PROJECT / 03 · ENTERPRISE NETWORKING

PHASE 1 · IMPLEMENTED

Two sites.
One connected network.

An enterprise network connecting Swansea headquarters and the Cardiff branch. Built in Cisco Packet Tracer with departmental VLANs, efficient IPv4 addressing, dynamic routing and centrally managed DHCP.

Cisco Packet TracerVLANs & 802.1QVLSMOSPF Area 0DHCP relaySSH

Explore the topology ↓Download reference files · ZIP

02Connected sites

06Cisco network devices

12Client PCs

01Central server

THE REQUIREMENT

Connect two offices while keeping departments in separate broadcast domains. Give clients at both sites their addresses from a single Swansea server, and exchange routes dynamically between the sites. Preserve the completed Phase 1 simulation as the baseline for a later resilience phase.

SWANSEA / HEADQUARTERS

Routing at the core

A Cisco 3560 routes between HQ VLANs using switched virtual interfaces. Two Cisco 2960 access switches connect eight PCs, while the central server occupies a dedicated server VLAN.

CARDIFF / BRANCH

Router-on-a-stick

A Cisco 2911 provides the branch VLAN gateways over an 802.1Q trunk to the access switch. Four PCs connect locally, and DHCP requests are relayed to Swansea over the Ethernet WAN.

THE NETWORK TOPOLOGY

Download screenshot ↗

Actual Packet Tracer topology: Swansea contains HQ-R1, HQ-CORE, HQ-SW1, HQ-SW2, HQ-SERVER and eight PCs; an Ethernet WAN joins HQ-R1 to Cardiff BR-R1, BR-SW1 and four PCs. — The implemented topology supplied from Packet Tracer. The screenshot shows the device layout and link indicators; detailed routing and DHCP test outputs are separate evidence.

Explore the blueprint and port reference

Blueprint of the reference port and routing design, including both transit networks, trunks and the central DHCP server. — Blueprint of the configuration reference design. Download vector diagram · SVG ↗

The physical port map is included in the architecture document.

VLANs & IPv4 ADDRESSING

The reference design uses different subnets at each site, even where VLAN IDs are shared. Each VLAN gateway uses its first usable address. Network management uses VLAN 99; server addressing is static.

Configuration reference: VLAN-to-subnet mappings
VLAN	Swansea subnet	HQ gateway	Cardiff subnet	Branch gateway
10	10.10.0.0/27	10.10.0.1	10.20.0.0/27	10.20.0.1
20	10.10.0.32/27	10.10.0.33	—	—
30	10.10.0.64/28	10.10.0.65	—	—
40	10.10.0.128/26	10.10.0.129	10.20.0.32/27	10.20.0.33
50 · Server	10.10.0.80/28	10.10.0.81	—	—
99 · Management	10.10.0.96/28	10.10.0.97	10.20.0.64/28	10.20.0.65

ETHERNET WAN10.10.0.112/30

CORE ↔ HQ ROUTER10.10.0.116/30

CENTRAL SERVER10.10.0.82/28

Download the full addressing table · Markdown ↗

ROUTING & NETWORK SERVICES

01 / ROUTE EXCHANGE

OSPF Area 0

HQ-CORE, HQ-R1 and BR-R1 exchange the site networks through OSPF. The routed core uplink and Ethernet WAN establish neighbour relationships; client-facing interfaces are passive.

02 / ADDRESS ALLOCATION

One DHCP server, both sites

The Swansea server provides six client pools. Helper addresses on the HQ SVIs and branch router subinterfaces forward DHCP requests from each client VLAN. Management and server addresses are reserved outside the client pools.

03 / ADMINISTRATION

A lab security baseline

The reference configurations include SSH with local login, management access restrictions, limited trunk VLANs, unused-port shutdown and endpoint port security. Credentials are replaced with placeholders in the downloads.

04 / NEXT PHASE

Resilience improvements

Phase 2 will explore redundant paths, gateway or switching redundancy and failover testing. The direct WAN and single core remain deliberate single points of failure in the Phase 1 baseline.

CONFIGURATION EXAMPLES

HQ VLAN gateway and DHCP relay

An SVI on HQ-CORE routes VLAN 10 and forwards DHCP broadcasts to the central server.

interface Vlan10
 ip address 10.10.0.1 255.255.255.224
 ip helper-address 10.10.0.82
 no shutdown

Cardiff router-on-a-stick

The branch gateway tags VLAN 40 traffic on its switch-facing link.

interface GigabitEthernet0/0.40
 encapsulation dot1Q 40
 ip address 10.20.0.33 255.255.255.224
 ip helper-address 10.10.0.82

OSPF on the HQ router

Only the two transit interfaces establish OSPF adjacencies.

router ospf 1
 router-id 2.2.2.2
 passive-interface default
 no passive-interface GigabitEthernet0/0
 no passive-interface GigabitEthernet0/1
 network 10.10.0.116 0.0.0.3 area 0
 network 10.10.0.112 0.0.0.3 area 0

PROJECT FILES

CONFIGURATION REFERENCES

Explore the six device templates, server instructions and build documentation. These are the references prepared for the project; final running-configuration exports and recorded test outputs are not included. Department descriptions in the templates are suggested labels.

HQ-CORESVIs · DHCP relay · OSPF · HQ trunksTXT ↓ HQ-R1Core transit · Ethernet WAN · OSPFTXT ↓ BR-R1Router-on-a-stick · DHCP relay · OSPFTXT ↓ HQ-SW1VLANs 10 / 20 · PC ports · ManagementTXT ↓ HQ-SW2VLANs 30 / 40 · PC ports · ManagementTXT ↓ BR-SW1Branch VLANs · Trunk · ManagementTXT ↓

DHCP server setup ↗Step-by-step build guide ↗Verification plan ↗Readme ↗

Download all reference files · ZIP Download blueprint · SVG

The templates contain password placeholders. Replace them privately before reuse and check command support against your Packet Tracer device models.

VERIFICATION & TROUBLESHOOTING

Phase 1 is complete following implementation and DHCP troubleshooting. The verification plan covers same-VLAN and inter-VLAN connectivity, bidirectional site access, OSPF neighbours and routes, central DHCP, management access and configuration persistence. The topology screenshot is included above; captured command outputs and individual test results will extend the evidence.

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Two sites.One connected network.