Category
HTTP Strict Transport Security is a instruction from a website telling your browser to only ever connect to it over HTTPS — and to refuse to proceed if anything is wrong, without offering you a way
A certificate authority (CA) issues them, and what most certificates prove is narrower than people assume: control of the domain name, and nothing else. What a certificate contains. The domain name
A point of presence (PoP) is a physical location where a network has equipment that other networks or customers can connect to — the places where an abstract "network" actually touches the ground.
Successive specifications for twisted-pair Ethernet cable, differing in how well they resist interference — which is what determines the speed and distance they can support. What all of them share.
Power over Ethernet (PoE) delivers electrical power along the same cable that carries data, so a device needs only one connection rather than a network cable and a mains adapter. Why it is useful.
Continuously and invisibly — your phone is constantly measuring nearby cells and the network moves your connection between them, ideally without you noticing. What a cell actually is. A mast site is
The principle that networks should carry all traffic equally, without favouring or discriminating between sources, destinations or applications on commercial grounds. What it prohibits, specifically:
The final connection from a network's local distribution point to each individual building is disproportionately expensive, and that single fact shapes almost everything about broadband availability,
Cable broadband delivers internet over the coaxial television network, using a standard called DOCSIS — Data Over Cable Service Interface Specification — that defines how data shares that cable with
Fixed wireless access (FWA) delivers broadband to a building over a radio link rather than a wire — typically from a mobile network's 4G or 5G masts to a receiver in your home. Why it exists. Digging
Because latency over satellite is dominated by orbital altitude, and the difference between orbits is a factor of forty. Geostationary orbit (GEO), at roughly 35,786 km. A satellite there orbits at
Through submarine fibre optic cables lying on the seabed — not satellites, which carry a negligible share of intercontinental traffic despite what most people assume. The scale. Well over 95% of
Maximum transmission unit is the largest packet size a link will carry — and a mismatch produces one of the most confusing faults in networking: most things work, but some websites hang after loading
The path your packets take toward a destination, hop by hop — and it is genuinely useful for diagnosis, provided you know which parts of it to ignore. How it works — a clever trick. Every IP packet
Time to live is how long a DNS record may be cached before it must be looked up again — and it is the reason a change you made an hour ago is still not visible to everyone. Why caching exists.
Each record type answers a different question about a domain, which is why a single domain has many records and why editing the wrong one breaks something unrelated. A — maps a name to an IPv4
DNS over HTTPS (DoH) encrypts your DNS queries so that whoever carries your traffic cannot read which sites you are looking up. It closes a genuine privacy gap and shifts trust rather than
A virtual LAN splits one physical network into several logically separate ones, so devices on different VLANs cannot see each other even though they share the same switch and cabling. How it works.
A set of techniques for deciding which traffic gets priority when there is not enough capacity for everything — because the only time prioritisation matters is when a link is full. The problem. A
Because a video call does not need much bandwidth — it needs packets arriving consistently, and these two measures describe whether they do. Latency is how long a packet takes to travel, measured as
Layers of headers wrapped around your data, each added by a different part of the networking stack and each read by a different piece of equipment along the way. Why layers exist. Each layer solves
TCP guarantees delivery; UDP does not — and that single trade-off determines which one every internet application uses. TCP (Transmission Control Protocol). A connection-oriented, reliable protocol:
A physical location where many independent networks connect to one another directly, rather than sending traffic through a chain of intermediaries. The problem it solves. Without exchanges, two
Network Address Translation lets many devices share one public IP address, by rewriting addresses and ports as traffic passes through the router. Why it exists. IPv4 provides around 4.3 billion