Networking Basics
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IP Address is a unique id given to a device in a network
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IP Address enables data communication b/w hosts
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We have two IP Addressing formats
- IPv4
- IPv6
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IPv4 Addresses:
- consists of 32 bits divided into 4 sections called as octects
- Each octet contains 8 bits (1 byte) separate by a dot
- Sample IPv4 Addresses
192.168.0.198
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IP Address is combination of
- network id
- host id
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It is not possible to tell what is network id or what is host id just by ip address, we need a subnet mask for that.
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Example of using sm to calculate size of the network
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if we continue with subnet mask as decimal number we have 3 possible sizes for host id
- one octet => 2^8-2 => 254 devices
- two octets => 2^16-2 => 65534 devices
- three octets => 2^24-2 => 16777214 devices
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Lets assume you are trying to create a network with 500 devices
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To assign an IP Address range to your network there are two popular addressing schemes
- Classful Addressing
- Classless Addressing
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Classful Addressing:
- This was introduced in 1981 where IPv4 Addresses were divided into 5 classes (A to E)
- This was introduced in 1981 where IPv4 Addresses were divided into 5 classes (A to E)
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Classless Interdomain routing (CIDR) was introduced in 1993 to replace classfull addressing. It uses Variable length subnet masks
CIDR
- In classfull addressing we have looked at subnet mask as a decimal number so we had 3 possibilities
- 255.255.255.0 => one octet (n/w size)
- 255.255.0.0 => two octets (n/w size)
- 255.0.0.0 => three octets (n/w size)
- In this approach we look at subnet mask as a binary number
