  As enterprises increasingly migrate their applications to the cloud, the
demand for secure and cost-effective Wide Area Networking (WAN) solutions for
data transmission between branches and data centers grows. Among these
solutions, Software-Defined Wide Area Networking (SD-WAN) has emerged as a
promising approach. However, existing SD-WAN implementations largely rely on
IPSec tunnels for data encryption between edge routers, resulting in drawbacks
such as extended setup times and limited throughput. Additionally, the SD-WAN
control plane rarely takes both latency and monetary cost into consideration
when determining routes between nodes, resulting in unsatisfactory Quality of
Service (QoS). We propose WirePlanner, an SD-WAN solution that employs a novel
algorithm for path discovery, optimizing both latency and cost, and configures
WireGuard tunnels for secure and efficient data transmission. WirePlanner
considers two payment methods: Pay-As-You-Go, where users pay for a fixed
amount of bandwidth over a certain duration, and Pay-For-Data-Transfer, where
users pay for the volume of transmitted data. Given an underlay topology of
edge routers and a user-defined budget constraint, WirePlanner identifies a
path between nodes that minimizes latency and remains within the budget, while
utilizing WireGuard for secure data transmission.
