Determining the Network ID for a Given IP Address and Subnet Mask

Understanding how to determine the network ID for an IP address and subnet mask is crucial for any network administrator or student of network theory. This process is commonly referred to as subnetting. Given an IP address of 172.16.1.154 and a subnet mask of 255.255.254.0, we can derive the network ID. This guide will walk you through the steps involved.

Step-by-Step Process

Understanding the Subnet Mask

The subnet mask 255.255.254.0 is written in decimal notation. Let’s first convert this subnet mask to binary for clarity:

255.255.254.0 (decimal) 11111111.11111111.11111110.00000000 (binary)

Applying the Subnet Mask

The process involves using the subnet mask to identify which bits belong to the network and which belong to the host. Here’s a detailed breakdown:

First Octet: The first (8) bits (11111111) is all 1s, indicating the entire first octet is part of the network. Second Octet: The second (8) bits (11111111) is all 1s, indicating the entire second octet is part of the network. Third Octet: The third (8) bits (11111110) is all ones except for the last bit, which is 0, indicating that the first two bits of the third octet are part of the network. Fourth Octet: The last (8) bits (00000000) is all 0s, indicating the entire fourth octet is part of the host address.

Calculating the Network ID

To calculate the network ID, we perform a bitwise AND operation between the IP address and the subnet mask. This operation is also known as masking. Here’s how it works with our specific IP and subnet mask:

172.16.1.154 (decimal) 10101100.00010000.0000001.10011010 (binary)

255.255.254.0 (decimal) 11111111.11111111.11111110.00000000 (binary)

Performing the bitwise AND operation:

10101100.00010000.00000010.10011010 (172.16.1.154)
AND
11111111.11111111.11111110.00000000 (255.255.254.0)
-----------------------------------------
10101100.00010000.00000010.00000000 (172.16.0.0)

The result of this operation is the network ID, 172.16.0.0.

Conclusion

By understanding how to perform subnetting, network administrators can effectively manage the IP addressing within a network. The process of converting the given IP and subnet mask to binary and then performing the bitwise AND operation helps in identifying the network ID, which is a vital step in both theoretical and practical network scenarios.

Additional Information

Keyword Research

IP address subnet mask network ID subnetting IP subnetting

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