A USPS hub is a central place where mail is sorted, processed, and distributed. Hubs are distribution centers that service a number of regional post offices within a certain geographical area. When a package arrives at a USPS hub, it means that it has arrived at a sorting facility prior to being sent to the local post office for final delivery. The hub network helps mail get streamed to the right places, and cuts costs for the Postal Service and those sending the mail. The objective of the hub network is to allow mail to be destination entered for downstream delivery units, thus allowing customers to enter closer to destination for a service benefit. Anything currently eligible to be dropped at a Destination Delivery Unit (DDU) can be dropped at a Hub, but will receive the Hub (DSCF) discount. The Critical Entry Time (CET) for all Hub facilities will be 1600. Hours of Operation will vary by facility, and will be available in FAST and published in the Mail Direction File (MDF).