- plural form of Ra
ras - Computer Definition
- Registration/Admission/Status. In H.323-compliant multimedia networks, the protocol that supports communications between terminals (i.e., endpoint devices) and the gatekeeper. See also H.323, gatekeeper, multimedia, and terminal.
- Remote Access Server. A host computer on a local area network (LAN) and equipped with modems to serve the needs of end users for dial-up access to internal computer resources through the public switched telephone network (PSTN).An RAS also can take the form of purpose-built hardware with either integral modems or ISDN interfaces. An RAS generally is associated with a Remote Authentication Dial-In User Service (RADIUS) server that performs authentication, authorization, and accounting functions to ensure network security. See also authentication, authorization, ISDN, LAN, modem, NAS, PSTN, RADIUS, and security.
(1) See network access server.
(3) (Registration, Admission and Signaling) In an H.323 audio or video system, the RAS is a control channel over which H.225 signaling messages are sent. It provides a central point that all devices monitor for an incoming call signal. See H.225 and H.323.
(4) (Reliability Availability Serviceability) Originally an IBM term, it refers to a computer system's overall reliability, its ability to respond to a failure and its ability to undergo maintenance without shutting it down entirely.
(5) (Row Address Strobe) A clock signal in a memory chip used to pinpoint the row of a particular bit in a row-column matrix. See CAS.