[Iccrg] Re: Iccrg Digest, Vol 81, Issue 8

[[e-mail] (Arjuna Sathiaseelan)]

this sounds great actually..probably reduced to 3/4th cwnd on ecn marks?

arjuna
On Oct 27, 2012 12:06 PM, <[e-mail]> wrote:

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> Today's Topics:
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>    1. Agenda (Michael Welzl)
>    2. Why don't we stop treating ECN and loss similarly? (Michael Welzl)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 27 Oct 2012 10:20:13 +0200
> From: Michael Welzl <[e-mail]>
> Subject: [Iccrg] Agenda
> To: iccrg list <[e-mail]>
> Message-ID: <[e-mail]>
> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>
> Hi,
>
> There is still space on our agenda - currently, it looks like this:
>
>
> ICCRG agenda, IETF 85, Atlanta, Monday, 5 November, 13:00-15:00, Salon A
>
> Rong Pan: "A new algorithm for dealing with buffer bloat", 20+10 min
>
> Nestor Michael C. Tiglao: "Transport layer caching mechanisms and
> optimization", 20+10 min
>
> Open discussion about the applicability of more precise ECN signalling
>
>
> Cheers,
> Michael
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 27 Oct 2012 11:26:59 +0200
> From: Michael Welzl <[e-mail]>
> Subject: [Iccrg] Why don't we stop treating ECN and loss similarly?
> To: iccrg list <[e-mail]>
> Message-ID: <[e-mail]>
> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>
> Hi,
>
> Here's an idea, inspired by something Bob Briscoe posted to the TSVWG
> list recently in a discussion of draft-carlberg-tsvwg-ecn-reactions.
> However, this possibly stupid idea is my own responsibility alone  :-)
>
>
> According to RFC 3168, senders must react to ECN just as if packets
> had been dropped. This is to maintain fairness between ECN-compatible
> and non-compatible flows.
> Because of this requirement, AQMs cannot ECN-mark packets more
> aggressively than it drops packets from non-ECN-capable flows - else
> ECN-marked flows would be at a disadvantage.
>
> We have seen various non-standard congestion control behaviors can co-
> exist reasonably well with standard TCP in practice. If it was
> possible to have a milder congestion reaction to ECN-based reaction,
> it would also be possible to ECN-mark packets earlier, leading to a
> bigger advantage for everyone using ECN. And none of this is possible
> when we have the "treat an ECN mark just like loss" rule in place.
>
> Hence, my question: to incentivize ECN usage and enable better
> behavior when it's used, shouldn't we remove this rule?
>
> Note that this is not even about a more fine-grain interpretation of
> ECN feedback - it's more like an intermediate step.
>
> I'm curious what everyone thinks... am I missing something?
>
> Cheers,
> Michael
>
>
>
>
> ------------------------------
>
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> End of Iccrg Digest, Vol 81, Issue 8
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>
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>From [e-mail]  Sat Oct 27 12:16:31 2012
From: [e-mail] (Arjuna Sathiaseelan)
Date: Sat Oct 27 12:10:26 2012
Subject: [Iccrg] Re: Iccrg Digest, Vol 81, Issue 8
In-Reply-To: <CAPaG1Akg8qycZkZ+Y_9mKBOAR_K_9MDj0kF_c1gN263-=[e-mail]>
References: <[e-mail]>
	<CAPaG1Akg8qycZkZ+Y_9mKBOAR_K_9MDj0kF_c1gN263-=[e-mail]>
Message-ID: <[e-mail]>

or proportional rate reduction - even better?

just random thoughts..
On Oct 27, 2012 12:10 PM, "Arjuna Sathiaseelan" <
[e-mail]> wrote:

> this sounds great actually..probably reduced to 3/4th cwnd on ecn marks?
>
> arjuna
> On Oct 27, 2012 12:06 PM, <[e-mail]> wrote:
>
>> Send Iccrg mailing list submissions to
>>         [e-mail]
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>>         http://oakham.cs.ucl.ac.uk/mailman/listinfo/iccrg
>> or, via email, send a message with subject or body 'help' to
>>         [e-mail]
>>
>> You can reach the person managing the list at
>>         [e-mail]
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of Iccrg digest..."
>>
>>
>> Today's Topics:
>>
>>    1. Agenda (Michael Welzl)
>>    2. Why don't we stop treating ECN and loss similarly? (Michael Welzl)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Sat, 27 Oct 2012 10:20:13 +0200
>> From: Michael Welzl <[e-mail]>
>> Subject: [Iccrg] Agenda
>> To: iccrg list <[e-mail]>
>> Message-ID: <[e-mail]>
>> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>>
>> Hi,
>>
>> There is still space on our agenda - currently, it looks like this:
>>
>>
>> ICCRG agenda, IETF 85, Atlanta, Monday, 5 November, 13:00-15:00, Salon A
>>
>> Rong Pan: "A new algorithm for dealing with buffer bloat", 20+10 min
>>
>> Nestor Michael C. Tiglao: "Transport layer caching mechanisms and
>> optimization", 20+10 min
>>
>> Open discussion about the applicability of more precise ECN signalling
>>
>>
>> Cheers,
>> Michael
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Sat, 27 Oct 2012 11:26:59 +0200
>> From: Michael Welzl <[e-mail]>
>> Subject: [Iccrg] Why don't we stop treating ECN and loss similarly?
>> To: iccrg list <[e-mail]>
>> Message-ID: <[e-mail]>
>> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>>
>> Hi,
>>
>> Here's an idea, inspired by something Bob Briscoe posted to the TSVWG
>> list recently in a discussion of draft-carlberg-tsvwg-ecn-reactions.
>> However, this possibly stupid idea is my own responsibility alone  :-)
>>
>>
>> According to RFC 3168, senders must react to ECN just as if packets
>> had been dropped. This is to maintain fairness between ECN-compatible
>> and non-compatible flows.
>> Because of this requirement, AQMs cannot ECN-mark packets more
>> aggressively than it drops packets from non-ECN-capable flows - else
>> ECN-marked flows would be at a disadvantage.
>>
>> We have seen various non-standard congestion control behaviors can co-
>> exist reasonably well with standard TCP in practice. If it was
>> possible to have a milder congestion reaction to ECN-based reaction,
>> it would also be possible to ECN-mark packets earlier, leading to a
>> bigger advantage for everyone using ECN. And none of this is possible
>> when we have the "treat an ECN mark just like loss" rule in place.
>>
>> Hence, my question: to incentivize ECN usage and enable better
>> behavior when it's used, shouldn't we remove this rule?
>>
>> Note that this is not even about a more fine-grain interpretation of
>> ECN feedback - it's more like an intermediate step.
>>
>> I'm curious what everyone thinks... am I missing something?
>>
>> Cheers,
>> Michael
>>
>>
>>
>>
>> ------------------------------
>>
>> _______________________________________________
>> Iccrg mailing list
>> [e-mail]
>> http://oakham.cs.ucl.ac.uk/mailman/listinfo/iccrg
>>
>>
>> End of Iccrg Digest, Vol 81, Issue 8
>> ************************************
>>
>
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>From [e-mail]  Sat Oct 27 12:55:59 2012
From: [e-mail] (John Leslie)
Date: Sat Oct 27 12:50:13 2012
Subject: [Iccrg] Why don't we stop treating ECN and loss similarly?
In-Reply-To: <[e-mail]>
References: <[e-mail]>
Message-ID: <20121027115559.GS27557@verdi>

Michael Welzl <[e-mail]> wrote:
> 
> According to RFC 3168, senders must react to ECN just as if packets  
> had been dropped. This is to maintain fairness between ECN-compatible  
> and non-compatible flows.
> Because of this requirement, AQMs cannot ECN-mark packets more  
> aggressively than it drops packets from non-ECN-capable flows - else  
> ECN-marked flows would be at a disadvantage.

   As Bob has pointed out, theory clearly shows that the less-aggressive
reaction-to-loss will starve the more-aggressive...

> We have seen various non-standard congestion control behaviors can
> co-exist reasonably well with standard TCP in practice.

   Yes! At the risk of setting-off Bob, this suggests that the theory
may not completely correspond to reality. ;^)

> If it was possible to have a milder congestion reaction to ECN-based
> reaction, it would also be possible to ECN-mark packets earlier,
> leading to a bigger advantage for everyone using ECN.

   This, of course, would be trivial if we had a gradation of ECN
marking...

> And none of this is possible when we have the "treat an ECN mark
> just like loss" rule in place.

   Rules can be relaxed in research projects...

> Hence, my question: to incentivize ECN usage and enable better  
> behavior when it's used, shouldn't we remove this rule?

   There is certainly room for research which "partially" relaxes
this rule.

> Note that this is not even about a more fine-grain interpretation of  
> ECN feedback - it's more like an intermediate step.

   I'll remind folks that the RMCAT WG needs to convince folks that
a less-aggressive response to ECN/loss, coupled with a less-
aggressive ramp-up in the absence of ECN/loss, is safe.

   Early indications are that this will prove acceptable...

--
John Leslie <[e-mail]>