Client Pull can be used to have live video update in a window every __seconds, because the document is reloaded automatically every __seconds. Updating every 0 seconds refreshes as fast as the computer and network can run.
Server Push: the server sends data any time it wants. For example, if I set WebCam to transmit 2 frames per second onto the 'net, then, provided your computer and net connection are fast enough, you should see 2 frames per second appear. However, it gets more interesting, because I can send video at a nonconstant frame rate. For example, I can send a frame whenever I think something interesting is happening, or I can have a program running that determines if the video signal is similar to the previous signal, and only sends a frame when the signal changes appreciably. For example, if I fall asleep with WebCam running, it might only transmit a frame every time I roll around, tossing and turning in my sleep, sending frames erattically only whenever the WebCam moves or shakes appreciably.
If you really want to learn more about Client Pull and Server Push, just take a look at http://home.netscape.com/home/demo/1.1b1/pushpull.html.
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