CCNA IP Addressing

IP Addressing

An IP address is a unique identification number assigned to an IP network that indicates the location of the host in the network.

The main purpose of IP is to allow one network host to communicate with hosts in another network without having to control the type of host.

The IP address is 32 bits long and is divided into 4 bytes (8 bits per byte).

You can use three ways to express

1) Dotted decimal

2) Binary

3) Hex

Generally binary and hexadecimal are easy to identify and easy to use. But Hex will also be used.

The reason that the 1P address is a structured address and does not select a flat addressing scheme is.

1) The structural address advantage is that the total address is 2^32=4 294 967 296.

2) The determination of planar addressing scheme is related to routing selection.

IP is a structured address, and all are part of the network address, and part of it is the host address.

Network address

Network addresses uniquely identify the network, and each network has an equal network address. For example, 172.16.12.1, the network address is 172.16.

Host Address

Each machine in the network has a node address (host address), an IP address of the foreign network is the node address, each node address must be unique, because the host of a network is unique. For example 172.16.12.1, the network address is 172.16 and the host address is 12.1.

According to the network model, the Internet has designed five kinds of network models, such as Class A, Class B, Class C, Class D and E.

8-bit 8-bit 8-bit 8-bit

Class A network bit host bit host bit

Class B network bit network bit host bit host bits

Class C Network bit network bit network bit host bit

Class D for multicast

Class E for scientific research

Reserved IP Address

Network bits are all 0 current network segments

Network bits are all 1 of all network segments

Host bit is 0 any host in the network segment

Host bits are all 1 all hosts in the network segment

Both the network bit and the host bit are 0 default routes, which can replace any network

Both the network bit and the host bit are 1 broadcast addresses, representing all the hosts in the network

127.0.0.1 for loop-back testing

Class A address range

Format Network.node.node.node

The first bit of the network address must be 0

So the network address range is 00000000-01111111.

So the network address value is 0-127 (but 0 and 127 are not valid network addresses)

The host address has 3 bits, but it cannot be all set to 0 or 1. So each network segment can have 2^24-2 hosts.

Class B address range

Format Netwodrk.network.node.node

The first two bits in the network must be 10

So the network address range is 10000000-10111111.

So the network address value 128-191

A host that can exist in each network is 2^16-2

Class C address range

Format Network.network.network.node

The first bit of the network bit must be 110

Network value range is 192-223

Class D, Class E

224-239 for multicast

240-255 for scientific research

Private IP Address

Can be used for private networks, but not routable in the Internet.

Purpose: To solve the impending depletion of IP address resources, to help save valuable IP resources.

The reserved IP private address has

Address type reserved address space

Class A 10.0.0.0-10.255.255.255

Class B 172.16.0.0-172.31.255.255

Class C 192.168.0.0-192.168.255.255

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CCNA IP Addressing