Subject: [stir] 4474bis: Why only RECOMMEND when multiple identities?

From: Christer Holmberg <[email-masked]>
Date: Fri, 9 Sep 2016 11:32:50 +0000

Hi,

Section 8 of draft-4474bis says (or, that’s at least my reading) that, if the SIP request contains multiple identities (e.g. if the request in addition to the From header field contains one or more P-Asserted-Identity header fields), it is RECOMMENDED to include “canon”, so that the verifier knows which identity to verify.

Why is this only RECOMMENDED? If there are more than one identity, shouldn’t it be a MUST? I don’t think we want the verifier to try all identities, and see which one (if any) works, do we?

Now, the text DOES talk about “local policy” when it comes to choosing between From and PAI for deriving the identity, so perhaps we could say “MUST, unless local policy defines from where the identity is retrieved”, or something like that…

Regards,

Christer