Impact Analysis of Tunnel Probing Protocol on SD-WAN's Mainstream Traffic
Pavan Iddalagi, Amrita Mishra · 2023
Software defined wide area network (SD-WAN) manages its egressing traffic via sophisticated application aware routing (AAR) policies wherein the traffic is tunneled between the edges for providing additional security. One of the key challenges in SD-WAN involves regular monitoring of the tunnel liveliness by timely measurement of service level agreement (SLA) parameters which are in turn used for selection of the uplink that matches the admin configured SLA. However, any tunnel health probing protocol by itself incurs delay, jitter and bandwidth overhead in the uplink during prime usage hours of an organization. Existing SD-WAN solutions do not investigate the impact of tunnel health probing protocols on mainstream traffic. Thus, motivated by this shortcoming, the current work presents extensive research on impact analysis of the popular bidirectional forwarding detection (BFD) protocol on mainstream traffic egressing the SD-WAN. A practical SD-WAN test-bed is realized via various open source tools along with novel test cases for performing the impact analysis. Simulation results demonstrate that BFD traffic introduces additional delay, jitter and also forms an overhead in the uplink affecting the mainstream traffic. Finally, based on the empirical experiments, an optimal value of the BFD echo transmit interval is deduced to improve the overall network performance during congestion.