Re: [dnssd] Review of draft-ietf-dnssd-srp-12

[Esko Dijk <[e-mail]>]

> No, this wouldn't be correct. The additional constraints you want to remove are to ensure that if the Service Instruction is an Add, the Service Description Instruction is also an Add, and if the Service Instruction is a Delete, the Service Description instruction is also a delete. We could explain that in 2.3.2, but currently we do not.

That sounds more straightforward than the current text in the I-D! What about this text, then:

An instruction is a Service Discovery Instruction if it contains

   *  exactly one "Add to an RRSet" ([RFC2136], Section 2.5.1) or exactly one "Delete an RR from an
      RRSet" ([RFC2136], Section 2.5.4) RR update,
   *  which updates a PTR RR,
   *  the target of which is a Service Instance Name,
   *  for which name a Service Description Instruction is present in the
      SRP Update, and
   *  if the RR update is an "Add to an RRSet"
      instruction, that Service Description Instruction
      contains an "Add to an RRset" RR update for the SRV RR
      describing that service; and
   *  if the RR update is a "Delete an RR from an
      RRSet" update, the Service Description Instruction
      contains an "Delete an RR from an RRset" RR update;
   *  and no other add or delete RR updates.

This does modify the logic slightly (in second-last bullet) compared to the original but that’s now based on your explanation.
So one change is to define Service Discovery Instruction without recursively referring to Service Discovery Instruction itself, which I found confusing. Instead it refers to the “exactly one RR update” of the first bullet using the term “RR update”. That works because there’s exactly one. And also it removes the double negation that was present and the unclarity of the negative “does not match” in the definition (does not match against … ?) .

I’d like to reiterate one comment on 2.3.1.1 independent of the above. Not sure if you agree with that :
* Update sentence to: “it contains exactly one "Add to an RRSet" ([RFC2136], Section 2.5.1<https://datatracker.ietf.org/doc/html/rfc2136#section-2.5.1>) or exactly one "Delete an RR from an RRSet" ([RFC2136], Section 2.5.4<https://datatracker.ietf.org/doc/html/rfc2136#section-2.5.1>) RR update,” to point to the correct section numbers.

Best regards
Esko