Posted: 6/25/2015 6:38:31 PM EDT
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So I always knew the most important buzz words/phrases: connection-oriented versus UDP; datagrams called "segments"; ports 21, 22, 23, 25, 80; 3 way handshake, MSS, something about windows; etc. Im being forced to really learn it to be able to complete assignments for this CS class Im in, and its not being taught in the class, so Im having to do it all on my own.
Its amazingly intricate and brilliant in what it achieves. http://www.tcpipguide.com/free/t_TCPIPTransmissionControlProtocolTCP.htm is what I've been reading. Now, Its a LOT, quite the long read, but the author did a fantastic job of breaking it all up into very small sections. Pop Quiz: we all know UDP is preferred for connectionless type of traffic such as voice and video that can sustain periodic packet loss. So why is VOIP staying on UDP while video has moved primarily to TCP? |
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So why is VOIP staying on UDP while video has moved primarily to TCP? What's the context? Monitoring TCP could tell Netflix to lower the bitrate if they are seeing lots of delays. If it is a live event (analogous to VOIP conversation) then UDP would probably be preferred -- just blast the data out there as quick as you can, and if the helicopter / on-scene feed is jittery then it is jittery. ... but that is after about 30 seconds of thought. People that know better could provide better answers. |
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no, you were dead on, DASH
(yes live video conference applications mostly still use UDP though) |
| As a recipient of a computer science degree, I wanted to let you know that the class not teaching parts of the material is intentional. The educational goal is to not just convey the information to you, but to force you into adapting and learning on your own, because by the time you graduate everything you learned outside of core fundamentals will be pointlessly out of date. |
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The educational goal is to not just convey the information to you, but to force you into adapting and learning on your own, because by the time you graduate everything you learned outside of core fundamentals will be pointlessly out of date. boom.jpg i don't have a CS degree, but during the my time in college i learned very quickly that the really smart kids were the ones asking particular types of questions of the professors, not the ones who answered the professors' questions. |
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The educational goal is to not just convey the information to you, but to force you into adapting and learning on your own, because by the time you graduate everything you learned outside of core fundamentals will be pointlessly out of date. I dont recall it being the case for undergrad. I trudged through all the different sorts we wrote, and all the different data structures we implemented, and all the proofs we did, primarily through classroom instruction. Im not complaining about it, but did notice the big difference here in the MS program. For the most part, undergrad, besides calc, discrete math, and data structures, was a piece of cake for me to easily get by with no extra effort. As a result I was a very shitty student, barely got a B average, ZFG. Now for some reason Im compelled to get an A. It was free for me then and its free for me now, (corporate reimbursement with a C average) so "my money" isnt the difference. Well I have to make Bs for most of my CS classes now, for the reimbursement, so I guess its a part of it, but I can tell its not the only thing. |
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Quoted:
Pop Quiz: we all know UDP is preferred for connectionless type of traffic such as voice and video that can sustain periodic packet loss. So why is VOIP staying on UDP while video has moved primarily to TCP? Many video protocols only send deltas based on periodic keyframes, so loss of a packet or receiving them out-of-order can cause video corruption until the next keyframe arrives. VOIP doesn't work that way. |
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I would say the other reason is people really don't like missing visual things and they NOTICE it, where as if you miss an audible thing, much of the time you won't notice. People would rather have a pause while it buffers than miss visual frames. If you ever used RealNetworks Real Player formats back in the 90s you learned to hate their lossy approach to video. It was terrible.
If you're going back for your masters I'm sure you've had the experience where a project starts out with UDP and keeps adding features until at some point you say, "You know we're re-implementing TCP right? We can't do a better job than them, lets just use it". I worked in telecom routing for quite a while and always found the voice compression algorithms fascinating. Optimize for transmitting silence as that is what most of the call is, and then you get even better rates by clipping out frequencies we can't hear. Then make optimizations based around the psychology of how people hear words and which details are really important. Then it is a matter of fancy math compression, but those first two optimizations make such a huge difference for nearly zero computational power. |
