Re: [Dime] Mirja Kühlewind's Discuss on draft-ietf-dime-drmp-05: (with DISCUSS and COMMENT)

Steve Donovan <srdonovan@usdonovans.com> Wed, 01 June 2016 10:41 UTC

Return-Path: <srdonovan@usdonovans.com>
X-Original-To: dime@ietfa.amsl.com
Delivered-To: dime@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1EE8E12D0C6; Wed, 1 Jun 2016 03:41:18 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.121
X-Spam-Level:
X-Spam-Status: No, score=-1.121 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, SPF_NEUTRAL=0.779] autolearn=no autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id N0b4EDywxDJX; Wed, 1 Jun 2016 03:41:16 -0700 (PDT)
Received: from biz131.inmotionhosting.com (biz131.inmotionhosting.com [74.124.197.190]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id B08D612D098; Wed, 1 Jun 2016 03:41:16 -0700 (PDT)
Received: from [199.119.128.74] (port=57518 helo=Steves-MacBook-Air.local) by biz131.inmotionhosting.com with esmtpsa (TLSv1.2:DHE-RSA-AES256-SHA:256) (Exim 4.86_1) (envelope-from <srdonovan@usdonovans.com>) id 1b83aH-003KPq-Dg; Wed, 01 Jun 2016 03:41:15 -0700
To: Stephen Farrell <stephen.farrell@cs.tcd.ie>, Alexey Melnikov <aamelnikov@fastmail.fm>, "Mirja Kuehlewind (IETF)" <ietf@kuehlewind.net>
References: <20160504111323.8242.20592.idtracker@ietfa.amsl.com> <A8821F45-B9BA-4ACF-8EBF-01B64C100359@fastmail.fm> <B4F433FB-B2A2-4EDA-8ECF-5812BCB7517A@kuehlewind.net> <1462363396.2794286.597809745.0662E7A7@webmail.messagingengine.com> <033661D5-7963-4726-81C0-854E25C659D3@kuehlewind.net> <e6d1ab6472f14ec3b4b6b024563150ff@CSRRDU1EXM025.corp.csra.com> <F0C35A63-ADCA-4502-AC3B-C2DF5FA6EDFD@kuehlewind.net> <1462451530.3147432.598960497.7062C294@webmail.messagingengine.com> <4B86AEB1-415C-4AE3-82F7-368C38B19560@kuehlewind.net> <57324CE8.6040109@usdonovans.com> <74E6ECC0-283D-4A14-AF19-66E76EBAA743@kuehlewind.net> <B348BA8A-5A92-4E44-8ECA-76E4F3E03426@fastmail.fm> <6EF5DC36-1BEF-47EE-BB3B-83BE5E115AE3@kuehlewind.net> <993A9C1D-1B91-4A6D-B7DA-F5E829763E17@fastmail.fm> <A37DCA0E-8C6D-4056-9B0C-63A25C6C37DA@kuehlewind.net> <1464524906.507204.621875065.5A6A91A2@webmail.messagingengine.com> <b6afc0ef-bab5-0d6e-ad5c-3b5a96ae86d3@usdonovans.com> <574EB69E.8020509@cs.tcd.ie>
From: Steve Donovan <srdonovan@usdonovans.com>
Message-ID: <5d0bf77a-6e13-24ab-0f84-d94d413500dc@usdonovans.com>
Date: Wed, 1 Jun 2016 05:41:08 -0500
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Thunderbird/45.1.0
MIME-Version: 1.0
In-Reply-To: <574EB69E.8020509@cs.tcd.ie>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
X-OutGoing-Spam-Status: No, score=-1.0
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - biz131.inmotionhosting.com
X-AntiAbuse: Original Domain - ietf.org
X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse: Sender Address Domain - usdonovans.com
X-Get-Message-Sender-Via: biz131.inmotionhosting.com: authenticated_id: srdonovan@usdonovans.com
X-Authenticated-Sender: biz131.inmotionhosting.com: srdonovan@usdonovans.com
X-Source:
X-Source-Args:
X-Source-Dir:
Archived-At: <http://mailarchive.ietf.org/arch/msg/dime/o2regfKx2zOiOXNZ6UlNeiT0voI>
Cc: draft-ietf-dime-drmp@ietf.org, dime-chairs@ietf.org, dime@ietf.org, The IESG <iesg@ietf.org>
Subject: Re: [Dime] =?utf-8?q?Mirja_K=C3=BChlewind=27s_Discuss_on_draft-ietf-d?= =?utf-8?q?ime-drmp-05=3A_=28with_DISCUSS_and_COMMENT=29?=
X-BeenThere: dime@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: Diameter Maintanence and Extentions Working Group <dime.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dime>, <mailto:dime-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dime/>
List-Post: <mailto:dime@ietf.org>
List-Help: <mailto:dime-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dime>, <mailto:dime-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 01 Jun 2016 10:41:18 -0000

I'll generate a revision later today.

Steve

On 6/1/16 5:19 AM, Stephen Farrell wrote:
> Great. And Alissa's discuss is cleared so if you want to
> go ahead and shoot out a revision with these changes then
> I can send the approval and get this shipped off to the
> RFC editor. (If doing a revision is a problem, send me
> the changes in OLD/NEW form and I can enter them as an
> RFC editor note and they'll be done later on.)
>
> Cheers,
> S.
>
> On 01/06/16 11:16, Steve Donovan wrote:
>> I'm okay with this suggestion.
>>
>> Regards,
>>
>> Steve
>>
>> On 5/29/16 7:28 AM, Alexey Melnikov wrote:
>>> Hi,
>>> Finally getting back to this.
>>>
>>> I think authors did a good job in the latest version by adding sections
>>> 1.1 (Applicability) and 10 (Considerations When Defining Application
>>> Priorities).
>>>
>>> I would like to suggest the following clarification:
>>>
>>> In Section 8:
>>>
>>> Unchanged:
>>>      Diameter nodes MUST have a default priority to apply to transactions
>>>      that do not have an explicit priority set in the DRMP AVP.
>>>
>>> OLD:
>>>      Diameter nodes SHOULD use the PRIORITY_10 priority as this default
>>>      value.
>>>
>>> NEW:
>>>      In order to guaranty consistent handling of messages from nonupgraded
>>>      Diameter clients,
>>>      Diameter nodes SHOULD use the PRIORITY_10 priority as this default
>>>      priority value. PRIORITY_10 is a mid range priority that corresponds
>>>      to "normal" traffic and thus would be a suitable default for most
>>>      deployments,
>>>      while still allowing different Diameter applications to designate
>>>      other
>>>      priorities for lower and higher priority traffic.
>>>
>>> Best Regards,
>>> Alexey
>>>
>>> On Wed, May 11, 2016, at 06:39 PM, Mirja Kuehlewind (IETF) wrote:
>>>> Hi Alexey,
>>>>
>>>> yes, please provide some text and maybe a warning.
>>>>
>>>> I’ve cleared my discuss as no actual changes to the spec are needed
>>>> based
>>>> on the common understand we have now, however, I would still like to see
>>>> further text in the doc about points that came up in this discussion.
>>>>
>>>> Thanks!
>>>> Mirja
>>>>
>>>>
>>>>> Am 11.05.2016 um 13:13 schrieb Alexe Melnikov <aamelnikov@fastmail.fm>fm>:
>>>>>
>>>>> Hi Mirja,
>>>>>
>>>>>> On 11 May 2016, at 07:07, Mirja Kuehlewind (IETF)
>>>>>> <ietf@kuehlewind.net> wrote:
>>>>>>
>>>>>> Okay let me go for an example here and see if that can be a use
>>>>>> case that we are talking about.
>>>>> Yes, this is helpful.
>>>>>> You have a system where some clients run a communication service
>>>>>> for emergency doctors as well as for firefighters and then there
>>>>>> are also ‚normal‘ users that run some kind of communication service.
>>>>>>
>>>>>> Now you actually have an emergency: some part of the system is down
>>>>>> and the number of request is high such that the system is overloaded.
>>>>>>
>>>>>> Both the emergency doctors have would have two different priority
>>>>>> classes, one for important message about instruction (what and
>>>>>> where people should do something) and one for communication between
>>>>>> the doctors/firefighters which has still higher priority than any
>>>>>> other communication of the other people (as you assume doctors and
>>>>>> firefighters are more responsible to not misuse this communication
>>>>>> channel).
>>>>>>
>>>>>> Now only the emergency doctors communication service was upgraded
>>>>>> to use this extension, but the firefighter’s administrations is
>>>>>> just too slow or they currently have not enough money because they
>>>>>> have specialized expensive hardware and software that is not easy
>>>>>> to change.
>>>>> "Doctor, it hurts when I do that..." - "Don't do that!"
>>>>>
>>>>> I don't think this would be a common deployment case.
>>>>>
>>>>> I agree that there is an issue in the scenario you specified.
>>>>> Default priority helps with a single application + normal
>>>>> (unupgraded) traffic. I do think it helps with the most common case.
>>>>> So instead of having lots of SHOULDs and MAYs, I suggest we add text
>>>>> describing possible issues and when multiple DIAMETER applications
>>>>> are deployed we either recommend that all clients are upgraded to
>>>>> support this extension at the same time or at least deployments
>>>>> specify compatible policies for different applications.
>>>>>
>>>>> I can suggest some text.
>>>>>
>>>>>> Is it okay in this situation that the private chat of two doctors
>>>>>> about their last ski-holidays starves requests to access the
>>>>>> network to send instructor message to the firefighters?
>>>>> We can't prevent all problems like this, as the above is really a
>>>>> social problem combined with misconfiguration. But we can warn about
>>>>> it.
>>>>>> (And how do i make sure that that all other other requests actually
>>>>>> select a lower priority than 10…? But that’s a different question…)
>>>>>>
>>>>>> Mirja
>>>>>>
>>>>>>
>>>>>>> Am 11.05.2016 um 06:59 schrieb Alexey Melnikov
>>>>>>> <aamelnikov@fastmail.fm>fm>:
>>>>>>>
>>>>>>> Hi Mirja,
>>>>>>>
>>>>>>> On 10 May 2016, at 17:59, Mirja Kuehlewind (IETF)
>>>>>>> <ietf@kuehlewind.net> wrote:
>>>>>>>
>>>>>>>>>> I don’t think it is a good idea to assign a default priority to
>>>>>>>>>> non-priority-defined requests at all. If you have high priority
>>>>>>>>>> traffic that does not support this extension (yet) this traffic
>>>>>>>>>> could be starved by lower priority traffic when assigning a
>>>>>>>>>> middle range priority. I don’t think that is what you want to
>>>>>>>>>> achieve.
>>>>>>>>> SRD> Actually, this is what we want to achieve.  It is an
>>>>>>>>> requirement that messages explicitly marked as high priority get
>>>>>>>>> treated even if it results in starving lower priority messages.
>>>>>>>>> The starving of lower priority messages is not an problem, it is
>>>>>>>>> a requirement.
>>>>>>>> I think we are still talking past each other.
>>>>>>> Most definitely :-).
>>>>>>>
>>>>>>>> If you explicitly assign a priority, starvation might be okay.
>>>>>>>> However, if you don’t have a priority explicitly signaled, the
>>>>>>>> transaction might have a very high priority
>>>>>>> So some agent in the system needs to decide that a transaction is
>>>>>>> important.
>>>>>>>> but you just don’t know and by assigning a random mid-range
>>>>>>>> priority this important request could get starved.
>>>>>>> Here I disagree with you, because the way to know that a
>>>>>>> transaction is important is to upgrade client to explicitly assign
>>>>>>> high priority to it. So default priority is a backward
>>>>>>> compatibility mechanism, that would work for most common cases.
>>>>>>> You seem to be suggesting that when this extension is deployed all
>>>>>>> clients need to be updated at the same time. This is not realistic.