It- cyber security questions (300 word response)

Explain the Internet Protocol (IP) in detail. If necessary, include a diagram or an example in your posting/answer (a picture or an example is worth a thousand words!)  Your answer/posting should answer one or more questions below:

– What is an IP address? Why is an IP address important? Can you convert a 8 bit binary number to a decimal number (or a decimal number to a 8 bit binary number)? Does an IP address consist of four octets (or how many bits in an IP address?)? Is 123.234.23.256 a valid IP address? Can you convert an IP address in decimal form to one in binary format? Explain how. Any example? 

– What is a classful IP address? Classful vs Classless IP address (what is the difference?). 

– What is a subnet mask? Why do we need a subnet mask? If an IP address alone good enough? What is a (default) subnet mask of a class A (or B and C) IP address? If an IP address is classful, do we really need a subnet mask information? For example, 221.123.12.7 is a class A IP address? What is the (default) subnet mask of 221.123.12.7? 

– An IP address is called hierarchical as it is made up of two parts: a network portion and a host portion. What are a network portion and a host portion of an IP address? To answer this question, you should understand the job of a subnet mask.  

– Explain private IP addresses vs public IP addresses. What is the difference? Why do we need a private IP address?

– What is an IP header? In the IP header, there are many different IP header fields. What do you think the most important fields are in the IP header? 

– Explain a OSI model. In the OSI model, Is IP a layer 3 (or a network layer) protocol ? Is a router a layer 3 device (or why explain why a router is called a layer 3 device)

Do NOT discuss the followings:

-IP version 6 

– IP subnetting or VLSM (Variable Length Subnetting Mask)