Okay, so I am programming for my networking course and I have to implement a project in Java using UDP. We are implementing an HTTP server and client along with a \'gremlin\' fu
if UDP is by definition unreliable, why am I having to simulate unreliability here?
It is very useful to have a controlled mechanism to simulate worst case scenarios and how both your client and server can respond to them. The instructor will likely want you to demonstrate how robust the system can be.
You are also talking about payload validity here and not just packet loss.
This led me to question whether or not UDP, lose a packet, corrupt a packet, or deliver it out of order if the server and client were two processes on the same machine and it wasn't having to go out over the actual network.
It is obviously less likely over the loopback adapter, but this is not impossible.
I found a few forum posts on the topic here and here.
I am also wondering what the chances of actually losing a packet, having it corrupted, or having them delivered out of order in reality would usually be over the internet between two geographically distant hosts.
This question would probably need to be narrowed down a bit. There are several factors both application level (packet size and frequency) as well as limitations/traffic of routers and switches along the path.
I couldn't find any hard numbers on this but it seems to be fairly low... like sub 5%.
You may be interested in The Internet Traffic Report and possibly pages such as this.