[OpenSIPStack] OpenSBC terminate connection

[André M. <an...@ma...>]

Hello,

I have seen a strange behavior with the OpenSBC1.1.5RC1. The scenario is 
as follows:

The OpenSBC is configured in B2BUAUpperReg mode.

I place a call from a SIP client (A) to a PSTN Phone (B). The connection 
is established whithout any problems. A goes on hook and sends a BYE to 
which the SBC immediately replies with a 200 OK.

Another BYE message is being sent out to the softswitch platform.

The softswitch challenges authentication and therefore responds with a 
401  unauthorized message. Since the SBC, at least that's my assumption, 
has already successfully terminated the internal connection there is no 
match and the requested authenticated BYE will never be send out. This 
behavior results in ghost connections and the billing runs until B goes 
on-hook as well.

I have tested the same scenario with my SIP client directly connected to 
our softswitch platform and did not detect the problem there. Upon 
receiving the 401 unauthorized message, the client resends the BYE 
containing the authentication information.

I have checked the RFC 3261 this morning and tried to find out whether 
it is a regular behavior to reply to a BYE message with authentication 
challenge or not. I could not find any hint there.

How difficult is it to change this behavior and wait for confirmation 
before terminating the entire connection ?

Regards,

Andre