[vlc] Re: vlm experiences

[Warren Young]

list at scttransport.dk wrote:
> VLM currently has a DOS bug
> 
> Meaning it will keep sending data to clients even after they have stopped
> watching the stream, if they don't close it by pressing stop

This may not be something that VLC can do something about.  RTSP is a 
UDP-based protocol, meaning that the server just blindly throws packets 
at the client.  There is nothing at the UDP level to say whether a given 
packet is received, lost, duplicated, or mangled; the server just hopes 
for the best and keeps throwing packets at the client.  If the client 
goes away without explicitly telling the server to stop sending packets, 
you'll get the very symptom you describe.  This can happen if the client 
program crashes, or the OS kernel freezes up, or the network link is 
severed, or the power goes out, or....

Compare a TCP-based protocol, like FTP.  If the client goes away 
unexpectedly, one of two things will happen: a) the server will receive 
a RST packet from the client if it can still communicate, or if not, 
then b) the TCP sliding window will quickly fill up so the server will 
stop sending packets.  Eventually case b) will cause the server to time 
out and drop the connection.  All this logic is helpful in most 
situations, which is why most protocols are based on TCP, but for 
streaming video, they tend to get in the way too often.

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