On 17/05/16 19:32, Eric Voit (evoit) wrote:
> Hi Stephen,
> 
> And some thoughts on your comments too...

Those're all good.
Cheers,
S

> 
>> From: Eric Voit, May 17, 2016 1:46 PM
>>
>> Hi Stephen,
>>
>>> Stephen Farrell, May 03, 2016 8:23 PM
>>>
>>> Stephen Farrell has entered the following ballot position for
>>> draft-ietf-i2rs-pub-sub-requirements-06: Discuss
>>>
>>> When responding, please keep the subject line intact and reply to all
>>> email addresses included in the To and CC lines. (Feel free to cut
>>> this introductory paragraph, however.)
>>>
>>>
>>> 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-i2rs-pub-sub-requirements/
>>>
>>>
>>>
>>> ----------------------------------------------------------------------
>>> DISCUSS:
>>> ----------------------------------------------------------------------
>>>
>>>
>>> I have what I hope are two very easily sorted things that I'd like to chat 
>>> about:
>>>
>>> (1) 4.2.5, para2: Hang on - this is 2016 isn't it? :-) Why would we
>>> ever have a pub/sub service whose subscribers can pretend to be the service?
>>
>> I am not sure I understand.  The Subscription Service is located on the 
>> Publisher.
>> Having the Publisher and Subscriber mutually authenticate each other makes
>> sense.
>>
>> If you mean something else and you are wondering if whether a Subscriber can
>> also be a Publisher for the information it receives, yes it can.  Having a
>> collector/controller as a middle-man is a very valid implementation.  But 
>> there is
>> nothing which binds such independent subscriptions together.
>>
>>> (2) Don't you need a statement somewhere that commensurate security
>>> needs to be provided for pushed notifications as was used for the original
>> subscription?
>>> That might be a little hard to phrase correctly but I hope we agree
>>> that the notifications ought not be significantly less secure than the
>> subscription.
>>
>> We had some interactions with Ben Campbell on this topic.    In general we 
>> are
>> doing our best to decouple the subscription establishment and maintenance
>> from the underlying transport options.  This is because there are
>> implementations (for example wholly within an MSDC) which don't require
>> payload encryption.  Still most implementations should have transport
>> encryption.  So after several interactions with Ben, the text leading off 
>> Section
>> 4.2.5 now reads:
>>
>>    Some uses of this Subscription Service will push privacy-sensitive
>>    updates and metadata.  Good deployment practices will bind this
>>    generated information within secure, encrypted transport layer
>>    mechanisms.  For example if NETCONF is used as transport, then
>>    [RFC5539] would be a valid option to secure the transported
>>    information.  The Subscription Service can also be used with emerging
>>    deployment contexts as well.  As an example, deployments based on
>>    [i2rs-usecase] can apply these requirements in conjunction with those
>>    documented within [i2rs-protocol-security] to secure ephemeral state
>>    information being pushed from a Network Element.
>>
>> Does this hit your objective?
>>
>> Eric
>>
>>>
>>> ----------------------------------------------------------------------
>>> COMMENT:
>>> ----------------------------------------------------------------------
>>>
>>>
>>> - I wondered if this was maybe of interest to more than just i2rs, and
>>> if so, whether any effort had been made to try figure out if these
>>> requirements work for folks who don't care about i2rs? It'd seem a
>>> shame to work on this but stop one step short of being appropriately 
>>> general.
>>> (But you probably already checked that I guess.)
> 
> Yes, we have attempted to aggregate requirements from other sources.   At the 
> beginning there were discussions across I2RS, NETCONF, NETMOD WGs and Ops and 
> Routing ADs to arrange for general applicability.
> 
>>> - 4.2.2, last para: The MUST here seems like it may be quite onerous, in
>> general.
>>> Did someone think all of that through? For example, what if the reason
>>> for declining is that the Subscriber doesn't have sufficient privilege?
>>> Saying what privilege is needed would be a breach of least-privilege.
>>> Transient errors may also make this very hard to do well. I'd suggest
>>> s/MUST/MAY/ and to also turn the information returned into a hint and not a
>> promise.
> 
> Thanks, you make good points...
> 
> (1) Changing text to explicitly show that these are hints.  
> (2) Changing text to SHOULD.
> (3) If the subscriber doesn't have privilege, then the target YANG path would 
> not exist (or be found).   Which would be a normal error, not a constrained 
> resource error.  And this requirement was aimed at resource constraints.   
> Which means the text needs to be tweaked. 
> 
> To meet these 3 points, how about the text: "In cases where a Subscription 
> Request cannot be fulfilled due to insufficient platform resources, the 
> Subscription Service SHOULD include within its decline hints on criteria that 
> would have been acceptable when the Subscription Request was made."
> 
>>> - 4.2.5, para 1: saying there "MUST be mutual authentication" is odd -
>>> the usual terms would be "MUST implement" or "MUST use" which of those
>>> does "MUST be"
>>> mean?
> 
> MUST use.  Will change text.   
> 
>>> - 4.2.8: when you say fetch... by whom? Is there an implicit
>>> requirement in the title of the subsection?
> 
> What is implicit is that some mechanism to meet operational requirements of 
> this section should exist.   The entity doing the fetching could be an NMS.
> 
> Thanks,
> Eric
> 
>>>
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> 

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