Re: [babel] [netmod] NULL value for ip-address

[tom petch <[e-mail]>]

From: STARK, BARBARA H <[e-mail]>
Sent: 15 September 2021 13:51

> Barbara
>
> Top posting a slightly different question.
>
> Belatedly doing my homework, I see that not all the NULL are uint16.  One,
> next-hop, is ip-address.  We have the options discussed for uint16 but could also
> use zero (or some other value) to mean NULL.  Zero is of course the way the
> default is commonly represented.
>
> How is this handled in TR-181?  How would you like it handled in YANG?
>
> Tom Petch

Hi Tom,
In discussion with Mahesh, he has indicated preference for union with a "null" enumeration to handle the uint16 cases. He's also indicated he would prefer to do that for the ip-address.
I see the YANG ip-address type is a union of ipv4-address and ipv6-address types, both of which are strings.
In BBF, there is the IPAddress datatype which is a string(45) with IPv4 and IPv6 formats allowed. There are also IPv4Address and IPv6Address datatypes that are defined as derivatives of the IPAddress datatype. An empty string is used for "unspecified or inapplicable addresses". Strings, unlike ints, have the luxury of being empty.
I'm perfectly fine with Mahesh's choice to use the union with a "null" enum in all cases. It seems like a good solution.

<tp>

OK.

Two digressions.  One is that the RFC6991 YANG ip-address includes a zone, a string of indeterminate length and flexible syntax, both for IPv4 and IPv6 so when this is specified, I wonder if the author is aware of this and the -no-zone alternative which, on occasions, is more appropriate.

Second, left field. when I first posted, I had great difficulty in specifying the e-mail addresses I was sending to (still do:-(.  I included the document shepherd, and you because I knew what your address is and it is easy to type correctly:-)  The addresses I might have included, but did not,  were your fellow author (who is now on the thread); and the WG Chairs, the address for the I-D and perhaps the AD.  I trust that these others will be involved when needed.

Tom Petch


Thx,
Barbara

> From: netmod <[e-mail]> on behalf of tom petch
> <[e-mail]>
> Sent: 15 September 2021 10:04
>
> From: netmod <[e-mail]> on behalf of Jürgen Schönwälder
> <[e-mail]>
> Sent: 15 September 2021 00:53
>

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