CIDR
Classless inter-domain routing
Problem Statement
Classless inter domain routing is one of the concept of IPV4. We know in IPV4 our internet address is been created with the four segments separated by "." like 100.1.2.122. To make internet working this address has to be unique on the internet so that one system can identify and communicate with other. With the evolution of the internet it became difficult to manage the all Ips and provide the unique ips to all machine, which forces concept of subnet cto evolve.
With the Subnet, a computer address has to be unique in the subnet, and then subnet address has to be unique over the network. Its like your IP of the computer has to be unique across your router and then your router IP has to be unique across your ISP, then your ISP might be having a fixed IP.
Hence here is an requirement to specify the address of the computers over the network because these systems talk to each other over the network. To communicate every system has to have a unique ip in a network hence if two of the local compute want to transfer data then both check ip address and see if network network address for both are same or not.
Example if Address are like
192.168.0.1 and 192.168.0.2 and 192.168. is the network address then both belongs to same subnet.
Now there are only three ways to create a network name it will be
*.*.*
*.*
*
where * represents any number from 1-255 and network can have three choices of system under a subnet.
2 *8 = 256
(2*8)*8 = 66536
But lets say we want a number in between then we need to put a cross in between like
11111111.11111111.1111 | 1111.11111111
---------------------------- ----------------
Network address address of systems
we have cut it at 20th place hence bits till 20th place are the network address and last 12 bits are network address, This is been done in the notation of CIDR which tells, how many bits are used for the network like a.b.c.d/24 mean initial 24 bits are been used for the network and rest are free.
Example
if we say 192.160.0.0/24 is the notation been given then
11001000.10100000.00000000.00000000
------------------------------------ ------------
Nw Add System
11001000.10100000.00000000.00000001
------------------------------------ ------------
Nw Add System
Both of the systems are belongs to same network.
Another example
a.b.c.d./22
10100000.10110000.000000|00.00000001 = 160.176.0.1
10100000.10110000.000000|11.10110001 = 160.176.2.177
Both of the above belongs to same subnet.
we have to give this notation in cloud environments to declare how may instances are going to be created under a subnet also this is pretty useful to understand with the cidr notation if two machines are local or remote to each other.
References
https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing
With the Subnet, a computer address has to be unique in the subnet, and then subnet address has to be unique over the network. Its like your IP of the computer has to be unique across your router and then your router IP has to be unique across your ISP, then your ISP might be having a fixed IP.
Hence here is an requirement to specify the address of the computers over the network because these systems talk to each other over the network. To communicate every system has to have a unique ip in a network hence if two of the local compute want to transfer data then both check ip address and see if network network address for both are same or not.
Example if Address are like
192.168.0.1 and 192.168.0.2 and 192.168. is the network address then both belongs to same subnet.
Now there are only three ways to create a network name it will be
*.*.*
*.*
*
where * represents any number from 1-255 and network can have three choices of system under a subnet.
2 *8 = 256
(2*8)*8 = 66536
((2*8)*8)*8 = 16777216
But lets say we want a number in between then we need to put a cross in between like
11111111.11111111.1111 | 1111.11111111
---------------------------- ----------------
Network address address of systems
we have cut it at 20th place hence bits till 20th place are the network address and last 12 bits are network address, This is been done in the notation of CIDR which tells, how many bits are used for the network like a.b.c.d/24 mean initial 24 bits are been used for the network and rest are free.
Example
if we say 192.160.0.0/24 is the notation been given then
11001000.10100000.00000000.00000000
------------------------------------ ------------
Nw Add System
11001000.10100000.00000000.00000001
------------------------------------ ------------
Nw Add System
Both of the systems are belongs to same network.
Another example
a.b.c.d./22
10100000.10110000.000000|00.00000001 = 160.176.0.1
10100000.10110000.000000|11.10110001 = 160.176.2.177
Both of the above belongs to same subnet.
we have to give this notation in cloud environments to declare how may instances are going to be created under a subnet also this is pretty useful to understand with the cidr notation if two machines are local or remote to each other.
References
https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing
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