Enterprise local network

This SAÉ put me in the shoes of a networks & telecoms technician tasked with opening a branch office for the fictional company “Rudy and Theodor Company”. The branch replicates the same local network structure and must be able to host up to about sixty workstations, grouped according to their users' activity. My role: prepare, configure and test all the equipment (switches, router, PCs) and network services, then prove that everything works as required by the specification.

The network is split into four groups, each isolated in its own VLAN: Management and administration (VLAN 10), Standard users (VLAN 20), Servers (VLAN 30) and Network administrator (VLAN 40, the only one allowed to access the devices). The hardware is standardised on Cisco Catalyst 2960 switches and 2800-series routers. Addressing is based on the class B network 172.20.0.0/16, with each branch receiving a /24 that is then subnetted per VLAN according to the number of hosts.

I built a complete lab in EVE-NG: a router, a switch, one Virtual PC per VLAN (for ping and DHCP tests) and an Ubuntu Linux server. I did the cabling and the layer 2 configuration (assigning ports to VLANs, trunk link), then the logical configuration with static and dynamic addresses, the router interface taking the highest address of each subnet. DHCP was first hosted on the switch, then migrated to the Linux server (isc-dhcp-server), with ip helper-address commands to relay requests across inter-VLAN routing.

The project also let me look at 802.1Q-tagged frames in Wireshark (capture of an inter-VLAN ping on the switch-router link, then a port-mirroring capture to compare ICMP messages with and without tags). Finally, I made the infrastructure more reliable by adding a second switch configured through VTP v2: a “server” switch automatically propagates its VLAN table to the “client” switch over the trunk link, which avoids reconfiguring everything by hand.

Design, simulate and configure on EVE-NG the complete local network of a branch office (~60 workstations): physical and logical structure, one VLAN per department, DHCP, inter-VLAN routing and VTP synchronisation, then prove it works through testing.

The VLANs were not synchronised automatically between the two switches. After troubleshooting, I set up VTP to propagate the VLAN configuration from a “server” switch, which made extending the network reliable.

Organising the network into dedicated VLANs for each department (Management, Users, Servers, Administration) to isolate traffic, then only opening the necessary flows through inter-VLAN routing.

Documented addressing plan and naming conventions, saved Cisco configurations, and compliance with the branch office specification.