Which network mask is the equivalent of 255.255.248.0?
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A. B. C. D.B
The network mask 255.255.248.0 is expressed in dotted decimal notation, which is a way of representing the binary values that define a network mask in a more readable format. In this notation, each octet of the mask represents 8 bits of the total 32 bits in the mask.
To convert the dotted decimal representation of the mask to its equivalent prefix length notation (also known as CIDR notation), we count the number of consecutive 1 bits in the binary representation of the mask. This count gives us the number of network bits in the mask, which we can then use to derive the prefix length.
To perform this conversion for the mask 255.255.248.0, we can convert each octet to binary notation and count the number of consecutive 1 bits:
255 = 11111111 255 = 11111111 248 = 11111000 0 = 00000000
When we count the number of consecutive 1 bits in these binary values, we find that there are 21 in total. This means that the mask has 21 network bits and 11 host bits. To express this in prefix length notation, we simply write the number of network bits after a forward slash (/) symbol. Therefore, the equivalent prefix length for the mask 255.255.248.0 is /21.
Therefore, the correct answer to the question is B. /21.