Hi Fabien
Thanks for your comment.
Please see inline,
________________________________
De : Fabien VERHAEGHE [mailto:[EMAIL PROTECTED]
Envoyé : vendredi 10 août 2007 14:26
À : [EMAIL PROTECTED]
Objet : [Pce] PCEP Request ID
Hello all,
I have a little comment/suggestion on PCEP regarding the request Id.
In section 7.3.1 states that
"The Request-ID-number value combined with the source IP address of the
PCC and the PCE address uniquely
identify the path computation request context".
I agree with that, however there may be 2 requests with same request Id
exchanged on the same session in
the case of session between 2 PCEs.
One Path Request being sent by PCE#1 to PCE#2 and the other one by
PCE#2 to PCE#1.
I don't think there is any problem with that but I am a little
concerned about potential misinterpretation especially
in PCErr and PCNotif message.
If a PCNtf/PCErr message contains an RP object, nothing indicates if it
is related to the Request from PCE#1 to PCE#2
or the one from PCE#2 to PCE#1, except the notification/error type and
value.
I guess this is why for instance for the "Pending Request cancelled"
notification there are 2 values. One for PCC and
one for the PCE.
Yes, this is exactly the reason why there are two values.
One of the problem, from an implementation perspective, is that we must
first ready the Notification type/value in order to retrieve
the correct PathRequest.
Anyway, you have to parse the entire message.
There are other implementations that first parse the whole message and
then start processing the objects.
This is IMO and implementation issue.
Another problem is if an implementation does not recognize a given
Error type/value, then it can't tell for sure which PathRequest it
is related to.
Anyway an Error related to a request is always sent in the PCE-PCC
direction
So it seems to me it would be more consistent to add a bit in the RP
object (in the flag field) to indicate the
"direction" of the PathRequest.
For instance if the bit is set the Message that carry the RP object is
related to the request sent by the destination of the message.
Hence, an RP object would actually uniquely indentifies a PathRequest.
There maybe an ambiguity only in a few error/notif situations, and I
don't think adding a generic bit would be really useful.
By the way this would be a significant change wilth potentially new
error situations to handle (what do you do if the direction PCC to PCE is set
in a reply message?) .
Is that OK with you if we keep as is?
Best Regards,
JL
Regards
Fabien Verhaeghe
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