Relay Access Card

Research on Advanced Communications in Europe

Project sponsored by the EC for the development of broadband networking capabilities.

Actual cellular Radio Frequency (RF) channel as identified in the United States by the Federal Communications FCC. For analogue, the channel is 30KHz wide. In CDMA, the radio channel is 1.25 MHz wide.

Remote Authentication Dial-In User Service

Database for authenticating modem and ISDN connections and for tracking connection time.

Rate-Adaptive DSL. ADSL technology from Westell in which software is able to determine the rate at which signals can be transmitted on a given customer phone line and adjust the delivery rate accordingly.

Random Access Memory

A solid-state memory device used for transient memory storage. Allows you to enter and retrieve information from any storage position.

Réseaux Associés pour la Recherche Européenne

Association of European universities and research centres designed to promote an advanced telecommunications infrastructure in the European scientific community.

Reverse Address Resolution Protocol

Protocol in the TCP/IP stack that provides a method for finding IP addresses based on MAC addresses.

In ATM, a value associated with one or more virtual circuits that defines the speed at which an individual virtual circuit transmits data to the remote end. Each rate queue represents a portion of the overall bandwidth available on an ATM link. The combined bandwidth of all configured rate queues should not exceed the total available bandwidth.

Regional Bell Operating Company

There are seven (also known as Baby Bells) which own the local exchange carriers in the US following the divestiture/break-up of AT&T (‘Ma Bell’) in 1984.

Remote Copy Protocol

Protocol that allows users to copy files to and from a file system residing on a remote host or server on the network. The RCP protocol uses TCP to ensure the reliable delivery of data.

Relational Database Management System

A structured computer information storage and retrieval system where the basic unit is a Table with Rows and Columns. Data is defined, accessed and modified with SQL statements.

Remote Defect Identifiaction

In ATM, when the physical layer detects loss of signal or cell synchronization, RDI cells are used to report a VPC/VCC failure. RDI cells are sent upstream by a VPC/VCC endpoint to notify the source VPC/VCC endpoint of the downstream failure.

A transmission or data processing operating mode by which data is entered in an interactive session; pertaining to an application whereby response to input is fast enough to affect subsequent input such as a process-control system; describing processing in which the results are used to influence an ongoing process.

In internetworking, the duplication of devices, services, or connections so that, in the event of a failure, the redundant devices, services, or connections can perform the work of those that failed. (2) In telephony, the portion of the total information contained in a message that can be eliminated without loss of essential information or meaning.

Computer, router, switch, or other system that contains two or more of each of the most important subsystems, such as two disk drives, two CPUs, or two power supplies.

Error correction code for bit errors, e.g., in AAL-1 type transmission

Bridge that connects physically disparate network segments via WAN links.

Radio Frequency

Refers to wireless transmission of radio signals as opposed to wires or cables to carry signals; refers to a frequency band which is higher then audio frequencies, but lower than the infrared frequencies. (2) A range of electromagnetic frequencies above sound and below visible light, generally in the 30Khz to 300GHz range, used for all broadcast transmission including AM and FM radio, television, short-wave, microwave, and satellite transmissions.

Employee working within the RF engineering department involved with cell layout, RF system design, identifying target buildings for antenna installation, planning in-building distribution, and implementation of new services; provide a direct input to civil engineering and customer activations; typical tasks might include provisioning IP addresses, VPI/VCI, and DLCI, putting hubs in place, frequency reuse planning, and RF network engineering.

Radio Frequency Interference

Disruption of signal by radio waves at the same frequency as the desired signal.

Regional Holding Company

Request Initialization Mode

Connection of two or more stations in a logically circular topology. Information is passed sequentially between active stations. Token Ring, FDDI, and CDDI are based on this topology.

Routing Information Protocol

An IAB protocol which is used by IP routers to determine the optimal path along which to move a packet.

Reduced Instruction Set Computing

Redundant Link Manager

Resource Management

Management of critical resources in an ATM network. Two critical resources are buffer space and trunk bandwidth. Provisioning can be used to allocate network resources in order to separate traffic flows according to service characteristics.

Remote Monitoring

Radio Network Controller

Moving seamlessly from one AP coverage area to another with no loss in connectivity.

Remote Operation Service Element

A international-standard protocol that serves as an interface between software applications on different nodes.

A sophisticated, protocol-sensitive device that examines data packets and finds the best route for them between sender and receiver. Selects the cheapest, fastest, or least busy of all available routes.

Reverse Path Forwarding

Multicasting technique in which a multicast datagram is forwarded out of all but the receiving interface if the receiving interface is the one used to forward unicast datagrams to the source of the multicast datagram.

Relative Rate

In ATM, one of the congestion feedback modes provided by ABR service. In RR mode, switches set a bit in forward and backward RM cells to indicate congestion.

Rivest, Shamir, and Adelman

Public-key cryptographic system named after its inventors. It may be used for encryption and authentication.

Remote Shell Protocol

Protocol that allows a user to execute commands on a remote system without having to log in to the system. For example, RSH can be used to remotely examine the status of a number of access servers without connecting to each communication server, executing the command, and then disconnecting from the communication server.

Route Switch Module

Route/Switch Processor

Remote Source-Route Bridging

SRB over WAN links.

Resource Reservation Protocol

Protocol that supports the reservation of resources across an IP network. Applications running on IP end systems can use RSVP to indicate to other nodes the nature (bandwidth, jitter, maximum burst, and so forth) of the packet streams they want to receive.

RTP Control Protocol

Protocol that monitors the QOS of an IPv6 RTP connection and conveys information about the on-going session.

Routing Table Protocol

VINES routing protocol based on RIP. Distributes network topology information and aids VINES servers in finding neighbouring clients, servers, and routers. Uses delay as a routing metric.

Real-Time Transport Protocol

One of the IPv6 protocols. RTP is designed to provide end-to-end network transport functions for applications transmitting real-time data, such as audio, video, or simulation data, over multicast or unicast network services. RTP provides services such as payload type identification, sequence numbering, time-stamping, and delivery monitoring to real-time applications.

Rapid Transport Protocol

Provides pacing and error recovery for APPN data as it crosses the APPN network. With RTP, error recovery and flow control are done end-to-end rather than at every node. RTP prevents congestion rather than reacts to it.

Real Time Streaming Protocol

Enables the controlled delivery of real-time data, such as audio and video. Sources of data can include both live data feeds, such live audio and video, and stored content, such as pre-recorded events. RTSP is designed to work with established protocols, such as RTP and HTTP.

Radio Termination Unit

Real Time Variable Bit Rate

A form of ATM transmission in which clock frequency can vary, but maximum delay and maximum variation of delay between cells are guaranteed. A typical use is real-time videoconferencing.

Request/Response Unit

Request and response messages exchanged between NAUs in an SNA network.

Reliable User Data Protocol

Number of Receive Slots