In ECET 2026 Computer Science, Computer Networks (CN) is one of the most scoring subjects. Among CN topics, IP Addressing is very important because direct questions on Classful IPs, Subnetting, and Address Ranges are common every year.
📘 Concept Notes – IP Addressing Basics
🌐 What is an IP Address?
- IP address = unique number assigned to every device in a network.
- Used to identify host and locate host in network.
- Consists of 32 bits (IPv4) or 128 bits (IPv6).
- Divided into Network ID + Host ID.
🏷️ Types of IP Addressing
- IPv4 Address (32-bit, 4 octets, e.g.,
192.168.1.1) - IPv6 Address (128-bit, written in hex, e.g.,
2001:0db8:85a3::8a2e:0370:7334)
📚 IP Address Classes (IPv4)
| Class | Range (First Octet) | Example | Use |
|---|---|---|---|
| A | 0 – 127 | 10.0.0.1 | Large Networks |
| B | 128 – 191 | 172.16.0.1 | Medium Networks |
| C | 192 – 223 | 192.168.1.1 | Small Networks |
| D | 224 – 239 | – | Multicast |
| E | 240 – 255 | – | Research |
⚙️ Formulas
Where:
- nnn = Borrowed bits for subnet
- hhh = Remaining host bits
🔟 10 Most Expected MCQs – ECET 2026 CN (IP Addressing)
Q1. IPv4 address size is:
A) 32 bits
B) 64 bits
C) 128 bits
D) 16 bits
Q2. Which class of IP address provides maximum hosts?
A) Class A
B) Class B
C) Class C
D) Class D
Q3. Which of the following is a private IP?
A) 192.168.1.1
B) 11.0.0.1
C) 172.32.5.1
D) 8.8.8.8
Q4. The default subnet mask of Class B is:
A) 255.0.0.0
B) 255.255.0.0
C) 255.255.255.0
D) 255.255.255.255
Q5. IPv6 address size is:
A) 32 bits
B) 64 bits
C) 128 bits
D) 256 bits
Q6. How many hosts can a Class C network support (without subnetting)?
A) 128
B) 254
C) 512
D) 1024
Q7. Subnetting is used to:
A) Increase security
B) Reduce broadcast traffic
C) Create smaller networks
D) All of the above
Q8. Which of the following is a multicast address class?
A) A
B) B
C) C
D) D
Q9. Formula to calculate number of subnets?
A) 
B) 
C) 
D) 
Q10. The loopback IP address is:
A) 192.168.1.1
B) 127.0.0.1
C) 0.0.0.0
D) 255.255.255.255
✅ Answer Key
| Q.No | Answer |
|---|---|
| Q1 | A |
| Q2 | A |
| Q3 | A |
| Q4 | B |
| Q5 | C |
| Q6 | B |
| Q7 | D |
| Q8 | D |
| Q9 | A |
| Q10 | B |
🧠 Explanations
- Q1 → A: IPv4 is 32-bit.
- Q2 → A: Class A supports largest hosts (≈16 million).
- Q3 → A: Private IP ranges include 192.168.x.x.
- Q4 → B: Class B default mask is 255.255.0.0.
- Q5 → C: IPv6 = 128 bits.
- Q6 → B: Class C gives 254 usable hosts.
- Q7 → D: Subnetting reduces broadcast + increases security.
- Q8 → D: Class D = multicast.
- Q9 → A: is subnet formula.
- Q10 → B: 127.0.0.1 is loopback address.
🎯 Why This Practice Matters
IP Addressing is always repeated in ECET exams.
- Easy to score 2–3 marks from direct questions.
- Helps in real-world networking jobs (system admin, cloud, etc.).
- Strong base for subnetting, routing, and security.
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