IPv4 subnetting

What do you know about IPv4?

     Having a 32 bit address
     Format (ddd.ddd.ddd.ddd)
     Divided into classes A, B, C, D, E
     IP Reserved

     # 10.0.0.0 - 10,255,255,255 - reserved for local intranet networks
     # 127.0.0.0 - 127 255 255 255 - reserved for local loop on each computer
     # 172.16.0.0 - 172.31.255.255 - reserved for local intranet networks
     # 192.168.0.0 - 192 168 255 255 - reserved for local intranet networks
     # 224.0.0.0 - 239 255 255 255 - used for multicast routing

An easy way to do subnetting are:

Subnetting is used to subdivide the IP group into smaller groups so as to facilitate the management and Setting routing.


example

ip subnet zero=default

class C

IP: 192.168.1.111 SUBNET: 255.255.255.128 (/25)

then:

255 255 255 128 converted in binary 11111111.11111111.11111111.10000000(/25)

1. ip range normal for this class there are 256 ie 0-255 so (max range - the 4th octet of the subnet) = 256-128 = 128 is 192.168.1.0 - 192.168.1.127

2. 2 rank in the last octet binary number. 2 rank 7 = 128



So obtained is

1. Range = IP subnet 1: 192.168.1.0 - 192.168.1.127 subnet 2: 192.168.1.128 - 192.168.1.255

2. Number of subnets = 2 rank number 1 in the binary number 2 rank last octet = 1: 2

2. Host IP = Range - 2 (ip network and broadcast): 126

3. Network = subnet 1: 192.168.1.0 subnet 2:192.168.1.128

4. Broadcast = subnet 1: 192.168.1.127 subnet 2: 192.168.1.255

5. IP 192.168.1.111 is on subnet 1


class B

There is a network address 172.16.0.0/18

172.16.0.0/28 found on the class B subnet mask / 18 means 11111111.11111111.11000000.00000000 (255.255.192.0).

calculation

Number of Subnet = 2 to the power x, where x is the number of binary number 1 on the last 2 octets. So the number of subnet mask is 2 to the power 2 = 4 subnets
 
The number of hosts per subnet = 2 to the power y-2, where y is the inverse of x is the large number of binary 0 in the last octet of the subnet mask 2. So the hosts 214-2 = 16.382
 
Block Subnet = 256-192 = 64, the next subnet is 64 + 64 = 128, and 128 +64 = 192. So the full subnet is 0, 64, 128, 192.

Subnet	172.16.0.0	172.16.64.0	172.16.128.0	172.16.192.0
Host Pertama	172.16.0.1	172.16.64.1	172.16.128.1	172.16.192.1
Host Terakhir	172.16.63.254	172.16.127.254	172.16.191.254	172.16.255.254
Broadcast	172.16.63.255	172.16.127.255	172.16.191.255	172.16..255.255

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