Computer networks
⏱ ~3-min readAceMark Guide
What this topic is really about
In the original classful IPv4 scheme, addresses whose first octet falls between 192 and 223 are designated Class C, giving a default subnet mask of 255.255.255.0; 192.168.1.1 therefore lies in Class C. Many students mistakenly pick Class B because its first octet range (128‑191) is close, but 192 exceeds that range, making the Class B choice incorrect.
UDP is preferred for video streaming because its low overhead and lack of retransmissions ensure real-time playback without lag. TCP is incorrect because its connection-oriented nature and retransmission mechanism introduce latency, which disrupts live streams. HTTP is an application layer protocol, not a transport layer protocol.
See the mechanism
The Open Systems Interconnection (OSI) model standardizes network communications into seven distinct layers, ranging from the Physical layer up to the Application layer. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.
An exam-style question, fully explained
The OSI model has how many layers?
- Identify what the question tests: The OSI model has how many layers.
- The Open Systems Interconnection (OSI) model standardizes network communications into seven distinct layers, ranging from the Physical layer up to the Application layer.
- The TCP/IP model, by contrast, is often described as having only four or five layers.
Traps the examiner sets
- Many students mistakenly pick Class B because its first octet range (128‑191) is close, but 192 exceeds that range, making the Class B choice incorrect.
- TCP is incorrect because its connection-oriented nature and retransmission mechanism introduce latency, which disrupts live streams.
Test your recall
Answer each from memory — you'll see instantly whether you're right and why.
Run a focused 10-question mini-mock on Computer networks and see it stick.
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