Re: [Pce] Whither Stateless PCE?

[Robert Varga <[e-mail]>]

On 09/08/2016 03:10 PM, Olivier Dugeon wrote:
> Hello Robert,
> 
> Le 08/09/2016 11:38, Robert Varga a écrit :
>> On 09/07/2016 05:57 PM, Ina Minei wrote:
>>> I think if we replace MUST with SHOULD in the text you provided that
>>> would work for the transition. Can implementors comment on the impact?
>> The change in PCRpt format is incompatible with fielded installations.
>>
>> OpenDaylight will refuse a PCRpt consisting of (LSP, NO-PATH) and will
>> raise an Mandatory Object Missing PCErr, leading to failure to perform
>> initial state synchronization. The requirement has been there since
>> revision 05 (at least) and has been clarified in revision 16.
> Agree. But, as we face to some interoperability issues between various
> implementation, whatever the solution we choose, we need new release, so
> new version of firmware in the routers and new software for the PCE. So,
> I prefer to have a clear fix without any ambiguity instead of patch what
> wil continue to be subject to misinterpretation.
> 
> Regarding OpenDayLight, I think that the modification is not too huge:

I do agree that the change is not that big, but it will lead to the same
interoperability issues we have had with -02 and -07, which required
explicit configuration to deal with network-wide upgrades.

Unlike the previous break in protocol, the draft now has an IANA early
allocation, which prohibits us from breaking the protocol. Quoting
https://tools.ietf.org/html/rfc7120#section-2:

   c.  The specifications of these code points must be stable; i.e., if
       there is a change, implementations based on the earlier and later
       specifications must be seamlessly interoperable.

Bye,
Robert