Network topology is the documented layout of an environment: how devices, servers, links, VLANs, subnets, and security zones are arranged and connected. It can be physical, showing cables and switches, or logical, showing traffic paths and segmentation. In practice, topology diagrams and related address plans help teams understand where systems live and how data flows.
In cyber security, topology matters because it exposes the structure attackers need to move efficiently. A clear diagram can reveal choke points, remote access paths, backup networks, privileged management segments, and weak boundaries between business systems. During intrusions, stolen topology notes can help threat actors plan lateral movement, identify high-value hosts, and locate recovery infrastructure. Defenders use topology to design segmentation, restrict trust relationships, and verify that critical services are isolated and monitored.