Classful Addressing (Part 3) | Summary and Q&A

TL;DR

Learn how subnet masks determine if devices belong to the same network and how they enable or restrict communication between them.

Key Insights

• 🤔 The subnet mask is essential for determining whether devices belong to the same network or different networks based on the IP address.
• 🔍 There are five classes of IPv4 addresses (A, B, C, D, and E), but the focus is on classes A, B, and C.
• ✏️ Default subnet masks for Class A, B, and C are 255.0.0.0, 255.255.0.0, and 255.255.255.0 respectively.
• 🔐 Subnet masks do not contain network or host portions of an IP address but guide where to locate these portions in the IP address.
• 🌐 Devices with IP addresses starting with the same octets can belong to the same network, determined by the subnet mask provided.
• 📶 Switches can facilitate communication between devices belonging to the same network.
• 🔁 Router is required for communication between devices belonging to different networks.
• ❌ The homework question asks to identify an invalid subnet mask from the given options.

Transcript

we will now see the part three of class full addressing what we are going to learn in today's lecture upon the completion of this session the learner will be able to identify whether the nodes belonging to same network or different network with examples we are going to take some examples and we are going to understand whether the ip addresses belon... Read More

Questions & Answers

Q: What is the role of a subnet mask in determining network communication?

A subnet mask accompanies an IP address and helps identify the network and host portions of the address. It does not contain this information by itself, but when combined with the IP address, it determines which part is the network and which part is the host.

Q: Can devices with different IP addresses belong to the same network?

Whether devices with different IP addresses can belong to the same network depends on the subnet mask. If the first few octets of the IP addresses match according to the subnet mask rules, they belong to the same network and can communicate without a router.

Q: What is the default subnet mask for a class A IP address?

The default subnet mask for a class A IP address is 255.0.0.0, which means that only the first octet needs to match for devices to belong to the same network.

Q: Can a class C subnet mask be used for class A IP addresses?

Yes, a class C subnet mask can be used for class A IP addresses. While it is not common, it is technically possible. However, a class A subnet mask cannot be used for class C IP addresses.

Q: How does a subnet mask determine if two devices can communicate with each other?

The subnet mask checks if the octets of the IP addresses match according to its rules. If the necessary octets match, the devices belong to the same network and can communicate without a router. If the necessary octets do not match, a router is required for communication.

Q: What happens if the subnet mask is 255.255.255.0 for two IP addresses starting with 10.10.10 and 10.10.20?

The subnet mask indicates that the first three octets should match. Since the second and third octets do not match, the devices do not belong to the same network and cannot communicate with each other without a router.

Answer:

Summary & Key Takeaways

• Subnet masks are used to define the network and host portions of an IP address.

• Each IP address class (A, B, and C) has its own default subnet mask.

• Subnet masks determine if devices belong to the same network and if they can communicate with each other without the need for a router.