About this video

• Video Title: Subnetting using VLSM IP Version 4 Complete Example Packet Tracer
• Channel: Zeyad Ali
• Speakers: Zeyad Ali
• Duration: 13:27

Overview

This video provides a comprehensive, step-by-step guide to subnetting using Variable Length Subnet Masking (VLSM) for IP Version 4. It demonstrates how to divide a given IP address range into smaller subnets to accommodate various network requirements, including Local Area Networks (LANs) and Wide Area Networks (WANs), using Cisco Packet Tracer for a practical example. The tutorial covers the calculation of subnets, subnet masks, and the assignment of IP addresses to routers and hosts, culminating in the configuration of network devices within the simulated environment.

Key takeaways

• VLSM Application: The video demonstrates how to apply VLSM to efficiently allocate IP address space across a network with varying host requirements.
• Subnet Calculation: It details the process of calculating the necessary bits for host requirements and determining the appropriate subnet mask for each network segment.
• IP Addressing Scheme: The tutorial outlines a systematic approach to assigning network addresses, usable host addresses, and broadcast addresses for each subnet.
• Router and Host Configuration: The video provides a practical walkthrough of configuring router interfaces and host devices with their respective IP addresses and default gateways.
• WAN Link Configuration: It explains the specific subnetting requirements for WAN links (serial connections), typically using /30 subnets.
• Switch Management IP: The process of assigning management IP addresses and default gateways to switches for network access is also covered.

The video explains that for WAN links, a /30 subnet mask is used, which provides four IP addresses: one for the network, one for the broadcast, and two for the interfaces on either side of the WAN link. The previous subnet ended at address 239, meaning the next available network address is 240. From this 240 network address, the usable IP addresses are 241 and 242. The next network address would then be 244, which is used for the second WAN link.

In the context of the second WAN link discussed in the video, the network address is 192.168.1.240 with a /30 subnet mask. This means the addresses available in this subnet are:

• 192.168.1.240: Network Address
• 192.168.1.241: First Usable IP Address (assigned to one router interface)
• 192.168.1.242: Second Usable IP Address (assigned to the other router interface)
• 192.168.1.243: Broadcast Address

The video then moves on to the next network segment for the other WAN link. After the 192.168.1.243 broadcast address, the next network address begins at 192.168.1.244. This 192.168.1.244 address is the network address for the second WAN link, which also uses a /30 subnet mask. Therefore, the usable IP addresses for this second WAN link would be 192.168.1.245 and 192.168.1.246.

You are absolutely correct. With a /30 subnet mask for the 192.168.1.244 network:

• 192.168.1.244 is the Network Address.
• 192.168.1.245 is the first usable IP address.
• 192.168.1.246 is the second usable IP address.
• 192.168.1.247 is the Broadcast Address.

So, 192.168.1.247 would indeed be the broadcast address for the network starting at 192.168.1.244 with a /30 subnet mask.