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

"Ben Campbell" <ben@nostrum.com> Tue, 10 May 2016 16:49 UTC

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From: "Ben Campbell" <ben@nostrum.com>
To: "Steve Donovan" <srdonovan@usdonovans.com>
Date: Tue, 10 May 2016 12:49:26 -0400
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Subject: Re: [Dime] Ben Campbell's Discuss on draft-ietf-dime-drmp-05: (with DISCUSS and COMMENT)
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I'm going to clear the discuss at this point--I wanted discussion to 
happen and it is happening. More inline:

On 10 May 2016, at 9:38, Steve Donovan wrote:

> See inline.
>
> On 5/6/16 3:45 PM, Ben Campbell wrote:
>> On 6 May 2016, at 14:48, Steve Donovan wrote:
>>
>>

[...]

>>>>
>>>> The potential "priority scheme" might help here. But why does a 
>>>> trusted environment matter? Lets say you have trusted clients from 
>>>> vender A and from vendor B, but they select priorities differently?
>>> SRD> They aren't trusted if they aren't using the defined standards.
>>
>> What standard? The application specification? (See my question in 
>> Alissa's thread about whether DRMP can be applied to legacy 
>> applications that don't (yet) define it's use.)
> SRD> I mean application specification or operator policy.  DRMP can 
> apply to legacy applications in two ways.  First, the default priority 
> applies if no priority is explicitly included in the message.  Second, 
> operators can define their own priority scheme.

Okay. That seems to imply a need for configurability, but I'll leave it 
to you whether that should be a standard requirement, or a market 
requirement.

>>
>>> In addition, trusted environment generally means operated by a 
>>> single entity.  That operator has the job of ensuring that what you 
>>> are proposing would not happen.
>>
>> I can accept if that is the case, but it's not a very satisfying 
>> answer. It leads to having profiles for each operator. (I realize 
>> that the primary users of Diameter have always had operator-specific 
>> profiles of standards, so maybe there's nothing to do here.) This 
>> might at least imply a requirement that priority definitions need to 
>> be configurable.
> SRD> I don't see that it means a profile per operator.  3GPP is likely 
> to create a profile that spans all of its applications and could be 
> used by all operators following the 3GPP standards.

Sure, but it still _might_ require per-operator profiles, right? Even 
3GPP networks tend to have operator specific "flavors" of protocols.

But I recognize this is not unusual for most (if not all) of the 
environments that Diameter is used in.

[...]

>> So this may be down to a nit--but the text as written says that the 
>> receiver of a _request_ "SHOULD" use the included priority, but the 
>> receiver of a response "MUST" use the priority. Now, maybe these are 
>> just different ways of encoding the idea that the node may not 
>> implement DRMP. But the former seems to allow the node to override 
>> the priority in the message if it has good reason, but the latter 
>> does not allow the same for a response.
>>
>> As I mention in the discussion about my last discuss point, it seems 
>> odd that a client cannot choose it's own idea of priority over the 
>> servers if it thinks it has a good reason.
> SRD> Thanks for bearing with me on this one.  I see your point now and 
> agree it should be reworded to include allowing for local policy to 
> override what is carried in the message.
>>
Thanks--I realize my first round of comments obscured the point a bit 
:-)