Exercício Exemplo.

Dada a rede:

146.164.0.0/16 (classe b)
255.255.0.0 (mascara padrão classe b)

Preciso de 1800 hosts

[1] Qual numero sendo 2^X preciso para 1800 host ?

2^11=2048 logo dá para 1800

bits na classe B
11111111 11111111 00000000 00000000

[2] Quantos bits preciso roubar dos hosts  para não desperdiçar IPs?

11 bits, logo preciso 3+8 (em vermelho) deixando 5 (em azul) para sub rede. Logo roubo 5 bits (azul sublinhado) que eram de host para serem sub-rede.

11111111 11111111 11111000 00000000

logo fica 255.255.248.0 ou /21 (bits de rede)

[3] Quantas sub net poderei ter ?

Como tenho 5 bits pra usar como subnets (em azul sublinhado) terei  32 ou seja 2^5=32

[4] Quais os  ranges de sub redes que poderei dividir ?

Sabendo que cada rede tem 2048 hosts ocupando 11 bits (2^11) ou seja 3 no terceiro + 8 no quarto e ultimo octeto +. Somando 8.0 (2^3) de rede em rede.

 

Subrede

Hosts válidos

Broadcast

01

146.164.0.0

146.164.0.1 to 146.164.7.254

146.164.7.255

02

146.164.8.0    

146.164.8.1 to 146.164.15.254

146.164.15.255

03

146.164.16.0

146.164.16.1 to 146.164.23.254

146.164.23.255

04

146.164.24.0

146.164.24.1 to 146.164.31.254

146.164.31.255

05

146.164.32.0

146.164.32.1 to 146.164.39.254

146.164.39.255

06

146.164.40.0

146.164.40.1 to 146.164.47.254

146.164.47.255

07

146.164.48.0

146.164.48.1 to 146.164.55.254

146.164.55.255

08

146.164.56.0

146.164.56.1 to 146.164.63.254

146.164.63.255

09

146.164.64.0

146.164.64.1 to 146.164.71.254

146.164.71.255

10

146.164.72.0

146.164.72.1 to 146.164.79.254

146.164.79.255

11

146.164.80.0

146.164.80.1 to 146.164.87.254

146.164.87.255

12

146.164.88.0   

146.164.88.1 to 146.164.95.254   

146.164.95.255 

13

146.164.96.0

146.164.96.1 to 146.164.103.254

146.164.103.255

14

146.164.104.0

146.164.104.1 to 146.164.111.254

146.164.111.255

15

146.164.112.0

146.164.112.1 to 146.164.119.254

146.164.119.255

16

146.164.120.0

146.164.120.1 to 146.164.127.254

146.164.127.255

17

146.164.128.0

146.164.128.1 to 146.164.135.254

146.164.135.255

18

146.164.136.0

146.164.136.1 to 146.164.143.254

146.164.143.255

19

146.164.144.0

146.164.144.1 to 146.164.151.254

146.164.151.255

20

146.164.152.0

146.164.152.1 to 146.164.159.254

146.164.159.255

21

146.164.160.0

146.164.160.1 to 146.164.167.254

146.164.167.255

22

146.164.168.0

146.164.168.1 to 146.164.175.254

146.164.175.255

23

146.164.176.0

146.164.176.1 to 146.164.183.254

146.164.183.255

24

146.164.184.0

146.164.184.1 to 146.164.191.254

146.164.191.255

25

146.164.192.0

146.164.192.1 to 146.164.199.254

146.164.199.255

26

146.164.200.0

146.164.192.1 to 146.164.207.254

146.164.207.255

27

146.164.208.0

146.164.192.1 to 146.164.215.254

146.164.215.255

28

146.164.216.0

146.164.192.1 to 146.164.223.254

146.164.223.255

29

146.164.224.0

146.164.192.1 to 146.164.231.254

146.164.231.255

30

146.164.232.0

146.164.192.1 to 146.164.239.254

146.164.239.255

31

146.164.240.0

146.164.192.1 to 146.164.247.254

146.164.247.255

32

146.164.248.0

146.164.192.1 to 146.164.255.254

146.164.255.255