[SIPForum-discussion] Question on Target refresh

[Ramesh Kandasamy]

Reposting the query below.

Thanks
Ramesh

On Thu, May 2, 2019 at 2:03 PM Ramesh Kandasamy <ramelcom at gmail.com> wrote:

> Hi all,
>
> I have a question on the below call flow and if it is related to target
> refresh.
>
> SIP UA establishes a TCP connection with SIP Proxy to initiate the call.
>     INVITE from SIP UA was sent from TCP port, say p1.
> Call got answered and ongoing.
> At some point, SIP UA closes TCP port p1 by exchanging TCP FIN/FIN ack.
> Later within the same dialog, SIP UA establishes another TCP connection
> with the same SIP Proxy for the same call to send SIP INFO.
>    INFO from SIP UA was sent from TCP port, say p2.
> SIP Proxy sends back the INFO response to this new TCP port p2.
> But subsequent SIP requests are not routed from SIP Proxy to this new TCP
> port p2 of SIP UA. Rather, it attempts to send on p1 which fails.
>
> My question is, is this INFO above considered as target refresh? Please
> note that Contact and dialog-id (From, To, Call-Id, R-uri) between the
> initial INVITE (from p1) and INFO (from p2) remains the same. IP address
> doesn't change either.
>
> My thought is that the above flow is allowed and this is not a target
> refresh. So, So, any subsequent SIP requests from SIP Proxy should ideally
> be sent to this new TCP port p2.
>
> Please advise.
>
> Thanks
> Ramesh
>
>
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