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UDP - Packet Loss in Real Life?

Posted by Cliff on from the network-intricacies dept.

PacketStorm asks: "There's always an argument between TCP and UDP users. TCP users complain that UDP is non-determinstic and lossy, while UDP users complain that TCP is slower and nobody needs all the features anyway. So the question is - has anyone actually seen/experienced UDP loss in high-traffic environments? Is the degeneration of UDP any better or worse than TCP in a congested environment? TCP also craps out in times of congestion, but at least you know - or do you? Experiences?"

4 of 127 comments (clear)

  1. both are usefull by f0rtytw0 · · Score: 4, Insightful

    UDP for streaminig video and games and other sorts of things where it doesn't matter if you miss a couple of packets and TCP where you can't miss packets such as file transfers. There everyone happy go home now.

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  2. What argument? by jkujawa · · Score: 4, Insightful

    Jesus. Both have their uses. You use TCP if you need the reliability, and a stateful connection. You use UDP if it doesn't matter that a packet gets dropped here or there. Things like games and streaming media are good examples. This is rather like comparing Pepsi to milk. They both have their place. It's the job of a good engineer to determine which is most apropriate.

  3. Re:UDP packet loss by Jeremi · · Score: 5, Insightful
    However, with UDP, it's laughably easy. You just do one recvfrom() and you get a packet and it also fills in a data structure to tell you where it came from.

    ... or maybe you don't get the packet, because a router was loaded down and had to drop it. Now you gotta implement a timeout and retransmit protocol. Not to mention that packets may arrive out-of-order from the way they were sent, so you if ordering is important (and it usually is) you have to implement some sort of sequencing tag systems too. A few dozen hours later, you find out you've implemented something that looks suspiciously like a primitive version of TCP... :^)

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  4. Re:UDP Experience QWZX by Anonymous Coward · · Score: 5, Insightful

    /me bangs his head on his desk over and over at the sheer stupidity of this.

    Dude, I hate sound flame-y, but do you have any understanding of what you implemented? That you got lucky and it "works" is totally irrelevent to the fact that it's completely unreliable. All it takes is one flakey piece of Ethernet dropping packets to SCREW UP FREAKING TIMESHEETS.

    This reminds me of the morons who use MySQL for financial transactions (i.e., no transactions, no foreign keys, etc) who justify their ignorance with "well, it works so far!!"

    They point isn't whether it works or not, the point is that when it fails, it fails spectacularly. Like your system. Just because you can keep spinning the chamber and the russian roulette gun never goes off doesn't mean it never will.

    Seriously, you screwed up bad. These are the kinds of stories that really make me think that programmers should have some sort of licensing.