Network Jitter Analysis with varying TCP for Internet Communications
Sneha Thombre · 2018
Conventionally, IP network planning, design and optimization is mostly based on the throughput and average delay which can often be easily calculated. Network Jitter, on the other hand, is much more difficult to evaluate, but it is particularly important to manage the QoS of real-time and interactive services such as VoIP and streaming video. Queuing delay and congestion control are closely related to jitter and happen at the network layer, therefore jitter is analyzed at the network layer in this paper. Initially arrival and service processes for multiplexed TCP and UDP traffic at the output queue, of the router are modeled. The model accounts for the fraction of TCP and UDP datagrams, the arrival and service distributions of TCP and UDP with their respective datagram sizes. Network Jitter is then derived using the arrival and service process model for tagged traffic flow of either TCP or UDP with background traffic. The derivation is extended to calculate end-to-end network jitter of a tagged stream. The findings of the analysis is then compared with NS2 simulations. The interesting finding is that network jitter increases for the tagged traffic as the fraction of TCP increases in the background traffic. Higher the quantum of TCP is the background traffic worst is the network jitter for tagged traffic. This is particularly important because TCP dominates the overall traffic. The simulation results fairly agree with the analytical values. The conclusion is true for Cubic, Reno and compound TCP flavors.