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Computer Network Viva Questions and Answers Semester 5 Mumbai University
Table of Contents
Module 1: Introduction to Networking ( Computer Network Viva )
Q1) What is a computer network?
A1) A computer network is a collection of interconnected devices that can communicate and share resources.
Q2) What are some common network devices?
A2) Common network devices include routers, switches, hubs, and modems.
Q3) Describe the difference between circuit-switched networks and packet-switching networks.
A3) Circuit-switched networks establish a dedicated path for the entire duration of a call, while packet-switching networks break data into packets that are independently routed.
Q4) What are the main network types, and what do they stand for?
A4) LAN (Local Area Network), MAN (Metropolitan Area Network), and WAN (Wide Area Network).
Q5) What is the OSI reference model, and how many layers does it have?
A5) The OSI model has seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.
Q6) How does the TCP/IP model differ from the OSI model?
A6) The TCP/IP model combines the OSI model’s physical and data link layers into one, resulting in four layers: Network Interface, Internet, Transport, and Application.
Q7) Explain the concept of network topology.
A7) Network topology refers to the physical or logical layout of devices and connections in a network, such as bus, star, ring, or mesh.
Q8) What is the role of a network switch in a LAN?
A8) A network switch is a device that connects devices within a LAN and forwards data packets only to the intended recipient.
Q9) What is the difference between a LAN and a WAN?
A9) A LAN covers a small geographical area, like a home or office, while a WAN spans larger areas, such as cities or even countries.
Q10) Define NAT in the context of networking.
A10) NAT (Network Address Translation) is a technique that allows multiple devices within a local network to share a single public IP address for accessing the internet.
Q11) How does the concept of virtual LAN (VLAN) work in networking?
A11) VLANs allow network segmentation, separating devices into logical groups even if they are on the same physical network.
Q12) What are the advantages of using a hub in a network?
A12) Hubs are simple devices that can connect multiple devices in a LAN, but they lack the intelligence to make data forwarding decisions.
Q13) Differentiate between full-duplex and half-duplex communication in networking.
A13) Full-duplex allows simultaneous two-way communication, while half-duplex only permits communication in one direction at a time.
Q14) What is the purpose of the OSI model’s Presentation Layer?
A14) The Presentation Layer is responsible for data translation, encryption, and compression to ensure data compatibility between different systems.
Q15) Explain the role of ARP (Address Resolution Protocol) in networking.
A15) ARP is used to map an IP address to a MAC address, enabling data transmission within a local network.
Module 2: Physical and Data Link Layer
Q1) What is the primary function of the Physical Layer in networking?
A1) The Physical Layer is responsible for the physical transmission of data over the network medium, including encoding, modulation, and signal transmission.
Q2) Name three types of guided transmission media.
A2) Twisted pair, coaxial cable, and fiber optics.
Q3) What are the key services provided by the Data Link Layer?
A3) Services provided by the Data Link Layer include framing, error control, and flow control.
Q4) Explain the purpose of error detection and correction in the Data Link Layer.
A4) Error detection and correction techniques are used to ensure data integrity during transmission, such as Hamming Code, CRC, and checksum.
Q5) Describe the Stop and Wait data link protocol.
A5) Stop and Wait is a simple data link protocol where the sender transmits one frame and waits for an acknowledgment before sending the next frame.
Q6) What is the purpose of the Medium Access Control (MAC) sublayer?
A6) The MAC sublayer is responsible for channel access control and preventing data collisions in shared media networks.
Q7) Compare ALOHA and Carrier Sense Multiple Access (CSMA) protocols.
A7) ALOHA allows stations to transmit data at any time, while CSMA listens for carrier signals before transmitting to avoid collisions.
Q8) Explain the concept of channel allocation problem in networking.
A8) Channel allocation problem involves allocating shared network resources efficiently among multiple users to avoid conflicts and maximize utilization.
Q9) What are the key differences between the OSI and TCP/IP reference models?
A9) The OSI model has seven layers, while the TCP/IP model has four. The layer structures and terminology also differ between the two models.
Q10) Define “guided transmission media” and provide examples.
A10) Guided transmission media are physical pathways that use cables or wires for data transmission. Examples include twisted pair, coaxial cable, and fiber optics.
Q11) What is the purpose of the Data Link Layer’s Flow Control mechanism?
A11) Flow control ensures that data is transmitted at a rate that the receiver can handle, preventing congestion and data loss.
Q12) Explain the role of Ethernet in the Data Link Layer.
A12) Ethernet is a widely used LAN technology that operates in the Data Link Layer, providing a frame-based data link for local networks.
Q13) What are the advantages of using fiber optics as a transmission medium?
A13) Fiber optics offer high bandwidth, low attenuation, immunity to electromagnetic interference, and secure data transmission.
Q14) Define MAC address and explain its significance in networking.
A14) A MAC address is a unique hardware address assigned to network interface cards. It is crucial for data link layer functions like addressing and frame delivery.
Q15) How does the Data Link Layer handle error detection and correction?
A15) The Data Link Layer uses techniques like CRC (Cyclic Redundancy Check) to detect errors and retransmission of frames to correct errors.
Module 3: Network Layer
Q1) What are the primary functions of the Network Layer?
A1) The Network Layer is responsible for logical addressing, routing, and forwarding of data packets.
Q2) Explain the difference between IPv4 and IPv6 addressing.
A2) IPv4 uses 32-bit addresses, while IPv6 uses 128-bit addresses, allowing for a much larger address space.
Q3) What is Subnetting in IPv4 addressing?
A3) Subnetting involves dividing an IP network into smaller, more manageable subnetworks to optimize address utilization.
Q4) Define NAT (Network Address Translation) and its purpose.
A4) NAT is a technique that allows multiple devices within a local network to share a single public IP address for internet access, preserving address space.
Q5) Differentiate between routed and routing protocols.
A5) Routed protocols are used for data transmission, while routing protocols are used to determine the best path for data.
Q6) What are the Shortest Path algorithms used in routing?
A6) Shortest Path algorithms, such as Dijkstra’s algorithm, find the most efficient path from source to destination in a network.
Q7) Describe the operation of Link State routing protocols.
A7) Link State routing protocols build a complete network topology database and use Dijkstra’s algorithm to compute the shortest path.
Q8) How does Distance Vector Routing differ from Link State Routing?
A8) Distance Vector routing protocols rely on distance and direction information to make routing decisions, whereas Link State routing protocols use the entire network topology.
Q9) Explain the concept of Network Address Translation (NAT) and its use.
A9) NAT translates private IP addresses into a single public IP address for internet access, preserving address space.
Q10) What is a routing algorithm, and why is it necessary in networking?
A10) A routing algorithm is used to determine the best path for data to travel from the source to the destination in a network, optimizing data transmission.
Q11) What is the purpose of subnet masks in IP addressing?
A11) Subnet masks are used to distinguish between the network and host portions of an IP address, aiding in routing and subnetting.
Q12) Explain the concept of dynamic routing protocols in networking.
A12) Dynamic routing protocols enable routers to exchange routing information and adapt to changes in network topology automatically.
Q13) How does IP fragmentation work in the network layer?
A13) IP fragmentation divides large IP packets into smaller fragments for transmission across networks with lower Maximum Transmission Unit (MTU) sizes.
Q14) What is the purpose of the Internet Control Message Protocol (ICMP) in networking?
A14) ICMP is used for error reporting and diagnostics, providing feedback on network problems like unreachable hosts or time-exceeded messages.
Q15) How does CIDR (Classless Inter-Domain Routing) improve IP addressing?
A15) CIDR allows for more efficient use of IP addresses by specifying variable-length subnet masks, reducing IP address wastage.
Module 4: Transport Layer and Application Layer
Q1) What are the key responsibilities of the Transport Layer?
A1) The Transport Layer provides end-to-end communication services, including segmentation, error recovery, and flow control.
Q2) Explain the purpose of sockets in networking.
A2) Sockets provide an interface for application programs to communicate over a network using IP addresses and port numbers.
Q3) Describe the TCP handshake process.
A3) The TCP handshake involves three steps: SYN, SYN-ACK, and ACK, to establish a reliable connection between sender and receiver.
Q4) Differentiate between UDP and TCP.
A4) UDP is connectionless and provides no guarantee of data delivery, while TCP is connection-oriented and ensures reliable data transmission.
Q5) What is TCP flow control, and how does it work?
A5) TCP flow control manages the rate of data transfer to avoid congestion by adjusting the window size based on receiver capacity.
Q6) Name some common application layer protocols and their purposes.
A6) HTTP (web browsing), SMTP (email), Telnet (remote login), FTP (file transfer), DHCP (dynamic IP assignment), and DNS (domain name resolution).
Q7) What are the types of name servers in DNS, and how do they differ?
A7) DNS servers can be authoritative (provide official domain records) or recursive (resolve queries by querying other DNS servers).
Q8) How does HTTP work, and what are its main methods?
A8) HTTP is a protocol for transferring hypertext data on the World Wide Web and uses methods like GET, POST, and PUT to interact with web resources.
Q9) Explain the role of the FTP protocol in file transfer.
A9) FTP (File Transfer Protocol) is used to upload and download files to and from a remote server.
Q10) What is DHCP, and how does it simplify network configuration?
A10) DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses and network configuration settings to devices, simplifying network setup.
Q11) What is the purpose of the Telnet protocol in networking?
A11) Telnet is a protocol that allows remote terminal access and control of network devices and servers.
Q12) Explain the role of SMTP in email communication.
A12) SMTP (Simple Mail Transfer Protocol) is responsible for sending and relaying email messages between mail servers.
Q13) How does DNS resolve domain names to IP addresses?
A13) DNS (Domain Name System) uses a distributed hierarchical system to map human-readable domain names to IP addresses, facilitating web browsing and email communication.
Q14) Define the purpose of the Application Layer in networking.
A14) The Application Layer provides a platform for software applications to interact with the network, enabling tasks like email, web browsing, and remote access.
Q15) What is the difference between HTTP and HTTPS in web communication?
A15) HTTP is a non-secure protocol for web communication, while HTTPS (HTTP Secure) encrypts data to ensure secure, private web interactions.
Module 5: Enterprise Network Design
Q1) What is the Cisco Service Oriented Network Architecture (SONA)?
A1) SONA is a framework developed by Cisco for designing and deploying network services in an enterprise environment.
Q2) Describe the top-down vs. bottom-up approach to network design.
A2) The top-down approach starts with high-level goals and works down to details, while the bottom-up approach starts with details and builds up to the overall design.
Q3) What are the three layers in the Classic Three-Layer Hierarchical Model for network design?
A3) The three layers are Core, Distribution, and Access layers.
Q4) What considerations are important when designing a campus network?
A4) Factors like scalability, security, and efficient traffic flow are crucial when designing a campus network.
Q5) Explain the concept of network topology in the context of network design.
A5) Network topology refers to the physical or logical layout of devices and connections in a network, which impacts design decisions.
Q6) What is the purpose of the Core layer in the hierarchical network design model?
A6) The Core layer provides high-speed, high-capacity connectivity to ensure efficient data transfer across the entire network.
Q7) Describe the role of the Access layer in the network design model.
A7) The Access layer connects end-user devices to the network and provides services like VLAN assignment and security checks.
Q8) What are the primary design considerations when implementing a distribution layer?
A8) The distribution layer focuses on routing, filtering, and traffic management to ensure optimized network performance.
Q9) Explain the importance of redundancy in network design.
A9) Redundancy is critical for network reliability, as it provides backup paths and devices to ensure continuous operation in case of failures.
Q10) How can network segmentation improve security in enterprise network design?
A10) Network segmentation separates network segments, limiting the impact of security breaches and reducing the attack surface.
Q11) What is the role of VLANs in network design, and how do they work?
A11) VLANs (Virtual Local Area Networks) divide a physical network into logical segments, enhancing security and traffic management.
Q12) How does Quality of Service (QoS) impact network design and performance?
A12) QoS prioritizes network traffic to ensure that critical applications receive adequate bandwidth and low latency, improving performance.
Q13) What are the key considerations for remote access and mobile device integration in network design?
A13) Considerations include VPN implementation, mobile device security, and support for remote users accessing the network.
Q14) How can network monitoring and management tools enhance network design?
A14) Network monitoring tools provide real-time visibility into network performance, helping in troubleshooting and optimizing network design.
Q15) What are the advantages of implementing a scalable and modular network design?
A15) Scalable and modular designs can adapt to changing needs, accommodate growth, and simplify maintenance and upgrades.
Module 6: Software Defined Networks
Q1) What is Software Defined Networking (SDN) and its fundamental characteristics?
A1) SDN is an approach to networking that separates the control plane from the data plane. Its characteristics include centralized control, programmability, and automation.
Q2) What are the key building blocks of SDN architecture?
A2) The building blocks include the SDN controller, the southbound APIs, and the northbound APIs, which enable communication and control within the SDN network.
Q3) Explain the roles of the Control Plane and Data Plane in SDN.
A3) The Control Plane manages network policies and decisions, while the Data Plane forwards data packets based on those policies.
Q4) What are OpenFlow messages, and how do they operate in SDN?
A4) OpenFlow messages are used to communicate between the SDN controller and network switches. They include commands for configuring and controlling network devices.
Q5) Differentiate between symmetric and asynchronous OpenFlow messages.
A5) Symmetric messages flow between the controller and switch in both directions, while asynchronous messages are initiated by the switch to notify the controller of events.
Q6) What are PoX and NoX architectures in SDN OpenFlow controllers?
A6) PoX and NoX are open-source SDN controllers that implement the OpenFlow protocol, providing control and management of SDN networks.
Q7) How does SDN improve network management and agility?
A7) SDN simplifies network management by centralizing control, automating tasks, and enabling dynamic configuration changes to adapt to network requirements.
Q8) Explain the concept of network virtualization in the context of SDN.
A8) Network virtualization allows the creation of multiple virtual networks on a shared physical infrastructure, enhancing resource utilization and isolation.
Q9) What are the security considerations in SDN implementation?
A9) Security concerns include controller security, the risk of controller compromise, and protection against Distributed Denial of Service (DDoS) attacks on the controller.
Q10) Describe the concept of SD-WAN (Software-Defined Wide Area Network).
A10) SD-WAN is an SDN technology applied to wide area networks, providing centralized control and policy-based routing for branch offices and remote locations.
Q11) How does SDN support network automation and orchestration?
A11) SDN enables automation and orchestration by allowing the network to be dynamically configured and adjusted based on changing requirements and conditions.
Q12) What is the role of APIs (Application Programming Interfaces) in SDN?
A12) APIs in SDN allow applications to communicate with the SDN controller to request and configure network services, making it programmable and extensible.
Q13) How can SDN benefit cloud computing and data center environments?
A13) SDN can improve resource allocation, scalability, and flexibility in cloud and data center networks, enhancing overall performance and efficiency.
Q14) What challenges may organizations face when implementing SDN?
A14) Challenges include integration with existing infrastructure, security concerns, and the need for specialized skills in SDN technologies.
Q15) How does SDN impact network traffic optimization and Quality of Service (QoS)?
A15) SDN allows for dynamic traffic optimization and QoS adjustments, ensuring that critical applications receive the necessary network resources for optimal performance.