- 🖧 Routers: 18
- 🔀 Switches: 20
- 💻 PCs: 34
OSPF (Open Shortest Path First) is a link-state routing protocol. Routers exchange Link-State Advertisements (LSAs) to describe their interfaces and neighbors. Each router builds the same link-state database (LSDB) and runs Dijkstra’s SPF algorithm to calculate the shortest paths.
- Areas: The network is split into Area 0 (backbone) and Areas 1, 2, 3.
- Backbone: Area 0 is mandatory in multi-area OSPF; all other areas must connect to it.
- ABR (Area Border Router): Routers between Area 0 and other areas. They maintain LSDBs for multiple areas and summarize LSAs.
- Result: With OSPF, all PCs across all areas can connect through shortest, loop-free paths.
A central DHCP service assigns IP addresses, subnet masks, default gateways, and DNS servers automatically (here DNS is not provided). This avoids manual configuration errors and speeds up network deployment.
The network uses VLANs to separate devices into logical subnets. Each VLAN:
- Maps to one IP subnet
- Has a dedicated DHCP pool
- Gets routed by its default gateway on the router/L3 switch
This ensures clients receive the correct addressing information for their VLAN.
Links between switches and routers are configured as 802.1Q trunks. This tagging ensures:
- VLAN frames keep their identity end-to-end
- DHCP requests from each VLAN are forwarded correctly
- Inter-VLAN routing works without confusion
- ✅ Show how OSPF backbone & ABRs provide scalable multi-area routing
- ✅ Demonstrate automatic IP allocation with DHCP per VLAN
- ✅ Use IEEE 802.1Q encapsulation to carry VLAN traffic across trunks
- ✅ Prove that all PCs in the lab can connect with each other through correct routing
| Router | Interface | IP Address | Area |
|---|---|---|---|
| Router 00 | Se0/1/0 | 192.186.10.11 | 0 |
| Router 00 | G0/0/0 | 192.186.100.1 | 0 |
| Router 0 | Se0/1/0 | 192.172.10.10 | 0 |
| Router 0 | Se0/1/1 | 192.172.30.10 | 0 |
| Router 0 | Se0/2/0 | 192.172.20.10 | 0 |
| Router 0 | Se0/2/1 | 192.186.10.10 | 0 |
| Router 0 | G0/0/0 | 172.28.100.1 | 0 |
| Router 10 | Se0/1/0 | 192.172.10.11 | 0 |
| Router 10 | Se0/1/1 | 192.168.11.11 | 1 |
| Router 10 | Se0/2/0 | 192.168.114.11 | 1 |
| Router 10 | G0/0/0 | 172.28.10.1 | 1 |
| Router 11 | Se0/1/0 | 192.168.11.10 | 1 |
| Router 11 | Se0/1/1 | 192.168.12.10 | 1 |
| Router 11 | G0/0/0 | 172.28.11.1 | 1 |
| Router 12 | Se0/1/0 | 192.168.13.11 | 1 |
| Router 12 | Se0/1/1 | 192.168.12.11 | 1 |
| Router 12 | G0/0/0 | 172.28.12.1 | 1 |
| Router 13 | Se0/1/0 | 192.168.14.10 | 1 |
| Router 13 | Se0/1/1 | 192.168.13.10 | 1 |
| Router 13 | Se0/2/0 | 192.168.115.10 | 1 |
| Router 13 | G0/0/0 | 172.28.13.1 | 1 |
| Router 14 | Se0/1/0 | 192.168.114.12 | 1 |
| Router 14 | Se0/1/1 | 192.168.14.12 | 1 |
| Router 14 | G0/0/0 | 172.28.14.1 | 1 |
| Router 15 | Se0/1/0 | 192.168.115.11 | 1 |
| Router 15 | G0/0/0 | 172.28.15.1 | 1 |
| Router 20 | Se0/1/0 | 192.172.20.11 | 0 |
| Router 20 | Se0/1/1 | 192.168.21.11 | 2 |
| Router 20 | Se0/2/0 | 192.168.225.11 | 2 |
| Router 21 | Se0/1/0 | 192.168.21.10 | 2 |
| Router 21 | Se0/1/1 | 192.168.22.10 | 2 |
| Router 21 | G0/0/0 | 172.28.21.1 | 2 |
| Router 22 | Se0/1/0 | 192.168.22.11 | 2 |
| Router 22 | Se0/1/1 | 192.168.23.11 | 2 |
| Router 22 | G0/0/0 | 172.28.221.1 | 2 |
| Router 22 | G0/0/1 | 172.28.222.1 | 2 |
| Router 23 | Se0/1/0 | 192.168.23.10 | 2 |
| Router 23 | Se0/1/1 | 192.168.24.10 | 2 |
| Router 23 | G0/0/0 | 172.28.23.1 | 2 |
| Router 24 | Se0/1/0 | 192.168.25.11 | 2 |
| Router 24 | Se0/1/1 | 192.168.24.11 | 2 |
| Router 24 | G0/0/0 | 172.28.24.1 | 2 |
| Router 25 | Se0/1/0 | 192.168.225.12 | 2 |
| Router 25 | Se0/1/1 | 192.168.25.12 | 2 |
| Router 25 | G0/0/0 | 172.28.25.1 | 2 |
| Router 30 | Se0/1/0 | 192.172.30.11 | 0 |
| Router 30 | Se0/1/1 | 192.168.33.11 | 3 |
| Router 30 | Se0/2/0 | 192.168.131.11 | 3 |
| Router 30 | G0/0/0 | 172.28.30.1 | 3 |
| Router 31 | Se0/1/0 | 192.168.31.10 | 3 |
| Router 31 | Se0/1/1 | 192.168.131.10 | 3 |
| Router 31 | G0/0/0 | 172.28.31.1 | 3 |
| Router 32 | Se0/1/0 | 192.168.32.11 | 3 |
| Router 32 | Se0/1/1 | 192.168.31.11 | 3 |
| Router 32 | G0/0/1 | 172.28.36.1 | 3 |
| Router 32 | G0/0/0 | 172.28.37.1 | 3 |
| Router 33 | Se0/1/0 | 192.168.33.10 | 3 |
| Router 33 | Se0/1/1 | 192.168.32.10 | 3 |
| Router 33 | G0/0/1 | 172.28.38.1 | 3 |
| Router 33 | G0/0/0 | 172.28.39.1 | 3 |
show ip ospf neighbor
show ip ospf database
show ip route ospf
show vlan brief
show interfaces trunk
show ip dhcp binding
show ip dhcp pool
ping <remote-PC>
traceroute <remote-PC>