What is an IP Address?

What is an IP Address?

An IP address (Internet Protocol address) is a unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It serves two main purposes:

1. Identification: It identifies the host or network interface.

2. Location Addressing: It provides the location of the host in the network.

An IP address is written as a series of numbers separated by periods (for IPv4) or colons (for IPv6). For example:

• IPv4: 192.168.1.1

• IPv6: 2001:0db8:85a3:0000:0000:8a2e:0370:7334

Types of IP Addresses:

1. Public IP Address: Accessible over the internet, assigned by Internet Service Providers (ISPs).

2. Private IP Address: Used within private networks (e.g., homes or offices).

3. Static IP Address: Manually assigned and does not change.

4. Dynamic IP Address: Automatically assigned by a DHCP server and may change over time.

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Classes of IP Addresses

In IPv4, IP addresses are divided into five classes: A, B, C, D, and E. These classes determine the size of the network and the number of hosts it can support.

Class A

• Range: 1.0.0.0 to 126.255.255.255

• Default Subnet Mask: 255.0.0.0

• Number of Networks: 128 (2^7 - 2 for reserved addresses)

• Hosts per Network: ~16.7 million (2^24 - 2 for network and broadcast addresses)

• Purpose: Designed for large networks (e.g., multinational corporations).

Class B

• Range: 128.0.0.0 to 191.255.255.255

• Default Subnet Mask: 255.255.0.0

• Number of Networks: 16,384 (2^14)

• Hosts per Network: ~65,000 (2^16 - 2)

• Purpose: Suitable for medium-sized networks (e.g., universities).

Class C

• Range: 192.0.0.0 to 223.255.255.255

• Default Subnet Mask: 255.255.255.0

• Number of Networks: ~2 million (2^21)

• Hosts per Network: 254 (2^8 - 2)

• Purpose: Ideal for small networks (e.g., small businesses).

Class D

• Range: 224.0.0.0 to 239.255.255.255

• Purpose: Reserved for multicast groups. Used for sending data to multiple destinations simultaneously.

Class E

• Range: 240.0.0.0 to 255.255.255.255

• Purpose: Reserved for experimental purposes and future use. Not commonly used in standard networking.

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Key Concepts in IP Addressing

1. Subnetting: Dividing a network into smaller sub-networks to improve efficiency and security.

2. CIDR (Classless Inter-Domain Routing): Introduced to replace the class-based system, CIDR allows more flexible allocation of IP addresses.

3. IPv6: The successor to IPv4, offering a vastly larger address space and improved functionality, due to the exhaustion of IPv4 addresses.

Conclusion IP addresses are fundamental to network communication, acting as unique identifiers for devices and enabling efficient data routing. Understanding IP classes and their applications helps in designing and managing networks effectively.