Module 1: Introduction to Networking
Q1: What are the main components of a computer network?
A1: The main components of a computer network include network hardware (e.g., routers, switches, hubs), network software (e.g., operating systems, network protocols), and communication media (e.g., cables, wireless signals).
Q2: Compare the OSI model and TCP/IP model in terms of number of layers.
A2: The OSI model has 7 layers (Physical, Data Link, Network, Transport, Session, Presentation, Application), while the TCP/IP model has 4 layers (Network Interface, Internet, Transport, Application).
Q3: What is the difference between connection-oriented and connectionless services?
A3: Connection-oriented services establish a dedicated connection before data transfer and ensure reliable delivery, while connectionless services send data without establishing a connection and don’t guarantee delivery.
Q4: Name three network topologies.
A4: Three common network topologies are bus topology, star topology, and ring topology.
Module 2: Physical Layer
Q5: What is the electromagnetic spectrum?
A5: The electromagnetic spectrum is the range of all types of electromagnetic radiation, including radio waves, microwaves, visible light, X-rays, and gamma rays.
Q6: Compare twisted pair and coaxial cable in terms of bandwidth and susceptibility to interference.
A6: Coaxial cable generally offers higher bandwidth and better resistance to electromagnetic interference compared to twisted pair cable.
Q7: What is the main advantage of fiber optic cables over copper cables?
A7: Fiber optic cables offer much higher bandwidth, longer transmission distances, and greater resistance to electromagnetic interference compared to copper cables.
Module 3: Data Link Layer
Q8: What are the main functions of the Data Link Layer?
A8: The main functions of the Data Link Layer include framing, error control, and flow control.
Q9: Explain the difference between error detection and error correction.
A9: Error detection identifies the presence of errors in transmitted data, while error correction not only detects errors but also corrects them without requiring retransmission.
Q10: What is the purpose of the CRC in error detection?
A10: CRC (Cyclic Redundancy Check) is used to detect accidental changes to raw data, providing a strong guarantee of data integrity.
Q11: Describe the Stop-and-Wait protocol.
A11: In the Stop-and-Wait protocol, the sender sends a frame and waits for an acknowledgment before sending the next frame. It’s simple but inefficient for high-speed networks.
Q12: What is the main difference between Go-Back-N and Selective Repeat protocols?
A12: In Go-Back-N, if an error is detected, all subsequent frames are retransmitted. In Selective Repeat, only the erroneous frame is retransmitted.
Q13: Explain the CSMA/CD protocol used in Ethernet.
A13: CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is a protocol where devices listen for traffic before transmitting, and if a collision is detected, they wait a random time before retrying.
Module 4: Network Layer
Q14: What is the purpose of IP addressing?
A14: IP addressing provides a unique identifier for each device on a network, enabling proper routing of data packets between source and destination.
Q15: Explain the difference between classful and classless IP addressing.
A15: Classful addressing divides the IP address space into fixed classes (A, B, C, D, E), while classless addressing (CIDR) allows for more flexible subnet mask lengths.
Q16: What is subnetting and why is it used?
A16: Subnetting is the process of dividing a larger network into smaller subnetworks. It’s used to improve network performance, security, and address allocation efficiency.
Q17: Describe the purpose of Network Address Translation (NAT).
A17: NAT allows multiple devices on a private network to share a single public IP address, conserving IPv4 addresses and providing a level of security by hiding internal network structure.
Q18: What are the main differences between IPv4 and IPv6?
A18: IPv6 has a much larger address space (128-bit vs 32-bit), built-in security features, and improved header structure compared to IPv4.
Q19: Explain the Dijkstra’s algorithm for shortest path routing.
A19: Dijkstra’s algorithm finds the shortest path between nodes in a graph by iteratively selecting the unvisited node with the smallest tentative distance and updating the distances to its neighbors.
Q20: What is the difference between Link State and Distance Vector routing protocols?
A20: Link State protocols maintain a complete view of network topology and calculate best paths, while Distance Vector protocols only know distances to their neighbors and exchange this information periodically.
Q21: What is the purpose of the ICMP protocol?
A21: ICMP (Internet Control Message Protocol) is used for error reporting and network diagnostics, such as ping and traceroute operations.
Q22: Describe the token bucket algorithm for congestion control.
A22: The token bucket algorithm controls network traffic by using a “bucket” that fills at a constant rate with tokens. Packets can only be sent if there are enough tokens in the bucket, limiting the overall transmission rate.
Module 5: Transport Layer
Q23: What are the main differences between UDP and TCP?
A23: TCP is connection-oriented, reliable, and provides flow control and congestion control. UDP is connectionless, unreliable, and doesn’t provide these features, but it’s faster and has less overhead.
Q24: Explain the three-way handshake process in TCP connection establishment.
A24: The three-way handshake involves: 1) Client sends SYN, 2) Server responds with SYN-ACK, 3) Client sends ACK. This establishes a reliable connection between client and server.
Q25: What is the purpose of flow control in TCP?
A25: Flow control prevents the sender from overwhelming the receiver by adjusting the transmission rate based on the receiver’s processing capacity.
Q26: Describe the slow start mechanism in TCP congestion control.
A26: Slow start is a congestion control algorithm where TCP slowly increases the amount of data transmitted until it finds the network’s maximum carrying capacity.
Module 6: Application Layer
Q27: What is the primary function of DNS?
A27: DNS (Domain Name System) translates human-readable domain names into IP addresses that computers use to identify each other on the network.
Q28: Explain the difference between authoritative and recursive DNS servers.
A28: Authoritative DNS servers hold the actual DNS records for a domain, while recursive DNS servers query other servers on behalf of clients to resolve domain names.
Q29: What is the purpose of the HTTP protocol?
A29: HTTP (Hypertext Transfer Protocol) is used for transmitting hypermedia documents, such as HTML, on the World Wide Web.
Q30: Describe the basic operation of SMTP.
A30: SMTP (Simple Mail Transfer Protocol) is used for sending email messages between servers. It defines how email messages should be formatted, encrypted, and transferred between mail servers.
Experiments and Practical Questions
Q31: How do you crimp an RJ45 connector onto a CAT6 cable?
A31: To crimp an RJ45 connector: 1) Strip the cable jacket, 2) Untwist and arrange wires according to TIA/EIA-568B standard, 3) Insert wires into the connector, 4) Use the crimping tool to secure the connector.
Q32: What is the purpose of the ‘ping’ command?
A32: The ‘ping’ command is used to test the reachability of a host on an IP network and measure the round-trip time for messages sent from the originating host to a destination computer.
Q33: How do you use the ‘tracert’ command, and what information does it provide?
A33: The ‘tracert’ command is used by typing ‘tracert [destination]’ in the command prompt. It shows the route packets take to reach the destination and the time taken for each hop.
Q34: What information can you obtain using the ‘netstat’ command?
A34: The ‘netstat’ command displays active TCP connections, ports on which the computer is listening, Ethernet statistics, the IP routing table, IPv4 statistics, and IPv6 statistics.
Q35: How do you configure static routing in Packet Tracer?
A35: In Packet Tracer, configure static routing by: 1) Select the router, 2) Go to Config tab, 3) Click Routing, 4) Add static route with destination network, subnet mask, and next hop address or exit interface.
Q36: What is the purpose of network discovery tools like Nmap?
A36: Network discovery tools like Nmap are used to discover hosts, services, operating systems, and vulnerabilities on a network, helping in network mapping and security auditing.
Q37: How can Wireshark be used to analyze network traffic?
A37: Wireshark captures and displays the contents of network packets in real-time. It can be used to inspect protocol details, troubleshoot network issues, and detect security problems by analyzing captured packets.
Q38: What information can you gather about Ethernet frames using Wireshark?
A38: Using Wireshark, you can observe Ethernet frame details such as source and destination MAC addresses, frame type, frame size, and the encapsulated protocol.
Q39: How do you capture and analyze ARP packets using Wireshark?
A39: To capture ARP packets in Wireshark: 1) Start a capture, 2) Apply filter “arp”, 3) Generate ARP traffic, 4) Analyze captured packets to see MAC-IP address bindings and ARP request/response processes.
Q40: What is the purpose of simulating CSMA/CD in network simulators?
A40: Simulating CSMA/CD helps understand how Ethernet handles multiple access and collision detection, allowing students to observe the protocol’s behavior under various network conditions without physical hardware.
Q41: How do you set up multiple IP addresses on a single LAN interface in Linux?
A41: Use the ‘ip’ command: ‘sudo ip addr add 192.168.1.2/24 dev eth0’ adds an IP to the eth0 interface. Repeat with different IPs to add multiple addresses.
Q42: How do you add a new route to the routing table in Linux?
A42: Use the ‘ip route add’ command. For example: ‘sudo ip route add 10.0.0.0/24 via 192.168.1.1’ adds a route to the 10.0.0.0/24 network through the gateway 192.168.1.1.
Q43: What is the purpose of IP forwarding, and how do you enable it in Linux?
A43: IP forwarding allows a Linux system to act as a router. Enable it with: ‘sudo sysctl -w net.ipv4.ip_forward=1’ or by editing /etc/sysctl.conf.
Q44: How do you configure a basic VPN using Packet Tracer?
A44: In Packet Tracer, set up a VPN by: 1) Configure two routers with public IPs, 2) Set up IPsec policies on both routers, 3) Configure interesting traffic to be encrypted, 4) Establish the VPN tunnel between the routers.
Q45: What is RIP, and how does it differ from OSPF?
A45: RIP (Routing Information Protocol) is a distance-vector protocol that uses hop count as its metric. OSPF (Open Shortest Path First) is a link-state protocol that uses cost-based metrics and is more scalable for larger networks.
Q46: How do you implement basic socket programming for a TCP client-server application?
A46: For a basic TCP client-server: 1) Create a server socket that listens on a specific port, 2) Create a client socket that connects to the server’s IP and port, 3) Implement send and receive functions for data exchange, 4) Close the connection when done.
Q47: What are the main steps in performing file transfer using FTP?
A47: Main steps for FTP file transfer: 1) Connect to FTP server, 2) Authenticate with username and password, 3) Navigate to the desired directory, 4) Set transfer mode (ASCII or binary), 5) Upload or download files, 6) Close the connection.
Q48: How does Telnet differ from SSH in terms of security?
A48: Telnet transmits data, including passwords, in plain text, making it vulnerable to interception. SSH (Secure Shell) encrypts all data, providing a secure method for remote login and other secure network services.
Q49: What is the purpose of DHCP, and how does it work?
A49: DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses and other network configuration to devices. It works through a discover-offer-request-acknowledge process between clients and the DHCP server.
Q50: How do you analyze HTTP headers using Wireshark?
A50: To analyze HTTP headers in Wireshark: 1) Capture traffic and filter for HTTP, 2) Select an HTTP packet, 3) Expand the HTTP section in the packet details pane to view headers like GET/POST methods, Host, User-Agent, Content-Type, etc.
