Subnetting - papersocean

Computer Networks:

Physical Layers

Data link Layer(DLL)

Network Layer

Transport Layer:

Session and Presentation Layer:

Application Layer:

Network Layer

Subnetting:

Subnetting is the process of Breaking Down of an IP Network into smaller sub-network called as subnets.

Each Subnet is a non physical description (or ID) for a physical sub-network (usually as switch network of host containing a single router in a multi router network).

the IP address is 32 bit long one part of address indicates network ID and other part indicate The Host on the network host ID..

Masking:

Masking is the process that extract the address of the physical network from an IP address masking can be done weather we have Subnetting or not if we have not subnet the network masking Express the sub network address from an IP address.

Purpose of subnetting:

For a larger organization the maintenance would be hard to maintain so we divide the IP address into subnet to make it easier to maintain.
improve speed,
The receipt IP address is added to the Subnet Mask to get the destination of the message.

Example of Subnetting:

Suppose we have and Class C IP address i.e 200.20.10.0
In this IP address we have 0 to 255,

Total IP Address would be 256 but IP which we can use only 254 IP addresses.

200.20.10.0 would be network ID (1sr IP)
200.20.10.255 would be broadcasting ID. (Last IP)

Let suppose we have to two department (A, B), we perform a submitting on this IP 200.20.10.0

200.20.10._ _ _ _ _ _ _ _
For two Department (A,B) as we have only two department so we need only one bit to represent to department that is the first bit.

The first department (B) represent with 200.20.10.0 _ _ _ _ _ _ _

One the first IP would be 200.20.10.000000000 (200.20.10.0)
And the last IP would be 200.20.10.01111111 (200.20.10.127)

ranges: 0-127
Usable IP = 128-2=126
network ID (Subnet ID):200.20.10.0.0
Broadcast Address :200.20.10.127

And the second department (A) represent with 200.20.10.1_ _ _ _ _ _ _

The first IP would be 200.20.10.100000000 (200.20.10.128)
The last IP would be 200. 20.10.11111111 (200.20.10.255)

ranges: 128-255
Usable IP = 128-2=126

network ID (Subnet ID):200.20.10.128
Broadcast Address:200.20.10.255

The outer router: Class C mask is 255.255.255. 0
But as we divide subnet the IP address into 2. We need the Subnet Mask.
To find the subnet mass.

Check the number of bit we reserved.
In this case as we have only two department A and B so reserve bit is one.

10000000

And the decimal of they bIt is 128
So the subnet mass is 255.255.255.128.

whenever a message is received by the outer router it simply forward to the internal router where the subnet Mask have done.