CCNA/CCNP preparation notes

by Andreas Ryf
OSI reference model
IP Network Classes
Summary
Subnetting
Cables & fibres
Terms
Links
BCMSN
ONT

Class A:

First Bit must be 0

0XXXXXXX.XXXXXXXX.XXXXXXXX.XXXXXXXX

Network.Host.Host.Host

0 - 127 theoretical

1 - 126 useable

 

- Private address space: 10.x.x.x  (0000'1010.XXXXXXXX.XXXXXXXX.XXXXXXXX)

- Invalid addresses: 127.x.x.x (0111'1111.XXXXXXXX.XXXXXXXX.XXXXXXXX) (diagnostics)

 

7 bits for network address, 128 minus 2 = 126 networks

16'777'214 hosts

 

CIDR notation: 110.213.45.80/8

 

 

Class B:

First Bits must be 10

10XXXXXX.XXXXXXXX.XXXXXXXX.XXXXXXXX

Network.Network.Host.Host

128.0 - 191.255

 

- Private address space: 172.16.x.x  (1010'1100.XXXXXXXX.XXXXXXXX.XXXXXXXX)

 

14 bits for network address = 16'384 networks

65'534 hosts

 

CIDR notation: 134.88.213.4/16

 

Class C:

First Bits must be 110

110XXXXX.XXXXXXXX.XXXXXXXX.XXXXXXXX

Network.Network.Network.Host

192 - 223

 

- Private address space: 192.168.x.x  (1100'0000.1010.1XXXXXXX.XXXXXXXX)

 

21 bits for network address = 2'097'152 networks

254 hosts

 

CIDR notation: 212.75.3.12/24

 


 

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