Computer Networks and Internet Concepts
Computer Networks and Internet Concepts
This domain tests network types, topologies, devices, protocols and web services. A network connects computers to share resources. LAN covers a small area, MAN a city, WAN a large geographic area; the Internet is a global network of networks. Topologies include bus, star, ring and mesh; star is common because one faulty link affects one node.
Devices and protocols
Hub broadcasts, switch forwards by MAC address, router forwards between networks by IP address, modem modulates and demodulates. Transmission media: twisted pair, coaxial, fibre-optic, radio. TCP/IP is the core protocol suite; HTTP and HTTPS transfer web pages, FTP files, SMTP sends mail, DNS resolves domain names to IP addresses. An IP address identifies an interface; a URL locates a resource.
Worked example
In https://www.example.com/page, https is the protocol, www.example.com is the domain name, and /page is the path. DNS resolves the domain to an IP address; the browser then sends an HTTPS request to the server, which returns the page. The s in HTTPS indicates TLS encryption, unlike plain HTTP.
Traps
A hub is not a switch. An IP address is not a MAC address. HTTP is not a mail protocol. A URL is not the same as a domain name. www is a host-name convention, not a required part of every URL. Do not confuse the Internet with the WWW.