Subject: Re: [sipcore] #29: B2BUAs passing H-I through?

From: "Worley, Dale R (Dale)" <[email-masked]>
Date: Fri, 10 Sep 2010 15:50:36 -0400

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From: [email-masked] [[email-masked]] On Behalf Of Hadriel Kaplan [[email-masked]]

Since a B2BUA is a UAC and UAS, one might think it should follow the rules for a UAC and UAS in this draft, restarting/clearing the H-I on each side. 

What you really want is a sentence/para saying a B2BUA would follow the rules for a Proxy with regards to H-I for requests which it forwards, unless local policy says otherwise; while for requests it generates itself it should act as a UAC.  For example if it generates a dialog-creating INVITE due to receiving a REFER, it would act as a UAC per the 4424bis draft, but if it is merely forwarding a dialog-creating INVITE (i.e. generating one due to receiving one) then it should follow the rules for a Proxy and copy the received H-I and add an entry, etc.  Right?
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Yes.  Or perhaps even more flexibly -- E.g., a B2BUA that is creating an INVITE due to receiving a REFER, but that continues a dialog "from the other side", might send the new INVITE with the H-I received well in the past, when the other side dialog was created.  But the main point is as you stated, as the text stands now, a B2BUA sending an INVITE is acting as a UAC and must reinitialize the H-I.

Dale