What would cause UDP packets to be dropped when being sent to localhost?

Question

I\'m sending very large (64000 bytes) datagrams. I realize that the MTU is much smaller than 64000 bytes (a typical value is around 1500 bytes, from my reading), but I would

Answer 1

I don't know what makes you expect a percentage less then 1% of dropped packets for UDP.

That being said, based on RFC 1122 (see section 3.3.2), the maximum buffer size guaranteed not to be split into multiple IP datagrams is 576 bytes. Larger UDP datagrams may be transmitted but they will likely be split into multiple IP datagrams to be reassembled at the receiving end point.

I would imagine that a reason contributing to the high rate of dropped packets you're seeing is that if one IP packet that was part of a large UDP datagram is lost, the whole UDP datagram will be lost. And you're counting UDP datagrams - not IP packets.