Dhruv,

thanks in return for discussing these comments.

Thanks for the new paragraph, and thanks for pointing me to what I 
should have found myself.

on the unsupported/unknown, it is clearer now. Thanks.

-m

Le 2019-07-10 à 20:15, Dhruv Dhody a écrit :
> Hi Martin,
> 
> Thanks for further discussion, see in-line..
> 
> <snip>
>>>
>>>
>>>> Sending ASSOC-Type-List TLV is optional but it might be mandatory to send
>>>> some to-be-defined Association types. Isn't that somehow conflicting?
>>>>
>>> [[Dhruv Dhody]] The aim was to say that right now this TLV is optional, but 
>>> a future association type (say disjoint) can specify that if you want to 
>>> use *this particular association type* you need to include the TLV. So if 
>>> an implementation does not support this particular association type, the 
>>> TLV would be optional, and if it needs to support this, then the TLV 
>>> becomes mandatory to include.
>>
>> I understand the aim, but I fail to understand how it doesn't lead to
>> conflicting requirements.
>> This doc says, the whole TLV is optional.
>> A future doc might say: this assoc-type in this TLV is mandatory.
>>
>> By construction the future doc is thus saying that the TLV is mandatory,
>> which conflicts with the base spec.
>>
>> Couldn't you lay out the path for the future by saying something like:
>> * MUST be sent if it contains at least an assoc-type which must be sent
>> and MAY NOT be sent otherwise.
>>
> 
> [Dhruv]: I agree, I can update the text to say -
> 
>     Association type (to be defined in other documents) can specify if
>     the association type advertisement is mandatory for it.  Thus, the
>     ASSOC-Type-List TLV MUST be included if at least one mandatory
>     association type needs to be advertised and the ASSOC-Type-List TLV
>     MAY be included otherwise.
> 
> I used MAY, as MAY NOT is not RFC 2119 keyword.
> 
>>
>> As a side question, sorry I didn't go back to the doc, but how should
>> the systems behave in the case where there are two assoc types: one
>> mandatory and the other not.
>> MUST the system advertise both in the list or can it only advertise the
>> mandatory one? And how will the receiver treat that latter case? I'm
>> asking because I think you cover the case of not sending the whole TLV
>> and then the receiver MUST interpret that as an absence of information
>> on the list of supported Association types (rather than the Association
>> type is not supported), but if it receives the TLV without the assoc
>> type, should it still interpret it as an absence of info or as not
>> supported?
>>
> 
> We have this text in the I-D that covers these conditions -
> 
>     For an association type that specifies
>     that the advertisement is mandatory, a missing Assoc-type in the
>     ASSOC-Type-List TLV (or missing ASSOC-Type-List TLV) is to be
>     interpreted as the association type is not supported by the PCEP
>     speaker.
> 
>     The absence of the ASSOC-Type-List TLV in an OPEN object MUST be
>     interpreted as an absence of information on the list of supported
>     Association types (rather than the Association type is not
>     supported).  In this case, the PCEP speaker could still use the
>     ASSOCIATION object: if the peer does not support the association, it
>     will react as per the procedure described in Section 6.4.
> 
>     In case the use of the ASSOC-Type-List TLV is triggered by support
>     for a mandatory association type, then it is RECOMMENDED that the
>     PCEP implementation include all supported Association types
>     (including optional) to ease the operations of the PCEP peer.
> 
> <snip>
>>>
>>>> Could you clarify the difference between a PCEP speaker does not recognize
>>>> the ASSOCIATION object and a PCE peer is ... unable to process the
>>>> ASSOCIATION I see that the errors thrown are different.
>>>>
>>> [[Dhruv Dhody]] The difference is between ASSOCIATION Object being unknown 
>>> (former) and Object being known *but* not supported/processed (latter).
>>
>> That doesn't really clarify. What is the difference between unknown and
>> not supported?
> 
> Unknown - I parse the PCEP object header, and find an object-type, I
> dont know what this object type means and it is unknown.
> Not Supported - I parse the PCEP object header, and find an
> object-type that i am aware of but for some reason do not support.
> This could be because of feature being disabled via configuration for
> instance.
> 
> Note that these errors are defined in PCEP since its inception in RFC 5440.
> 
> Last Commit: 
> https://github.com/dhruvdhody-huawei/ietf/commit/a00b161661a334d800bab99dedbd2012e3951651
> 
> Please let me know if any further change is needed.
> 
> Thanks!
> Dhruv
> 
> <snip>
>>> Working Copy: 
>>> https://raw.githubusercontent.com/dhruvdhody-huawei/ietf/master/draft-ietf-pce-association-group-10.txt
>>> Diff: 
>>> https://tools.ietf.org/rfcdiff?url1=draft-ietf-pce-association-group-09&url2=https://raw.githubusercontent.com/dhruvdhody-huawei/ietf/master/draft-ietf-pce-association-group-10.txt
> 
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