Lec-43: Class C in IP addressing with Example | Classful Addressing | Network Layer

Summary

This video provides a comprehensive explanation of Class C in IPv4 addressing. It covers key concepts such as the range of Class C IP addresses (192 to 223), how to identify a Class C address by examining the first octet, and the number of networks and hosts possible within Class C. The video explains that Class C offers 2^21 networks, each with 254 usable hosts out of 256 possible IP addresses. It also illustrates how subnetting works with examples, highlighting the importance of network and broadcast addresses. This is essential knowledge for anyone working with IP addressing.

Takeaways

• 😀 Class C IP addresses belong to the range 192 to 223 in IPv4 addressing.
• 😀 Class C is part of Classful addressing, which divides IP addresses into five classes: A, B, C, D, and E.
• 😀 IPv4 addresses are 32 bits long and are represented in four octets, typically shown in dotted decimal notation.
• 😀 The first octet in Class C addresses begins with the fixed binary value '110'.
• 😀 The range of IP addresses in Class C is from 192.0.0.0 to 223.255.255.255.
• 😀 Class C supports 2^29 total IP addresses, which is approximately 12.5% of all IPv4 addresses.
• 😀 The number of possible networks in Class C is 2^21, roughly 20 million networks.
• 😀 Each Class C network can support 256 IP addresses, but only 254 are usable by hosts.
• 😀 The first and last IP addresses in any Class C network are reserved for the network address and the broadcast address.
• 😀 The subnet mask for Class C addresses is 255.255.255.0, indicating that the first 24 bits are for the network, and the last 8 bits are for hosts.
• 😀 In Class C addressing, you cannot change the first three bits of the first octet (fixed as '110').

Q & A

What is the range of Class C IP addresses?

Class C IP addresses range from 192.0.0.0 to 223.255.255.255, based on the first octet of the address.

How can you determine if an IP address belongs to Class C?

To determine if an IP address belongs to Class C, check the first octet. If the first octet is between 192 and 223, the IP address is a Class C address.

How many total IP addresses are there in Class C?

Class C has 2^29 possible IP addresses, which is approximately 12.5% of the total available IP addresses in IPv4.

How many networks are possible in Class C?

There are 2^21 possible networks in Class C, which equals approximately 20 million networks.

What is the subnet mask for Class C?

The subnet mask for Class C is 255.255.255.0, which reserves the first three octets for the network and the last octet for hosts.

How many hosts can be assigned in a Class C network?

A Class C network can support up to 256 hosts. However, the first and last IP addresses are reserved (Network ID and Broadcast Address), so there are 254 usable IP addresses for hosts.

Why are the first and last addresses in a Class C network reserved?

The first address is reserved as the Network ID, which identifies the network, while the last address is reserved for the Broadcast Address, used for sending messages to all hosts in the network.

How do you calculate the Network ID from an IP address in Class C?

To calculate the Network ID, perform a bitwise AND operation between the IP address and the subnet mask. For Class C, the subnet mask is 255.255.255.0.

What does the value '2^21' represent in the context of Class C?

The value '2^21' represents the total number of possible networks in Class C, which is approximately 20 million networks.

How many usable IP addresses are there in a Class C network?

In a Class C network, there are 254 usable IP addresses for hosts, as the first and last addresses are reserved.