Addressing and Subnet Formats:

Imagine your home address as a public IP address. It's unique and identifies your location for anyone who has it. In contrast, a private IP address is like an apartment number within your building. It identifies a specific device on your home network, but isn't visible from the outside world.

Here's a breakdown of the key differences between private and public IP addresses:

• **Scope:** Public IP addresses are **globally unique** and accessible from the entire internet. Private IP addresses are for internal network use only and are not routable on the public internet.
• **Assignment:** Public IP addresses are assigned by your Internet Service Provider (ISP) to your network router. Private IP addresses are assigned by your network router to devices connected to it.
• **Cost:** Public IP addresses might be associated with a fee from your ISP, especially for static IPs (unchanging addresses). Private IP addresses are free to use within your network.
• **Security:** Public IP addresses are directly exposed to the internet, making them more vulnerable. Private IP addresses offer an extra layer of security as they are not directly reachable from the public internet.

Here's a table summarizing the key points:

| Feature | Public IP Address | Private IP Address | |----------------|---------------------------------|------------------------------------| | Scope | Globally routable | Internal network only | | Assignment | By ISP | By network router | | Cost | May be associated with a fee | Free | | Security | More vulnerable | More secure |

Common private IP address ranges include 192.168.0.0/16, 172.16.0.0/12, and 10.0.0.0/8. You can find your device's private IP address through network settings or by using command prompts like "ipconfig" (Windows) or "ifconfig" (Mac).

To access the internet, devices on your network use the public IP address assigned to your router. The router acts as a translator, converting private IP addresses of your devices to the public IP for communication and then routing the received data back to the correct device using its private IP.

Subnetting is a technique used to divide a large network into smaller logical subnetworks. It allows for more efficient use of IP addresses, improved network security, and better network performance. Here's a breakdown of the key concepts and calculations involved in subnetting:

Concepts:

• IP Address: A unique identifier assigned to devices on a network. (e.g., 192.168.1.1)
• Subnet Mask: Defines the network and host portions of an IP address. (e.g., 255.255.255.0)
• Network Address: The address of the entire subnet, identifying the network itself. (e.g., 192.168.1.0)
• Broadcast Address: The last address in the subnet, used for network broadcasts but not assignable to any device. (e.g., 192.168.1.255)
• Usable Host Range: The range of IP addresses within a subnet that can be assigned to devices (excluding the network and broadcast addresses). (e.g., 192.168.1.1 - 192.168.1.254)

Calculations:

Subnetting concepts and calculations

Subnetting involves calculating the following:

1. Number of Subnets: Determine how many subnets you need to create from the original network. This depends on the number of devices you need to accommodate in each subnet.
2. Subnet Mask: By borrowing bits from the host portion of the IP address and assigning them to the subnet portion, you define the subnet mask. There are online subnet calculators and formulas to help with this calculation.
3. Network Address and Broadcast Address: Using the subnet mask and the original network address, you can calculate the network address and broadcast address for each subnet.

Here are some resources to help you visualize and practice subnetting calculations:

• Subnet Calculator: https://www.calculator.net/ip-subnet-calculator.html
• Video Tutorial: https://www.youtube.com/watch?v=oZGZRtaGyG8

Benefits of Subnetting:

• Efficient IP Address Allocation: Allows you to create subnets with the appropriate size for your needs, preventing wasted IP addresses.
• Improved Network Security: Isolates subnets, limiting the impact of security breaches to a single subnet.
• Better Network Performance: Reduces network congestion by limiting broadcast traffic within each subnet.

By understanding subnetting concepts and calculations, you can effectively manage IP addresses, enhance network security, and optimize network performance for your specific needs.

Subnetting is a technique used to divide a large network into smaller logical subnetworks. It allows for more efficient use of IP addresses, improved network security, and better network performance. Here's a breakdown of the key concepts and calculations involved in subnetting:

Concepts:

• IP Address: A unique identifier assigned to devices on a network. (e.g., 192.168.1.1)
• Subnet Mask: Defines the network and host portions of an IP address. (e.g., 255.255.255.0)
• Network Address: The address of the entire subnet, identifying the network itself. (e.g., 192.168.1.0)
• Broadcast Address: The last address in the subnet, used for network broadcasts but not assignable to any device. (e.g., 192.168.1.255)
• Usable Host Range: The range of IP addresses within a subnet that can be assigned to devices (excluding the network and broadcast addresses). (e.g., 192.168.1.1 - 192.168.1.254)

Calculations:

Subnetting involves calculating the following:

1. Number of Subnets: Determine how many subnets you need to create from the original network. This depends on the number of devices you need to accommodate in each subnet.
2. Subnet Mask: By borrowing bits from the host portion of the IP address and assigning them to the subnet portion, you define the subnet mask. There are online subnet calculators and formulas to help with this calculation.
3. Network Address and Broadcast Address: Using the subnet mask and the original network address, you can calculate the network address and broadcast address for each subnet.

Here are some resources to help you visualize and practice subnetting calculations:

• Subnet Calculator: https://www.calculator.net/ip-subnet-calculator.html
• Video Tutorial: https://www.youtube.com/watch?v=oZGZRtaGyG8

Benefits of Subnetting:

• Efficient IP Address Allocation: Allows you to create subnets with the appropriate size for your needs, preventing wasted IP addresses.
• Improved Network Security: Isolates subnets, limiting the impact of security breaches to a single subnet.
• Better Network Performance: Reduces network congestion by limiting broadcast traffic within each subnet.

By understanding subnetting concepts and calculations, you can effectively manage IP addresses, enhance network security, and optimize network performance for your specific needs.

VLSM, which stands for Variable Length Subnet Mask, is an advanced subnetting technique that allows you to create subnets with different subnet masks within the same network. This provides greater flexibility and efficiency in IP address allocation compared to traditional fixed-length subnet masks.

Here's how VLSM works:

• Traditional Subnetting: In a typical subnetting scenario, a single subnet mask is applied to the entire network. This might lead to wasted IP addresses if some subnets require fewer devices than others.
• VLSM Approach: With VLSM, you can divide the original network into subnets with varying sizes. Each subnet gets its own subnet mask, customized to accommodate the specific number of devices it needs to support.

Benefits of VLSM:

• Efficient IP Address Utilization: VLSM minimizes wasted IP addresses by creating subnets that precisely match the device requirements.
• Improved Network Design: Allows for a more scalable and adaptable network structure that can accommodate future growth.
• Enhanced Network Security: By isolating subnets with different security needs, VLSM can improve overall network security.

Implementing VLSM

Implementing VLSM involves several steps:

1. Network Requirements Analysis: Determine the number of devices and desired IP address allocation for each subnet within the network.
2. Subnet Mask Calculation: Using the device count and the concept of usable IP addresses per subnet mask, calculate the appropriate subnet mask for each subnet. Here, online subnet calculators or reference tables can be helpful.
3. Subnet Creation: Divide the original network into subnets based on the calculated subnet masks. This defines the network address, broadcast address, and usable host range for each subnet.

Example:

Imagine you have a network with a /24 subnet mask (192.168.1.0/24) and need to create subnets for two departments:

• Department A: 20 devices
• Department B: 60 devices

Using a traditional subnet mask wouldn't be ideal. Instead, with VLSM, you could create:

• Subnet 1 for Department A: /27 subnet mask (usable devices: 30)
• Subnet 2 for Department B: /26 subnet mask (usable devices: 62)

This way, you efficiently utilize IP addresses while providing each department with the necessary allocation.

In summary, VLSM offers a powerful and flexible approach to network design, enabling optimal IP address allocation, improved scalability, and enhanced network security. While it requires more planning and calculation compared to traditional subnetting, the benefits can be significant for complex network environments.

Classless Inter-Domain Routing (CIDR) notation

CIDR, which stands for Classless Inter-Domain Routing, is a notation system used to express both an IP address and its subnet mask in a single, compact format. It eliminates the need for separate subnet masks, simplifying IP address management and routing.

Traditional Subnetting vs. CIDR Notation

Before CIDR, IP addresses were classified into classes (A, B, and C) based on the leading octets (groups of 8 bits) in the address. Each class had a predefined subnet mask. However, this system became inefficient as the internet grew and the demand for IP addresses increased.

CIDR introduced a more flexible approach:

• Subnet Mask Removed: CIDR notation removes the need for a separate subnet mask. Instead, it incorporates the subnet mask information directly into the IP address itself.
• Slash Notation: A forward slash (/) followed by a number is appended to the IP address. This number represents the number of contiguous leading 1's in the subnet mask. For example, 192.168.1.0/24 signifies an IP address with a /24 subnet mask (255.255.255.0 in binary).

Here's a table summarizing the differences:

Feature	Traditional Subnetting	CIDR Notation
Subnet Mask	Separate entity	Integrated
Notation	IP address + Subnet Mask	IP address / Prefix Length
Example	192.168.1.0 (255.255.255.0)	192.168.1.0/24

Benefits of CIDR Notation

CIDR notation offers several advantages:

• Efficiency: Simplifies IP address management by combining address and subnet mask information.
• Flexibility: Enables the creation of subnets with varying sizes, optimizing IP address allocation.
• Scalability: Supports the creation of hierarchical routing structures for large networks.
• Standardization: Provides a universal way to represent IP addresses and subnets.

Understanding CIDR Notation

Here are some key points to remember about CIDR notation:

• The higher the prefix length (/ value), the more bits are dedicated to the network portion, resulting in smaller subnets with fewer usable IP addresses.
• Conversely, a lower prefix length creates larger subnets with more usable IP addresses.
• CIDR calculators are available online to help you convert between IP addresses and subnet masks in CIDR notation.

By understanding CIDR notation, you can effectively manage IP addresses in modern network environments, ensuring efficient allocation and optimal routing.

Next: Endpoints and Media Types