CompTIA Network+ Preparation · lesson 6 of 30 · 25 min
Physical and Logical Topologies
A physical topology describes how devices are physically connected. A logical topology describes how data flows. The Network+ exam tests both, plus hybrid and specialized topologies used in modern networks.
Network Types
Three-Tier vs Two-Tier Architecture
Flashcard Drill
Star topology All devices connect to a central switch — most common in modern LANs. Full mesh Every device connects to every other — maximum redundancy, expensive. Spine-leaf Data center topology — every leaf connects to every spine for equal-cost paths. WAN Wide Area Network — connects geographically separated sites; lower speed, higher latency. SAN Storage Area Network — dedicated high-speed network for storage devices. SDWAN Software-Defined WAN — uses internet links with overlay for cost-effective WAN. Three-tier hierarchy Core → Distribution → Access — scalable enterprise network design. Collapsed core Two-tier design combining core and distribution — used in medium-sized networks. Point-to-point Direct dedicated link between exactly two devices. Hybrid topology Combination of two or more topology types — most real-world networks.
Worked Scenario: Choosing the Right Topology
Scenario
A company is designing a new data center with 200 servers that need low-latency, equal-cost paths to each other. Which topology should they use, and why?
Answer: Spine-leaf topology. In a spine-leaf design, every leaf switch connects to every spine switch. This means any server can reach any other server in exactly two hops (leaf → spine → leaf), guaranteeing equal-cost paths and predictable latency. Traditional three-tier (core/distribution/access) creates unequal path lengths for east-west traffic, which is the dominant traffic pattern in modern data centers.
For the campus network connecting the data center to offices, a three-tier hierarchy (core/distribution/access) is appropriate — it scales well and provides fault isolation at each layer.
Knowledge Check — 12 Questions
Network Topologies (Network+)
Which topology is most common in modern enterprise LANs?
- Bus
- Ring
- Star
- Mesh
Answer: Star
Star topology (all devices connect to a central switch) is the standard for modern LANs.
Which topology provides maximum redundancy?
- Star
- Bus
- Full mesh
- Ring
Answer: Full mesh
Full mesh connects every device to every other — maximum redundancy but expensive.
Spine-leaf topology is primarily used in:
- Home networks
- Data centers
- WAN connections
- Campus networks
- Answer: Data centers
Spine-leaf provides equal-cost paths and low latency — ideal for data center east-west traffic.
A network spanning a city or metropolitan area is called a _____.
Answer: MAN
MAN (Metropolitan Area Network) connects multiple LANs across a city.
Which network type uses software to manage WAN links over internet connections?
- SAN
- SDWAN
- MAN
- CAN
Answer: SDWAN
SDWAN (Software-Defined WAN) uses internet links with an overlay for cost-effective WAN connectivity.
In a three-tier hierarchy, which layer connects end devices?
- Core
- Distribution
- Access
- Aggregation
Answer: Access
The access layer connects end devices (PCs, phones, APs) to the network.
A bus topology has a single point of failure.
- True
- False
Answer: True
A break anywhere on the bus cable disrupts all devices — single point of failure.
Which topology combines core and distribution into one layer?
- Three-tier
- Collapsed core
- Spine-leaf
- Full mesh
Answer: Collapsed core
Collapsed core (two-tier) combines core and distribution — used in medium-sized networks.
A SAN is used for:
- Wireless access
- Dedicated storage networking
- Internet access
- VoIP
- Answer: Dedicated storage networking
SAN (Storage Area Network) provides dedicated high-speed connectivity for storage devices.
A direct dedicated link between exactly two devices is called a _____ link.
Answer: point-to-point
Point-to-point topology connects exactly two devices with a dedicated link.
In spine-leaf, how many hops does it take for any server to reach any other server?
- 1
- 2
- 3
- Varies
Answer: 2
Spine-leaf guarantees exactly 2 hops: leaf → spine → leaf. This ensures equal-cost, predictable latency.
Which network type covers multiple buildings on a single campus?
- LAN
- WAN
- CAN
- MAN
Answer: CAN
CAN (Campus Area Network) covers multiple buildings on a single campus — larger than a LAN, smaller than a MAN.
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