UDP will drop data if there is congestion. Basically, if you care about congestion and data loss, you should not use UDP.
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If you do UDP and TCP. The UDP transfer will loose data during congestion, while the TCP transfer will slow down and try harder.
This has some usage. For instance, videoconferences software will do TCP and UDP. The TCP is used for control data -low volume data that needs to work- (authentication/joining room/leaving/adjusting quality), the UDP is used for audio/video (some pieces may be lost during congestion, it's okay).
If you use UDP for everything, you'll randomly loose control AND audio/video. It's the worst of both worlds.
Not to be dismissive but I think the guy who gave you the advise doesn't really understand networking (or doesn't explain very well or was talking about some weird usage we don't know about).
Error checking can easily be added to udp for control data. Infact in IPv6 it's mandatory. At one moment you say udp will lose out, but we know tcp will back off on its reattempts exponentially based on the congestion window. Thus udp would win out. The argument wasn't that it was a significant impact, the argument is that they can cause interference.
But it's the driver of the NIC that manages its network packet queue! Then it uses a an interrupt to signal the OS that data is available or that the window is open for transmit. I'm totally aware there's a lot more to it, I do socket programming everyday.
UDP will drop data if there is congestion. Basically, if you care about congestion and data loss, you should not use UDP.
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If you do UDP and TCP. The UDP transfer will loose data during congestion, while the TCP transfer will slow down and try harder.
This has some usage. For instance, videoconferences software will do TCP and UDP. The TCP is used for control data -low volume data that needs to work- (authentication/joining room/leaving/adjusting quality), the UDP is used for audio/video (some pieces may be lost during congestion, it's okay).
If you use UDP for everything, you'll randomly loose control AND audio/video. It's the worst of both worlds.
Not to be dismissive but I think the guy who gave you the advise doesn't really understand networking (or doesn't explain very well or was talking about some weird usage we don't know about).