Re: [netmod] diffserv model questions

"Aseem Choudhary (asechoud)" <asechoud@cisco.com> Tue, 19 May 2015 22:49 UTC

From: "Aseem Choudhary (asechoud)" <asechoud@cisco.com>
To: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
Thread-Topic: [netmod] diffserv model questions
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Date: Tue, 19 May 2015 22:49:18 +0000
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Subject: Re: [netmod] diffserv model questions
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On 5/19/15, 1:39 PM, "Juergen Schoenwaelder"
<j.schoenwaelder@jacobs-university.de> wrote:

>On Tue, May 19, 2015 at 07:57:26PM +0000, Aseem Choudhary (asechoud)
>wrote:
>> Hi Juergen,
>> 
>> Please find the replies inline.
>> 
>> -thanks,
>> Aseem
>> 
>> On 5/18/15, 10:20 AM, "Juergen Schoenwaelder"
>> <j.schoenwaelder@jacobs-university.de> wrote:
>> 
>> >Hi,
>> >
>> >what is the purpose of the feature policy-template-support in
>> >draft-asechoud-netmod-diffserv-model-01.txt? Can I use the model
>> >without this feature?
>> >
>> >I also note that no implementable object is left in
>> >ietf-diffserv-policy if I do not support the feature
>> >policy-template-support. Is this useful?
>> 
>> [AC] ietf-diffserv-policy module defines policy as a template. The other
>> option is to configure & apply it directly under target as defined in
>> ietf-diffserv-target module.
>
>OK, but why is there a feature since this 'policy' is an extension
>defined in a separate YANG model?

[AC] OK, I see the point you are making, but there are some changes
regarding it in next version which will alleviate your concern.
>
>> >Is it a bug or a feature to support inline classifier definitions? Is
>> >it correct that actions are always 'inline' so to say? Is this a bug
>> >or a feature?
>> 
>> [AC] Classifier can be defined inline or can be defined as a separate
>> template and referred in the policy definition.
>
>Yes, but is this a bug or a feature? From an implementation
>perspective, this sounds like extra cost. So what is the benefit of
>having both options?

[AC] There are pros and cons of defining either way: When defined as a
separate template, it becomes reusable objects. Any change in the object
updates the referencing objects too.
     While when defined inline, it is local change only. Any modification
has to be done on every instance.
    There are use-cases where users may use template and others where they
define inline. There are vendors which support either/or/both. Also,
Inline is defined as a feature.

>
>> All the actions are defined inline. This is the most common use-case.
>
>Hm. Why are classifiers and actions treated differently? Perhaps some
>discussion of the design decisions somewhere in the document would be
>useful.

[AC]  Actions are typically not reusable objects. Like metering rate or
RED thresholds are specific values vs classification of voice, video or
data.
      I will take this point of adding to the document.
>
>/js
>
>-- 
>Juergen Schoenwaelder           Jacobs University Bremen gGmbH
>Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
>Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>

[netmod] diffserv model questions Juergen Schoenwaelder
Re: [netmod] diffserv model questions Aseem Choudhary (asechoud)
Re: [netmod] diffserv model questions Juergen Schoenwaelder
Re: [netmod] diffserv model questions Aseem Choudhary (asechoud)
Re: [netmod] diffserv model questions Aseem Choudhary (asechoud)