TCP/IP protocol detailed Volume 1 chapter II Internet address structure

INTERNET Address Structure

Each device connected to the Internet must have at least one IP address. The IP address is also required for devices that are used in a private network based on the TCP/IP protocol.

Represents the IP address IPV4 address:

32bit
The points are divided into four groups or dotted decimal notation. such as 165.195.130.105

IPV6 Address:

128bit
Represented by four 16-bit binary numbers for a block or field. For example5f05:2000:80ad:5800:0058:0800:2023:1d71

The presentation has the following consensus:

1. Block leading 0 must be omitted, as the above address can be written as5f05:2000:80ad:5800:58:800:2023:1d71
   
2. All zeros can be :: omitted, but in order to avoid ambiguity, it can be used only once and is used where the length of the omitted block is the longest (when more than one block has the same length, omitting the higher bits). For example, 2001：0：0：0：2：0：0：1 you can write2001::2:0:0:1

Basic IP Address Structure

IP addresses can be grouped by type and size, and those used to identify network interfaces that are connected to the Internet or some private intranet are called unicast addresses . There are also broadcast, multicast, and anycast addresses. However, IPV6 does not have an anycast address.

Categorical addressing

The IPV4 address space is initially divided into five major classes as shown in

The A,b,c class is used for unicast addresses, and D is for multicast and e-address retention.

Its address space is zoned as shown

It is easy to see that a, Class B network number wastes too many host numbers , and Class C does not provide enough host numbers for many sites. Just like some classrooms in school, some classrooms are small. When the academic office assigns the classroom according to the above method, there will be some classrooms with only a few seats being used, while some classrooms have many people without seats . So someone might have suggested building a bigger classroom, so there's a IPv6. There have also been proposals for more optimal distribution, which we will talk about later.

Subnet addressing

The idea of subnet addressing is to assign the network number of the A,b,c class to the site, leaving some remaining host numbers for the site to allocate itself. This approach allows site administrators to compromise on the number of subnets and the number of hosts expected for each subnet, reducing coordination with other sites.

It's like the school does not assign classrooms to each class, but instead throws the task to the college to deal with. The flexible compromise of the college was a slight solution to this vexed question.

So what is subnet addressing? How does it work?

One hours a day to write a blog is the time to review the end of it!

TCP/IP protocol detailed Volume 1 chapter II Internet address structure