[Serusers] call transfer INVITE / REFER

[Steve Blair]

Iqbal wrote:

> just to get clarification
>
> blind=?

   You press the transfer button, enter the destination phone number 
then hang up. You
   don't wait to speak to anyone to complete the transfer.

> attended= user calls u, u transfer the call

   You press the transfer button, enter the destination phone number 
wait until someone
answers, explain who the original caller is then "hang up". At this 
point the original caller
and the person you transferred to are speaking to each other. Note that 
in attended or
consultative call transfer the way you "hang up" depends upon the phone 
set. Cisco phones
have a transfer button you have to press to join the two call legs 
together.

> unatteneded= is this just like forward on no answer
>
  This is my understanding although I have seen some people explain this 
as intelligent
forwarding. In their explanation intelligent forwarding lets the voice 
system determine
to which extension a caller is forwarded without the called party's 
phone ever ringing.
I usually just consider unattended the same as call forward always. :-)

> Samuel Osorio Calvo wrote:
>
>> The effective transferring is done using REFER messages but since there
>> are several transfer methods, some INVITEs can be triggered before (put
>> on-hold, contact the referee). So, depending on how the user has
>> configured the transfer in his/her phone (blind, attended,
>> unattended,are there more??) the SIP request that the phone sends when
>> the user presses the button is different.
>> Take a look at the draft specifying the different transfer methods for
>> a detailled view of the message flows
>> (draft-ietf-sipping-service-examples I don't remember the most recent
>> number....probably 7 or 8)
>>
>> Samuel.
>>
>>
>> Unclassified.
>>  
>>
>>>>> Iqbal <iqbal at gigo.co.uk> 07/05/05 03:57AM >>>
>>>>>       
>>>>
>>
>> which is why I am wondering if on pressing a transfer button request on
>> a
>> phone, should the first message being sent be a REFER or a INVITE,
>> cause
>> refer would make sense, although I havent looked at the rfc,
>>
>> If anyone has a IP phones transferring a ngrep of transfer would be
>> appreciated
>>
>> Iqbal
>>
>> On 7/4/2005, "Nils Ohlmeier" <lists at ohlmeier.org> wrote:
>>
>>  
>>
>>> Hi,
>>>
>>> take a look at the SDP of the INVITE. Probably it just puts the other
>>>   
>>
>> side
>>  
>>
>>> on-hold before sending the REFER.
>>> But I have no real clue how transfering without REFER should work.
>>>   
>>
>> (Except a
>>  
>>
>>> cumbersome solution with Replaces and 3pcc, which I have never.)
>>>
>>> Nils
>>>
>>> On Monday 04 July 2005 21:07, Iqbal wrote:
>>>   
>>>
>>>> Hi
>>>>
>>>> Should the call transfer use INVITE or REFER as a method, cause I
>>>>     
>>>
>> seem,
>>  
>>
>>>> to be getting INVITE, but this then causes problems with
>>>>     
>>>
>> authentication.
>>  
>>
>>>> A <-->B  then B transfer to C (all IP phones)
>>>>
>>>> This transfer seems fine, but it uses INVITE, no REFER . All phones
>>>>     
>>>
>> on
>>  
>>
>>>> same sip domain/server
>>>>
>>>> Now when this setup changes
>>>>
>>>> pstn <---->B and then B tried to transfer to C, we get nothing, well
>>>>     
>>>
>> we
>>  
>>
>>>> get 404 , it check the !location setting, and says ur not allowed.
>>>>
>>>> Is the REFER the first message to be sent, or is there a INVITE
>>>> transaction first,
>>>>
>>>> Iqbal
>>>>
>>>>
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>>>>     
>>>
>>>   
>>
>>
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>>
>> .
>>
>>  
>>
>
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