Networking Interview Questions Overview

Introduction

• Networking knowledge is crucial for interviews.
• Instructor: Vajija from Edureka.
• Aim: Help answer 50 common networking interview questions.

Key Networking Devices

Router, Hub, Switch

• Hub: Connects multiple Ethernet devices; least intelligent and complex.
• Switch: Connects devices on LAN; filters packets before forwarding; more effective than a hub.
• Router: Connects devices on LAN, MAN, WAN; highly configurable; filters and sends packets.

Basic Networking Concepts

Link

• Connection (physical or wireless) between two or more devices.

Node

• Point of intersection in a network; can send or receive data.
• Examples: Computers, printers, servers, modems.

Backbone Network

• Principal component that supports all other network components.
• High-capacity connectivity infrastructure.

Network Topology

• Physical layout of a network; various types such as bus, star, ring, mesh, tree, daisy chain, hybrid, point-to-point.
• Examples: In bus topology, devices share a common communication line.
• Star topology: All nodes connected to a central hub.

LAN (Local Area Network)

• Network within a small physical location; can be wired or wireless.
• Differentiates by topology, protocols, media.

Routers

• Transfer data packets within a network; performs traffic directing functions.
• Located at gateways; can be standalone devices or virtual machines.

Point-to-Point Network

• Physical connection between two nodes.

OSI Model

Overview

• Open Systems Interconnection; conceptual model standardizing communication functions.
• Seven layers: Physical, Data Link, Network, Transport, Session, Presentation, Application.
• Layers grouped into hardware (Physical, Data Link, Network) and software (Session, Presentation, Application).
• Transport layer known as the heart of the OSI model.

Brief Description of Each Layer

• Physical Layer: Transfers raw bits over a physical link.
• Data Link Layer: Reliable transmission of data frames between nodes.
• Network Layer: Manages multiple nodes, including addressing and routing.
• Transport Layer: Reliable transmission of data packets between network points.
• Session Layer: Manages communication sessions.
• Presentation Layer: Transmission of data between service devices and applications.
• Application Layer: Specifies shared communication protocols and interface methods.

Specific Networking Concepts

Anonymous FTP

• Allows user to access public data without identifying themselves.

Network

• Connection between devices; can be physical or wireless.
• Serves purposes like sharing hardware, communication, data sharing.

Subnet Mask

• Number describing range of IP addresses in a network; divides IP address into network and host address.
• Created by setting network bits to one, host bits to zero.

TCP/IP Model

• Compressed version of the OSI model; four layers: Process/Application, Host-to-Host/Transport, Internet/Network, Network Access.
• Defines rules for logical transmission of data.
• Main protocols: IP (IPv4, IPv6), ICMP, ARP.

UTP Cable

• Unshielded twisted pair cable; provides immunity to electrical noise and EMI.
• Maximum length: 100 meters.

HTTP

• Hypertext Transfer Protocol; allows communication over the internet using port 80.

NAT

• Network Address Translation; remaps IP address space, offers security by hiding internal network.

TCP and UDP

• TCP: Transmission Control Protocol; connection-oriented, reliable, error-free communication.
• UDP: User Datagram Protocol; low latency, loss-tolerating communication.

RIP

• Routing Information Protocol; dynamic routing protocol using hop count to find best path.

Firewall

• Network security system monitoring and controlling traffic based on predefined rules.

NOS

• Network Operating System; supports workstations, databases, PCs over a network.

Denial of Service (DoS)

• Attack preventing legitimate users from accessing network data; overloads server with requests.

ASCII

• American Standard Code for Information Interchange; character encoding standard for electronic communication.

IEEE

• Institute of Electrical and Electronics Engineers; world’s largest technical professional society.

MAC Address

• Media Access Control address; unique identifier assigned to network interfaces for communications within a network.

Piggybacking

• Delaying acknowledgment in two-way communication to attach it to the next outgoing data frame.

DNS

• Domain Name System; translates domain names to numerical IP addresses.

Domain vs. Workgroup

• Domains: Servers with centralized databases, can be on different LANs.
• Workgroups: Peers with individual databases, on the same LAN.

OSPF

• Open Shortest Path First; routing protocol finding best path for data packets.

Round-Trip Time (RTT)

• Time taken for a signal to be sent and acknowledgment received.

DHCP

• Dynamic Host Configuration Protocol; assigns IP addresses to network devices automatically.

ICMP

• Internet Control Message Protocol; supports IP by sending error messages.

Ping

• Tests reachability of a host on an IP network using ICMP.

Optic Fibers

• Advantages: Greater bandwidth, low power loss, immune to electromagnetic interference.

Client-Server Network

• Network where one computer (server) serves other computers (clients).

Antivirus Installation

• Best to install antivirus on all computers in a network.

Ethernet

• Network technology for LAN, MAN, WAN; uses cables for data transmission.

SLIP

• Serial Line Internet Protocol; allows internet access using a modem.

CSMA/CD vs. CSMA/CA

• CSMA/CD: Collision detected post-occurrence, used in wired networks.
• CSMA/CA: Collision avoidance pre-occurrence, used in wireless networks.

Tunnel Mode

• Used to encrypt whole IP packet; secure communications between gateways.

IPv6

• Internet Protocol version 6; provides unique IP addresses, resolves address shortage issue.

RSA Algorithm

• Cryptosystem for secure data transmission using public and private keys.

Encoder vs. Decoder

• Encoder: Converts data from one format to another, analog to digital.
• Decoder: Converts encoded data to actual format, digital to analog.

Sneaker Net

• Transfer of electronic information by physically moving media.

Protocol Components

• Syntax, semantics, and timing govern communication.

Conclusion

• Practice and review these concepts regularly.
• For doubts or queries, contact via the comment section.
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