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.