IP address classes and Subnet mask
An IP address is a unique identifier or numeric label used to identify devices connected to the network. This helps to develop a virtual connection between source and destination for packet communication in networking.
As we develop the network, we consider the scale, the number of devices connected to the network, and other requirements.
That IP address space is divided into 5 classes and then we can get a better idea of the range we need to use when we need to build a network.
- Class A
- Class B
- Class C
- Class D
- Class E
Important
- Dividing IP address space (2 * 32 no. of IP addresses) into 5 classes is called Classful addressing. In this concept, the number of hosts for each class is fixed.
- We use the concept of Classless Inter-Domain Routing (CIDR) concept because of the limitations of classful addressing.
Before short note
IP classes are identified by the 1st octet of the IP address (left most from all).
Each class has a fixed bit or bits.
Changing the remaining bits creates a specific class of IP addresses.
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| IP Classes |
Parts of the IP address
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| Network Part and Host Part - IP classes |
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Subnet mask - Short note
- Called Subent Mask or Network Mask.
- Helps to identify the network part and the host part in IP.
- Subnet mask can be written using dotted decimal notation.
- Class A, B, and C have default mask/ natural mask.
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| Subnet Mask - Class A, B, C |
Resources.
IP address - Definition and Details (no date). Available at: https://www.paessler.com/support/it-knowledge/it-explained/ip-address .
IP Addressing and Subnetting for New Users (no date) Cisco. Available at: https://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13788-3.html.
IP Address Classes Explained with Examples (no date) ComputerNetworkingNotes. Available at: https://www.computernetworkingnotes.com/ip-tutorials/ip-address-classes-explained-with-examples.html.
IP Address Classes (no date). Available at: https://www.guru99.com/ip-address-classes.html#1.
‘Introduction of Classful IP Addressing’ (2015) GeeksforGeeks, 8 July. Available at: https://www.geeksforgeeks.org/introduction-of-classful-ip-addressing/




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