ffmpeg rate emulation for realtime streaming

we sent the MPEG4 Encoded data thru ffmpeg in a RTP stream.At receiver side, we are not getting the correct number of frames.( Sequence Number of the Frames highly differ).
Like After the RTP Packet (Sequence) number 1526, I got the number as 3600 or something.
ffmpeg sends the Entire data at with 5 minutes( which can be streamed around 30 mins).So there might be the chance for TCP/IP stack overflow. It may causes some packet loss.
(Real Time) if we are sending the video data as same as stream time,then there will be no packet loss. So we send the data to RTP stream using rate emulation ( -re ) command in ffmpeg.
Eventhough we are sending data with this one, we got the packet loss problem.
Check it with the Ethreal packet capture.
Capture RTP packets using Ethreal and RTP stack application at the same time.