A

Advanced Technology Attachment (ATA)

The block-level protocol historically used in laptops, desktops, and low-end server platforms. See also direct attached storage (DAS).

anti-replay protection

A security service that detects the arrival of duplicate packets within a given window of packets or a bounded timeframe.

anycast

An IP routing feature that supports regionalized duplication of IP addresses; facilitates efficient location of globally distributed services.

Application Specific Integrated Circuit (ASIC)

An integrated circuit that performs a specific function.

asynchronous replication

A method of replicating data across long distances in which the states of the source and target disk images may be significantly out of sync at any point in time.

ATA Packet Interface (ATAPI)

An enhancement to the ATA protocol that enables support for device types other than magnetic disk.

Autonomous System (AS)

An administrative domain in which a common policy set is used for the configuration of routing protocols.

auto-sensing

The ability to detect the transmission rate of an attached Ethernet port; a subset of the auto-negotiation features supported by Ethernet.