[SR-Users] Transport protocol related question - how to bind a dialog to a negotiated transport protocol

[Klaus Feichtinger]

Thank you Daniel! Now its all clear and it is working fine.

regards,
Klaus
> Hello,
>
> the request within dialogs are sent to the address in the Contact 
> header of the request/response creating the dialog. In you trace, the 
> SUBSCRIBE has a Contact with no transport, the default one being UDP.
>
> Of course, a higher priority than Contact in sending would be 
> Record-Route, but it is not the case of your example.
>
> In other words, SIP allows to create dialogs on one transport and 
> request a follow up on another transport. Even the response to a 
> request can have different destination (ip, port or protocol) than the 
> address from where the request was sent, Via header specifying where 
> it should be sent.
>
> Cheers,
> Daniel
>
> On 11/06/14 21:32, Klaus Feichtinger wrote:
>> Hello,
>>
>> I wonder if it is allowed using transport protocol UDP for SIP NOTIFY 
>> requests (which are generated by Kamailio/presence module), when the 
>> SUBSCRIBE dialog was established using TCP as transport protocol.
>> In other words: this is a principal question if it is allowed 
>> changing the transport protocol for in-dialog transactions e.g. from 
>> TCP to UDP. Initially I rather thought that in-dialog transactions 
>> shall use the same transport protocol as the dialog itself (e.g. SIP 
>> INFO requests within a standard media session), except the message 
>> would be too big for UDP, where a change to TCP is recommended.
>>
>> Can anybody give me a hint, if the current behaviour of Kamailio is 
>> correct or not? Or - how can I bind Kamailio to a specific transport 
>> protocol (for messages that are created by modules themselves)? 
>> Kamailio is sending NOTIFY requests with UDP, even when the 
>> subscription was done with TCP (see excerpt below).
>>
>> 09:58:10.360749 IP (tos 0x0, ttl 64, id 35302, offset 0, flags [DF], 
>> proto TCP (6), length 444) 10.1.1.14.37883 > 10.1.1.44.5060: P, cksum 
>> 0x1cb3 (correct), 1:393(392) ack 1 win 457 <nop,nop,timestamp 
>> 624699305 795715664>
>> SUBSCRIBE sip:116006 at 10.1.1.44;transport=TCP SIP/2.0
>> Via: SIP/2.0/TCP 10.1.1.14:5070;rport;branch=z9hG4bK1540213071
>> From: <sip:1 at 10.1.1.14:5070>;tag=620071678
>> To: <sip:116006 at 10.1.1.44;transport=TCP>
>> Call-ID: 449986375
>> CSeq: 20 SUBSCRIBE
>> Contact: <sip:1 at 10.1.1.14:37883>
>> Max-Forwards: 70
>> Expires: 1200
>> Event: presence
>> Content-Length: 0
>>
>>
>> 09:58:10.361324 IP (tos 0x10, ttl 64, id 65438, offset 0, flags [DF], 
>> proto TCP (6), length 431) 10.1.1.44.5060 > 10.1.1.14.37883: P, cksum 
>> 0x29fb (correct), 1:380(379) ack 393 win 215 <nop,nop,timestamp 
>> 795715792 624699305>
>> SIP/2.0 202 OK
>> Via: SIP/2.0/TCP 10.1.1.14:5070;rport=37883;branch=z9hG4bK1540213071
>> From: <sip:1 at 10.1.1.14:5070>;tag=620071678
>> To: 
>> <sip:116006 at 10.1.1.44;transport=TCP>;tag=4f7a7e54f75c89f5b968c90011d693b5-9eed
>> Call-ID: 449986375
>> CSeq: 20 SUBSCRIBE
>> Expires: 1200
>> Contact: <sip:10.1.1.44:5060;transport=tcp>
>> Content-Length: 0
>>
>>
>> 09:58:10.361507 IP (tos 0x10, ttl 64, id 32295, offset 0, flags 
>> [none], proto UDP (17), length 484) 10.1.1.44.5060 > 10.1.1.14.37883: 
>> SIP, length: 456
>> NOTIFY sip:1 at 10.1.1.14:37883 SIP/2.0
>> Via: SIP/2.0/UDP 
>> 10.1.1.44;branch=z9hG4bKc408.509e6347000000000000000000000000.0
>> To: sip:1 at 10.1.1.14;tag=620071678
>> From: sip:116006 at 10.1.1.44;tag=4f7a7e54f75c89f5b968c90011d693b5-9eed
>> CSeq: 2 NOTIFY
>> Call-ID: 449986375
>> Content-Length: 0
>> User-Agent: kamailio (4.0.4 (i386/linux))
>> Max-Forwards: 70
>> Event: presence
>> Contact: <sip:10.1.1.44:5060;transport=tcp>
>> Subscription-State: active;expires=1200
>>
>> Thx
>> Klaus
>>
>>
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>
> -- 
> Daniel-Constantin Mierla -http://www.asipto.com
> http://twitter.com/#!/miconda  -http://www.linkedin.com/in/miconda
>
>
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