The Internet
The internet is the physical network connecting “everything” (sort of) into one network. It consists of routers, servers, wiring and fiber-optics:
The World Wide Web is the collection of websites (and other services) that run on top of the internet.
Internet Tiers
Layers 1 and 2: Underlying Connections to the Internet
Dial-up (POTS, PSTN) using a modem (uses PPP)
ISDN using 2 B channels and 1 D channel
DSL – symmetric vs asymmetric, ATM vs Ethernet (uses PPPoA or PPPoE) –> max 18,000 feet from nearest CO
T1 – this is 24 telephone lines in a bundle. (24 Bearer channels)
Cable (uses DOCSIS)
Optic (FTTN, FTTP)
WiFi (it’s wireless, but it’s not really called “wireless”)
Line-of-Sight Wireless
Cellular (correctly called “wireless”)
-Tethering
-Mobile hotspot
Satellite
Connecting Private Networks to Public Networks
NAT (network address translation)
Virtualization
The A+ doesn’t require a deep knowledge of virtualization, but you should know the following, at least:
- What a VMM is
- What a hypervisor is
- Type 1 hypervisors
- Type 2 hypervisors
We’ll be using virtual machines (VMs) in this class, on the open-source VirtualBox platform. Here’s what you need to do, assuming you’re on Windows:
- Download and install 7zip so you can handle .7z files. As with all software, download it from the source, not from a mass download site.
https://www.7-zip.org/download.html - Download and install Oracle VirtualBox. Select the version for “Windows Hosts”, of course.
https://www.virtualbox.org/wiki/Downloads - Go to a site you’ll learn to love, OSBoxes:
https://www.osboxes.org/
Click on “VM Images”, then select “VirtualBox Images”.
Download Ubuntu: plain, vanilla Ubuntu, not “Ubuntu MATE” or anything else. Just Ubuntu. - Now watch this video, and do as the narrator does, EXCEPT:
–>**Put your virtual machines, each in a separate folder, in C:\Users\Public\VirtualBoxVMs **<– Notice there are no spaces!!! No spaces!!! No spaces!!!
Type 1 Hypervisors, Type 2 Hypervisors, Docker Containers, Emulators like QEMU, etc.
Textbook Time
Chapters 21 an 22