Mobile Development Architecture

The OSI model is a seven-layer reference framework that separates networking into physical transmission, link, network, transport, session, presentation and application concerns, used to reason about where a problem sits rather than to describe any real protocol stack.

IP addressing is the scheme that gives every interface on a network a numeric address, with IPv4's four-byte addresses now supplemented by IPv6's much larger space, and with private ranges reserved for use inside networks that reach the internet through translation.

Subnetting divides an address block into smaller networks by choosing how many leading bits identify the network, written as a prefix length or a subnet mask, so that each subnet has its own range of host addresses and its own routing entry.

DNS is the distributed lookup system that turns a hostname such as getting-digital.net into the IP address a browser can connect to, by walking a chain of nameservers whose answers are then cached for a lifetime the domain's owner publishes.

SSL/TLS is the protocol that encrypts the connection between a browser and a server and, by way of a certificate signed by a certificate authority, proves the server is entitled to answer for the domain in the address bar.

A domain name is an address in the internet's public namespace that you rent through a registrar for a yearly fee, and it remains yours only while the registrar account holding it stays paid up and under your own control.