01 / NETWORKING
Ethernet
Ethernet is a family of wired networking technologies defined primarily by IEEE 802.3 and forms the foundation of most modern local-area networks. Ethernet operates at the physical and data-link layers, defining how devices transmit frames across a shared or switched medium. Modern Ethernet networks typically use switches and full-duplex links, with MAC addresses identifying network interfaces at Layer 2. Technologies such as VLANs, link aggregation and various physical media extend Ethernet for enterprise, data-centre and high-performance environments.
02 / NETWORKING
ARP
ARP (Address Resolution Protocol) is used to map IP addresses to MAC addresses on a local network. When a device needs to communicate with another device on the same network segment, it uses ARP to discover the destination's MAC address.
03 / NETWORKING
IPv4
IPv4 is the fourth version of the Internet Protocol and uses 32-bit addresses, providing approximately 4.3 billion possible address values. Addresses are divided into network and host portions using subnet masks or CIDR prefixes, allowing networks to be subdivided into smaller routing domains. IPv4 relies on mechanisms such as ARP for local address resolution and commonly uses NAT to allow private address spaces to communicate through shared public addresses. Despite its age and address limitations, IPv4 remains extensively deployed across the Internet and private networks.
04 / NETWORKING
IPv6
IPv6 was developed to address the limitations of IPv4, most notably its limited address space. It uses 128-bit addresses, providing an extremely large number of unique addresses and enabling hierarchical network allocation. IPv6 replaces ARP with Neighbor Discovery Protocol (NDP), uses ICMPv6 for essential control functions and supports mechanisms such as Stateless Address Autoconfiguration (SLAAC). IPv6 also simplifies certain aspects of routing and eliminates the architectural requirement for NAT between hosts and the public Internet.
05 / NETWORKING
TCP
Transmission Control Protocol (TCP) provides reliable, ordered and connection-oriented delivery of data between network applications. A TCP connection is established through a three-way handshake and uses sequence numbers, acknowledgements, retransmission and flow control to ensure that data arrives correctly. TCP also implements congestion-control algorithms that adapt transmission rates according to network conditions. It is widely used by protocols such as HTTP, HTTPS, SSH, SMTP and many database and application services.
06 / NETWORKING
UDP
User Datagram Protocol (UDP) provides a lightweight, connectionless transport mechanism without TCP's built-in reliability, ordering or congestion-control semantics. Applications send independent datagrams containing source and destination ports along with their payload, and delivery is not guaranteed. This reduced overhead makes UDP useful where low latency or application-controlled reliability is more important than guaranteed delivery. Common uses include DNS queries, DHCP, streaming, VoIP and protocols such as QUIC that implement advanced transport behaviour above UDP.
07 / NETWORKING
DNS
The Domain Name System (DNS) translates human-readable names such as example.com into IP addresses and provides a distributed database for Internet naming and service discovery. DNS uses a hierarchical structure involving root servers, top-level domains and authoritative name servers, with recursive resolvers performing queries on behalf of clients. Records such as A, AAAA, CNAME, MX, NS, TXT and SRV provide different types of information. DNS caching and TTL values reduce query traffic while improving response times.
08 / NETWORKING
DHCP
Dynamic Host Configuration Protocol (DHCP) automatically provides network configuration to clients, including IP addresses, subnet masks, default gateways and DNS servers. In a typical IPv4 exchange, a client broadcasts a DHCP Discover message, receives an Offer, sends a Request and receives an acknowledgement containing its lease. DHCP allows administrators to centrally manage address allocation and configuration while preventing many manual configuration errors. IPv6 uses DHCPv6 alongside mechanisms such as Router Advertisements and SLAAC, with the exact division of configuration responsibilities depending on the network design.