These days, most telecommunications traffic is routed through a packet-switching network, and it is frequently routed over the public internet. For example, speech data is converted into packets for call participants and routed ‘towards’ a receiver.
However, packet switching networks do not guarantee that packets will arrive on the same path as their destination.
https://www.callcentrehelper.com/how-jitter-frustrate-your-customers-188545.htm
