Star, mesh and bus topologies, the internet, DNS, hosting and the cloud, and the IP and MAC addresses that identify devices.
What you will learn
- Compare star, mesh and bus topologies
- Count the links in each
- Explain how DNS turns a name into an IP address
- Recognise IPv4, IPv6 and MAC addresses
Star, mesh and bus
- Star: every device has its own cable to a central switch. One broken cable affects one device; a failed switch stops everything. n devices need n cables.
- Mesh: devices are linked to several others, so data can take another route if a link fails. A full mesh links every device to every other: n devices need n(n - 1) รท 2 links, which gets expensive fast. The internet is a partial mesh of routers.
- Bus: every device has a short drop cable to one shared main cable, the backbone, with a terminator at each end to absorb the signal. It is cheap (little cable, no switch), but all data shares one cable, so collisions grow as traffic grows, and a break in the backbone stops the whole network.
The rest of this lesson and its 9 practice questions are locked.
In this lesson
- Star, mesh and bus
- The internet, DNS and the cloud
- Addresses
- Try it: Count the links
9 practice questions, marked as you go; about 25 minutes in all.
Key terms
Full, Backbone, Terminator, Internet, World Wide Web, URL, Domain name, DNS, Web hosting
In this unit: Networks and protocols
LANs, WANs and PANs, network hardware, star, mesh and bus topologies, the internet and DNS, IP and MAC addresses, protocols and layers, network security, and transfer time calculations.
- Networks and network hardware
- Topologies and the internet
- Protocols, layers and packets
- Network calculations
- Extended answers