Is 24 bit block a better addressing scheme in computer networking than a 16 bit block?

Answer 1

There is nothing inherently "better" about the 24-bit block address space. If by "better" you mean "able to contain more addresses," then yes. 24-, 20-, and 16-bit network ranges are also known as class A, B, and C, respectively, and refer to ranges of IP addresses. Every device that directly accesses the internet has a unique IP address. IP addresses are commonly represented as a set of four numbers (called "octets") separated by periods, e.g. "145.94.112.18". Each of the numbers can be in the range of 0-255, and some sets of numbers have special meanings. The range of IP addresses is divided up into three classes based on the first octet. If the first octet is from 0-127 it's class A, 128-191 is class B, and 192-223 is class C. The octets of an IP address are divided up into a network portion and a host portion depending on what class it is. In class A addresses, the first octet is the network portion and the remaining three are the host portion. For class B, it's two-and-two, and for class C the first three are network and the remaining one is host. What does this network/host division mean? Generally, large entities (such as a company) are assigned a single network block of IP addresses. For instance, IBM is in control of the 9.0.0.0 network block. This is a class A address, meaning that the network portion is 9 and the rest is the host portion. IBM can divide this space up (using a technique called subnetting) any way it sees fit. Every computer within IBM would have a different ip in the 9 network, e.g. 9.4.109.10, 9.212.34.88. A class A (or 24-bit) block address has three octets it can use to create different IP addresses, such as "9.0-255.0-255.0-255". A class C (or 16-bit) block address has only one octet it can use to create different IP addresses, such as "192.168.1.0-255". You can clearly see that a class C block address contains less potential addresses than a class A or B block address. This doesn't make class C addresses any worse than class A ones, though. A small business (or a home network) doesn't need a million different IP addresses, so a 16-bit block address is perfect for them and if they had a class A or B all those numbers would be wasted.