What is the prefix length associated with the default Class B subnet mask?

The prefix length associated with the default Class B subnet mask is /16. In networking, a Class B address has a default subnet mask of 255.255.0.0. This mask indicates that the first two octets (the first 16 bits) are used for the network portion of the address, while the remaining two octets (the last 16 bits) are available for host addresses within that network.

To express a subnet mask in CIDR (Classless Inter-Domain Routing) notation, the number of bits that are set to '1' in the subnet mask is counted. In the case of a Class B subnet mask (255.255.0.0), the first 16 bits are ones, resulting in the prefix length of /16.

Understanding this concept is crucial for network design and IP addressing, as it helps to determine how many hosts can be accommodated in a given network and how the addressing scheme is structured.