Use the code to calculate the length of the network prefix corresponding to the subnet mask: the length of the network prefix corresponding to the subnet mask 255.224.0.0 is ( )

Use the code to calculate the length of the network prefix corresponding to the subnet mask: the length of the network prefix corresponding to the subnet mask 255.224.0.0 is ( )

Subject :

(Single-choice question) The length of the network prefix corresponding to the subnet mask 255.224.0.0 is ( )

A. 8
B. 11
C. 12
D. 10

To determine the network prefix length corresponding to the subnet mask 255.224.0.0, we need to convert it into binary form first, and then count the number of consecutive 1s in it. These 1s make up the network ID portion of the IP address. The answer is a continuous 1-bit number, that is, option B, 11 bits.

demo code

The Python code is given below to demonstrate how to calculate:

import ipaddress

subnet_mask = '255.224.0.0'

# 将子网掩码转换为IPv4Interface对象
subnet_obj = ipaddress.IPv4Interface(subnet_mask)

# 将子网掩码转换为字符串并按点切割，以便进行二进制转换
subnet_str = str(subnet_obj.network_address).split('.')

binary_str = ''

# 分别将每个十进制数转换成8位的二进制数
for octet in subnet_str:
    binary_str += format(int(octet), '08b')

# 计算连续1的比特数, 这就是网络前缀长度
prefix_len = len(binary_str.split('0')[0])

print("The network prefix length for subnet mask", subnet_mask, "is", prefix_len)

After executing the above code, it will output the following:

The network prefix length for subnet mask 255.224.0.0 is 11

Therefore, the answer is option B, that is, the network prefix length corresponding to the subnet mask is 11.