Re: [pim] Updates to draft-ietf-pim-igmp-mld-extension, WG input wanted

Hi, Stig:

Is it useful to define the total length of “Extension TLV” at the beginning of the “Extension Format”?
As indicated in the https://datatracker.ietf.org/doc/html/draft-ietf-pim-igmp-mld-extension-07.txt#section-5

“The total length of the Extension MUST NOT exceed the remainder of
      the IP payload length.  For this validation, one only examines the
      content of the Extension Length fields.”

In the current format, to accomplish the validation, the implementation must walk through all the TLVs.

And, if such field exist, the former validation can also be easier, or just ignore it.

“There MUST NOT be any data in the IP payload after the last TLV.
      To check this, the parser needs to walk through each of the TLVs
      until there are less than four octets left in the IP payload.  If
      there are any octets left, validation fails.”

Aijun Wang
China Telecom

> On May 12, 2022, at 08:26, Stig Venaas <stig@venaas.com> wrote:
> 
> Dear pim WG
> 
> Based on the IESG evaluation of draft-ietf-pim-igmp-mld-extension I
> have made some larger changes, please see
> https://datatracker.ietf.org/doc/html/draft-ietf-pim-igmp-mld-extension-07.txt
> 
> There was a request to add experimental code-points. I've added 2, I
> think that should be sufficient. Different experiments can use the
> same code-points.
> 
> I was also asked to add a no-op TLV. This doesn't do much, but it
> might perhaps allow testing of implementations to see whether they are
> parsing TLVs correctly.
> 
> Finally, there were questions whether IETF Review is too strict for
> assignment of code-points. In my opinion we should be cautious with
> new extensions and IETF Review allows us to carefully review any
> extensions in the IETF. Alternatively we could for instance have
> relaxed it to just require a specification (this could be any
> document, not requiring review). Please let me know if you believe we
> should relax this.
> 
> Hoping to get input within two weeks (May 25th), so that we can move
> ahead with the publication, or revise as needed. Mike, let me know if
> we need to do anything else to get sufficient review.
> 
> Thanks,
> Stig
> 
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