We are using Lwip ported onto the
Analog Devices VDSP++ 4.5 (Blackfin family , Feb 2007 update) to implement an
RTSP/RTP streaming server.
To send RTP packets using UDP, we
are creating a socket of type SOCK_DGRAM, and then using sendto() to transmit
the RTP packets. After sending some packets, the sendto() function blocks, and
the RTP thread hangs pending for a semaphore.
We tried to change the socket to
non-blocking mode, but it does not seem to have any
effect.
Unlike a TCP connection, UDP does
not have flow/congestion control and does not need to wait for ACKs from the
receiver. Then what does the UDP sendto() function wait
for?
Thanks and
regards,
Aparna