Re: [netconf] Tsvart last call review of draft-ietf-netconf-netconf-event-notifications-17

["Eric Voit (evoit)" <[e-mail]>]

> From: Wesley Eddy, April 2, 2019 12:32 PM
> 
> Reviewer: Wesley Eddy
> Review result: Ready with Issues
> 
> This document has been reviewed as part of the transport area review team's
> ongoing effort to review key IETF documents. These comments were written
> primarily for the transport area directors, but are copied to the document's
> authors and WG to allow them to address any issues raised and also to the IETF
> discussion list for information.
> 
> When done at the time of IETF Last Call, the authors should consider this
> review as part of the last-call comments they receive. Please always CC tsv-
> [e-mail] if you reply to or forward this review.
> 
> I reviewed this in conjunction with the set of related WG documents on
> NETCONF/RESTCONF subscriptions and event notifications.  I also have some
> comments on other documents in the set, some of which may influence this
> once, since they are closely related.
> 
> In figure 3, and text on page 11, there is an example with a DiffServ codepoint
> value of "10".  This could be interpreted as binary, decimal, hexadecimal, etc.
>  It should be clear what the base is supposed to be.  It seemed pretty
> ambiguous in this and the related documents, so it's not apparent that an
> implementer would be sure to get it right or for it to be compatible.

Hi Wesley,

Figure 3 includes the XML definition <dscp>10</dscp>
This is below the XML namespace "urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications"
 
In the "ietf-subscribed-notifications" YANG model where this "dscp" tag is defined, it is shown to be of:
      type inet:dscp;

higher in that YANG model, "inet" points to RFC 6991: Common YANG Data Types.  This is a core document for YANG which any YANG implementer should be familiar.

Within RFC 6991, the definition of "dscp" is

     typedef dscp {
       type uint8 {
         range "0..63";
       }
       description
        "The dscp type represents a Differentiated Services Code Point
         that may be used for marking packets in a traffic stream.
         In the value set and its semantics, this type is equivalent
         to the Dscp textual convention of the SMIv2.";
       reference
        "RFC 3289: Management Information Base for the Differentiated
                   Services Architecture
         RFC 2474: Definition of the Differentiated Services Field
                   (DS Field) in the IPv4 and IPv6 Headers
         RFC 2780: IANA Allocation Guidelines For Values In
                   the Internet Protocol and Related Headers";
     }

Hopefully this will address the ambiguity.  

Thanks,
Eric


> I have other broad comments on the DSCP usage that will be in review
> comments for the subscribed-notifications draft where it is more appropriate.