UDP - Packet Loss in Real Life?

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?"

Comments

UDP packet loss

[fraxas]

I don't know if it means anything, but I have experienced UDP packet loss on a regular basis -- playing online games. Unit positions are most often tracked over UDP because it doesn't really matter if things warp around a little when the client receives an update that puts a unit somewhere other than where the client extrapolated it was. There was a big fiasco at launch-time for Anarchy Online -- they used TCP and not UDP for about 8 hours, during which time the game was unplayable because the servers couldn't maintain all the TCP connections. Interpret this as you will.

UDP Experience

[mchappee]

I'm firmly in the UDP camp. About 4 years ago we replaced our timeclocks at work (manufacturing facility) with hardened, wall-mounted PCs. I wrote a GTK app that started at boot up that takes the users card swipe, grabs their name from the database (for display only), and sends the clock number via UDP to the timeclock server.

During my initial proposal I mentioned to the PHBs that I would use the UDP protocol. One of my colleagues, wanting to sound important, said that UDP can be lossy. He went on to explain packet loss to the befuddled crowd. Well, the PHBs latched onto the term "packet loss". Packet loss this, packet loss that. They had no freakin' clue what it was, but it sounds pretty cool.

Anyway, I had to set up a test in which I had all of the timeclocks start a program at the same time. This program went into a tight loop of sending UDP packets (clock numbers) across the network to the server. Each one sent 1000 clock numbers, and every single one made it across. Obviously our 100mb network and proper use of subnets helped, but we haven't experienced any packet loss in the four years that these things have been running. So there. :-)

Matthew