[h323plus] problem about H.235

HI Simon and Jan after enabed the H235 media encryption, openmcu and H323 ep in the same network were work well . however , when they were in different networks， 1 . only audio PDU（200bytes）received at MCU , MCU can not receive video pdu（above 1000 bytes）.i am sure the ep had upload the audio and video packages . 2. the threads used for trasmit and receive data had been create , but no data send to H323 ep . some messages hint that PTLIB write Blocking ，but i don‘t know why , use fcntl() to set read/write NONBLOCKING , But not effective . please help thanks gary