Network Topologies (Star, Bus, Ring, Mesh, Ad hoc, Infrastructure, & Wireless Mesh Topology)

Network topologies (wired)

Definition / purpose

A network topology is the layout that determines how a network communicates between devices. Topologies are grouped into wired and wireless.

Star topology (most common wired)

• How it works: Every computer connects to a central wiring point (e.g., hub or switch). All data passes through the central device.
• Benefit: If one computer fails or a cable breaks, other computers are not affected because each has its own cable connection.
• Drawback: If the central hub/switch fails, then the entire set of connected devices goes down (single point of failure).

Ring topology

• How it works: Devices form a closed loop; each device has two neighbors. Data packets travel around the ring until reaching the destination.
• Use today: Rarely used.
• Benefit: Easy to install and easy to troubleshoot.
• Drawback: If one computer fails or there’s a cable break, data flow is disrupted across the ring.

Bus topology (old technology)

• How it works: All devices connect to a single shared backbone cable (described as coaxial). Devices use BNC/T connectors.
• Benefit: Cheap and easy to implement.
• Drawback: Requires termination at both ends using terminators. Loose/missing terminators or open connections cause signal reflection, disrupting data flow.

Mesh topology

• How it works: Every computer connects to every other computer.
• Benefit: High redundancy—if some connections fail, devices can still communicate via alternate paths.
• Tradeoff: Requires lots of cabling and network cards, so it’s expensive; therefore rare in LANs.
• Where used: More common in wide area networks; the video gives the Internet as an example (many routers create redundant paths and can reroute if some routers go down).

---

Wireless topologies

Infrastructure (Wi-Fi) topology

• How it works: Mix of wired + wireless, similar to star:
  • Wired computers connect to a switch.
  • A wireless access point (AP) connects to the same switch and bridges the wireless network to the wired network.
• Scaling: Not limited to one AP—multiple APs can be used depending on network needs.

Ad hoc topology

• How it works: No infrastructure—no cables, routers, servers, or access points.
• Topology: Peer-to-peer direct wireless connections between devices.
• Security implication: Because there’s no central device, each device handles its own security and permissions.
• Use case: Quick “on the fly” networks to share data without an existing Wi‑Fi network.

Wireless mesh topology

• How it works: Like wired mesh, but APs are wirelessly connected to each other.
• Motivation vs wired AP deployment: Wired interconnections require extra cabling and installation time; mesh avoids that by allowing AP-to-AP wireless links.
• How connectivity is relayed: A client connects to the nearest AP, and the AP relays traffic hop-by-hop through neighboring APs until it reaches the path back to the modem.
• Benefits: Seamless coverage (clients can have internet access via multiple APs) and strong redundancy—if some APs fail, others reroute traffic.

---

Main source / speakers

• Single narrator / instructor voice (no distinct named speakers mentioned).