Core-Edge Ring Lab
A 12-node EVE-NG topology exploring OSPF multi-area design across a core-edge ring network — dual-homed sites, ABR summarization, and a structured IP addressing plan across five OSPF areas.
Proxmox VE 8.4 host · VM ID 121
8 × Site (dual-homed)
CML Free refplat image
Areas 1–4: per-leg
8 ABR relationships
- ◦ Hierarchical multi-area design with Area 0 backbone ring
- ◦ All AGG nodes operating as ABRs (2–3 areas each)
- ◦ Dual-homed sites for redundancy — no single ABR dependency
- ◦ LSA type propagation (Type 1–4) across area boundaries
- ◦ Route summarization configured at each ABR boundary
- ◦ OSPF cost tuning for deterministic traffic paths
Network Topology
Click any node for configuration details. Use the legend to highlight individual areas.
| Link | Subnet | Site IP | AGG IP | Area |
|---|---|---|---|---|
| BACKBONE RING — AREA 0 | ||||
| AGG1 E0/0 ↔ AGG2 E0/0 | 10.1.0.0/30 | — | 10.1.0.1 / 10.1.0.2 | 0 |
| AGG2 E0/1 ↔ AGG3 E0/0 | 10.1.0.4/30 | — | 10.1.0.5 / 10.1.0.6 | 0 |
| AGG3 E0/1 ↔ AGG4 E0/0 | 10.1.0.8/30 | — | 10.1.0.9 / 10.1.0.10 | 0 |
| AGG4 E0/1 ↔ AGG1 E0/1 | 10.1.0.12/30 | — | 10.1.0.13 / 10.1.0.14 | 0 |
| LEG A — AREA 1 | ||||
| Site-A1 E0/0 ↔ AGG1 E0/2 | 10.1.1.0/30 | 10.1.1.2 | 10.1.1.1 | 1 |
| Site-A1 E0/1 ↔ AGG2 E0/2 | 10.1.1.12/30 | 10.1.1.14 | 10.1.1.13 | 1 |
| Site-A2 E0/0 ↔ AGG1 E0/3 | 10.1.1.4/30 | 10.1.1.6 | 10.1.1.5 | 1 |
| Site-A2 E0/1 ↔ AGG2 E0/3 | 10.1.1.8/30 | 10.1.1.10 | 10.1.1.9 | 1 |
| LEG B — AREA 2 | ||||
| Site-B1 E0/0 ↔ AGG2 E1/0 | 10.1.2.0/30 | 10.1.2.2 | 10.1.2.1 | 2 |
| Site-B1 E0/1 ↔ AGG3 E0/2 | 10.1.2.8/30 | 10.1.2.10 | 10.1.2.9 | 2 |
| Site-B2 E0/0 ↔ AGG2 E1/1 | 10.1.2.4/30 | 10.1.2.6 | 10.1.2.5 | 2 |
| Site-B2 E0/1 ↔ AGG3 E0/3 | 10.1.2.12/30 | 10.1.2.14 | 10.1.2.13 | 2 |
| LEG C — AREA 3 | ||||
| Site-C1 E0/0 ↔ AGG3 E1/0 | 10.1.3.0/30 | 10.1.3.2 | 10.1.3.1 | 3 |
| Site-C1 E0/1 ↔ AGG4 E0/2 | 10.1.3.8/30 | 10.1.3.10 | 10.1.3.9 | 3 |
| Site-C2 E0/0 ↔ AGG3 E1/1 | 10.1.3.4/30 | 10.1.3.6 | 10.1.3.5 | 3 |
| Site-C2 E0/1 ↔ AGG4 E0/3 | 10.1.3.12/30 | 10.1.3.14 | 10.1.3.13 | 3 |
| LEG D — AREA 4 | ||||
| Site-D1 E0/0 ↔ AGG4 E1/0 | 10.1.4.0/30 | 10.1.4.2 | 10.1.4.1 | 4 |
| Site-D1 E0/1 ↔ AGG1 E1/0 | 10.1.4.8/30 | 10.1.4.10 | 10.1.4.9 | 4 |
| Site-D2 E0/0 ↔ AGG4 E1/1 | 10.1.4.4/30 | 10.1.4.6 | 10.1.4.5 | 4 |
| Site-D2 E0/1 ↔ AGG1 E1/1 | 10.1.4.12/30 | 10.1.4.14 | 10.1.4.13 | 4 |
OSPF Multi-Area Design
All AGG nodes operate as ABRs, connecting Area 0 to per-leg stub areas and controlling LSA propagation across area boundaries.
Area 0 — Backbone
The four-node AGG ring. Carries Type 1 (router) and Type 2 (network) LSAs internally. Distributes Type 3 summary LSAs into all connected non-backbone areas.
Area 1 — Leg A
Sites A1 and A2 dual-home to both AGG1 and AGG2, both of which act as ABRs. Either AGG failure still leaves the area connected via the surviving ABR.
Area 2 — Leg B
Sites B1 and B2 dual-home to AGG2 and AGG3. The inter-area path traverses Area 0 to reach any other area — demonstrating the backbone's role as a routing hub.
Area 3 — Leg C
Sites C1 and C2 dual-home to AGG3 and AGG4. Type 3 LSAs from both ABRs advertise the Area 0 summary into this area, providing full inter-area reachability.
Area 4 — Leg D
Sites D1 and D2 dual-home to AGG4 and AGG1, completing the ring. AGG1 is therefore an ABR for Areas 0, 1, and 4 simultaneously — the most complex node in the topology and a natural study point for multi-area ABR behavior.