open issues. Eric Gray: I agree with Stewart, if issues
aren't in draft 00 people who only look at drafts will get the impression that
this is the direction. Suggest respin individual draft first. Stewart Bryant:
can ask for issues to be identified with draft, then respin individual draft
including the issues, then ask for adoption Greg Mirsky: I like this proposal.
Call for comments on current version. Identify ones that need to be integrated
before adoption, then call for adoption. Lou Berger: We will do this and call
it a two stage WG document. Eric: WG chair said after certain issues have been
addressed will call for adoption. Lou Berger: While not the norm, we will do a
two-stage adoption call on the document, the first stage will be to collect
issues *and* to add them to a rev of the *individual* draft.  Then conduct a
normal adoption call.

> 3   10:25  20  Title:  DetNet Flow Information Model Based on TSN
>                Presenter:  Balázs Varga
>                Draft: 
https://tools.ietf.org/html/draft-farkas-detnet-flow-information-model-01

Lou Berger: How many have read this doc? <Just a few. >
Before discussion of adoption, hear next talk by Mach.

> 4   10:45  10  Title:  Considerations for Flow Information Model WG document
>                Presenter:  Mach Chen
>                Draft:

Greg Mirsky: If use node scope performance metrics, how do we do this. What
metrics do we need? Maximum values? Other? How are they obtained? Mach Chen:
Use Maximum, since DetNet guarantees worst case. Greg Mirsky: How is latency
measured from node? Maybe different discussion. Dean Bogdanovic: Likes grouping
shown for information model. Good to keep same for lifecycle of draft. Are
these all we need, is the more? Lou Berger: Matches what IETF has been doing
for many years, these same 3 blocks. Perhaps with slightly different names.
Karl Weber: What do you mean by centralized in this context? the Internet?
Overlapping? Mach Chen: Borrowed from TSN, centralized model. Mostly about how
to use. János Farkas: We are talking about single admin domain, not big-I
Internet here. Lou Berger: Not covering control in this WG yet. This is a
reference model, not a requirement or plan. Control plane is currently out of
scope. Karl Weber: So this is documented in the drafts? Lou Berger: Yes, in the
architecture document Jeff Tantsura: So would you map in to the TE (yang) work
in TEAS. Another option is L2SM. Mach Chen: Yes. Lou Berger: (to Mach) Are you
asking for the issues you raise to be handled in the individual draft or in a
future WG draft? Mach Chen: We're open to either.

Lou Berger: Moving on to draft-farkas-detnet-flow-information-model-01:
How many would like to see the -01 draft adopted now? <A few, about same as
read it>. How many would like to see it improved, e.g., by incorporate Mach's
topics first? <About the same number.> No clear indication from the floor.
János Farkas: How do we proceed? Lou Berger: Discuss on list. Don't wait for
chairs on this. If you have text on these ideas, bring it. Given the lack of
response from the room need to talk to co-chair on next steps.  Perhaps
adoption call, perhaps not.

> 5   10:55  20  Title:  DetNet Security Considerations
>                Presenter:  Tal Mizrahi
>                Draft: 
https://tools.ietf.org/html/draft-sdt-detnet-security-01

Lou Berger: Poll: Should we have this type of document? <Reasonable number. >
How many have read it? <A little less (!). >
How many would like to see this as a foundation? <More than have read the draft>
we will take [adoption] to the list.
Pascal Thubert: Be realistic about impact - DetNet is intended to support
physical systems in the real world. So if flow doesn't go through, machines can
break, people can die.
  Lou Berger: As part of the adoption call, if you identify any issues you want
  addressed or text you want added, please send comments to the list.

> 6   11:15  15  Title:  Implementation Report: DetNet Data Plane Protection
>                Presenter:  János Farkas
>                Draft:  https://tools.ietf.org/html/draft-dt-detnet-dp-sol-01

Pascal Thubert: Did similar demo in 6Tisch. Can miss a single packet, but not a
certain number in a row, so for many control applications this is a good
technique. János Farkas: Single link is broken for this demo. Jeff Tantsura:
How many packets can you lose before you switch over? János Farkas: Any lost
packet is switched, so no packets are lost. Lou Berger: Classic 1+1 hitless
protection. János Farkas: Must keep track of sequence numbers (state) Kiran ??:
Out of order seq numbers? Assume incorrectly lost a packet? János Farkas: Can
handle this, but must keep track of delay on paths, etc, as spec'd in the
draft. ?: Out of order packets? If need to be ordered, must buffer. János
Farkas: Can handle this, somewhere you need to buffer. Norm Finn: IEEE 802.1CB
ready to be published. Covers these kinds of questions. Some are more expensive
answers than others. Can share URL.

> 7   11:30  30  Title:  802.1 TSN Summary and Discussion
>                Presenter:  János Farkas, Pat Thaler, Norm Finn
>                Reference:  http://www.ieee802.org/1/pages/tsn.html

Lou Berger: Doing shaping after replication? Are there 2 shapers?
Norm Finn: Not necessarily in that order, don't read too much into it.
Pascal Thubert: Used for constant bit rate? But transport/network may put into
different packetizing, e.g. 1 512 vs 2 256. Broken into deterministic-friendly
blocks? Lou Berger: Maybe beneficial for DetNet to provide transport protocol.
Pascal Thubert: Thinking of problem not solution. CBR traffic may be broken
into uneven size packets? Lou Berger: Do we need to talk to someone in the
transport area? Must be solved for users, IETF is the right place. TSN can
inform out process here. János Farkas: These slides are TSN only, as input to
what we do in DetNet. Pat Thaler: Mac logic/state is duplicated, but not a
separate address. John Dowdell: Any open source for TSN? János Farkas: The demo
code is our own, not open source. <closing meeting> Lou Berger: Will start
phase 1 of data plane solution adoption process, so please send comments to the
list. Lou Berger: Also likely to start adoption of Info model (as forcing
function).

> Adjourn 12:00

Note takers:
Jouni Korhonen (remote)
Ethan Grossman