Sure, but that's their *implementation* issue. Standards don't stop you from 
doing something stupid, but they shouln't stop you from doing something 
intelligent/creative either...

Lou
-----Original Message-----
From: JP Vasseur <[EMAIL PROTECTED]>

Date: Sat, 29 Nov 2008 14:05:46 
To: Lou Berger<[EMAIL PROTECTED]>
Cc: Adrian Farrel<[EMAIL PROTECTED]>; <[email protected]>
Subject: Re: [Pce] Path Key I-D : number of bits



On Nov 28, 2008, at 11:38 PM, Lou Berger wrote:

> So bits in this object are cheap and a 32 bit key would allow for
> potential future cases that we can already envision as well as
> today's known cases.  (BTW I know of one experimental usage of PCE
> that I suspect will want this immediately.)

Well, I may make a comment: in this case, I can see a *number* of
issues that they will be facing if they have a model where you can end
up with more than 65 K pending requests ...

>  IMO optimizing the subobject by 2/4 bytes is completely unwarranted.
>
> Now, that said, it is quite late in the process to raise this
> point.  (mea culpa.) If the only impact of this change is a minor
> delay in progressing the documents, then I think we should make the
> change now.  On the other hand, if changing this now also impacts
> implementations, I think we should only support longer keys once
> there is real (not today's theoretical) demand for them.
>
> So, IMO we should make this change based on implementation impact.
>
> Is there anyone with an implementation who wants to weigh in on the
> real/practical impact to them on this change?
>
> Lou
>
> At 06:37 PM 11/27/2008, Adrian Farrel wrote:
>> Hi,
>>
>> To repeat something discussed briefly in Minneapolis (this was
>> raised in CCAMP in discussion of draft-ietf-ccamp-path-key-
>> ero-02.txt, but more properly applies to draft-ietf-pce-path-
>> key-05.txt).
>>
>> The path key subobject is formed as...
>>
>>    0                   1                   2                   3
>>    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
>>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>   |L|    Type     |     Length    |           Path Key            |
>>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>   |                         PCE ID (4 bytes)                      |
>>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>
>> The question is: Are 16 bits enough for the Path Key? Isn't it
>> possible that more than 2^16 path segments will be computed and
>> "held" for possible expansion during signaling at any one time?
>>
>> My feeling is that this would not be the case. The keys are
>> relatively short lived, and can be recycled after a short safety
>> period as described in the draft.
>>
>> There are some special cases where resignaling of the LSP (from the
>> head end with the same path key) would require the key to be held
>> for longer, but the domain entry router can hold the key (in
>> association with the session) to avoid any issues in this case.
>>
>> Further, if there really are issues with depletion of keys, the PCE
>> could use another PCE ID to create a further 2^16 keys.
>>
>> What does the working group think?
>>
>> Thanks,
>> Adrian
>>
>>
>>
>
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