[stir] Brief review of draft-ietf-stir-rfc4474bis-08

[Alan Ford <[e-mail]>]

Hi all,

At IETF95, Robert suggested I should review draft-ietf-stir-rfc4474bis from an implementer's point-of-view... So I have :)  I was coming at this completely fresh - I had never read any of the document before and had very limited background on this topic... And I must first say it's a really accessible document, very easy to follow and understand. I have only a few very minor comments on clarity:

- Section 4, it took me a while to realise that the authentication service typically sat as a component of Alice's home SIP proxy. Whilst obvious once a bit more context was available, I'd suggest adding a sentence at the end of paragraph 5 (The proxy, ...) that reads something like "The proxy then forwards the request under normal to Bob's domain".

- Section 5.1, Step 4, paragraph 3... Similarly, just insert "at the receiver" after "In some cases, a request sent through an authentication service will be rejected by the verification service" - helps make the process a little clearer.

- Section 5.2, it is not clear if there should be anything different in the 488 for no Identity header, and unsupported ppt?

- Section 6.3, typo "bae64"

- Section 6.3, "result of the JSON object construction process", would it not be clearer to say "the PASSporT object" or similar? There is a clear definition of "canon" in the last paragraph of Section 8 which could be used earlier too.

- Section 6.4, "URL of the form" ? Is form the right word for content-type here?

- Section 6.4 references "this registry" -> what registry? Maybe this should reference IANA section? Also the ref to RFC7519 to define "RS256" should probably occur here.

- Section 7.2 - could the use of the key not in some way be restricted purely for use with SIP Identity? Therefore removing issues with giving it to a third-party service provider?

- Section 12.1, paragraph 4: "The To helps" and "over the To" -> insert "header" after "To" for clarity since it scans really strangely otherwise!

Cheers,
Alan