Networking study guide

1. Build the topology distinction first

When answering a topology question, identify whether the question is about the physical arrangement or the logical behaviour. For a physical star, explain that each host has its own physical link to a central networking device. For a logical bus, explain that communication follows shared-bus behaviour controlled by a bus protocol. Then state the important distinction: a network may be physically wired in a star but operate logically as a bus when a bus protocol and appropriate physical switching are used.

A strong answer does not simply write “star and bus are different.” It explains that physical topology describes how the network is wired, while logical topology describes how data communication operates. If a scenario gives a star-shaped physical layout but describes shared bus-style communication, both descriptions can be correct because they refer to different aspects of the same network.

2. Choose between peer-to-peer and client-server

Start by identifying whether the computers have equal status. If each computer can provide services directly to the others and none is nominated as a special provider, the model is peer-to-peer. If most computers request services and one or more nominated computers provide them, the model is client-server. Link the explanation to the service: a client may request a file or email service, while the relevant file server or email server provides it.

Do not identify a network model only from the number of computers. The key evidence is the relationship between the hosts and the way services are provided. Use “client” for the requester and “server” for the computer providing the service.

3. Reason about a wireless network

For a WiFi scenario, explain that WiFi is a wireless local area network based on international standards and is used to connect devices wirelessly. Check for both required components: the device needs a wireless network adapter, and the network needs a wireless access point. A complete answer should not treat WiFi as only a security method or only a hardware component.

For security, connect each measure to its purpose. WPA/WPA2 provides strong encryption of transmitted data. Disabling SSID broadcast prevents the network identifier from being openly broadcast. A MAC address allow list restricts connection permission to allowed MAC addresses. The SSID itself identifies the wireless network; it is not the same as the encryption mechanism.

4. Explain CSMA/CA in a sequence

For CSMA/CA, describe the reasoning in order: multiple devices share the wireless medium; a device senses whether the medium is in use; it attempts to transmit only as part of a collision-avoidance process. With RTS/CTS, add the request-to-send and clear-to-send exchange before the transmission. Without RTS/CTS, explain that carrier sensing and collision avoidance are used without that exchange. Keep the answer focused on avoiding collisions in wireless communication. CSMA/CD is not needed for this specification requirement.

Self-check questions

1. Can you explain why physical star and logical bus are not contradictory?
2. Can you identify the client and server when a computer requests a file from a file server?
3. Can you name both components required for a device to use a wireless network?
4. Can you distinguish the SSID, WPA/WPA2 and a MAC address allow list?
5. Can you explain the difference between CSMA/CA with RTS/CTS and CSMA/CA without RTS/CTS?

When checking an answer, look for a mechanism rather than a list of terms. Each term should be connected to its function or to the evidence in the scenario.