R

Random Access Memory (RAM)
RAM is the memory of a computer that can be read from or written to by computer hardware components such as a CPU.

Rapid Application Development (RAD)
RAD is a software development process that focuses on building a working program quickly, using visually oriented programming tools.

Repeater
A repeater is a Physical Layer device that connects one cable segment of a LAN to another, possibly connecting two different media types. For example, a repeater can connect a thin Ethernet cable to a thick Ethernet cable. It regenerates and boosts electrical signals, so it can be used to lengthen a network segment. Because a repeater reproduces exactly what it receives, bit by bit, it also reproduces errors. However, a repeater is very fast and causes very little delay.

Redirector
A redirector is a client software component in a client/server configuration. It is normally used in reference to the Novell NetWare NOS. The redirector is responsible for deciding if a request for a computer service (i.e., read a file) is for the local computer or network server.

Redundant Array of Inexpensive Disks (RAID)
RAID is a hard disk control technology that allows multiple hard disks to act as one device. RAID systems often mirror data on multiple disks of the array, providing built-in redundancy for important data.

Refraction
The tendency of a wave (such as light) to change direction when it passes from one medium into another in which the velocity of the wave is different is referred to as refraction. See index of refraction.

Remote Access Service (RAS)
The term RAS is normally used in the context of Windows NT, and the ability to access Windows NT and LAN services from a remote location.

Remote Monitoring (RMON)
RMON is a protocol that gathers network information at a central workstation. RMON defines additional MIBs that provide more detailed information about network use and status.

Remote Procedure Call (RPC)
RPC is a call made by a software program for services across a network connection, usually to a server.

Request for Comment (RFC)
An RFC is one of the working documents of the Internet research and development community. A document in this series may cover essentially any topic related to computer communication, and may be anything from a meeting report to the specification of a standard.

Router
A router is a Layer 3 device, with several ports that can each connect to a network or another router. A router examines the logical network address of each packet, then uses its internal routing table to forward the packet to the routing port associated with the best path to the packet's destination. If the packet is addressed to a network that is not connected to the router, the router forwards the packet to another router that is closer to the final destination. Each router, in turn, evaluates each packet and then delivers the packet or forwards it to another router.

Routing Information Protocol (RIP)
RIP is a distance-vector routing protocol supported by TCP/IP and Novell networks, designed for use within small autonomous systems.

Routing Loops
Routing loops are similar to active loops in bridged networks. Routing loops occur in networks that use the distance-vector routing algorithm, when multiple paths to the same node cause a routing table update from one router to come back to the router that originated the update. That router then misinterprets the data as an update from a neighbor, and repeats the whole update process.

Routing Protocols
Protocols used to build and maintain routing tables that describe the paths within, and between, autonomous systems are referred to as routing protocols.

Routing Table
A routing table is a database contained in a router, that includes detailed information on the paths (or routes) any packet can take through a network's routers to get from its source to its destination.

Runt Frame
An Ethernet frame that is smaller than the minimum frame size is referred to as a runt frame.

RSA
The acronym stands for Rivest, Shamir, and Adelman, the inventors of a widely used public-key encryption algorithm. The RSA encryption algorithm has become the de facto standard for industrial-strength encryption across the Internet. The strongest forms of RSA encryption are export restricted by the U.S. government, which considers it to be weapons-grade technology.

RS-232
RS-232 cables are used for connecting a computer to a modem. The RS-232 specification details the interface between the computer and modem.