Each network device has a counter for the number of dropped packets. When packets are dropped, the transport layer (layer 4 of the OSI model) is responsible for retransmission.
UDP is quick but unreliable. Its packets are neither retransmitted nor counted in the number of dropped packets. If you are dropping a lot of packets, and also sending a lot of UDP traffic, the problem may be worse than the network interface is letting on.
While TCP will retransmit packets, it will often take multiple seconds to do so, encouraging your applications to time out. RFC 6298 defines the retransmission timeout calculation. In short, your application will fare better with a reliable network infrastructure.
Dropping packets is most often the symptom of a hardware failure of the network card, network cables, or network devices like switches and routers. It could also be an issue of throughput, where you’re sending too much data for network components to handle. When network devices receive more traffic, they store the information in buffers. When the buffers are full, the new traffic is dropped.
