Shulou(Shulou.com)06/01 Report--

Hello, everyone, today Xiaoxiao updates the network part.

It is no stranger to you to hear the IP address, but there must be a lot of friends who are just familiar with it. I don't know the relationship between them. Today, Xiaoxiao will discuss the relationship between them with you.

Three elements of communication between host and host:

-IP address (IP address)

-Subnet mask (subnet mask)

-IP routing (IP router)

I. introduction of IP address

1) what is the IP address?

An IP address is an Internet protocol address.

2) what is the purpose of the IP address?

The network address used to identify a node.

3) what are the characteristics of IP address?

To a certain extent, the identity that uniquely represents a device.

4) the composition of the IP address?

IP addresses are made up of 32-bit binary (4 dotted decimal)

5) Classification of IP addresses?

-Class A 1-127 (default subnet mask: 255.0.0.0)

-Class B 128-191 (default subnet mask: 255.255.0.0)

-Class C 192-223 (default subnet mask: 255.255.255.0)

-Class D 224-239 (Multicast address, no subnet mask)

-Class E 240-255 (reserved, scientific address, no subnet mask)

6) the total number of IP addresses

Is 2 to the 32: a total of 4294967296

Due to the development of the network, there are few IP addresses left, so the following solutions are given:

-appearance of subnet mask

-divide public IP and private IP

-develop IPv6

Introduction of subnet mask

1) what is the subnet mask?

Used to identify the network bits and host bits in the IP address.

2) the composition of the subnet mask?

The subnet mask is also made up of 32-bit binary (4 dotted decimal)

3) what are the characteristics of the subnet mask?

-the network bit is always in front of the subnet mask and is represented by 1; the host bit is always behind, represented by 0

-1 and 0 never intersect.

4) what is the role of the subnet mask?

The subnet mask is actually designed to split the network, thereby reducing the waste of IP addresses.

It makes no sense for IP addresses to appear alone, so IP addresses and subnet masks must appear in pairs.

III. Subnetting

1) what is the range of private addresses?

-Class A 10.0.0.1-10.255.255.254

-Class B 172.16.0.1-172.31.255.254

-Class C 192.168.0.1-192.168.255.254

2) the role of public and private addresses?

The role of the public address: the public address can also be called the public network address, through which he can directly access the Internet, he is within the scope of the wide area network.

-the role of private addresses: private addresses can also be called private network addresses, which are specially used within the organization. They are within the scope of the local area network, and the Internet cannot be accessed outside the local area network.

3) Special IP address:

-Network address-the host bits are all 0; it represents a range

-broadcast address-the host bits are all 1; it represents all hosts in a network segment

-each network segment will have these two special addresses.

4) examples of subnetting:

Take 200.78.35.2 / 22 as an example

1. Write down the network address and broadcast address to which the IP address belongs

200.78.0010 0011. 0000 0010 / 22

-Network address: 200.78.32.0 / 22

-broadcast address: 200.78.35.255 / 22

2. Subnetting the network segment in which the address is located requires:

Divided into 4 network segments

42 hosts per network segment

Minimize the waste of IP addresses in each network segment

Write down the IP address range for each network segment

Train of thought:

First of all, determine which parts are immutable (a given network bit cannot be changed)

Secondly, the number of host bits of the new network segment is determined based on the number of hosts in each network segment.

Once the number of host bits is determined, the subnet mask of the new network segment is determined.

Finally, the network bits of the new network segment are determined based on the new mask, so that multiple different network segments can be changed except those bits that are not allowed to change.

New network segment 1: host bit nong6, so the network bit is 32-6 = 26

Number of host IP: 2 to the nth power-2 > = 42

200.78.32.0 / 22

200.78.0010 0000.0000 0000 / 26

New network segment 1: 200.78.32.0Universe 26

200.78.32.63/26

200.78.0010 0000.0100 0000 / 26

New network segment 2: 200.78.32.64Universe 26

200.78.32.127/26

200.78.0010 0000.1000 0000 / 26

New network segment 3: 200.78.32.128Universe 26

200.78.32.191/26

200.78.0010 0000.1100 0000 / 26

New network segment 4: 200.78.32.192 Comp26

200.78.32.255/26

For convenience, the last two paragraphs are replaced with binary.

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