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GLOSSARY

RADIUS - REMORE AUTHENTICATION DIAL-IN USER SERVICE
RAID - REDUNDANT ARRAY of INDEPENDENT DISKS
RBOC - REGIONAL BELL OPERATING COMPANY
RISC - REDUCED INSTRUCTION SET COMPUTER
REPEATER
RFC - REQUEST FOR COMMENT
RTF - RICH TEXT FORMAT
RIP - ROUTING INFORMATION PROTOCOL
RJ-xx - REGESTERED JACK
ROAMING SERVICE
ROSETTENET
ROUTER
RSVP - RESOURCE RESERVATION PROTOCOL


• RADIUS, Remote Authentication Dial-In User Service, is a client/server protocol and software that enables remote access servers to communicate with a central server to authenticate dial-in users and authorize their access to the requested system or service. RADIUS allows a company to maintain user profiles in a central database that all remote servers can share. It provides better security, allowing a company to set up a policy that can be applied at a single administered network point. Having a central service also means that it's easier to track usage for billing and for keeping network statistics. Created by Livingston (now owned by Lucent), RADIUS is a de facto industry standard used by Ascend and other network product companies and is a proposed IETF standard.
  

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• RAID, Redundant Array of Independent Disks, is a way of storing the same data in different places (thus, redundantly) on multiple hard disks. By placing data on multiple disks, I/O operations can overlap in a balanced way, improving performance. Since multiple disks increases the mean time between failure (MTBF), storing data redundantly also increases fault-tolerance.
  

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• RBOC Regional Bell Operating Company, is a term describing one of the U.S. regional telephone companies (or their successors) that were created as a result of the breakup of American Telephone and Telegraph Company (AT&T, known also as the Bell System or "Ma Bell") by a U.S. Federal Court consent decree on December 31, 1983. The seven original regional Bell operating companies were Ameritech, Bell Atlantic, BellSouth, NYNEX, Pacific Bell, Southwestern Bell, and US WEST. Each of these companies owned at least two Bell operating companies (Bell operating company). The BOCs were given the right to provide local phone service while AT&T was allowed to retain its long-distance service. The RBOCs and their constituent BOCs are part of the class of local exchange carriers (LECs).
  

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• RISC, Reduced Instruction Set Computer, is a microprocessor that is designed to perform a smaller number of types of computer instructions so that it can operate at a higher speed (perform more millions of instructions per second, or MIPS). Since each instruction type that a computer must perform requires additional transistors and circuitry, a larger list or set of computer instructions tends to make the microprocessor more complicated and slower in operation.
  

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• REPEATER is a device that receives a signal on an electromagnetic or optical transmission medium, amplifies the signal, and then retransmits it along the next leg of the medium. Repeaters overcome the attenuation caused by free-space electromagnetic-field divergence or cable loss. A series of repeaters make possible the extension of a signal over a distance. Repeaters are used to interconnect segments in a local area network (LAN). They're also used to amplify and extend wide area network transmission on wire and wireless media.
  

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• RFC, Request for Comments is a formal document from the Internet Engineering Task Force (IETF) that is the result of committee drafting and subsequent review by interested parties. Some RFCs are informational in nature. Of those that are intended to become Internet standards, the final version of the RFC becomes the standard and no further comments or changes are permitted. Change can occur, however, through subsequent RFCs that supersede or elaborate on all or parts of previous RFCs.
  

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• RTF, RICH TEXT FORMAT, is a file format that lets you exchange text files between different word processors in different operating systems. For example, you can create a file using Microsoft Word in Windows 98, save it as an RTF file (it will have a ".rtf" file name suffix), and send it to someone who uses WordPerfect 6.0 on Windows 3.1 and they will be able to open the file and read it. (In some cases, the RTF capability may be built into the word processor. In others, a separate reader or writer may be required.)
  

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• RIP, Routing Information Protocol, is a widely-used protocol for managing router information within a self-contained network such as a corporate local area network () or an interconnected group of such LANs. RIP is classified by the Internet Engineering Task Force (IETF) as one of several internal gateway protocols (Interior Gateway Protocol).
  

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• RJ-xx In the U. S., telephone jacks are also known as Registered Jacks that are registered with the U.S. Federal Communications Commission (FCC). The term jack sometimes means both receptacle and plug and sometimes just the receptacle.
  RJ-11
  The most common telephone jack is the RJ-11 jack, which can have six conductors but usually is implemented with four. The RJ-11 jack is likely to be the jack that your household or office phones are plugged into from the ordinary "untwisted" wire (sometimes called "gray satin" or "flat wire") people are most familiar with. Your computer modem is usually connected to an RJ-11 jack.
  RJ-14
  The RJ-14 is similar to the RJ-11, but the four wires are used for two phone lines. Each set carries one analog "conversation" (voice or data).
  RJ-45
  The RJ-45 is a single-line jack for digital transmission over ordinary phone wire, either untwisted or twisted. The interface has eight pins or positions. For connecting a modem, printer, or a data PBX at a data rate up to 19.2 Kbps , you can use untwisted wire. For faster transmissions in which you're connecting to an Ethernet 10BASET network, you need to use twisted pair wire. (Untwisted is usually a flat wire like common household phone extension wire. Twisted is often round.)
  There are two varieties of RJ-45: keyed and unkeyed. Keyed has a small bump on its end and the female complements it. Both jack and plug must match.
  

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• ROAMING SERVICE is the ability to get access to the Internet when away from home at the price of a local call or at a charge considerably less than the regular long-distance charges. For example, if you normally get access to the Internet from an access provider in Brooklyn, New York and are travelling to Hong Kong, you can call a designated access provider in Hong Kong. Instead of paying long distance charges to your local provider in Brooklyn, you pay the local phone connection charge in Hong Kong and possibly a modest additional charge for the service.
  

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• ROSETTENET is an organization set up by leading information technology companies to define and implement a common set of standards for e-business. RosettaNet is defining a common parts dictionary so that different companies can define the same product the same way. It is also defining up to 100 e-business transaction processes and standardizing them. Because RosettaNet is supported by all or most of the major companies in the IT industry, its standards are expected to be widely adopted.
  

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• ROUTER is a device or, in some cases, software in a computer, that determines the next network point to which a packet should be forwarded toward its destination. The router is connected to at least two networks and decides which way to send each information packet based on its current understanding of the state of the networks it is connected to. A router is located at any gateway (where one network meets another), including each Internet point-of-presence . A router is often included as part of a network switch.
  A router may create or maintain a table of the available routes and their conditions and use this information along with distance and cost (hops) algorithms to determine the best route for a given packet. Typically, a packet may travel through a number of network points with routers before arriving at its destination. Routing is a function associated with the Network layer (layer 3) in the standard model of network programming, the Open Systems Interconnection (OSI) model. A layer-3 switch is a switch that can perform routing functions.
  An edge router is a router that interfaces with an asynchronous transfer mode (ATM) network. A brouter is a network bridge combined with a router.
  

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• RSVP, Resource Reservation Protocol, is a set of communication rules that allows channels or paths on the Internet to be reserved for the multicast (one source to many receivers) transmission of video and other high-bandwidth messages. RSVP is part of the Internet Integrated Service (IIS) model, which ensures best-effort service, real-time service, and controlled link-sharing.
  

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