VoIP technolgies are not immune to system failures, from hacking to jitter, and these issues can present problems for companies who depend on their network.

Jitter is the measure of time between when a packet is expected to arrive to when it actually arrives. In other words, with a constant packet transmission rate of every 20 ms, every packet would be expected to arrive at the destination exactly every 20 ms. This situation is not always the case.