What causes jitter in an IP network?
An IP-network is a network that uses the IP protocol, which is part of the TCP/IP protocol suite. IP is currently the global standard for networking.
Jitter is a variation in packet transit delay, caused by queuing, contention and serialization effects on the path through the network.
Inter alia, jitter can be caused by congestion in the LAN, firewall routers, bottleneck access links, load sharing, route flapping, routing table updates and timing drifts.