Re: [Dime] Martin Stiemerling's Discuss on draft-ietf-dime-congestion-flow-attributes-01: (with DISCUSS and COMMENT)

["Black, David" <[e-mail]>]

Lyle,

>    The Congestion-Treatment AVP (AVP Code TBD) is of type Grouped. It
>    indicates how to treat traffic flow(s) when congestion is detected.
>    The detection of the congestion can be based on the reception of IP
>    packets packet  with  the CE (Congestion Experienced) codepoint set
>   (see [RFC 3168]) or by any other administratively defined criteria.

What does "traffic flow(s)" mean in this text?

A clear explanation of that should remove the concern that this draft might be
applying congestion treatment to just the CE-marked packets and not the entire
5-tuple (or more).

Thanks,
--David

> -----Original Message-----
> From: Bertz, Lyle T [CTO] [mailto:[e-mail]]
> Sent: Thursday, June 11, 2015 6:02 PM
> To: Martin Stiemerling; The IESG
> Cc: Black, David; [e-mail]; [e-mail]
> Subject: RE: [Dime] Martin Stiemerling's Discuss on draft-ietf-dime-
> congestion-flow-attributes-01: (with DISCUSS and COMMENT)
> 
> Martin,
> 
> Regarding the DISCUSS point the language in 3.2 is problematic, we will change
> 
>    The Congestion-Treatment AVP (AVP Code TBD) is of type Grouped and
>    indicates how congested traffic, i.e., traffic that has Explicit
>    Congestion Notification Congestion Experienced marking set or some
>    other administratively defined criteria, is treated.
> 
> to
> 
>    The Congestion-Treatment AVP (AVP Code TBD) is of type Grouped. It
>    indicates how to treat traffic flow(s) when congestion is detected.
>    The detection of the congestion can be based on the reception of IP
>    packets packet  with  the CE (Congestion Experienced) codepoint set
>   (see [RFC 3168]) or by any other administratively defined criteria.
> 
> The rationale for the word 'flow(s)' in the new language is the last sentence
> of the section  3.2 -  "The Congestion-Treatment AVP is an action and MUST be
> an attribute of the Filter-Rule Grouped AVP as defined in RFC5777. "  It is
> other AVPs in the Filter-Rule, e.g. Classifier, that describes the scope of
> traffic impacted.  Saying something in Section 3.2 that does not associate the
> Congestion-Treatment AVP to the Filter-Rule it is a part of only creates
> confusion.
> 
> ---------------------------------
> Per the COMMENT, you are correct.  We'll change
> 
> "The first AVP provides direct support for ECN [RFC3168] in the IP
>   header“
> 
> to your suggestion
> 
> "The first AVP provides direct support for filtering ECN
>   marked traffic[RFC3168]“
> 
> -----Original Message-----
> From: DiME [mailto:[e-mail]] On Behalf Of Martin Stiemerling
> Sent: Wednesday, June 10, 2015 3:36 PM
> To: The IESG
> Cc: [e-mail]; [e-mail]; [e-mail]
> Subject: [Dime] Martin Stiemerling's Discuss on draft-ietf-dime-congestion-
> flow-attributes-01: (with DISCUSS and COMMENT)
> 
> Martin Stiemerling has entered the following ballot position for
> draft-ietf-dime-congestion-flow-attributes-01: Discuss
> 
> When responding, please keep the subject line intact and reply to all email
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> 
> 
> Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
> for more information about IESG DISCUSS and COMMENT positions.
> 
> 
> The document, along with other ballot positions, can be found here:
> https://datatracker.ietf.org/doc/draft-ietf-dime-congestion-flow-attributes/
> 
> 
> 
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
> 
> No general objection to the publication of the document. However, I am
> relaying a question from David Black as a DISCUSS point.
> 
> I assume that the draft is more than unclear in Section 3.2  about what
> traffic means. Is it a particular flow, a single packet, etc?
> 
> "I found an ECN concern, and hence added the TSV ADs to the CC line.
> 
> Section 3.2 says:
> 
>    The Congestion-Treatment AVP (AVP Code TBD) is of type Grouped and
>    indicates how congested traffic, i.e., traffic that has Explicit
>    Congestion Notification Congestion Experienced marking set or some
>    other administratively defined criteria, is treated.
> 
> That appears to say that the congestion treatment may be applied solely to
> packets that have the CE (Congestion Experienced) marking.
> That would be a problem, because the defined semantics of a CE marking is that
> it applies to the entire flow (e.g., causes TCP to react as if a packet has
> been dropped), hence the congestion treatment ought to apply to the entire
> flow.
> 
> In other words, one wants to be able to use the ECN-IP-Codepoint AVP as part
> of the condition that determines whether the filter rule matches, but ignore
> that AVP (i.e., wildcard it) in determining what traffic the action applies
> to, so that the response to detecting a congested flow (i.e., packets with ECN
> field containing CE) applies to all packets in the flow, regardless of the
> value in the CE field.
> 
> Otherwise, the result may be ineffective, as it won't encompass packets in the
> congested flow that aren't CE-marked.
> 
> Am I reading the draft correctly?"
> 
> 
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
> 
> Section 1, 1st paragraph:
> It says "The first AVP provides direct support for ECN [RFC3168] in the IP
> header“. I am  sure that your draft is  ot providing any support for ECN in
> the IP header, as we have ECN in the IP header already, isn't it.
> I guess you mean something like this "The first AVP provides direct support
> for filtering ECN marked traffic[RFC3168]“
> 
> 
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