[SIPForum-discussion] Question on Target refresh

[Justin Davies]

Hi Ramesh,

If I understand you correctly, you are using an INFO method to change the media attributes?

Only re-INVITES and UPDATES can change the media. See rfc3311 for information on UPDATES. 



--
Justin Davies
justin at futureblue.com
+447427629649

> On 20 Jun 2019, at 18:40, Ramesh Kandasamy <ramelcom at gmail.com> wrote:
> 
> 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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