Dear all,

When i was reading about tm module ( http://www.iptel.org/ser/doc/modules/txt/tm.txt )

I found this section ...

******************************************************************************************************

1.3.2. fr_inv_timer (integer)

   Timer which hits if no final reply for an INVITE arrives after
   a provisional message was received (in seconds).

   Default value is 120 seconds.

   Example 1-2. Set fr_inv_timer parameter
...
modparam("tm", "fr_inv_timer", 200)
*****************************************************************************************************

 

But I could not understand here what is the meaning of "provisional message" and how fr_inv_timer behave..

Please some one teach me about this with some example...

thanks in advance..