Subject: RE: [Sip] Outbound: Questions on reg-id

From: "Christer Holmberg \(JO/LMF\)" <[email-masked]>
Date: Wed, 5 Apr 2006 16:55:35 +0200

Hi Hadriel, 

>1. Adding a few words saying that checking the Call-Id to detect 
>whether a REGISTER is a refresh or a new REGISTER after a reboot. The 
>document currently says that the reg-id alone is used to indicate 
>reboot, but I think we have agreed that is not the case.

Why do you need to know if the UA rebooted?  You only need to know if an
old flow/entry is stale.  If the UA detects a flow failure (STUN
XOR-MAPPED-ADDRESS change, socket failure, etc.), then it will send a
whole new register and it will probably be a new call-id.  If it wasn't
a new call-id, and it came in on a new flow to the registrar, the
registrar's supposed to update the flow it received it on anyway.  If it
came in on a new flow to the proxy, then it would create a new flow
token anyway.  Am I missing something?

[CHH] The idea was that if the Call-Id value wasn't new, the registrar
could assume the REGISTER is just a refresh. 

>2. Adding a few words saying that the same Call-Id value MAY be used
for all flows (assuming we agree there are no 
>impacts whether the same  values are used or not).

I don't agree.  They're unique requests.  

[CHH] I am not sure I undertand what you mean by "unique request"...
RFC3261 currently says that an UA SHOULD use the same Call-ID for ALL
REGISTERs it sends. The RFC does not (for obvious reasons) talk about
"flows", "reg-ids" etc. 

Now, if it is ok to use the same Call-ID for all REGISTERs/flows also
for outbound we don't need to add any text in order to extend/change
RFC3261. It would only be clarification text, to avoid questions in the
future.

However, IF we must use different Call-Ids for each flow I think that is
new functionality, compared to what is currently said in RFC3261.

Or, is there some text somewhere I've missed (it does happen :)?

Regards,

Christer

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