A mesh topology is the optimal choice for minimizing latency in a global SD-WAN. In a mesh configuration, every site can establish a direct, dynamic tunnel to every other site. This creates the shortest possible path for inter-site traffic, avoiding the delay associated with routing through a central hub. For a business with geographically dispersed offices in Asia, Europe, and the US, direct site-to-site communication is critical for latency-sensitive applications. The mesh topology directly supports this requirement by providing optimal, low-latency paths between all locations.

A. Star

Incorrect. This is a synonym for hub-and-spoke, which centralizes traffic and increases latency for site-to-site communication by forcing it through a central point.

B. Spine-and-leaf

Incorrect. This is a data center network fabric topology designed for high-bandwidth, east-west traffic within a data center, not for connecting geographically dispersed WAN sites.

D. Hub-and-spoke

Incorrect. This topology forces all communication between remote sites (spokes) to traverse a central hub, adding significant latency and contradicting the core requirement for the lowest possible latency.

1. Official Vendor Documentation: Cisco Systems

Inc. (2021). Cisco SD-WAN Design Guide. Section: "SD-WAN Overlay Topologies

" Sub-section: "Full-Mesh Topology." The guide states

"A full-mesh topology provides direct spoke-to-spoke communication with optimal latency... This is the preferred topology for enterprises that have a significant amount of spoke-to-spoke traffic."

2. Peer-Reviewed Academic Publication: Meddeb

A.

et al. (2022). "SD-WAN: A Survey of Functionality

Taxonomy

and Future Trends." IEEE Communications Surveys & Tutorials

vol. 24

no. 3

pp. 1588-1623. DOI: https://doi.org/10.1109/COMST.2022.3179808. Section IV-A

"Topology

" discusses how full-mesh topologies enable direct branch-to-branch communication

which is essential for minimizing latency for real-time applications.

3. University Courseware: Stanford University

CS244: Advanced Topics in Networking. Lecture notes on "Software Defined Networking." The course materials explain that a key advantage of SD-WAN is the ability to dynamically create optimal paths

such as a full mesh

to reduce latency compared to traditional hub-and-spoke WANs that backhaul traffic.