Re: [tsvwg] Another tunnel/VPN scenario (was RE: Reasons for WGLC/RFC asap)

Bob Briscoe <> Tue, 08 December 2020 21:30 UTC

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To: Steven Blake <>
Cc: Gorry Fairhurst <>, tsvwg IETF list <>
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From: Bob Briscoe <>
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Date: Tue, 08 Dec 2020 21:29:52 +0000
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Subject: Re: [tsvwg] Another tunnel/VPN scenario (was RE: Reasons for WGLC/RFC asap)
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On 04/12/2020 01:54, Steven Blake wrote:
> On Thu, 2020-12-03 at 16:40 +0000, Gorry Fairhurst wrote:
>> Just on that last point, perhaps we should be clearer by what
>> "experiment" means.
>> On 03/12/2020 15:52, Jonathan Morton wrote:
>>> Frankly, the sooner the WG understands and accepts that basic fact,
>>> the sooner we can move to a viable solution - one which does not
>>> redefine CE from the semantics established by RFC-3168 and RFC-
>>> 8511, and hence does not place burdens on networks which have no
>>> interest in the L4S experiment.
>> I think we need to be clear that I understand the proposal is to an
>> Internet-wide experimental deployment.
> Have single network experiments been attempted? Have cooperating
> peering network experiments been attempted? Why is an *Internet-wide*
> experiment the appropriate next step, especially when potential
> detrimental impacts to traffic flows of non-participating networks &
> hosts have been identified?

[BB] As I understand it, until the IETF assigns ECT(1) to the L4S 
experiment, no-one should be deploying L4S on the public Internet, 
whether in single networks, or pairs of peered networks. This confines 
us to experiments where one can only try to generate realistic traffic.

Or do you mean a single *isolated* network (or peered *isolated* 
networks)? If so, isn't that what DCTCP has been doing for some years now?

Put another way, if implementers/operators started deploying L4S on 
ECT(1), even in single networks but within the public Internet, wouldn't 
that mean that ECT(1) had become de facto assigned to L4S?


>> If succesful, I'd expect we'll discover things in the deployment
>> that
>> will make us consider new things, before this is approved as a PS.
>> The
>> WG might later decide to obsolete RFC-3168, or L4S, or neither, or
>> both.
>> That will be to decide in future. In persepective, about 15 years
>> passed
>> before the previous EXP use of ECT(1) was made made historic,
>> enabling this.
>> Gorry
> Is there a planned deadline to evaluate the results of the experiment,
> and either advance to PS or revert the allocation of ECT(1)?
> Regards,
> // Steve

Bob Briscoe