Re: [Netconf] mbj's WGLC review of yang-push-17

[Kent Watsen <[e-mail]>]

>Alexander Clemm <[e-mail]> wrote:
>> I am about to post -19 but I do not like the suggested change to go
>> from timeticks to seconds.
>> 
>> Seconds is a fairly coarse unit.  I would not be surprised to see
>> requirements for finer granularity in the future, even more so in
>> virtualization and controller scenarios in which we start to see YANG
>> being used.  There are applications that use single second periods
>> today so I think it is entirely conceivable to see need for subsecond
>> support down the line.  To allow periods only in units of seconds
>> would seem to unnecessarily hobble ourselves.  Keeping things to
>> timeticks is more futureproof IMHO.
>
> Ok.

I agree that seconds is too course. Hundredths of a second is maybe too
fine, but I won't complain.  That said, I think that it might be an
uncommon scenario and that having hundredths of a second will likely
result in very large numbers.

FWIW, yang:timeticks doesn't seem as intuitive as "units" - for example:

          leaf period {
-           type yang:timeticks;
+           type uint16;
+           units "Hundredths of a second";
            mandatory true;
            description
              "Duration of time which should occur between periodic
               push updates.";
          }

At least I know what this means right away.  I was hoping to find an example
in -19 illustrating its use, but it's none is present.  

BTW, I note that RFC 6991 says:

         When a schema
         node is defined that uses this type, the description of
         the schema node identifies both of the reference epochs.

Which I don't see in -19.

Would it make sense to use a 2-tuple?  Something like:

          leaf period {
            type uint16;
            mandatory true;
            description
              "Duration of time which should occur between periodic
               push updates.";
          }
          leaf period-units {
            type enumeration {
              enum hundredths;
              enum tenths;
              enum seconds;
              enum minutes;
              enum hours;
            }
            mandatory true;
          }



Kent // contributor