A NAS accelerator (network-attached storage accelerator) is a printed circuit card that offloads TCP/IP processing from a microprocessor. This can reduce latency, increase throughput, and reduce overhead costs in a storage area network (SAN). A NAS accelerator is also called a TCP/IP accelerator network interface card or a TCP offload engine (TOE) network interface card (TNIC).
A high-end NAS accelerator can process Internet functions including e-mail and Web browsing, file transfers, and file serving, as well as data backup and archiving. This allows all network applications to run faster, because the microprocessor is not burdened with TCP/IP processing. It is claimed that the installation of NAS accelerators can provide network performance improvement comparable to that obtained by doubling the number of processors, but at much lower cost.