Network Layer (Internet Layer)
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Just like houses need street addresses in order to have letters and packages delivered, electronic devices that are attached to the Internet need addresses in order to send/receive information. The Internet Protocol (IP) is primarily focused on providing exactly this functionality. When you connect to the Internet, your device is given an IP address that allows you to access the Internet and its various resources.
There are 2 versions of the Internet Protocol: IPv4 and IPv6. IPv4 uses 4 numbers, each in the range of 0-255, all separated by full stops. Examples of IPv4 addresses are:
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Header added by IP Protocol (Credit: APNIC blog)
Make up of an IPv4 address (Credit: Zenarmor)
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Addresses as numbers
When the Internet was initially created it was never anticipated to become as popular and as widely used as it is. IPv4 addresses having [0-255]:[0-255]:[0-255]:[0-255] means that we have 8 bits for each number which would look like 11000011.00110011.10101010.00001111 .... with this many binary digits we can make 2 to the power of 32 addresses: 4,294,967,296 - nearly 4.3 billion addresses. Clearly this is a large number, however, with the population of Earth being somewhere around 8 billion, if everyone had a cell phone this would not even be enough to provide an address for every phone.
To account for this we have done a few things:
1) Creation of IPv6
As covered above, this uses 32 hexadecimal characters meaning that we can make 16^32 combinations: 3.4 x 10^38.
For comparison, there are approximately the number of grains of sand on Earth's beaches is approximately 7.5 x 10^18. IPv6 has ≈ 4.53 x 10^19 more addresses than there is sand... so... a little bit more. With that in mind, even thinking conservatively, it's pretty much inconceivable that we could ever use up all of these.
2) NAT - Network Address Translation
Put simply, this involves putting local IP addresses behind a global IP address. For example, Freyberg High School is given a global IP address by our ISP, the school's router then gives out its own local IP addresses to the devices that connect to it: computers, phones, etc. Using Network Address Translation (or natting) allows us to extend the use of IPv4 addresses as we can use many, many devices operating underneath a single IPv4 address.
Please go through these pages at Khan Academy and make notes:
Khan Academy - IP addresses
Khan Academy - IP address hierarchy
Tasks:
1) What is the primary purpose of the Internet Protocol (IP)?
2) Explain the difference between IPv4 and IPv6 addresses in terms of format. Provide examples of both.
3) How many unique IPv4 addresses are possible, and why is this number considered limited?
4) Think of another analogy to help someone understand the vast number of IPv6 addresses compared to IPv4.
5) What is Network Address Translation (NAT), and how does it help extend the use of IPv4 addresses?
6) Explain the difference between a local IP address and a global IP address. How are they related?
7) Do you think that IPv6 addresses will ever run out? Why or why not?
When the Internet was initially created it was never anticipated to become as popular and as widely used as it is. IPv4 addresses having [0-255]:[0-255]:[0-255]:[0-255] means that we have 8 bits for each number which would look like 11000011.00110011.10101010.00001111 .... with this many binary digits we can make 2 to the power of 32 addresses: 4,294,967,296 - nearly 4.3 billion addresses. Clearly this is a large number, however, with the population of Earth being somewhere around 8 billion, if everyone had a cell phone this would not even be enough to provide an address for every phone.
To account for this we have done a few things:
- Created IPv6
- Invention of NAT
1) Creation of IPv6
As covered above, this uses 32 hexadecimal characters meaning that we can make 16^32 combinations: 3.4 x 10^38.
For comparison, there are approximately the number of grains of sand on Earth's beaches is approximately 7.5 x 10^18. IPv6 has ≈ 4.53 x 10^19 more addresses than there is sand... so... a little bit more. With that in mind, even thinking conservatively, it's pretty much inconceivable that we could ever use up all of these.
2) NAT - Network Address Translation
Put simply, this involves putting local IP addresses behind a global IP address. For example, Freyberg High School is given a global IP address by our ISP, the school's router then gives out its own local IP addresses to the devices that connect to it: computers, phones, etc. Using Network Address Translation (or natting) allows us to extend the use of IPv4 addresses as we can use many, many devices operating underneath a single IPv4 address.
Please go through these pages at Khan Academy and make notes:
Khan Academy - IP addresses
Khan Academy - IP address hierarchy
Tasks:
1) What is the primary purpose of the Internet Protocol (IP)?
2) Explain the difference between IPv4 and IPv6 addresses in terms of format. Provide examples of both.
3) How many unique IPv4 addresses are possible, and why is this number considered limited?
4) Think of another analogy to help someone understand the vast number of IPv6 addresses compared to IPv4.
5) What is Network Address Translation (NAT), and how does it help extend the use of IPv4 addresses?
6) Explain the difference between a local IP address and a global IP address. How are they related?
7) Do you think that IPv6 addresses will ever run out? Why or why not?
