Final answer:
VLSM stands for Variable-length subnet mask, which is used to divide an IP address space into subnets of varying sizes for more efficient address space usage.
Step-by-step explanation:
The acronym VLSM stands for Variable-length subnet mask. VLSM is a technique used in IP networking to divide an IP address space into subnets of varying sizes, optimizing and economizing the address space. This is contrary to the traditional fixed-length subnetting where each subnet is of equal size. Employing VLSM can lead to reduced wastage of IP addresses and allows for more efficient use of a limited IP address space.
For example, in a hypothetical organization with several departments, some may need more IP addresses than others. With VLSM, the network administrator can allocate IP subnets according to the actual number of hosts required for each department, rather than wasting addresses by allocating uniform subnet sizes that may be too large for some departments and too small for others.