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network1.notebook
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May 03, 2018
May 28:54 PM
Computer Network Basics
Learning Goal: By the end of today I will be familiar with computer addresses and how information moves from one computer to another on a network.
May 29:43 PM
When two computers communicate using a local network or the Internet, communication happens at three levels.
1. hardware
2. operation system
3. application
The first step in communication is one computer must find the other computer.
The second step is both computers must agree on the methods and rules of communication called protocols. Then one computer takes on the role of making requests from the other computer.
The computer making a request is called the client and the one answering the request is the called the server.
network1.notebook
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May 03, 2018
May 29:48 PM
TCP/IP Transmission Control Protocol/Internet Protocol
Data is broken down into packets of information; the packets contain the data/payload, where it came from, and where it wants to go.
May 29:57 PM
1. Hardware Level
network card, or built in network device which has its own, unique, Media Access Control (MAC) address
every electronic device has a unique MAC address, including your phone
MAC address is written in Hexadecimal
iPhone settings, general, about WiFi address is your MAC address
Status Lights
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May 03, 2018
May 210:06 PM
2. Operating System Level
operating systems use IP (Internet protocol) addresses to find other computers on a network
an IP address can be 32 bit or 128 bit strings
MAC address is only used to find a computer on a local network, an IP address can be used to find a computer anywhere on the Internet
an IP address can be assigned either dynamically (can change depending on network traffic) or they can be assigned statically (same address all the time)
DHCP Dynamic Host Configuration Protocol is the tool that assigns IP addresses
May 210:11 PM
32 bit IP addresses Internet Protocol version 4 (IPv4)
32 bit IP addresses are 4 groups of 8 bit packages
the largest 8 bit number possible to create is 255
think binary 1111 1111 (255)
an IPv4 address looks something like this:
255 . 255 . 255 . 255
if each of the four blocks has 256 numbers available to it, that makes for almost 4.3 billion combination of addresses
256 x 256 x 256 x 256 = 4.3 billion
28 x 28 x 28 x 28 = 232
unfortunately, these address are all used up now, which lead to the creation of Internet Protocol version 6 (IPv6) which has more values
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May 03, 2018
May 210:17 PM
Classes of IP Addresses and Ownership
Class A 256 Network addresses 16.7 million hosts
Class B 65536 Network addresses 65536 hosts
Class C 16.7 million Network addresses 256 hosts
Big communication companies and countries own the Class A licenses
May 210:25 PM
128 bit IP Address (IPv6) are written as 8 blocks of hexadecimal (base 16) numbers separated by colons (8x16=128)
for example:
2001:0000:0B80:0012:0056:0D88:9BB4:00AF
2001
0010 0000 0000 000116 bit binary (8x2 bits)
Total number of possible combinations?
65536 x 65536 x 65536 x 65536 x 65536 x65536 x 65536 x 65536
or
216 x 216 x 216 x 216 x 216 x 216 x 216 x 216
= 2128 (try putting that number in your calculator)
= 340,282,366,920,938,463,463,374,607,431,768,211,456
The largest 16 bit number you can make is 65535 (1111 1111 1111 11112)
network1.notebook
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May 03, 2018
May 210:47 PM
On Windows computers we can access a lot of the network information via the following:
Run cmd ipconfig
May 29:48 PM
TCP/IP Transmission Control Protocol/Internet Protocol
Data is broken down into packets of information; the packets contain the data/payload, where it came from, and where it wants to go.
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May 03, 2018
May 210:52 PM
Important Ideas you should takeaway:
three stages of information sharing (hardware, OS, application)
IPv4 and IPv6 are addresses that contain the location of the computer on the Internet
MAC address is the physical address of the computer, it is unique to each device
