Computer Networks — Quick Reference Cheatsheet
Essential Formulas & Rules
Core Topics
OSI & TCP/IP Model:
Key formula/rule: See fundamentals section for complete derivation
When to apply: When the problem mentions keywords related to osi & tcp/ip model
Physical Layer (Transmission Media):
Key formula/rule: See fundamentals section for complete derivation
When to apply: When the problem mentions keywords related to physical layer (transmission media)
Data Link Layer (MAC, Error Detection):
Key formula/rule: See fundamentals section for complete derivation
When to apply: When the problem mentions keywords related to data link layer (mac, error detection)
Network Layer (IP, Routing):
Key formula/rule: See fundamentals section for complete derivation
When to apply: When the problem mentions keywords related to network layer (ip, routing)
Transport Layer (TCP, UDP):
Key formula/rule: See fundamentals section for complete derivation
When to apply: When the problem mentions keywords related to transport layer (tcp, udp)
Application Layer (HTTP, DNS, SMTP):
Key formula/rule: See fundamentals section for complete derivation
When to apply: When the problem mentions keywords related to application layer (http, dns, smtp)
Problem-Solving Templates
Template 1: Identify → Apply → Verify
Template 2: For MCQs
Most Common Question Types
| Type | What to Do | Time Budget |
|---|
|---|---|---|
| Direct formula | Apply formula directly | 30-60 sec |
|---|---|---|
| Multi-step | Break into steps, apply each | 1-2 min |
| Concept-based | Recall definition + example | 45 sec |
| Data interpretation | Extract data, compute | 2-3 min |
Revision Strategy
1 month before exam:
1 week before:
1 day before:
Labs Section
The Labs section for Computer Networks has: