Once a packet is droped it's not always gone.
Ping's use UDP for testing purpose so that they can monitor line integrety allong with transmition times.UDP packets are not retransmited or acknoldged by the reciever so they can be lost. How UDP packets get droped is normaly do to an overloaded router. When more data is comming into the router than it can send out it has to do somthing so they just toss the packets out.
With TCP, packets will always be delivered (withing resone) but they can arive a tad late. What happens in TCP is the reciever of a packet always send an acknoldgement back to the sender. If the sender dosnt recieve an ack with in a specific period of time it retransmits the original until it recieves an ack.
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