eSpace U1911 connected with Avaya PBX by through QSIG trunk, when extension under Avaya PBX make an incoming call to extension under our U1911, our extension no ringing and incoming call fail.
the topology is as follow.
for example: extension A make an incoming call to extension 1 or extension 2, call fails.
our U1911 judged the SETUP signaling from Avaya as invalid.
After Avaya change the parameter and make it same with us. then the new SETUP signaling is as follows, and our PBX can solve it.
the peer PBX changed some parameter, then the SETUP signal change to valid, and our PBX can solve it.