That works for me, although I would probably lower-case the "MAY".
A
From: Pce [mailto:[email protected]] On Behalf Of Julien Meuric
Sent: 17 November 2017 17:30
To: Dhruv Dhody; Jonathan Hardwick
Cc: [email protected]; [email protected]
Subject: Re: [Pce] Shepherd's review of draft-ietf-pce-pcep-exp-codepoints
Hi,
IMHO, the correct wording lies in between. RFC 5440 set the default for PCEP ("A
PCEP-ERROR object is used to report a PCEP error"). Further specification (e.g.
RFC 8231) MAY add message-specific behavior, but I think it is wrong to mandate
a new behavior for each new message. I would thus suggest :
If the PCE does not understand or support an experimental object with
the P flag set in the Object Header, in the Path Computation Request
message (PCReq), the entire PCEP message is rejected and PCE responds
with a PCErr message with Error-Type="Unknown Object" or "Not
supported object" as described in [RFC5440]. Otherwise, the object is
ignored. Message-specific behavior MAY be specified (e.g., [RFC8231]
defines rules for a PCC to handle an unknown object in an Update
(PCUpd) message).
My 2 cents,
Julien
Nov. 13, 2017 - [email protected]:
<snip>
Section 5
The following paragraph does not tell the whole story.
A PCE that does not recognize an experimental PCEP object, will
reject the entire PCEP message and send a PCE error message with
Error- Type="Unknown Object" or "Not supported object" as described
in [RFC5440].
If the P flag is clear in the object header, then the PCE MAY ignore the object
instead of generating this error message. Also, you do not discuss what a PCC
would do on receipt of a PCUdp or PCInitiate containing an unrecognised
experimental object - it is inconsistent that you don't cover these cases.
(FWIW, RFC 8231 is a bit ambiguous about what a PCC should do about the PCUpd.
Section 6.2 says that a PCErr should be sent, but then it refers to section
7.3.3, which says that a PCRpt should be sent. Hmmm.)
[[[Dhruv Dhody]]] Yes. How about I update to this -
If the PCE does not understand or support an experimental object with
the P flag set in the Object Header, in the Path Computation Request
message (PCReq), the entire PCEP message is rejected and PCE responds
with a PCErr message with Error-Type="Unknown Object" or "Not
supported object" as described in [RFC5440]. Otherwise the object is
ignored. In case of stateful PCE messages [RFC8231], the P flag is
ignored and the unknown object handling is as per the stateful PCE
extensions.
And let's try to handle the inconsistency in RFC 8231 with an errata perhaps?
And handle PCE-initiated during AUTH48?
[Jon] I think this is OK, but if we are just going to point the reader at
RFC8231, then we might as well do the same with RFC5440, rather than duplicate
its text. And we should write something that allows for the possibility that
more message types may be relevant in future. How about
If a PCEP speaker does not understand or support an experimental object
then the way it handles this situation depends on the message type.
For example, a PCE handles an unknown object in the Path Computation Request
(PCReq) message according to the rules of [RFC5440]. A PCC handles an
unknown object in an Update (PCUpd) message according to the rules of
[RFC8231]
and, in an LSP Initiate Request (PCInitiate) message, according to the rules
of
[I-D.ietf-pce-pce-initiated-lsp]. Any document that adds a new PCEP message
type must specify how to handle unknown objects on that message.
Note that this last sentence is not an RFC2119 MUST because it defines author
behaviour, not device behaviour.
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