Q
QoS
Quality of service. An indicator of the performance of a transmission system on the Internet and other networks. QoS is measured in transmission rate, error rates, latency, and other characteristics, and can to some extent be guaranteed to a customer in advance. Asynchronous Transfer Mode technology supports QoS levels as do Lucent's new PacketStar® IP Switch.
Queuing
The act of "stacking" or holding calls to be answered by a specific person, trunk, or trunk group.
R
RARP
Reverse Address Resolution Protocol
RBOC
Regional Bell Operating Company
RDBMS
Regional database management system. A RDBMS that stores data in the form of related tables. Relational databases require few assumptions about how data is related or how it is extracted from the database, enabling the database to be viewed in many different ways. In contrast to flat-file databases, which consist of a single table, a relational system can spread the database over several tables. Most full-scale database systems are structured as an RDBMS.
RDP
Reliable Data Protocol
RF
Radio Frequency.
RF Input
The signal in dBm as presented to the input of a device.
RF Loss
A measure of RF signal loss through a device or link.
RF Output
The signal in dBm at the output of a device.
RFC
Request For Comments. The document series, begun in 1969, which describes the Internet suite of protocols and related experiments. Not all (in fact very few) RFCs describe Internet standards, but all Internet standards are written up as RFCs. The RFC series of documents is unusual in that the proposed protocols are forwarded by the Internet research and development community, acting on their own behalf, as opposed to the formally reviewed and standardized protocols that are promoted by organizations such as CCITT and ANSI. A complete list of RFCs can be found at http://www.internic.net/rfc/.
RG
Receiver Gain
RI
Ring Indicate
RIP
Routing Information Protocol. Routing information protocol teaches routers on a wide area network which routers have access to which addresses. This information is kept in a routing table on each router. As routers communicate with each other, they all update their routing tables to include each others' routing table information. In a large network environment, this exchange of information can keep the network connections up unnecessarily, and can result in very large routing tables on each router. You can apply a call filter to ignore RIP updates. You can also control how route information is propagated.
RJ-45 connector
Registered Jack-45. A telephone connector that holds up to eight wires. RJ-45 plugs and sockets are used in Ethernet and Token Ring devices.
RJ-48C
An eight-position keyed plug most commonly used for connecting T1 circuits. The RJ-48C is an eigh-position plug with four wires (two for transmit, two for receive) commonly connected. When the phone company delivers T1 to your offices, it usually terminates its T1 circuit on a RJ-48C. And it expects you to connect that RHJ-48C to your phone system or T1 channel bank and then to your phone system.
RPC
Remote Procedure Call
RPM
Remote Port Module. See Multiband RPM.
RS-#
Recommended Service #
RS-232
A set of EIA standards specifying various electrical and mechanical characteristics for interfaces between DTE and DCE data communications devices. The standard applies to both synchronous and asynchronous binary data transmission at rates below 64 kbit/s.
RS-366
An EIA standard for providing dialing commands to network access equipment. Uses RS-232 electrical specifications but different connector pinouts and signal functions.
RS-442
An EIA standard describing electrical characteristics for balanced-voltage digital interface circuits. Typically used for high-speed and synchronous data connections between DTE and DCE data communications devices.
RS-443
An EIA standard describing electrical characteristics for unbalanced-voltage digital interface circuits. Typically used for high-speed synchronous data connections between DTE and DCE data communications devices.
RS-449
An EIA standard for a 37-pin data communications connector, usually used with RS-422 or RS-423 electrical specifications.
RS-485
A standard for multipoint communications lines.
RSVP
Reservation Protocol
RTS
Request To Send
RVD
MIT Remote Virtual Disk Protocol Remote Access
Radio Channel
A cellular Radio Frequency channel as identified by the FCC. For analog, the channel is 30 kHz wide. In CDMA, which is a digital technology, the radio channel is 1.25 MHz wide.
Radio Frequency (RF)
A range of electromagnetic frequencies above sound and below visible light, generally in the 30 KHz to 300 GHz range, used for all broadcast transmission including AM and FM radio, television, short-wave, microwave, and satellite transmissions.
Radio Spectrum
Radio spectrum consists of radio waves of different frequencies (for example, 900 MHz). All radio spectra are regulated, with some licensed and others unlicensed.
Radio frequency
The RF carrier frequency of a given device.
Random Access Memory (RAM)
RAM is computer memory that holds data temporarily.
Range
In wireless communications, the distance that radio waves travel from a source (radio transmitter) before becoming too weak for a radio receiver to identify them.
Rate Adaptation
A capability that enables the rate-adaptive digital subscriber line (RADSL) signal to continue to transmit data even if noise is blocking some frequencies. Single, unshielded twisted-copper cable is subject to noise from external sources and nearby cables. Without rate adaptation, digital subscriber line (DSL) equipment cannot adjust to noise on the line and is forced to drop the signal entirely. Rate adaptation bypasses impaired frequencies, and the transmission continues. The system resumes the use of the bypassed frequencies as soon as the line is clear.
Read Only Memory (ROM)
ROM is computer memory whose contents can be read and executed, but not modified.
Reboot
To restart the computer and reload the operating system.
Receiver
A device which receives a transmitted signal.
Receiver gain
The difference between the RF signal presented to the input of the receiver versus the RF signal at the receiver output. This gain will not always represent itself as an increase in signal, since the losses in the receiver may be greater than its internal amplifier.
Red, Green, Blue (RGB)
The basic colors used in generating images on a color monitor or television screen. In RGB systems, various hues and shades are created additively, so that when all three colors are at their fullest intensity, the image is white.
Reduced Instruction Set Computing
A high-speed processor technology using a simple set of operating commands for faster processing and throughput used in workstation-class desktop computers.
Redundancy
Having one or more backup systems available in case the primary system fails.
Redundant Array Of Inexpensive Disks (RAID)
RAID technology is a method of using several hard disk drives in an array to provide fault tolerance. RAID improves redundancy and limits downtime.
Redundant link
A second connection between transmission and receive devices that operates only when integrity is lost on the active link.
Reflection
The abrupt change in the direction of light as it travels from one material to a dissimilar material. Some of the reflected power in a fiber gets transmitted back to the source.
Refraction
The bending of light as it passes through two dissimilar materials or in a medium whose refractive index varies smoothly. Important in fiber optic technology.
Refractive Index
The ratio of the speed of light in a vacuum to its speed in a given material such as glass. The larger the ratio, the more the light entering the material is bent. Important in fiber optic technology.
Regenerator
In a lightwave system, an electronic circuit that reconverts the electrical signals to light pulses and a laser that speeds them on their way.
Registration
In cellular communications systems, a handset must "register" with the system through this "handshake" process when a user logs onto the system for the first time.
Relational Database
A tabular database in which data is defined so that it can be reorganized and accessed in a number of different ways.
Remote Access Server
Any device that lets multiple remote users to access a network. Lucent's PortMaster 2 and PortMaster 3 products are remote access servers. A remote access server is sometimes called a RAS.
Remote Device
A unit that resides across the WAN.
Remote Job Entry (RJE)
The service offered by many networks that enables a (batch) job to be submitted from a remote site. Although the Internet has a protocol for RJE service, it is not popular because many machines on the Internet support do time sharing instead of batch processing.
Remote LAN Access
The process of allowing branch offices, telecommuters, and traveling computer users to access the corporate LAN backbone over dedicated or dialed, digital or analog lines.
Remote Loopback
Loopback performed between an application and remotely located access equipment or application. The signal is sent from the application over the network to the remote access equipment or application, from where it is looped back to the originating equipment.
Remote Management
A management feature that uses bandwidth between sites over the management subchannel established by the AIM (Ascend Inverse Multiplexing) protocol. Any Ascend unit can control, configure, and obtain statistical and diagnostic information about any other Ascend unit; multi-level security assures that unauthorized personnel do not have access to remote management functions.
Remote Switching Module
A component of the 5ESS® Switch that enables exchange carriers to provide new digital services in a remote area. It provides basic switching and call handling functions locally but relies on a 5ESS Switch host located elsewhere to provide other functions.
Resist
In microelectronics technology, a layer of material that serves as the sensitive coating in a lithographic process of chip manufacture. Also called photoresist. See
Resistor
An electronic device that limits the flow of current in a circuit.
Return loss
A comparison of impedance at the point of transmission and at termination.
Ring
A network topology where every node is connected to two others in a circle.
Roaming
In wireless communications, the movement by a user among many cells or zones. The term implies that the system can locate the handset as it "roams" and provide continuing service.
Rotary
A type of hunt group in which the incoming call hunts on a rotating basis for an available channel to ring and answer the call.
Route
The path that data takes from its source network to its destination network.
Router
An interconnection device that can connect individual LANs. Unlike bridges, which logically connect at OSI layer 2, routers provide logical paths at OSI layer 3. Like bridges, remote sites can be connected using routers over dedicated or switched lines to create WANs.
Routing
A device or setup that finds the best route between any two networks, even if there are several networks to traverse. (Contrast with bridge).
Routing Table
A list of destinations known to the router.Routing tables are built and used based on three protocols:
RIP - which continuously broadcasts routing updates every 30 seconds
ICMP - which can dynamically redirect packets to a more efficient route
ARP - which enables the Pipeline to respond to address queries with its own physical address
Rubber Bandwidth
A term used to describe a communications channel whose bandwidth can be increased or decreased without terminating and re-establishing the channel. Typically used with inverse multiplexing.
Reverse Address Resolution Protocol
RBOC
Regional Bell Operating Company
RDBMS
Regional database management system. A RDBMS that stores data in the form of related tables. Relational databases require few assumptions about how data is related or how it is extracted from the database, enabling the database to be viewed in many different ways. In contrast to flat-file databases, which consist of a single table, a relational system can spread the database over several tables. Most full-scale database systems are structured as an RDBMS.
RDP
Reliable Data Protocol
RF
Radio Frequency.
RF Input
The signal in dBm as presented to the input of a device.
RF Loss
A measure of RF signal loss through a device or link.
RF Output
The signal in dBm at the output of a device.
RFC
Request For Comments. The document series, begun in 1969, which describes the Internet suite of protocols and related experiments. Not all (in fact very few) RFCs describe Internet standards, but all Internet standards are written up as RFCs. The RFC series of documents is unusual in that the proposed protocols are forwarded by the Internet research and development community, acting on their own behalf, as opposed to the formally reviewed and standardized protocols that are promoted by organizations such as CCITT and ANSI. A complete list of RFCs can be found at http://www.internic.net/rfc/.
RG
Receiver Gain
RI
Ring Indicate
RIP
Routing Information Protocol. Routing information protocol teaches routers on a wide area network which routers have access to which addresses. This information is kept in a routing table on each router. As routers communicate with each other, they all update their routing tables to include each others' routing table information. In a large network environment, this exchange of information can keep the network connections up unnecessarily, and can result in very large routing tables on each router. You can apply a call filter to ignore RIP updates. You can also control how route information is propagated.
RJ-45 connector
Registered Jack-45. A telephone connector that holds up to eight wires. RJ-45 plugs and sockets are used in Ethernet and Token Ring devices.
RJ-48C
An eight-position keyed plug most commonly used for connecting T1 circuits. The RJ-48C is an eigh-position plug with four wires (two for transmit, two for receive) commonly connected. When the phone company delivers T1 to your offices, it usually terminates its T1 circuit on a RJ-48C. And it expects you to connect that RHJ-48C to your phone system or T1 channel bank and then to your phone system.
RPC
Remote Procedure Call
RPM
Remote Port Module. See Multiband RPM.
RS-#
Recommended Service #
RS-232
A set of EIA standards specifying various electrical and mechanical characteristics for interfaces between DTE and DCE data communications devices. The standard applies to both synchronous and asynchronous binary data transmission at rates below 64 kbit/s.
RS-366
An EIA standard for providing dialing commands to network access equipment. Uses RS-232 electrical specifications but different connector pinouts and signal functions.
RS-442
An EIA standard describing electrical characteristics for balanced-voltage digital interface circuits. Typically used for high-speed and synchronous data connections between DTE and DCE data communications devices.
RS-443
An EIA standard describing electrical characteristics for unbalanced-voltage digital interface circuits. Typically used for high-speed synchronous data connections between DTE and DCE data communications devices.
RS-449
An EIA standard for a 37-pin data communications connector, usually used with RS-422 or RS-423 electrical specifications.
RS-485
A standard for multipoint communications lines.
RSVP
Reservation Protocol
RTS
Request To Send
RVD
MIT Remote Virtual Disk Protocol Remote Access
Radio Channel
A cellular Radio Frequency channel as identified by the FCC. For analog, the channel is 30 kHz wide. In CDMA, which is a digital technology, the radio channel is 1.25 MHz wide.
Radio Frequency (RF)
A range of electromagnetic frequencies above sound and below visible light, generally in the 30 KHz to 300 GHz range, used for all broadcast transmission including AM and FM radio, television, short-wave, microwave, and satellite transmissions.
Radio Spectrum
Radio spectrum consists of radio waves of different frequencies (for example, 900 MHz). All radio spectra are regulated, with some licensed and others unlicensed.
Radio frequency
The RF carrier frequency of a given device.
Random Access Memory (RAM)
RAM is computer memory that holds data temporarily.
Range
In wireless communications, the distance that radio waves travel from a source (radio transmitter) before becoming too weak for a radio receiver to identify them.
Rate Adaptation
A capability that enables the rate-adaptive digital subscriber line (RADSL) signal to continue to transmit data even if noise is blocking some frequencies. Single, unshielded twisted-copper cable is subject to noise from external sources and nearby cables. Without rate adaptation, digital subscriber line (DSL) equipment cannot adjust to noise on the line and is forced to drop the signal entirely. Rate adaptation bypasses impaired frequencies, and the transmission continues. The system resumes the use of the bypassed frequencies as soon as the line is clear.
Read Only Memory (ROM)
ROM is computer memory whose contents can be read and executed, but not modified.
Reboot
To restart the computer and reload the operating system.
Receiver
A device which receives a transmitted signal.
Receiver gain
The difference between the RF signal presented to the input of the receiver versus the RF signal at the receiver output. This gain will not always represent itself as an increase in signal, since the losses in the receiver may be greater than its internal amplifier.
Red, Green, Blue (RGB)
The basic colors used in generating images on a color monitor or television screen. In RGB systems, various hues and shades are created additively, so that when all three colors are at their fullest intensity, the image is white.
Reduced Instruction Set Computing
A high-speed processor technology using a simple set of operating commands for faster processing and throughput used in workstation-class desktop computers.
Redundancy
Having one or more backup systems available in case the primary system fails.
Redundant Array Of Inexpensive Disks (RAID)
RAID technology is a method of using several hard disk drives in an array to provide fault tolerance. RAID improves redundancy and limits downtime.
Redundant link
A second connection between transmission and receive devices that operates only when integrity is lost on the active link.
Reflection
The abrupt change in the direction of light as it travels from one material to a dissimilar material. Some of the reflected power in a fiber gets transmitted back to the source.
Refraction
The bending of light as it passes through two dissimilar materials or in a medium whose refractive index varies smoothly. Important in fiber optic technology.
Refractive Index
The ratio of the speed of light in a vacuum to its speed in a given material such as glass. The larger the ratio, the more the light entering the material is bent. Important in fiber optic technology.
Regenerator
In a lightwave system, an electronic circuit that reconverts the electrical signals to light pulses and a laser that speeds them on their way.
Registration
In cellular communications systems, a handset must "register" with the system through this "handshake" process when a user logs onto the system for the first time.
Relational Database
A tabular database in which data is defined so that it can be reorganized and accessed in a number of different ways.
Remote Access Server
Any device that lets multiple remote users to access a network. Lucent's PortMaster 2 and PortMaster 3 products are remote access servers. A remote access server is sometimes called a RAS.
Remote Device
A unit that resides across the WAN.
Remote Job Entry (RJE)
The service offered by many networks that enables a (batch) job to be submitted from a remote site. Although the Internet has a protocol for RJE service, it is not popular because many machines on the Internet support do time sharing instead of batch processing.
Remote LAN Access
The process of allowing branch offices, telecommuters, and traveling computer users to access the corporate LAN backbone over dedicated or dialed, digital or analog lines.
Remote Loopback
Loopback performed between an application and remotely located access equipment or application. The signal is sent from the application over the network to the remote access equipment or application, from where it is looped back to the originating equipment.
Remote Management
A management feature that uses bandwidth between sites over the management subchannel established by the AIM (Ascend Inverse Multiplexing) protocol. Any Ascend unit can control, configure, and obtain statistical and diagnostic information about any other Ascend unit; multi-level security assures that unauthorized personnel do not have access to remote management functions.
Remote Switching Module
A component of the 5ESS® Switch that enables exchange carriers to provide new digital services in a remote area. It provides basic switching and call handling functions locally but relies on a 5ESS Switch host located elsewhere to provide other functions.
Resist
In microelectronics technology, a layer of material that serves as the sensitive coating in a lithographic process of chip manufacture. Also called photoresist. See
Resistor
An electronic device that limits the flow of current in a circuit.
Return loss
A comparison of impedance at the point of transmission and at termination.
Ring
A network topology where every node is connected to two others in a circle.
Roaming
In wireless communications, the movement by a user among many cells or zones. The term implies that the system can locate the handset as it "roams" and provide continuing service.
Rotary
A type of hunt group in which the incoming call hunts on a rotating basis for an available channel to ring and answer the call.
Route
The path that data takes from its source network to its destination network.
Router
An interconnection device that can connect individual LANs. Unlike bridges, which logically connect at OSI layer 2, routers provide logical paths at OSI layer 3. Like bridges, remote sites can be connected using routers over dedicated or switched lines to create WANs.
Routing
A device or setup that finds the best route between any two networks, even if there are several networks to traverse. (Contrast with bridge).
Routing Table
A list of destinations known to the router.Routing tables are built and used based on three protocols:
RIP - which continuously broadcasts routing updates every 30 seconds
ICMP - which can dynamically redirect packets to a more efficient route
ARP - which enables the Pipeline to respond to address queries with its own physical address
Rubber Bandwidth
A term used to describe a communications channel whose bandwidth can be increased or decreased without terminating and re-establishing the channel. Typically used with inverse multiplexing.
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