BE Computer Engineering (Pokhara University) Computer Networks (PU, CMP 344) Question Paper 2078
This is the official BE Computer Engineering (Pokhara University) Computer Networks (PU, CMP 344) question paper for 2078, as set in the regular annual examination. It carries 100 full marks and a time allowance of 180 minutes, across 11 questions. On Kekkei you can attempt this Computer Networks (PU, CMP 344) past paper online with a timer, get instant AI feedback and step-by-step solutions, and track the topics where you lose marks — completely free. Whether you are revising for your BE Computer Engineering (Pokhara University) Computer Networks (PU, CMP 344) exam or solving previous years' question papers, this 2078 paper is a great way to practise under real exam conditions.
Section A: Long Answer Questions
Attempt all / any as specified.
(a) Describe the seven layers of the OSI reference model, clearly stating the principal function and at least one protocol or PDU associated with each layer. (8)
(b) Compare the OSI model with the TCP/IP model. With the help of a diagram, show how the layers of the two models map onto one another and justify why the TCP/IP model became the de facto standard for the Internet. (6)
An organization has been allocated the block 192.168.40.0/24.
(a) The organization needs to create four departmental subnets requiring 60, 28, 12 and 5 usable hosts respectively. Using Variable Length Subnet Masking (VLSM), allocate appropriate subnets and for each subnet specify the network address, subnet mask, valid host range and broadcast address. (10)
(b) Explain the difference between classful and classless (CIDR) addressing, and state why CIDR was introduced. (4)
(a) Differentiate between distance-vector and link-state routing protocols, giving one example of each. (6)
(b) Consider the network below where the number on each link is its cost:
2 3
A -------- B -------- C
| | |
1| 4| 2|
| | |
D -------- E -------- F
1 5
Apply Dijkstra's shortest-path algorithm from source node A and determine the shortest path and total cost from A to every other node. Show the working at each step. (6)
(a) Using a timing diagram, explain TCP's three-way handshake for connection establishment and the connection-termination procedure. (6)
(b) Explain how TCP achieves reliable data transfer and congestion control. In your answer, describe slow start, congestion avoidance and the role of the congestion window (cwnd). (6)
Section B: Short Answer Questions
Attempt all / any as specified.
Compare TCP and UDP in terms of connection orientation, reliability, ordering, header overhead and typical applications. Give two real-world applications best suited to each protocol and justify your choice.
(a) Explain the working of the Domain Name System (DNS), describing the roles of root, top-level-domain and authoritative name servers, and the difference between iterative and recursive queries. (5)
(b) Differentiate between HTTP and HTTPS. (2)
Differentiate between a hub, a switch and a router with respect to the OSI layer at which they operate, their handling of collision and broadcast domains, and their addressing mechanism. Use a table where appropriate.
(a) Explain the CSMA/CA mechanism used in IEEE 802.11 wireless LANs and state why CSMA/CD is unsuitable for wireless networks. (4)
(b) What is the hidden terminal problem, and how do RTS/CTS frames help mitigate it? (3)
Explain the operation of the DHCP protocol. Describe the four messages exchanged in the DHCP DORA process and the purpose of each.
(a) What is the role of the Simple Network Management Protocol (SNMP)? Describe the components of an SNMP-managed network (manager, agent, MIB). (4)
(b) List any two faults that network management aims to detect and one corrective action for each. (2)
Write short notes on any TWO of the following:
(a) Network Address Translation (NAT)
(b) IPv4 versus IPv6 header and address space
(c) ARP and its working