Network jitter is the variation in delay across a series of packets. Delay is unavoidable, but consistent delay is preferable; excessive variation harms real-time applications such as voice and video calls. section 10.2.2
Jitter is measured in milliseconds. Cisco recommends keeping jitter at 30 ms or less for voice traffic. QoS aims to minimize jitter, delay, and packet loss during congestion. section 10.2.2 section 10.7
Distinguish jitter from related performance measurements:
- Delay measures one-way travel time from source to destination. section 10.2.2
- Round-trip time measures travel to the destination and the reply back to the sender. section 10.2.2
- Loss measures the percentage of packets that fail to reach their destination; Cisco recommends 1% or less for voice traffic. section 10.2.2
Figure 10.6 Jitter is the variation in delay in a series of packets.
Visualizes jitter as variation in packet delay across a series of packets. section 10.2.2
