New subject: [Serusers] Tags, forwarding, redirects, and picky UACs

12 Apr 2005

first, it's not about FROM tag, but TO tag...
second, it's better to do it for all provisional responses < 180 (for 
183 you might mess with early media)
third, here  it 's the  regexp:

 onreply_route[1]{
    if ( t_check_status("(1[0-7][0-9])|(180)") ) {
        subst('/^(To:.*)\;tag=[^;[:cntrl:]]*/\1/i');
    }
    break;
}

bogdan

Alistair Cunningham wrote:

...
  Bogdan-Andrei,

 Can you please give me a hint as to how to remove the tag? I've can do 
 something like:

 onreply_route[1] {
     if ( (status=~"180") ) {
     replace( ";tag=.*", "" );
     };
 }

 but this would remove the tag from all headers. I could add "From:" 
 into the regular expression, but this would then remove the whole From 
 header.

 Alistair Cunningham,
 Integrics Ltd,
 +44 (0)7870 699 479
 http://integrics.com/

 Bogdan-Andrei Iancu wrote:

> According to RFC 3261, the UAC *must* drop any To-tag received in a 
> provisional reply in favour of the To-tag advertised in the final 
> reply - be this it means not only to accept a final reply with a 
> different To-tag, but also to use it in generating sequential 
> messages (like ACK, re-INVITEs, etc)
>
> So you should report the problem to your UAC vendor. Meanwhile you 
> can do a trick in SER cfg - use a reply_route to remove the To-tag 
> from all provisional replies....this will make happy the UAC.
>
> bogdan
>
> Alistair Cunningham wrote:
>
>> I'm trying to implement forwarding to voicemail with a UAC that's picky
>> about the tags in the To: headers it receives.
>>
>> First, I tried the following:
>>
>> failure_route [1] {
>>     rewritehostport("192.168.1.1:5060");
>>     append_branch();
>>     t_relay();
>> }
>>
>> This failed because the UAC received a "180 Ringing" from the ringing
>> Grandstream phone via ser that contained a To: tag. After the timeout,
>> it received another 180 from Asterisk (the voicemail system) with a
>> different tag. Since it doesn't support forked INVITES, it dropped 
>> the call.
>>
>> Then I tried:
>>
>> failure_route [1] {
>>     rewritehostport("192.168.1.1:5060");
>>     t_reply( "302", "Moved Temporarily" );
>> }
>>
>> This time it receives the 180 from the phone as before. Then it 
>> receives
>> the 302. Alas, SER has ignored the tag from the phone, and created a 
>> new
>> one of it's own, so the UAC again drops the call.
>>
>> Does anyone know of a way round this? Can SER be persuaded to use a tag
>> it has already received? Can I strip the tag from the To: header in 
>> one or both of the responses? I'm willing to get my hands dirty with 
>> the SER source code if necessary.
>>
>
>
> 

Re: [Serusers] Tags, forwarding, redirects, and picky UACs