While WANs are incredibly useful and popular, they are not without drawbacks. First, WANs are slows than LANs due to the distance that separates the networked locations as well as the fact that public infrastructure is typically used, meaning that network capacity is being shared by many customers. Second, establishing a WAN is not an inexpensive undertaking. Third, WANs are technically complex. Establishing and maintaining a WAN virtually always requires the involvement of a telecommunications company.