The biggest cause of jitter on a network is excessive traffic. Traffic-shaping measures, such as prioritized queuing on network devices can improve performance for some applications while making jitter worse for others. For example, latency and jitter are very important for VoIP. So, many network administrators prioritize that traffic. However, VoIP traffic occurs in bursts, so the traffic of other applications will go fast, slow, fast, slow, creating a wide variation in transfer times as some of its packets get temporarily parked to make way for bursts of VoIP traffic.