NETWORK TOPOLOGY
& ARCHITECTURE
A practical guide to designing wired and wireless networks
Core / Router
Wired Switch Wireless AP
Desktop, Printer, Laptop, Phone Consists of topology diagrams, enterprise architecture, wired LAN design, Wi-Fi design, security, redundancy, and design recommendations.
Learning objective: Learn about how topology is used to describe the structure of the network and how architecture is used to design the network using the structure defined by the topology.
Topics Covered
- 1. Principles of network topology and architecture
- 2. Types of topologies: star, bus, ring, mesh, tree, and hybrid
- 3. Architecture of network in organizations: two-tier and three-tier architectures
- 4. Designing wired networks
- 5. Designing wireless networks
- 6. Merging wired and wireless networks
- 7. Security and best practices
- 8. Case study: network of a college campus
- 9. Fast comparison and glossary
1. Network Topology and Architecture Fundamentals
Network topology is explained as either the physical or logical arrangement of nodes and links. Physical topology refers to the actual layout of connections in the network, while the logical topology refers to how the data is transmitted from one device or segment of a network to another.
The network architecture takes into consideration the design factors of the switching, routing, addressing, security, services, monitoring, and redundancy in a network. The star physical topology may exist alongside several VLANs and routed subnets in terms of logic.
It also implies that there can be computers in the office connected to a switch working on star topology, where there can be VLANs separating the traffic coming from finance department, visitors, and staff, irrespective of whether they are on the same switch.
The right approach for planning the network should start with the needs assessment of users, applications, geographic locations, traffic, availability, security, budgeting, and scalability.
2. Common Network Topologies
Star Topology
Device 2
Device 1 Device 4
Central switch Device 5
Device 3 Device 6
In the star network topology, each endpoint is connected to a central switching or hub node. Such a network is easily scalable and easy to diagnose, as a failure of one end-point wire impacts only one end-point. The central node is a possible single point of failure if there is no backup built-in.
Figure: Star Network Topology (Conceptual Diagram; Not an Actual Installation Plan)
Network Topology & Architecture | Wired and Wireless Networks Page 2
Bus Network Topology
Device 1 Device 2 Device 3 Device 4 Device 5 Device 6 Node 5
A shared backbone cable connects devices. Though the idea is simple, the network is hard to scale and diagnose. Also, any backbone cable failure will disrupt the entire segment. Bus network topology is more of a theoretical discussion nowadays.
Figure: Bus Network Topology (Conceptual Diagram; Not an Actual Installation Plan)
Figure: Bus topology (conceptual diagram; not a physical installation plan).
Ring Topology
Node 1
Node 2
Node 3
Node 4
Traffic follows the ring path
Node 6 Node 5
The node links up with other nodes, creating a closed loop. Although some ring systems have alternate routes or restricted connections, an interruption in the ring network without any protection system will cause problems.
Figure: Ring topology (conceptual diagram; not a physical installation plan).
Mesh Topology
Network Topology & Architecture | Wired and Wireless Networks Page 3
Node 1
Node 2
Node 3
Node 4
Node 5
Multiple possible paths improve resilience
Node 6
Devices have multiple paths between them. The full mesh design is very connected but quite costly; the partial mesh allows for some redundancy. Mesh theory is applied to wide area networks, data centers, and wireless backhauls.
Figure: Mesh topology (illustrative diagram).
Tree Topology
Core
Distribution A Distribution B
Access 1 Access 2 Access 1 Access 2
A hierarchical arrangement of connected branches. It maps naturally to access, distribution, and core layers and supports structured growth. Figure: Tree topology (conceptual diagram; not a physical installation plan).
Hybrid Topology
Core / Router
Wired switch Wi-Fi AP
Desktop Printer Laptop Phone
Network Topology & Architecture | Wired and Wireless Networks - Page 4
Combines various topologies to address practical needs. The typical network architecture in an organization includes hierarchical wired LAN along with wireless access points and fiber optic redundancy links.
Figure: Hybrid network topology (Conceptual Diagram; Not physical diagram).
Network Topology & Architecture | Wired and Wireless Networks - Page 5
3. Enterprise Network Architecture
Enterprise network architecture refers to placement of network functions and their communication. A typical campus network architecture has three layers of network such as access, distribution, and core layers. In some cases, distribution and core are collapsed into a single layer.
Three-Tier Architecture
Core layer
Distribution layer
Access switch Access switch Access switch
Access layer connects end users’ devices including printers, cameras, telephones, and access points. The distribution layer links access switches and provides services such as inter-VLAN routing, security policy implementation, and route aggregation. The core layer provides a dependable and high-speed link between different parts of the network.
It is cost-effective and simple to implement in smaller networks, but the access-layer switches remain autonomous. The choice of the architectural style will depend on the size of the network, amount of traffic, and other factors.
Note: This is a logical division and does not require physical separation into three boxes. Modern devices are capable of performing multiple functions, although it should be clear how traffic will flow in the event of failures.
4. Wired Network Topology and Architecture
Wireless network systems normally incorporate the Ethernet made from copper wires at the endpoints and fiber optics for long distances and faster connectivity.
The typical devices used may include end user devices; access switches; distribution/core switches; layer 3 switches; routers; firewalls; copper or fiber optics; cables; patch panels; racks; and software.
VLANs allow creating a logical partitioning of LAN via switch technology. That is, for instance, employees, guests, CCTV cameras, VoIP phones, and servers can all be put in distinct VLANs. Inter-VLAN routing will determine how the data will flow according to specific routing and security policies.
Redundancy could be in terms of alternative uplinks, switch redundancy, power backup, redundant fiber optics, and configuration backups. RSTP will avoid any loops in Layer 2 network while proper configuration of routing protocols such as OSPF will help create redundant Layer 3 routes.
Best physical practices will include cable labeling, documenting switch ports, link testing, proper rack configuration, and diagram updates.
5. Wireless Network Topology and Architecture Enterprise Wi-Fi will be based on infrastructure mode: wireless clients connect to the access points, and the access points are connected to the wired network. APs may be managed by the wireless LAN controller or by the cloud
platform,
Network Topology & Architecture | Wired and Wireless Networks Page 6
depending on the solution.
Switch / LAN
Access point
Laptop
Phone Tablet
Dashed lines represent radio links
IoT device
Figure: The access point provides connectivity for the wireless clients to connect to the network. Dotted lines represent wireless connections.
Wireless topology needs to be evaluated in terms of RF coverage, capacity, interference, roaming, number of clients and building material. A site survey will aid in determining the placement of the access points and the frequencies. It is important not only to consider the coverage but also the capacity and interference.
The frequency of 2.4 GHz will provide good coverage, few overlapping frequencies, and lots of interference.
5 GHz results in good capacity. 6 GHz may provide more bandwidth if allowed locally by laws and the hardware supports it.
This mesh wireless network allows for wireless backhaul, which is why the access points can work without an Ethernet connection, but at the same time, wireless backhaul consumes RF and lowers down throughput.
It should have all features such as encryption, authentication, guest access capability, device segregation, security management, and software updates.
6. Integration of Wired and Wireless Networks
Network architecture usually entails both types of access for most organizations. Wired access through Ethernet would be the most suitable type of access to be used for stationary devices, whereas wireless access through Wi-Fi would be the best for mobility.
Core / Router
Wired switch Wi-Fi AP
Desktop Printer Laptop Phone
Diagram: Topology that merges wired end-nodes with wireless clients.
Integration may be achieved by assigning SSID of wireless clients and switch ports of wired nodes into appropriate VLANs/policy segments. For instance, staff Wi-Fi may allow access to authorized applications while the guest Wi-Fi allows internet access only.
The precise design is a function of the vendor's platform and security design.
DHCP assigns the IP address; DNS resolves domain names, routing routes packets between different subnets, and firewalls control allowed flows.
7. Security, Resiliency and Best Practices
• Grow with planning. Estimate device quantities, bandwidth, applications and any additional expansion.
• Segment your network. Utilize VLANs or other segmentation schemes for users, servers, guests, cameras, voice and IoT.
• Use least privilege. Grant only necessary access and use appropriate authentication and administrative controls.
• Eliminate single point of failures when possible. Consider redundant links, power supplies, devices, and different paths.
• Optimize for performance. Review switch capacity, uplink speed, PoE budget, Wi-Fi coverage, channel utilization and roaming.
• Monitor your network constantly. Monitor device availability, interface errors, bandwidth, wireless health, logging and security events.
• Document and back up. Keep your diagrams, IP plans, VLAN schemes, rack diagrams, port assignments and configuration backups ready to go.
• Test prior to turnover. Verify connectivity, failovers, roaming, access policies, performance and recovery.
8. Example: College Campus Network
Network Topology & Architecture | Wired and Wireless Networks Page 8
Core / Data Center
Building A Building B
Access switch
Wired users Wi-Fi AP
Wired users Wi-Fi AP
Figure: Schematic plan of the campus network including a core, building uplinks, access switches, wired end users and Wi-Fi access points. A college can host the core and services within a secured equipment room. The uplinks of all buildings are used for connecting them to the core network. The access switches are situated in computer labs, offices, printers, IP phones, and APs. Segments can be created for administrative, teaching, students, CCTV, server, and guest Wi-Fi networks.
Firewall allows the Internet access and inter-network communication.
Wireless SSIDs correspond to the proper access policy. Monitoring will help IT specialists to detect failed links and overloaded APs and other abnormal activities. Redundant links and equipment are considered in case there are any critical service requirements.
The design needs to be tested with regard to the number of concurrent users, e-learning applications, online exams, voice/video, security and budget constraints.
9. Quick Comparison
Topology
Strengths
Limitations
Common use
Star
Simple to manage; easy to isolate endpoint faults
Central switch can be a failure point
Office LANs
Bus
Simple concept
Shared medium; poor
scalability
Historical / learning
examples
Ring
Predictable path; protection possible in some designs
Depends on ring technology and protection
Specialized or legacy
systems
Mesh
Multiple paths; resilience
Cost and complexity
WAN, data center, wireless backhaul
Tree
Hierarchical and scalable
Upstream failure can affect branches
Campus LAN
Hybrid
Flexible and practical
Needs careful documentation
Most modern organizations
Key terms
AP: Access point. LAN: Local area network.
VLAN: Virtual local area network.
SSID: Service set identifier (Wi-Fi network name).
PoE: Power over Ethernet.
RSTP: Rapid Spanning Tree Protocol. OSPF: Open Shortest Path First. 802.1X: Port-based network access control system.
Conclusion
Network topology is the structure of how network devices are organized; network architecture refers to the workings of the whole system including scalability and security measures. Wired networks offer reliable connectivity, whereas wireless networks offer flexibility and mobility in addition to that. Proper design of both will ensure a robust network.
Network Topology & Architecture | Wired and Wireless Networks Page 9
The design of the network goes beyond connecting the nodes and entails planning a system for optimal performance and security, among others.
The diagrams provided are not actual representations and are simply conceptual drawings for educational purposes only.
Author:
Samir Khatib
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Samir Khatib
Expert trainer and consultant at SevenMentor with years of industry experience. Passionate about sharing knowledge and empowering the next generation of tech leaders.