[asterisk-dev] REFER and NOTIFY behavior

[Klaus Darilion]

Hi!

I just tested blind transfer notification with Asterisk (1.6.2.9) and it 
seems to be wrong:

Asterisk does:

U1(SIP)          Asterisk         U2(SIP)             U3(ISDN)
   |                  |              |                    |
   |----INVITE------->|              |                    |
   |                  |---INVITE---->|                    |
   |                  |<--200 OK-----|                    |
   |                  |---ACK------->|                    |
   |<------200 OK.----|              |                    |
   |----ACK---------->|              |                    |
   |                  |              |                    |
   |---REFER--------->|              |                    |
   |<--202 Accepted---|              |                    |
   |                  |              |                    |
   |                  |              |                    |
   |<--NOTIFY---------|              |                    |
   |  w/ 183 Ringing  |              |                    |
   |                  |              |                    |
   |<--NOTIFY---------|              |                    |
   |  w/ 200 OK       |              |                    |
   |                  |              |                    |
   |                  |----------------SETUP------------->|
   |                  |              |                    |

So Asterisk notifies the transferer that the blind transfer is ringing 
and was performed successfully although it does not even have tried to 
contact the target. I would expect that NOTIFY with sipfrag 183/200 is 
only sent when the PROGRESS/CONNECT is received from the transfer target.

Just as shown in  http://tools.ietf.org/html/rfc5359#section-2.4

regards
Klaus