Network Model v1 (Power-Constrained Phase)

Purpose

Document the as-built network state, the rationale behind it, and the intended evolution path. This is the baseline substrate for ingress, naming, and service exposure decisions.

As-Built Topology

Physical Topology

Internet
   |
ISP Modem (Bridge Mode)
   |
OpenWRT Router (Single NAT / DHCP / DNS)
   |
LAN Clients + Server Nodes
(IPMI connected on-demand only)

Logical Roles

IP Plan (Current)

• Single flat LAN (one subnet).
• DHCP and DNS are authoritative only on OpenWRT.
• Specific CIDR, DHCP ranges, and static reservations live in OpenWRT config.

Trade-offs (Intentional)

• No VLAN segmentation yet: Deferred due to hardware and power constraints.
• No dedicated firewall: OpenWRT fulfills boundary duties for now.
• No managed switch: The network spine is temporary; port/power constraints apply.
• IPMI not always-on: Connected only when needed to conserve ports and power.

Evolution Roadmap

• Phase 1 (Current): Single NAT/DHCP/DNS, flat LAN.
• Phase 2: Add managed switch and introduce VLANs.
• Phase 3: Dedicated firewall and segmented trust zones.

Related Decisions

• ADR 0005: No Inbound NAT for Internal Services
• ADR 0009: Eliminate Dual DHCP and Establish a Single Boundary