. Packet Loss is literally when you do not receive a packet. This can be caused by a variety of reasons such as corrupted frames, RF interference, half full duplex mismatches, dirty fibre connectors, oversubscribed links and routing issues. Packet loss is an issue since TCP based protocols will have to wait and retransmit lost frames. The key word here is ‘wait’ since waiting implies you are no longer transmitting. For example, if you had a 500ms delay on 10 Mb link, you lost the opportunity to transmit 5 Mb within that 500 ms time frame. If your application is UDP based, all bets are off and it is up the application to decide what to do. I’ve seen UDP based applications react to packet loss by terminating the connection, resend data or corrupt data. With VOIP you hear echo and distorted audio.