[Users] Dealing with reinvites

All, We have had a new issue arise within openser, basically we connect to a SIP carrier that uses Asterisk as a proxy. Naturally, this carrier is hellbent on offloading the RTP traffic, thus the reinvites. My issue is that they appear to be sending the second invite "too fast", before the initial RTP even gets a chance to establish. This was working just fine before, and I believe they changed something. Anyway, they're refusing to help with this issue, so now I must "fix" it on my end. OpenSER is in-part, the problem.. See below: (Sorry if formatting is off, dump from tethereal ..) 0.000000 204.13.233.13 -> 206.80.70.47 SIP/SDP Request: INVITE sip:8886963856@206.80.70.47, with session description 0.001752 206.80.70.47 -> 204.13.233.13 SIP Status: 100 trying -- your call is important to us 0.002723 206.80.70.47 -> 206.80.70.54 SIP/SDP Request: INVITE sip:+1314xxxxxxx@sip.stl.netlogic.net, with session description 0.010327 206.80.70.54 -> 206.80.70.47 SIP Status: 100 Trying 0.292175 206.80.70.54 -> 206.80.70.47 SIP Status: 180 Ringing 0.292692 206.80.70.47 -> 204.13.233.13 SIP Status: 180 Ringing 2.016246 206.80.70.54 -> 206.80.70.47 SIP/SDP Status: 200 OK, with session description 2.016893 206.80.70.47 -> 204.13.233.13 SIP/SDP Status: 200 OK, with session description 2.050871 204.13.233.13 -> 206.80.70.47 SIP Request: ACK sip:+1314xxxxxxx@206.80.70.54 2.051233 204.13.233.13 -> 206.80.70.47 SIP/SDP Request: INVITE sip:+1314xxxxxxx@206.80.70.54 2.051827 206.80.70.47 -> 204.13.233.13 SIP Status: 100 trying --<<KABOOM>>-- 2.051956 206.80.70.47 -> 206.80.70.54 SIP/SDP Request: INVITE sip:+1314xxxxxxx@206.80.70.54, 2.052112 206.80.70.47 -> 206.80.70.54 SIP Request: ACK sip:+13142664000@206.80.70.54 2.053028 206.80.70.54 -> 206.80.70.47 SIP/SDP Status: 200 OK, with session description 2.053336 206.80.70.54 -> 206.80.70.47 SIP Status: 503 Server error Where you see "kaboom", is the problem. If you notice, the time between the first ACK and second INVITE is about 1ms .. While this shouldn't be a problem, you'll notice when the ACK/INVITES are getting statefully forwarded, they're getting sent out of order. The end point is an Asterisk machine, thus the 503 error. Carrier_Ast --> OpenSER --> Netlogic_Ast I am using loose_route to forward, just like everyone else, they are even hitting loose_route in the correct order.. Thoughts? Suggestions? This seems like something internal to OpenSER, I have tried butchering the config to force the ACK out first and it just created more problems. Thanks! Matt S