[Users] Call not torn down when CANCEL sent before INVITE message is finished being processed

[Klaus Darilion]

Bogdan-Andrei Iancu wrote:
> Hi Klaus,
> 
> that was a second idea :).
> 
> actually you do not have to do anything special to keep the CANCEL in 
> memory - it will be kept as transaction if you forward it statefully.
> what I do not like in this approach is that for each INVITE you have to 
> search for a potential previous CANCEL  - which is quite consuming... I 
> would prefer an approach with minimum impact on the performance.

Hi Bogdan!

One one hand we care about fast transaction handling/matching, on the 
other hand we have problem with external lookups which take a long time 
(db, radius, DNS ...) compared to opensers internal processing.

For example: 4 clients send an INVITE to a domain with a broken 
delegation. Thus, all threads are busy doing DNS. Thus, a SIP proxy 
which can handle 1000000000 requests per second is oversized in real 
life scenarios, were the external processing is the bottleneck (unless 
we start 1000000000 threads).

Of course I'm happy that openser peforms quite well, but in my scenarios 
performance problems are always external. And I really would like a 
working INVITE/CANCEL which deals with these problems.

regards
klaus

> regards,
> bogdan
> 
> Klaus Darilion wrote:
> 
>>>> With the latest CVS build of OSER, when an INVITE is sent followed by a
>>>> CANCEL, before OSER has finished processing the initial INVITE, the
>>>> outbound call is not torn down, and SER routes the CANCEL message to
>>>> itself. 
>>>
>>>
>>> this is more a logical problem and not sure how it can be fixed (if 
>>> it can be fixed). The only idea it come into my mind is to delay the 
>>> CANCEL that does not match a transaction....but is quite ugly.
>>
>>
>>
>> What about forwarding the CANCEL and keept in in memory. For every 
>> incoming INVITE we will first check if there is already a CANCEL for 
>> this.
>>
>>
> 
>