The buffer for the client is controlled from the flash player. netstream.bufferTime(). The server will send out the stream as quickly as it can until it has filled the client buffer and then it will try to maintain it. For recorded streams, it will only send it as quickly as the connection will allow and you will see pauses on the client side while it rebuffers. For live streams, the server only buffers about 8 seconds and if the client has a slow connection then it will drop frames rather than increasing the buffer size.