Yes, with the modification that the server drops the 180 and do not send it
to user A, but the result is the same - User B has to wait for the timers to
timeout to give up the transaction.
I was hoping that the server could notify User B when it he tries to
continue the transaction that does no longer exist. The result of this could
be very un-user friendly, with a session invitation that will be removed
only when User B gives up the transaction.
In my opinion it is little a lack in the SIP protocol, please correct me if
I am wrong.

Thanks for the help everybody

/anton


On Thu, May 29, 2008 at 5:14 PM, Paul Kyzivat <[EMAIL PROTECTED]> wrote:

> I'm not an expert on this, but I think what should happen is:
>
> - the server receives the 100 and can match it to no transaction
> - since 100 is handled hop by hop, the server just drops it.
>
> You don't show what happens after that. But lets continue:
>
> - User B then sends 180
> - the server receives the 180 and can match it to no transaction.
> - proxy rules (assuming server is a proxy) say that in this case
>  it should forward the response as a stateless proxy would
> - User A receives the 180 and can match it to no transaction
> - so User A drops the 180
> - eventually User B sends some final response
> - server forwards the response statelessly
> - User A ignores the response
> - User B retransmits the final response a few times
>  but never receives an ACK
> - User B finally gives up on the transaction.
>
>
> Henrik Antonsson wrote:
>
>> Thanks for your answers.
>> Ok so I understand that 481 is not applicable for the INVITE. My question
>> is
>> more what should be the correct behaviour for the client when the server
>> ignores 1xx. I will clarify my scenario:
>>
>> User A               Server            User B
>>  |     INVITE         |                  |
>>  |------------------->|            ----  |
>>  |                    |--------------> | | (User B is blocked and the
>> INVITE request is
>>  |                    |         |  ----  |  queued in the network)
>>  |                    |         |        |
>>  |                    |         |        |
>>  |                    |         |        |
>>  |                    |         |        |
>>  |   408 TIMEOUT      |         |        |
>>  |<-------------------|         |        |
>>  |                    |         |        |
>>  |                    |         |------->| (User B recieves a late INVITE)
>>  |                    |      100 TRYING  |
>>  |                    |<-----------------|
>>  |                    |         |        |
>>
>> Here is my problem, maybe I can blaim the network though but User B have
>> no
>> idea that the transaction does no longer exist. I was hoping that the
>> server
>> should respond to the 100 from User B but as you said that don't happen.
>> The only way to resolve this state is to wait for a timeout when sending
>> the
>> 200 OK, is that correct?
>>
>> BR
>> anton
>>
>>
>> On Thu, May 29, 2008 at 2:55 PM, <[EMAIL PROTECTED]> wrote:
>>
>>  Few comments inline...
>>>
>>> Thanks,
>>> Nataraju A B
>>> ESN: 6-877-8567
>>>
>>>  -----Original Message-----
>>>> From: [EMAIL PROTECTED]
>>>> [mailto:[EMAIL PROTECTED] On
>>>> Behalf Of Henrik Antonsson
>>>> Sent: Thursday, May 29, 2008 5:58 PM
>>>> To: [email protected]
>>>> Subject: [Sip-implementors] 1xx response for a non-existing
>>>> transaction?
>>>>
>>>> Hi
>>>>
>>>> I've read some specifications on SIP but I can't find
>>>> anything about what should happend if a client sends a 1xx to
>>>> the server when the transaction no longer exists.
>>>> My scenario is that the INVITE from A to B is queued in the
>>>> network, the server tries and then timeout and sending A a
>>>> 408 response. At this state the transaction no longer exists
>>>> a suppose. When eventually B receives the INVITE (as it was
>>>> buffered in the network) how does B find out that the
>>>> transaction does not exist? B sends 100 TRYING and 180
>>>> RINGING and 200 OK if the user accepts. Do I have to wait for
>>>> the timeout as the there will be no ACK from the server from
>>>> the 200 OK or should the server respond with 481 or any other
>>>> code when B sends 1xx codes?
>>>>
>>>>  [ABN] I am not sure I understood your question correctly. Here are few
>>> pointers in the similar lines...
>>>
>>> [ABN] client would never send out 1xx response in any cases. Till the
>>> server receives INVITE, where is question waiting for INVITE txn. The
>>> server side processing starts only when the INVITE message is received.
>>>
>>> 481 would never be applicable for initial (dialog creating) INVITE
>>> transaction. It would be applicable for mid dialog requests, for
>>> instance BYE, UPDATE, PRACK requests after the dialog is created.
>>>
>>> If the issue was INV, 200, and followed no ACK reply. Then the expected
>>> behavior is to terminate the call with BYE/200 transaction. The call
>>> should be terminated, whether 481/200 received for BYE request.
>>>
>>>  Thanks
>>>> anton
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