A computer network is a system of interconnected devices, such as computers, servers, smartphones, and printers, that communicate to exchange data. They communicate using wired or wireless connections and can range from small home networks to the global Internet.
- Resource Sharing: Allows sharing of hardware like printers, scanners, and storage devices, reducing cost.
- Data Sharing: Enables users to share files, applications, and databases easily.
- Communication: Supports email, video conferencing, instant messaging, and web access.
- Data Management: Helps in storing, securing, and backing up data efficiently.
- Remote Access: Allows users to access systems and cloud services from anywhere.
- Better Collaboration: Improves teamwork and information exchange among users.
Fundamentals of Computer Networks
Computer networking starts with these fundamental concepts. It explains what a computer network is, its benefits, key characteristics, and the essential hardware components involved.
Network Models
Computer networks rely on these foundational frameworks to standardize communication. It explains the layered structures of the OSI and TCP/IP models and highlights how they organize network functions for efficient data flow.
Physical Layer
Network communication rests on these physical foundations. It explains network topologies, transmission media, and data transmission modes.
Data Link Layer
Data link layer is all about how data is reliably transferred between directly connected devices and handles data framing, error detection and correction, flow control, and switching techniques.
- Data Link Layer
- Switching Techniques
- Virtual LAN
- Link Aggregation
- Framing
- Error Detection
- Error Correction
- Error Control
- Flow Control
- Stop and wait ARQ
- Sliding Window Protocol- Go Back N
- Sliding Window Protocol- Selective Repeat
- Piggybacking
Network Layer
Logical addressing and routing of data packets are explained, including IP addressing, IPv4 vs IPv6, and public and private addresses.
- Network Layer
- Classful Network Addressing
- Classless Network Addressing
- IPv4 Header Format
- IPv4 vs IPv6
- Private vs Public IP addresses
Subnetting
Covers IP address management using subnetting and VLSM to divide large networks into smaller, manageable subnets and calculate address ranges.
- Subnetting basics
- Subnet masks
- Calculate network, broadcast and host addresses
- Variable Length Subnet Masking (VLSM)
- Advanced VLSM
- Supernetting
Routing
This subsection explains how data is routed across networks, covering static vs. dynamic routing, routing algorithms, and Network Address Translation (NAT).
- What is Routing?
- Static vs Dynamic Routing
- Link State Routing
- Distance Vector Routing
- Network Address Translation(NAT)
Network Layer Protocols
Covers key Network Layer protocols such as ARP for device discovery, ICMP for error reporting, DHCP for automatic IP assignment, and dynamic routing protocols like RIP, OSPF, and BGP.
- Address Resolution Protocol(ARP)
- Reverse Address Resolution Protocol(RARP)
- Dynamic Host Configuration Protocol(DHCP)
- Internet Control Message Protocol(ICMP)
- Internet Group Management Protocol(IGMP)
- Routing Information Protocol(RIP)
- Open Shortest Path First(OSPF)
- Intermediate System to Intermediate System(IS-IS)
- Enhanced Interior Gateway Routing Protocol(EIGRP)
- Border Gateway Protocol(BGP)
- Multiprotocol Label Switching(MPLS)
- Internet Protocol(IP)
- Generic Routing Encapsulation(GRE)
Transport Layer
Explains how applications communicate reliably using TCP and UDP, including connection setup, flow control, error checking, and congestion management.
- Transport Layer
- TCP Protocol
- TCP 3-Way Handshake Process
- Services and Segment structure in TCP
- TCP Connection Establishment
- TCP Termination
- Congestion Control in TCP
- UDP Protocol
- TCP vs UDP Protocol
- Stream Control Transmission Protocol(SCTP)
- Datagram Congestion Control Protocol(DCCP)
- Reliable User Datagram Protocol(RUDP)
- Quick UDP Internet Connections(QUIC)
Session Layer
Session management and communication control are discussed through the Session Layer, including protocols such as RPC and PPTP.
Presentation Layer
Data formatting and security functions are provided by the Presentation Layer, along with protocols such as AFP, NCP, SSL, and MIME.
- Presentation Layer
- Services Provided by Presentation Layer
- Application Filing Protocol(AFP)
- NetWare Core Protocol (NCP)
- Secure Socket Layer (SSL)
- Remote Procedure Call(RPC)
- Point-to-Point Tunneling Protocol(PPTP)
- Multipurpose Internet Mail Extensions(MIME)
Application Layer
The Application Layer interfaces with end-users, covering client-server models and core internet services like the web and email.
Application Layer Protocols
Key application protocols such as DNS, HTTP/HTTPS, SMTP, POP3, IMAP, and FTP are discussed in the context of everyday network applications.
- Domain Name System (DNS)
- File Transfer Protocol (FTP)
- Simple Mail Transfer Protocol (SMTP)
- Simple Network Management Protocol (SNMP)
- HyperText Transfer Protocol(HTTP)
- HyperText Transfer Protocol Secure(HTTPS)
- Post Office Protocol v3(POP3)
- Internet Message Access Protocol(IMAP)
- Lightweight Directory Access Protocol(LDAP)
- Network Time Protocol(NTP)
- Trivial File Transfer Protocol(TFTP)
- Network News Transfer Protocol(NNTP)
- Message Queuing Telemetry Transport(MQTT)
- Session Initiation Protocol(SIP)
- Server Message Block(SMB)
Network Performance and Quality
Network performance and quality are discussed, including congestion control, QoS for multimedia, and traffic-shaping techniques such as token and leaky bucket.
Network Security
Essential network security concepts such as authentication, encryption, firewalls, IDS/IPS, and VPN are discussed.
- AuthenÂticÂation
- Encryption
- Firewalls
- MAC Address Filtering
- Intrusion Detection System
- Intrusion Prevention System
- VPN
Wireless and Special Networks
Wireless communication includes technologies like Wi-Fi, Bluetooth, Zigbee, and mobile cellular networks.
Modern Networking Concepts
Cloud networking concepts are discussed, including service models, VPN-based secure access, NFV, and emerging technologies such as 5G and network slicing.
- Software Defined Networking (SDN)
- Network Function Virtualization (NFV)
- Types of Cloud Services
- IoT Networking
- Network Slicing in 5G
Quickly review our Last Minute Notes on Computer Networks and test your knowledge with our practice quiz.