Re: [netmod] WG LC draft-ietf-netmod-module-tags-02 - 10/2/18 - 10/16/18

[Christian Hopps <[e-mail]>]

Andy Bierman <[e-mail]> writes:
>
> This draft needs to define the module-tag encoding wrt/
>    - valid characters (e.g., some subset of UTF-8)
>    - min/max length (e.g., implementation MUST support at least 64 chars
> and can support larger)

I'm looking for suggestions on how to do this subset. We had intended to allow for as wide as possible content; however, I think disallowing tabs, newlines, carriage returns is more than reasonable. Has a type like this already been standardized or is there an example available somewhere?

> Section 3 (Tag Prefixes) seems to imply that all modules tags follow a
> structure to specify the naming authority.
>
> According to the YANG module, the data type is a plain string, which
> includes lots of
> problematic chars and zero-length strings.
>
> Does the string "routing" match "ietf:routing" or "vendor:routing"? How
> about "routing:bgp"?

No. Do we need to state that non-matching strings don't match?

> Is the char ":" allowed in a tag?

Yes, why not?

> Is "vendor::::::::" a valid tag?

Again why not?

The only thing the draft talks about are standard prefixes. Why should a standard enumerate a subset of the unbounded set of things it isn't standardizing? This seems more confusing (why was X included as OK but not Y) than just sticking to what it *is* standardizing.

Perhaps a bit of text saying more explicitly that only the prefix is restricted would help though?

> IMO this draft does not need to define any specific module-tag content but
> it does need to define
> in precise terms how a protocol encodes a module-tag and how a module-tag
> match is determined.

We considered leaving out all the predefined tags, but conversely we also thought it would be useful to establish a base set. We went with the latter obviously. Perhaps it just needs to be trimmed down more?

Thanks,
Chris.

>
>
> Thanks,
>> Chris.
>>
>
> Andy