Storage consolidation is good and storage that is direct attached to servers is bad for storage consolidation. This is a key argument for networked storage and has been prevailing wisdom during much of this decade. Direct attached SAS storage disrupts the argument by being both good for consolidation while still being direct attached.
Networked storage typically shares storage resources among multiple servers via a network switch. Depending on need, networked storage might be accessed at the file level (Network Attached Storage) or at the block level via either Fibre Channel Storage Area Network (SAN) or iSCSI/Ethernet SAN.