Re: [TICTOC] Yangdoctors early review of draft-ietf-tictoc-1588v2-yang-10

Radek Krejčí <rkrejci@cesnet.cz> Thu, 25 October 2018 14:16 UTC

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Date: Thu, 25 Oct 2018 16:16:02 +0200
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Subject: Re: [TICTOC] Yangdoctors early review of draft-ietf-tictoc-1588v2-yang-10
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Hi Yuanlong,
let me clarify it - so, we are talking about the YANG module's prefix, right? And "used by other PTP applications" means imported in some other YANG module, right? Then the prefix connected with such an import is arbitrary and it is scoped only to the YANG module where the ptp module is imported. So even if the prefix in the ptp module changes, the modules which imports ptp module does not need to change the prefix they use for the ptp import. I agree, that it is always better when the prefixes matches (and yes, RFC says SHOULD be the same), I'm just saying that it is not a problem when they don't (implementation must be able to handle it because of possible collisions).

The reason why the text seems weird to me is because it does not make sense to me that preserving the prefix is possible because (this is how I understand the paragraph, maybe wrongly) the nodes within the modules are compatible. RFC 7950 allow me to change or preserve the prefix despite the compatibility of the nodes. So what about the following text?

OLD

   Under the assumptions of section A.1, the first IEEE 1588 YANG
   module prefix can be the same as the last IETF 1588 YANG module
   prefix (i.e. "ptp"), since the nodes within both YANG modules are
   compatible.

NEW

   Under the assumptions of section A.1, it will be useful and
   convenient for other YANG modules using 1588 YANG module to keep
   the module prefix of the first IEEE 1588 YANG modules same as in
   the last IETF 1588 YANG module (i.e. "ptp").

Regards,
Radek



Dne 25. 10. 18 v 11:08 Jiangyuanlong napsal(a):
> Radek,
>
> Sorry that my 2nd comment is not correct.
> The module's prefix, i.e., "ptp", is used by other PTP applications (according to RFC7950, the prefix defined by a module SHOULD be used when the module is imported). 
> If the same prefix "ptp" is used, these PTP applications don't need to change their YANG codes (i.e., always use the same prefix "ptp" to access PTP nodes), but only change a URN namespace when migrating from IETF to IEEE-1588.
> Thus it is more convenient for an implementation to migrate from IETF 1588 YANG to IEEE 1588 YANG.
> Since the IETF will transfer the development work of the 1588 YANG to IEEE-1588, it is unlikely that another new 1588 YANG module's prefix will be introduced in the IETF.
>
> Do you have any suggestions to improve the texts?
>
> Thanks,
> Yuanlong
>
> -----Original Message-----
> From: TICTOC [mailto:tictoc-bounces@ietf.org] On Behalf Of Jiangyuanlong
> Sent: Thursday, October 25, 2018 4:20 PM
> To: Radek Krejčí <rkrejci@cesnet.cz>; yang-doctors@ietf.org
> Cc: draft-ietf-tictoc-1588v2-yang.all@ietf.org; tictoc@ietf.org
> Subject: Re: [TICTOC] Yangdoctors early review of draft-ietf-tictoc-1588v2-yang-10
>
> Hi Radek,
>
> Thanks much for the review.
> Please see my comments in the line.
>
> Best regards,
> Yuanlong
>
> -----Original Message-----
> From: Radek Krejčí [mailto:rkrejci@cesnet.cz] 
> Sent: Thursday, October 25, 2018 2:50 PM
> To: yang-doctors@ietf.org
> Cc: draft-ietf-tictoc-1588v2-yang.all@ietf.org; tictoc@ietf.org
> Subject: Yangdoctors early review of draft-ietf-tictoc-1588v2-yang-10
>
> Reviewer: Radek Krejčí
> Review result: Ready with Nits
>
> This is my YANG-doctor review of draft-ietf-tictoc-1588v2-yang-10. I have reviewed it mainly from the YANG perspective, since I'm not familiar with IEEE 1588.
>
> The draft as well as the YANG module ietf-ptp@2018-09-10 are in a good shape and ready to publish. I have only 2, say, editorial notes.
>
> 1) email of Rodney Cummings in the module's contact statement misses (in contrast to emails of other authors) starting ('<') and ending ('>') tags.
> [YJ] Good catch, I found this inconsistence too, and we will update it in the next revision.
>
> 2) I don't see any reason for the following paragraph in the appendix A3:
>
>    Under the assumptions of section A.1, the first IEEE 1588 YANG
>    module prefix can be the same as the last IETF 1588 YANG module
>    prefix (i.e. "ptp"), since the nodes within both YANG modules are
>    compatible.
>
> Since the module's prefix is used only locally, it may change when the module is updated (RFC 7950, sec. 11). So the mentioned paragraph seems pointless to me (and therefore confusing for readers).
> [YJ] Good catch, there is a misspelling here, "prefix" should be "postfix" in A.3, it is not the "prefix" statement in the YANG. The logic is, both "ieee1588-ptp" and "ietf-ptp" have a "ptp" postfix.
>
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