Re: [Sip] INVITE after a terminated dialog?

[Paul Kyzivat <[e-mail]>]

Jane,

Can you provide a call flow for what is happening? Its a little hard to 
follow from the textual description.

But in the meantime there is one fundamental principle of importance 
here: every transaction completes independently.

Jane Jiang wrote:
> Hi All,
>  
> There is a weird situation with us:
> (1) A Linksys phone sends an INVITE out with incorrect destination TN.  
> As a result, our application server will set up a call between the 
> Linksys phone and an IVR
> (2) A user incorrectly hits the on-hold key, which is basically sending 
> a re-INVITE to the IVR
> (3) Our server seems to have answered the re-INVITE with a BYE
> (4) The Linksys phone responds to the BYE with a 200
> (5) Afterwards, the Linksys phone still thinks that its original 
> re-INVITE has not been responded.  So, it will keep resend re-INVITE
>  
> The consequence of these re-INVITEs is a registration migration, which 
> we don't like.  We have been trying to figure out which side is not 
> following RFC 3261, the phone, the SBCs are wrong, or the application 
> servers.
>  
> I am wondering:
> (A) Is it legal for a server to ignore the re-INVITE and respond with a 
> BYE and has nothing in between?

While the BYE may in some way have been provoked by the reINVITE, the 
two are distinct. The reINVITE still needs to be answered with some 
final response which then must be ACKed, and the BYE also needs to be 
responded to.

> (B) If a UA has responded to a BYE with 200, is it supposed to forget 
> about the re-INVITE request that it has sent out and not try to resend 
> the re-INVITE, assuming a dialog has already been terminated with the 
> BYE/200 transaction?  Maybe in another sentence, is it legal to send our 
> re-INVITEs outside an dialog, even if these re-INVITEs are the repeats 
> of an original in-dialog re-INVITE?

It is not legal to send a *new* reINVITE after the dialog has been 
terminated. But it is appropriate to continue retransmissions if no 
response has been received.

	Paul


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