Unable to connect devices in scale test

i have scale test with 10k devices, odl is running on one machine and testtool on another.

after first batch in scale test (batches for 4k, 4k and 2k devices) there are timeouts in log and second and third batch is not connected. also pending info is displayed:

2015-04-08 10:40:05,117 | INFO | 0]-nio2-thread-6 | ClientSessionImpl | 211 - org.apache.sshd.core - 0.14.0 | Start flagging packets as pending until key exchange is done
2015-04-08 10:40:05,118 | INFO | 0]-nio2-thread-6 | ClientSessionImpl | 211 - org.apache.sshd.core - 0.14.0 | Server version string: SSH-2.0-SSHD-CORE-0.12.0
2015-04-08 10:40:05,121 | INFO | 0]-nio2-thread-6 | ClientSessionImpl | 211 - org.apache.sshd.core - 0.14.0 | Client session created

2015-04-07 12:47:17,913 | INFO | ]-timer-thread-1 | ClientSessionImpl | 153 - org.apache.sshd.core - 0.14.0 | Disconnecting: Session has timed out waiting for authentication after 120000 ms.

strange is, that first batch is successfully connected. it starts from 27.3.2015. and at this time there was used new ssh library, so problem may be with this library