The Static prefix model assigns IPv6 prefixes manually to each Border Router (and, in some cases, to groups of devices within the mesh). Each device then derives its own address from the assigned prefix using standard IPv6 mechanisms, giving operators full control over how address space is distributed and used.

This model is predictable and straightforward, but it requires careful planning and documentation to prevent address overlaps or inefficient usage.

When to use

Choose Static prefix if:

  • The deployment requires strict, operator-controlled address assignment.

  • The upstream network does not provide or support Prefix delegation.

  • The Wi-SUN network is relatively small or limited to a handful of Border Routers.

  • Predictability is more important than flexibility or scalability.

Pros and cons

  • Pros

    • Provides fully deterministic and predictable addresses. Offers the best stability.

    • Simple to deploy in small or contained networks.

    • Independent of upstream DHCPv6-PD support or external infrastructure.

    • Gives operators full control over prefix usage and hierarchy.

  • Cons

    • Does not scale well to large or multi-site deployments.

    • Increases administrative overhead for documentation and tracking.

    • Susceptible to configuration errors and overlapping prefixes.

    • Readdressing may be required as networks expand or merge.

Considerations

Static prefix requires disciplined planning and documentation:

  • Prefix partitioning: Each Border Router must use a unique prefix to avoid conflicts. Plan prefix boundaries carefully if multiple meshes coexist.

  • Scalability: Manual allocation quickly becomes impractical in large-scale or dynamic deployments.

  • Operational responsibility: All responsibility for planning, tracking, and adjusting address pools lies with the operator.

  • Capacity planning: Prefix sizes should accommodate future node growth while maintaining efficient address utilization.