Introduction to IP Addresses

You might be hearing a lot about IP addresses, but what exactly is it?

  Every machine on the internet has a unique number which identifies it (IP address), example could be: 216.27.61.137.  There are two sections to an IP address; the first section contains the identification numbers of the network that the computer belongs to, and the second portion of the address identifies the actual computer.  This design of IP addresses is called IPv4 because it contains 4 sets of numbers which can range from 1 to 255 and are 32-bit numbers.

To make IP addresses easier to remember and comprehend, IP addresses are usually expressed in decimal number format (ie. 216.27.61.137), but computers communicate in the binary numbering system (ie 1010111000).  An example is the same IP address as in the example above in binary format: 11011000.00011011.00111101.10001001.

The numbers in an IP address are called ‘octets’, because they each have 8 positions in the binary numbering system. If they are all added together, you get 32, hence they are called 32-bit numbers.  Go ahead, count them in the example above, once they are all added up the total value equals to 32. These octets are used to serve as classes of IP addresses, which we will discuss in just a minute!

IP addresses can either be static or dynamic.  Static addresses never change; they are permanent allowing remote computers to connect to you.

Dynamic IP addresses are temporary and are assigned each time the computer or device accesses the internet; they are borrowed from a pool of addresses, so each time your computer will connect to the internet, the first available IP address will be assigned to your machine for the time you are connected to the internet.

IPv4 addresses are broken down into several classes, A to E!

Class A: A 0.0.0.0 to 126.255.255.255

Class B: 128.0.0.0 to 191.255.255.255

Class C: 192.0.0.0 to 223.255.255.255

Class D: 224.0.0.0 to 239.255.255.255

Class E: 240.0.0.0 to 247.255.255.255

So your next question probably is; what the heck does all this mean?  I’ll explain, let’s start off with Class A first. 

In the class A addressing scheme, the first octet, (each set of numbers in the address are called octets) ranging from 1 - 126, describes the network you're sending a packet to. The rest of the octets describe the node. (ie. kind of like a City, and a Mailbox)

In a Class B address, the first two octets represent the network and the last two describe the node.  An example of an organization that would use Class B addresses could be a large college campus

Class C addresses start with 192, go up to 223, and the first three octets describe the network and the last octet describes the node.

Class C networks are usually given to small ISP's and organizations that only have a few nodes on their network. Big companies like Microsoft or Apple, and the government organizations are given Class A addresses because they're bound to have lots of nodes.

Class D addresses are for multicasting

Class E addresses are reserved for future use.

With all these IP classes there are a total of 4.3 billion possible combinations of IP addresses in the IPv4 addressing scheme.

The internet’s operations go in such a manner that data is transferred in small packets that are routed independently across networks by a communications protocol called internet protocol (IP).  IPv4 has been used as the foundation for most internet communications, but since the growth of the internet, more addresses are required which IPv4 cannot acquire, thus IPv6 allows a much greater combination for numerical addresses.

In next week’s blog we will continue this topic and explain how IPv6 addressing works!

See you then!