Persubnet

Persubnet is a networking concept describing a subnet whose identity and address space remain effectively persistent across changes in network attachment or topology. In a persubnet design, the subnet boundary and its address prefix are maintained by a control plane or overlay mechanism, even as devices move between networks, VPNs, or cloud segments. The goal is to provide stable addressing and routing context for applications that require continuity, such as mobile workloads or edge deployments.

Implementation typically relies on software-defined networking (SDN) or virtualized overlays. A central controller or distributed controllers assign and propagate a persistent subnet identifier to participating devices, while the underlying IP addresses may be re-assigned by the network without breaking the perceived subnet. Overlay tunnels (for example VXLAN or GRE) or secure underlays connect devices to the same logical subnet across diverse physical sites. Policy-based routing and identity-based addressing help ensure traffic is delivered to the correct endpoints within the persubnet.

Applications include mobile data workloads, edge computing, IoT ecosystems, disaster recovery networks, and multi-cloud connectivity where reconfiguration costs are high. Benefits include reduced re-addressing, smoother mobility, and simplified access control within a stable subnet context. However, persubnet designs introduce control-plane complexity, potential single points of failure, and interoperability challenges across different vendors and cloud providers.

Standards status: Persubnet is not a widely standardized term in formal protocols; it appears in academic discussions and vendor literature as a design pattern or capability within broader SDN, overlay, or WAN architectures. Practitioners should assess compatibility with existing addressing plans and security requirements when adopting a persubnet approach.

See also: Subnet, Overlay network, SDN, VPN, VXLAN, NFV, LISP.