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RE: Yangdoctors early review of draft-ietf-netconf-yang-push-06

2017-05-16 15:59:03
Hi Bert,

Thanks very much for the review.  Some thoughts in-line...

From: Bert Wijnen, May 16, 2017 8:38 AM

Reviewer: Bert Wijnen
Review result: On the Right Track


- last para of sect 3.5.
  This seems to me to make it difficult to create interoperable
  implementations. Or is there a way for a client to figure out what
  is or is not support, other than tryal and error?

Minimal XPATH syntax support is really a subscription independent issue.  At 
this time, I am not aware of anyone attempting to constrain which XPATH 
capabilities should be the minimum set for the industry.  One of the reasons is 
that going with a minimum common denominator for a high volume information set  
(like routing changes) might constrain the availability of low volume, high 
value filters (like configuration changes).     I would very much welcome 
someone who wanted to attempt work in this area.   As David Waltermire said to 
me on this topic today, it might be possible to identify a minimum XPATH filter 
capability set for various roles in the network element.  But this is 
non-trivial work.

For now, I am assuming any vendor will be able to articulate what the syntax 
capabilities are for their platforms.  And they can do outside the standards 
arena.  A good way to do this would be to pre-populate example filters in the 
"filters" objects. 

- page 41:

     /* YANG Parser Pyang crashing on the following syntax below

  So does the definition get skipped? Or what needs to happen here?

There is a coming in pyang 1.7.2 which fixes the bug...     
https://github.com/mbj4668/pyang/issues/300 

See
https://github.com/mbj4668/pyang/commit/b891cc3dd3a4547f9eddd83882e9872bc2066c6d
 

All we need to do is await the new version.

Consistency

- last bullet on page 7 talks about "YANG subtrees". I do not see that term
  in netconf or yang documents. Those just talk about "subtrees".
Maybe I am
  not looking good enough?

Will remove the word YANG

- top of page 8 I see the words "xpath", "Xpath" and "XPath"
  is there a difference?

No.  Will fix.
 
Nits

Nice catches.  Will fix the items below.

Eric

- you may want to check the reference/citation occurrences of [subscribe]
  at several places it points to
     draft-ietf-netconf-yang-push-06#ref-subscribe
  whereas I think it intends to point to the [subscribe] in the
  normative references section
- first bullet on page 5:
     Enhancements to filters. Specifically the filter MUST at identify at
     least one targeted yang
   s/at//  -- the first "at" seems superfluous
   plus, you are using capitalized MUST with out reference/citation of
   RFC2119
- page 36:

    leaf dependency {
      type sn:subscription-id;
      description
        "Provides the Subscription ID of a parent subscription which
         has absolute priority should that parent have push updates
         ready to egress the publisher. In other words, there should be
         no streaming of objects from the current subscription if of
         the parent has something ready to push.";
      reference
        "RFC-7540, section 5.3.1";
    }

     s/if of/if/ ??


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