Hello!

I successfully build and run OpenBTS 2.8, but I have problem when user end call.
Sometimes when user end call I can see in log:

Jun 21 17:38:10 kalim openbts: INFO 140657520527104 SIPEngine.cpp:710:MODWaitForCANCELOK: user IMSI001011876543210 state MODCanceling
Jun 21 17:38:10 kalim openbts: WARNING 140657520527104 SIPEngine.cpp:721:MODWaitForCANCELOK: unexpected 487 response to CANCEL, from proxy 127.0.0.1:5060. Assuming other end has cleared
Jun 21 17:38:10 kalim openbts: INFO 140657520527104 SIPEngine.cpp:650:MODWaitFor487: user IMSI001011876543210 state Canceled
Jun 21 17:38:10 kalim openbts: WARNING 140657520527104 SIPEngine.cpp:661:MODWaitFor487: unexpected 200 response to CANCEL, from proxy 127.0.0.1:5060
Jun 21 17:38:10 kalim openbts: INFO 140657520527104 CallControl.cpp:170:abortAndRemoveCall: cause: location=1 cause=0x15, transaction: 41870339 C0T1 TCH/F IMSI=001011876543210 L3TI=8 SIP-call-id=1848787102 SIP-proxy=127.0.0.1:5060 MOC to=7002 GSMState=null SIPState=Canceled (0 sec)
Jun 21 17:38:10 kalim openbts: INFO 140657520527104 CallControl.cpp:156:abortCall: cause: location=1 cause=0x15, transaction: 41870339 C0T1 TCH/F IMSI=001011876543210 L3TI=8 SIP-call-id=1848787102 SIP-proxy=127.0.0.1:5060 MOC to=7002 GSMState=null SIPState=Canceled (0 sec)
Jun 21 17:38:10 kalim openbts: INFO 140657520527104 CallControl.cpp:103:forceGSMClearing: Q.931 state null
Jun 21 17:38:10 kalim openbts: INFO 140657520527104 CallControl.cpp:124:forceSIPClearing: SIP state Canceled
Jun 21 17:38:10 kalim openbts: WARNING 140657561949952 SIPInterface.cpp:261:drive: cannot parse SIP message: SIP/2.0 487 Request Terminated#015#012Via: SIP/2.0/UDP 127.0.0.1:5062;branch=z9hG4bKobts285a45076e24baae8c;received=127.0.0.1#015#012From: IMSI001011876543210 <sip:IMSI001011876543210@127.0.0.1>;tag=ocfqxgkqmhaluevc#015#012To: <sip:7002@127.0.0.1>;tag=as39e083ad#015#012Call-ID: 1848787102@127.0.0.1#015#012CSeq: 576 INVITE#015#012Server: Asterisk PBX 1.8.14.0-rc1#015#012Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH#015#012Supported: replaces, timer#015#012Content-Length: 0#015#012#015
Jun 21 17:38:45  openbts: last message repeated 8 times
Jun 21 17:38:51 kalim transceiver: ERR 140465765422848 UHDDevice.cpp:770:recv_async_msg: An internal send buffer has emptied at 181.027 sec.
Jun 21 17:38:51 kalim transceiver: ERR 140465765422848 UHDDevice.cpp:770:recv_async_msg: Packet time was too late or too early at 181.029 sec.
Jun 21 17:38:51 kalim transceiver: ERR 140465765422848 UHDDevice.cpp:770:recv_async_msg: Packet time was too late or too early at 181.029 sec.
Jun 21 17:38:58 kalim transceiver: ERR 140465765422848 UHDDevice.cpp:770:recv_async_msg: An internal send buffer has emptied at 187.775 sec.
Jun 21 17:38:58 kalim transceiver: ERR 140465765422848 UHDDevice.cpp:770:recv_async_msg: Packet time was too late or too early at 187.782 sec.
Jun 21 17:39:16  transceiver: last message repeated 2 times

I also see a few consecutive messages "Status: 487 Request Terminated" in wireshark. When this messages show up in wireshark I can't phone to other user.
Command "calls" in OpenBTS CLI show one transacion in table with GSMState=null and SIPState=Canceled. This transaction is not remove from table until I restart OpenBTS.
It doesn't happen any time, but only sometime and I can't see any dependency when this can happen.

What should I do to smoothly clean call? Do I have configure Asterisk in some special way?

Additionaly I add my configuration:
- OpenBTS 2.8 (version from ttsou github)
- USRP N210 with WBX board
- Trimble GPS
- Ubuntu 12.04 64-bit
- Asterisk 1.8.14.0-rc1 (realtime)
I use file extensions.conf from /openbts-p2.8/AsteriskConfig/. 

Best regards,
Kali