Computer Networks (IT-502) - Important Questions

Describe the TCP/IP reference model and compare/differentiate it with the ISO-OSI model.

Define PAN, LAN, WAN (and internetwork) and compare them in terms of coverage area, speed and applications.

Explain the ISO-OSI reference model and describe the functions of each of the seven layers.

Explain the purpose of the physical layer and discuss various physical transmission media.

When is RARP required, how does it work, and what are its limitations?

Explain Address Resolution Protocol (ARP) and discuss its packet format

Compare delays in connectionless vs connection-oriented services and determine which has less delay for large vs small messages.

Explain the purpose of ARP and why ARP request is broadcast while ARP reply is unicast

Explain the OSI reference model with brief description of layers and highlight the critique of the OSI model and protocols.

Describe the TCP/IP reference model and list its advantages and disadvantages.

Describe the OSI model with functions of each layer and compare similarities and differences with the TCP/IP protocol suite.

Justify the need for ARP and RARP in data transfer and determine default subnet mask for given Class C address

Explain the working of the CSMA protocol and what a station should do when the channel is busy or idle

Explain what bit stuffing (and byte stuffing) is, with example, and why it is needed in HDLC.

Show sender/receiver window positions for a Go-Back-N ARQ sequence with given sequence-number bits and window size.

What is CSMA/CD? How does it work? Distinguish between 1-Persistent and Non-Persistent CSMA.

Explain flow control and error control mechanisms in the Data Link Layer.

Describe the Stop-and-Wait protocol and explain its working with a suitable diagram.

Explain the HDLC protocol and describe its frame format.

Describe the functions of the LLC and MAC sublayers.

Explain the architecture of IEEE 802.11 and differentiate IEEE 802.11a and IEEE 802.11b.

Given bit stream and generator polynomial $x^3+1$, compute CRC codeword transmitted and show detection of single-bit error.

Explain random access protocols and ALOHA, including pure vs slotted ALOHA and their differences.

Numerical on infinite-population slotted ALOHA: calculate channel throughput from idle probability and determine overload vs underload.

Explain the IPv4 header / datagram format and the importance of each field.

Write short note on IPv6 (as part of choice among IPv6, BOOTP, Bridges, TCP Timers).

Given an address in CIDR notation a.b.c.d/n, find the number of addresses in the block and the first and last addresses.

State major differences between Distance Vector Routing and Link State Routing and discuss how they work.

Given an IPv4 address, identify its class, default subnet mask, network ID and host ID, and broadcast address.

Explain various error reporting messages in ICMP protocol.

Given classful IPv4 addresses, find the netid/network ID and hostid/host ID.

Compare shortest path / link-state routing and distance vector routing for a static topology and justify which is preferred.

Compute shortest paths from a source vertex using the Bellman-Ford algorithm given delays and neighbor vectors.

Explain the difference between broadcast routing and multicast routing.

Create 16 subnet for IP address $200.133.175.0$, each with 16 host (including all the reserved addresses), also provide the addresses range of each subnet's hosts.

Explain Routing Information Protocol (RIP) and how the RIP routing table gets updated.

Explain the duties / functionalities of the Transport Layer.

Explain the UDP Encapsulation and protocol layering.

Define Transmission Control Protocol (TCP) and explain the TCP header format.

Explain the Transport Layer in detail. How process-to-process delivery is achieved in computer networks?

Compare open-loop congestion control and closed-loop congestion control.

Explain the concept of Quality of Service (QoS) in the transport layer

Explain User Datagram Protocol (UDP) in detail.

Explain how TCP connection establishment and release (three-way handshake and termination) works.

Explain the SACK-permitted option and how the time-stamp option provides protection against wrapped sequence numbers.

Explain the Leaky Bucket and Token Bucket algorithms with flow charts

Explain the differences between TCP and UDP protocols.

What is congestion control and how can hosts regulate their sending rate for congestion control?

Explain Simple Mail Transfer Protocol (SMTP) / ESMTP and message transfer using it.

Why is an application such as POP needed for electronic messaging?

Explain why gateway is called protocol converter and also explain its working in detail.

Explain the E-mail system architecture and describe the working principles of SMTP.

Explain Simple Network Management Protocol (SNMP) and discuss its components.

Write short notes on any three of: SNMP, IMAP, TFTP, FDDI.

Explain the principle of HTTP operation.

Explain remote login in detail.

Explain how a DNS resolver bootstraps the domain name lookup process / working of the DNS system.

What is File Transfer Protocol (FTP)? Briefly describe FTP Connection, Communication and Command processing. 8

Explain the working of the DNS system and HTTP.

What is store-and-forward switching and cut-through switching? 4

Explain the basics of Line coding in physical layer. Code the binary stream $010011100$ in: