[SR-Users] 100rel without direct reachability

[Daniel-Constantin Mierla]

On 6/19/11 12:03 AM, Alex Balashov wrote:
> My understanding is that the deficiency in the standard here is that B is not required to copy RR headers into provisional responses, only final ones.
indeed, if 183 does not copy record-route headers is not much to do in A 
side -- I expected that any 1xx reply apart of 100, and especially 183 
to mirror record-route headers. I searched a bit and in several cases I 
could spot, the 183 had the R-R headers.

So the fault would be now in B, but if there is no _MUST_ for 183 to 
mirror R-R, then it is in IETF WG :-) ...

Maybe you can fix it via Kamailio configuration file:
- if there is no R-R header in 183 and you know it is going to be a 
bridged call (via some flag set or a special onreply route), then insert 
the headers manually with append_hf(R-R: <sip:ip1;lr>\r\nR-R: 
<sip:ip2;lr>\r\n");

Then see if A is following the R-R.

Cheers,
Daniel
>
> --
> Alex Balashov - Principal
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> On Jun 18, 2011, at 5:59 PM, Alex Balashov<abalashov at evaristesys.com>  wrote:
>
>> On Jun 18, 2011, at 5:35 PM, Daniel-Constantin Mierla<miconda at gmail.com>  wrote:
>>
>>> iirc, the PRACK should follow the record-routing as part of its early dialog state. At least, from my experience the PRACKs I saw so far were sent to the proxy address due to record routing, not directly to contact address in 183. Without following the record routing, I see no way to go even for cases with NAT. For me looks like A is buggy, but I haven't checked actually the specs at this time.
>>>
>> Daniel,
>>
>> Sorry, perhaps I was not clear.  A is a softphone initiating a call through Kamailio.  Kamailio forwards the call to UAS B with Record-Route header added, and UAS B sends 183s back to A through Kamailio, with 100rel Require'd.  There are no RR headers seen by A, and so it does not know to send PRACK to something but the Contact in the 183.
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Daniel-Constantin Mierla -- http://www.asipto.com
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