Subject: Re: [core] Lenght shim

From: Simon Lemay <[email-masked]>
Date: Wed, 02 Sep 2015 23:08:56 +0000

Hi all,

Sorry for the delay

Carsten writes:
"A new szx=7 to enable larger block sizes could simply indicate that the
total body is to assembled serially from the payloads provided in
sequence; this only really makes sense when keeping a sequence of blocks
within an instance of a sequence-preserving transport.  But I would
write this up separately, not in this draft"

I do like this idea for larger payload, where would the writing need to be?
in the Block Draft?

as for "new blocksize needs to be a clean fraction of the 1024byte block.", I
ment multiplier (:P, my bad) to allow for block size message to be proxied,
but this would require some testing to see how feasible and easy it is to
implement

To Gengyu question, as it was discussed at IETF, the risk of keeping all
unused field on reliable transport is that they may be overloaded and get
different meaning on different transport layer, example adding a different
semantic to RST type.  As for the proxy situation, i saw the approach
number 1 that Hannes mentioned, but the proxy question is a very valid one
that needs a lot of exploration.

As for the length, since this is the last issue before we bring the draft
as a working group item,  I think it would be good to have a conference
call with everybody who is interested in the subject to voice concern one
more time, and come up with an unique approach

i create a doodle, i added as much options as possible time wise to get the
maximum amount of people.

http://doodle.com/xti53ksybm95pzh4

Cheers

Simon

On Tue, Aug 25, 2015 at 5:50 AM Hannes Tschofenig <[email-masked]>
wrote:

> Hi Gengyu,
>
> thanks for your response and the question you raised. Here is my
> impression about what happens in this case:
>
> On 08/20/2015 12:25 PM, weigengyu wrote:
> > But if the usage senario is that there are three nodes;
> > C is a CoAP client, S is a CoAP server, and I is an intermediary.
> >        CoAP Client -------------- Intermediary --------------- CoAP
> Server
> >                C                                   I S
> >
> > Suppose, transport layer protocol between C and I is TCP and that beween
> > I and S is UDP.
> > If all the CoAP messages between C and I are NON,
> > which message between I and S shoule be CON?
>
> The CoAP client would use TCP with the gateway and the data transfer
> would be transmitted reliably due to the nature of TCP (regardless of
> what CoAP says).
>
> Then, when the data is at the gateway a new CoAP over UDP message would
> be created and sent to the CoAP server. For the CoAP client the
> interaction with the CoAP server isn't visible since the entire
> communication terminates at the gateway. As such, the gateway needs to
> have some application level knowledge to know whether the application
> demands reliable transport or not.
>
> I see two possible approaches:
>
> 1) The gateway assumes that the use of TCP between the client and itself
> is an indication that the client wants reliable data transfer and
> therefore would replicate this functionality also in the exchange of
> data between the gateway and the server. It would therefore use CON.
>
> 2) The gateway re-uses whatever is conveyed in the CoAP message.  For
> example, if the CoAP message from the client is a CON then it would be a
> CON also on the other side.
>
> Do you believe the draft should recommend one way or should this be left
> open for deployments to choose?
>
> Ciao
> Hannes
>
>

---

From: Carsten Bormann <[email-masked]>
Date: Thu, 03 Sep 2015 02:29:43 +0200

Simon Lemay wrote:
> I do like this idea for larger payload, where would the writing need to
> be? in the Block Draft?  

Procedurally, the Block Draft is done in the WG and is being submitted
to the IESG (any day now).
So the answer should be: A third draft, or we may want to pull this in
here in the TCP/TLS draft if this is really considered an indispensable
part of the TCP binding.

> as for "new blocksize needs to be a clean fraction of the 1024byte
> block.", I ment multiplier (:P, my bad) to allow for block size message
> to be proxied, but this would require some testing to see
> how feasible and easy it is to implement

Right; if this is about block-by-block proxying, this would still be a
bit icky because it's not easy to reconstruct the block number.
Prototyping is the right way to get this right, and that is another
reason for a third draft.

> As for the length, since this is the last issue before we bring the
> draft as a working group item,  I think it would be good to have a
> conference call with everybody who is interested in the subject to voice
> concern one more time, and come up with an unique approach
> 
> i create a doodle, i added as much options as possible time wise to get
> the maximum amount of people.
> 

As a WG chair, I need to point out that anything that is discussed on
such an informal call would be like a hallway discussion at an IETF; if
we really want to nail down things, we might call a virtual interim
(i.e., such a phone call formally announced with a two-week announcement
interval) -- but the two are not mutually exclusive.

Grüße, Carsten

---

From: Simon Lemay <[email-masked]>
Date: Mon, 07 Sep 2015 18:31:45 +0000

Hi All,

So there is only 2 people who have given there availability for the
"hallway virtual meeting" (http://doodle.com/xti53ksybm95pzh4)  (thanks you
:))

So at this point, it might be better to Jump to the Virtual interim, and
schedule it.  I am not sure what the process it for that, but i would like
to get it started so we can have the interim in 2 week.

Chairmans, how can we get the ball rolling on this?

Thanks

Simon

---

From: Carsten Bormann <[email-masked]>
Date: Mon, 07 Sep 2015 22:15:00 +0200

> Chairmans, how can we get the ball rolling on this?

Hmm.  Do people even care about the issue?  Should Andrew toss a coin?

We should schedule a virtual interim if we can get a bit more than three
people to join.  Maybe we should start with another doodle?

Grüße, Carsten

---

From: Simon Lemay <[email-masked]>
Date: Tue, 08 Sep 2015 20:34:18 +0000

Yes i think we should start a Doodle for the interim meeting.

Thanks

Simon

---

From: Simon Lemay <[email-masked]>
Date: Tue, 15 Sep 2015 14:55:01 +0000

Any News on The interim meeting?,  is it Something I can do or does
Chairmans have to do it?

Thanks

Simon

---

From: Carsten Bormann <[email-masked]>
Date: Tue, 15 Sep 2015 17:00:01 +0200

Setting up a Doodle for Week 41 is something you could be doing.
(We need to get more people involved, and then put in the schedule > two
weeks before the event, hence Week 41.)

Grüße, Carsten

Simon Lemay wrote:
> On Tue, Sep 8, 2015 at 1:34 PM Simon Lemay <[email-masked]
> <mailto:[email-masked]>> wrote:
> 
>     On Mon, Sep 7, 2015 at 1:15 PM Carsten Bormann <[email-masked]
>     <mailto:[email-masked]>> wrote:
> 
>         Simon Lemay wrote: