Re: [Taps] IETF planning

Michael Welzl <> Tue, 27 October 2015 13:47 UTC

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From: Michael Welzl <>
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Date: Tue, 27 Oct 2015 14:47:15 +0100
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To: Aaron Falk <>
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Cc: "<> Fairhurst" <>, Brian Trammell <>, "" <>, Stein Gjessing <>
Subject: Re: [Taps] IETF planning
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> On 26. okt. 2015, at 17.35, Aaron Falk <> wrote:
> On Mon, Oct 26, 2015 at 9:46 AM, Michael Welzl < <>> wrote:
> Working towards a realistic end-goal of a deployable system.
> So we’re i) describing services; ii) narrowing them down somehow; iii) describing how to build this thing.
> My concern is with iii) being something feasible and useful, not an obscure sci-fi document.
> Uh, yeah.  That's our charter.  Narrowing down is in doc 2.  Are you making the case we should do it in doc 1?  

Well, just because we narrow down in doc 2 doesn’t mean that doc 1 has to contain everything under the sun as a starting point. Consider the discussion around RTP in draft-ietf-taps-transports - I think the consensus was to have only very short text on RTP in there, not a list of all the protocol features. The starting point for draft-welzl-taps-transports should probably be limited in a similar way, but I’d suggest limiting it more than draft-ietf-taps-transports - partially because draft-ietf-taps-transports can already show that certain protocols are not adding new transport features to the mix that don’t yet exist.

Of course, the main reason behind my argument is to keep draft-welzl-taps-transports within a reasonable length. Look at its length now, with only two protocols!  I think the length is inevitable, but if we have good reasons not to cover certain protocols, I think we should keep them out. At least it’s a valuable discussion to have!

> Say we include DCCP. It’ll add some services that aren’t in the other protocols listed so far in this mail - e.g. drop notification (see section 3.6.3 in draft-ietf-taps-transports). Say, in step ii), we find no good arguments to remove drop notification. Then, in step iii), we’ll have to say how a TAPS system can support drop notification. So, to build a working TAPS system, one has to either:
> - include DCCP in the code base
> - extend other protocols to provide this functionality
> None of these two options are very helpful if we want to TAPS to be real thing one day.
> a: TAPS is not chartered to do anything normative.  Doc 3 is about experimenting.

Sure! But it’s still about stuff that someone should be able to build - I just don’t want doc 3 to become a sci-fi literature piece  :-)

> b: You are having the discussion that we planned to have for Doc 2.  Make your case to drop those protocols then.  Or, if no one wants to write sections for the additional protocols for Doc 1a (an extended version of draft-welzl-taps-transports), then folks are voting with their feet on the utility of keeping them.

See my arguments above; about getting sections done for draft-welzl-taps-transports, I don’t worry too much: this is only the very first version, we haven’t asked anyone for inputs yet (and I can volunteer to cover a few more protocols myself).

> c: One of the goals of TAPS is to enable deployment of transport protocols such as DCCP where networks permit it without forcing application (or library) authors to handle probe and fallback.  If we don't include protocols that aren't seeing deployment, what is the value of this activity?

This is a very good point. I’m not sure - do we really need to cover absolutely all protocols that are in draft-ietf-transports in draft-welzl-taps-transports, then? I am concerned about the implementability of the final beast…