CN Most IMP Topics for GTU Exam (27-12-2021)

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Note: Not rely on below topics only. Also Revised previous 2 CN Question paper, it was very tough.


CN Question Paper – Winter 2020, Summer 2021


CN MIMP Topics

Unit – 1

Define: Network, Topology, Types of delay, Throughput, Loss


Compare LAN, MAN and WAN

Switching Techniques

All topologies

Transmission Modes

OSI Model

TCP/IP Model

Difference between OSI and TCP/IP

Client-server architecture


Unit – 2

Web Cookies

HTTP (all topics)

Persistent http vs non persistent http

Email Architecture, Components & protocols

DNS (All topics)


Unit – 3

Multiplexing and demultiplexing

TCP Connection theory (3 phases)

Noisy and noiseless channel protocol (Sliding window, stop and wait, selective repeat etc…)

Leaky bucket algo


TCP Header

 Rdt model (RDT – Reliable data transfer)

UDP Header

Difference TCP and UDP.

Difference or Short note on Connection oriented and connection less service

TCP congestion and approach of congestion

Difference between flow control and congestion control


Unit – 4

Link state and distance vector routing algo.

Compare link state and distance vector

IPV4 header

Difference between IPV4 and IPV6

IP address and classes, Subnet mask

Routing Loop. How to avoid routing loop?

Broadcast, multicast and unicast.

NAT (Network Address Translation)

DHCP & BootP


Unit – 5

Bit and byte stuffing

CRC with example

Slotted Aloha

Compare slotted and pure aloha

CSMA/CD (1-persistent, persistent, n-persistent)

Network Devices Functionality (Repeater, Hub, Bridge, Switch, Router and Gateway)


Examples may be asked in Paper

Unit – 2: HTTP related

Unit – 3: UDP related

Unit – 4: Subnetting, bandwidth, delay related

Unit – 5: Bit and byte stuffing, CRC, Parity checking


Some of the examples:


Chapter 2: Application Layer

1.  Consider the following HTTP message and answer the following questions: (May - 15)

1) Does browser request a non-persistent or a persistent connection?

2) Which is the (complete) URL of the document requested by the user?

3) Which HTML method is used to retrieve the requested URL?


2.  Consider the following HTTP message and answer the following questions: (May - 16)

1)      From which browser URL is requested?

2)      Does browser request a non-persistent or a persistent connection?

3)      Which is the (complete) URL of the document requested by the user?

4)      Which HTML method is used to retrieve the requested URL?


Chapter 3: Transport Layer

1.      The following is a dump of a UDP header in hexadecimal format.  (May - 16)


a.       What is the source port number?

b.      What is the destination port number?

c.       What is the total length of the user datagram?

d.      What is the length of the data?

Chapter 4: Network Layer

1.  Consider sending real-time voice from Host A to Host B over a packet-switched network (VoIP). Host A converts analog voice to a digital 64 kbps bit stream on the fly. Host A then groups the bits into 56-byte packets. There is one link between Hosts A and B; its Transmission rate is 2Mbps and its propagation delay is 10 msec. As soon as Host A gathers a packet, it sends it to Host B. As soon as Host B receives an entire packet, it converts the packet’s bits to an analog signal. How much time elapses from the time a bit is created (from the original analog signal at Host A) until the bit is decoded (as part of the analog signal at Host B)? (May -15)


2.      Consider a router that interconnects three subnets: Subnet 1, Subnet 2, and Subnet 3. Suppose all of the interfaces in each of these three subnets are required to have the prefix 223.1.17/24. Also suppose that Subnet 1 is required to support at least 60 interfaces, Subnet 2 is to support at least 90 interfaces, and Subnet 3 is to support at least 12 interfaces. Provide three network addresses (of the form a.b.c.d/x) that satisfy these constraints.  (May -15, Dec - 15)


3.   Suppose a process in Host C has a UDP socket with port number 6789. Suppose both Host A and Host B each sends a UDP segment to Host C with destination port number 6789. Will both of these segments be directed to the same socket at Host C? If so, how will the process at Host C know that these two segments originated from two different hosts? (May -15)


4.  Suppose datagrams are limited to 1,500 bytes (including header) between source Host A and destination Host B. Assuming a 20-byte IP header, how many datagrams would be required to send an MP3 consisting of 5 million bytes? Explain how you computed your answer.  (May -15, Dec - 15)


5.     An ISP is granted a block of addresses starting with The ISP wants to distribute these blocks to 100 organizations with each organization receiving 8 addresses only. Design the subblocks and give the slash notation for each sub block. Find out how many addresses are still available after these allocations. (May -16)

6.     One of the addresses in a block is Find the first address and the last address in the block. (May -16)

7.   An organization is granted a block starting with /16. The ISP wants to distribute these addresses to three groups of customers as follows    (June -17)

a) The first group has 64 customers: each needs 256 addresses.

b) The second group has 128 customers: each needs 128 addresses.

c) The third group has 128 customers: each needs 64 addresses.

8.    A network with bandwidth of 10 Mbps can pass only an average of 12,000 frames per minute with each frame carrying an average of 10,000 bits. What is the throughput of this network?

Above Example Solution: Click here

Computer Network unit wise video lecture (Playlist) link 

Unit - 1:

Unit - 2:

Unit - 3:

Unit - 4:

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