What is the dotted decimal equivalent of a /31 prefix length?

To determine the dotted decimal equivalent of a /31 prefix length, it is essential to understand what the prefix length represents. A /31 subnet mask indicates that 31 bits are used for the network portion of the address, leaving only 1 bit for the host portion.

In binary notation, a /31 subnet mask would look like this:

11111111.11111111.11111111.11111110

This translates to the last octet being 254 in decimal form, represented in dotted decimal as 255.255.255.254.

Using a /31 subnet typically allows for the creation of two IP addresses, which can be used for point-to-point links. In this kind of setup, both addresses can effectively be used by devices, as there are no host addresses that fall under the same subnet requirements.

This is why 255.255.255.254 is the correct answer for the dotted decimal equivalent of a /31 prefix length, as it reflects the appropriate binary and decimal conversions for a subnet mask defining a very small subnet size.