Discuss the pros and cons of four LAN technologies.

Ethernet (IEEE 802.3)

• Pros:
  • Widespread adoption with strong interoperability.
  • Hardware, like Network Interface Cards and switches, is affordable.
  • Offers scalability with various speed options, including Fast, Gigabit, and 10 Gigabit Ethernet.
  • Supports a flexible star topology using switches.
  • Includes robust error detection with Cyclic Redundancy Check (CRC).
• Cons:
  • Early shared-media versions could have performance issues due to collisions under heavy network load; modern switching minimizes this.
  • Physical cabling for large setups can be complex.
• Example: Most common local area networks in homes and offices use Ethernet to connect computers, printers, and servers to a central switch.

Wi-Fi (Wireless LAN - IEEE 802.11)

• Pros:
  • Provides mobility for users within the network's coverage area.
  • Simplifies deployment by not needing physical cables to devices.
  • Supports diverse devices such as laptops, smartphones, and IoT devices.
  • Reduces cabling infrastructure costs.
• Cons:
  • Signals are exposed to potential interception, raising security concerns.
  • It offers lower bandwidth and higher latency compared to wired Ethernet for similar costs.
  • It is susceptible to interference from other wireless devices and environmental factors.
  • Has a limited range, and signal strength can decrease with distance or obstacles.
• Example: Home wireless networks let smartphones and laptops access the internet without cables.

Token Ring (IEEE 802.5)

• Pros:
  • Guarantees access time due to its deterministic token-passing.
  • Ensures fairness since all stations get a chance to transmit.
  • Maintains good performance under heavy network load because collisions do not happen.
  • It includes built-in priority mechanisms for different traffic types.
• Cons:
  • Implementation and management are more involved than Ethernet.
  • Hardware is more expensive.
  • A lost token or a malfunctioning station can disrupt the entire ring.
  • It is less scalable than modern switched Ethernet.
  • This technology has been largely replaced by Ethernet in enterprise networks.
• Example: Historically, it was used in IBM mainframe environments to provide reliable data transfer.

Fiber Distributed Data Interface (FDDI)

• Pros:
  • Provided high bandwidth (100 Mbps) for its time.
  • Uses fiber optic cable, which offers immunity to electromagnetic and radio frequency interference, and supports longer transmission distances.
  • It has a dual counter-rotating ring design for fault tolerance and redundancy.
  • It uses a token-passing method for deterministic access.
• Cons:
  • Hardware and fiber optic cabling are expensive.
  • Installation and maintenance are complex.
  • It uses a less flexible ring topology.
  • It has been largely replaced by Gigabit Ethernet for backbone applications.
• Example: It served as a high-speed backbone connecting departmental LANs or buildings before Gigabit Ethernet became common.