R

R is a programming language and free software environment for statistical computing and graphics that is supported by the R Foundation for Statistical Computing. The R language is widely used among statisticians and data miners for developing statistical software and data analysis. Polls, surveys of data miners, and studies of scholarly literature databases show that R's popularity has increased substantially in recent years. As of June 2018, R ranks 10th in the TIOBE index, a measure of popularity of programming languages.

RACI

Responsible, Accountable, Consulted, and Informed

A responsibility assignment matrix (RAM), also known as RACI matrix or linear responsibility chart (LRC), describes the participation by various roles in completing tasks or deliverables for a project or business process. It is especially useful in clarifying roles and responsibilities in cross-functional/departmental projects and processes.

 

RAD

rapid application development

an approach based on the concept that products can be developed faster and of higher quality through: gathering requirements using workshops or focus groups; prototyping and early, reiterative user testing of designs; reusing software components; and using less formality in communication documents, such as reviews.

RAD

rapid application development

agile development method; enables developers to build solutions quickly by talking directly to end users to meet business requirement.

RAD Environment

Refers to a software tool the combines one or more programming languages with an IDE and a toolbox of modular software user interface components.

Radius

Remote Authentication Dial In User Service

• • Protocol described by RFC 2865 (http://www.ietf.org/rfc/rfc2865.txt)
    
  • Provides
    
    • Authentication
      
    • Authorisation
      
    • Accounting
      
  • TTT use FreeRADIUS Implementation
    
     
    
     

Rainbow

Opal business solutions, gata does into Remedy 7.6 (Service inventory)

RAN

radio access network

A radio access network (RAN) is part of a mobile telecommunication system. It implements a radio access technology. Conceptually, it resides between a device such as a mobile phone, a computer, or any remotely controlled machine and provides connection with its core network (CN). Depending on the standard, mobile phones and other wireless connected devices are varyingly known as user equipment (UE), terminal equipment, mobile station (MS), etc. RAN functionality is typically provided by a silicon chip residing in both the core network as well as the user equipment.
 
Examples of radio access network types are:

• GRAN: GSM radio access network
  
• GERAN: essentially the same as GRAN but specifying the inclusion of EDGE packet radio services
  
• UTRAN: UMTS radio access network
  
• E-UTRAN: The Long Term Evolution (LTE) high speed and low latency radio access network
  
  It is also possible for a single handset/phone to be simultaneously connected to multiple radio access networks. Handsets capable of this are sometimes called dual-mode handsets. For instance it is common for handsets to support both GSM and UMTS (a.k.a. "3G") radio access technologies. Such devices seamlessly transfer an ongoing call between different radio access networks without the user noticing any disruption in service.
  
   

RANAP

Radio Access Network Application Part

In telecommunications networks, RANAP (an acronym for Radio Access Network Application Part) is a protocol specified by 3GPP in TS 25.413 and used in UMTS for signaling between the Core Network, which can be a MSC or SGSN, and the UTRAN. RANAP is carried over Iu-interface.
 
RANAP signalling protocol resides in the control plane of Radio network layer of Iu interface in the UMTS (Universal Mobile Telecommunication System) protocol stack. Iu interface is the interface between RNC (Radio Network Controller) and CN (Core Network). nb. For Iu-ps transport RANAP is carried on SCTP if IP interface used on this.
 
RANAP handles signaling for the Iu-PS - RNC and 3G SGSN and Iu-CS - RNC and 3G MSC . It also provides the signaling channel to transparently pass messages between the User Equipment (UE) and the CN.
 
In LTE, RANAP has been replaced by S1AP.

RANCID

Really Awesome New Cisco config Differ

A network management application released under a BSD-style license. RANCID uses Expect to connect to the routers, send some commands and put the results in files.

Rapid Application Development

RAD

A collection of software development techniques that focuses on user interface prototyping techniques and tools to create applications in an incremental fashion.

RARP

Dynamic IP Address Allocation – Reverse Address Resolution protocol

The Reverse Address Resolution Protocol (RARP) is an obsolete computer networking protocol used by a client computer to request its Internet Protocol (IPv4) address from a computer network, when all it has available is its link layer or hardware address, such as a MAC address. The client broadcasts the request and does not need prior knowledge of the network topology or the identities of servers capable of fulfilling its request.
 
RARP is described in Internet Engineering Task Force (IETF) publication RFC 903. It has been rendered obsolete by the Bootstrap Protocol (BOOTP) and the modern Dynamic Host Configuration Protocol (DHCP), which both support a much greater feature set than RARP.
 
RARP requires one or more server hosts to maintain a database of mappings of Link Layer addresses to their respective protocol addresses. Media Access Control (MAC) addresses need to be individually configured on the servers by an administrator. RARP is limited to serving only IP addresses.
 
Reverse ARP differs from the Inverse Address Resolution Protocol (InARP) described in RFC 2390, which is designed to obtain the IP address associated with a local Frame Relay data link connection identifier. InARP is not used in Ethernet.
 
Modern Day Uses
Although the original uses for RARP have been overcome by different protocols, some modern day protocols use RARP. Examples are:
 
Cisco's Overlay Transport Virtualization (OTV). RARP is used to update the layer 2 forwarding tables when a MAC address moves between data centers.

RAS

Remote Access Server

Refers to any combination of hardware and software that enable the remote access to a network; often used in dial-up networking scenarios. These devices typically use a RADIUS service.

RAS

Registration, Admission, and Status

Registration, admission, and status (RAS) is a component of a network protocol that involves the addition of (or refusal to add) new authorized users, the admission of (or refusal to admit) authorized users based on available bandwidth, and the tracking of the status of all users. Formally, RAS is part of the H.225 protocol for H.323 communications networks, designed to support multimedia bandwidths. RAS is an important signalling component in networks using voice over IP (VoIP).

RDBMS

relational database management system

A relational database management system (RDBMS) is a database management system (DBMS) based on the relational model invented by Edgar F. Codd at IBM's San Jose Research Laboratory. Most databases in widespread use today are based on his relational database model.
 
RDBMSs have been a common choice for the storage of information in databases used for financial records, manufacturing and logistical information, personnel data, and other applications since the 1980s. Relational databases have often replaced legacy hierarchical databases and network databases because they were easier to implement and administer. Nonetheless, relational databases received continued, unsuccessful challenges by object database management systems in the 1980s and 1990s, (which were introduced in an attempt to address the so-called object-relational impedance mismatch between relational databases and object-oriented application programs), as well as by XML database management systems in the 1990s. However, due to the expanse of technologies, such as horizontal scaling of computer clusters, NoSQL databases have recently become popular as an alternative to RDBMS databases

 

RDP

Remote Desktop Protocol

Remote Desktop Protocol (RDP) is a proprietary protocol developed by Microsoft, which provides a user with a graphical interface to connect to another computer over a network connection. The user employs RDP client software for this purpose, while the other computer must run RDP server software.
 
Clients exist for most versions of Microsoft Windows (including Windows Mobile), Linux, Unix, macOS, iOS, Android, and other operating systems. RDP servers are built into Windows operating systems; an RDP server for Unix and OS X also exists. By default, the server listens on TCP port 3389[1] and UDP port 3389.[2]
 
Microsoft currently refers to their official RDP client software as Remote Desktop Connection, formerly "Terminal Services Client".
 
The protocol is an extension of the ITU-T T.128 application sharing protocol.

Reading Inspection

An inspection in which all components of the full inspection process are done except the inspection meeting.

refactoring

a process that improves the internal structure of a software system without changing its external behaviour.

Refactoring

Refactoring consists of improving the internal structure of an existing program's source code, while preserving its external behavior.

Reference

CxRef

CxOne reference material type, see CxOneOverview for description.

regression testing

the process of testing changes to computer programs to make sure that the older programming still works with the new changes.

Regular expression

A regular expression, regex or regexp (sometimes called a rational expression) is, in theoretical computer science and formal language theory, a sequence of characters that define a search pattern. Usually this pattern is then used by string searching algorithms for "find" or "find and replace" operations on strings, or for input validation.

Relative Estimation

Relative estimation consists of estimating tasks or user stories by comparison or by grouping of items of equivalent difficulty.

Release

A software release. Providing a deployable version of a software system to a customer, e.g., test group, client, customer, etc.

Release Management

The identification, packaging, and delivery of the elements of the product to an external or internal customer.

Release Test

Test to ensure software is ready for a release.

Requirement

A detailed description of what the software is supposed to do

Requirements

are written as 'stories' that are collated into a prioritised list called the 'Backlog'.

Requirements

Software requirements. Determining and capturing what a software system should do. Also denotes the requirements CKA. See CxStand_Requirements for more information.

Requirements Lead

Responsible for defining, maintaining, and tracing product requirements. Ensures proper end-user documentation is developed from the requirements.

REST

Representational State Transfer

Representational State Transfer (REST) is an architectural style that defines a set of constraints and properties based on HTTP. Web Services that conform to the REST architectural style, or RESTful web services, provide interoperability between computer systems on the Internet. REST-compliant web services allow the requesting systems to access and manipulate textual representations of web resources by using a uniform and predefined set of stateless operations. Other kinds of web services, such as SOAP web services, expose their own arbitrary sets of operations.
 
"Web resources" were first defined on the World Wide Web as documents or files identified by their URLs. However, today they have a much more generic and abstract definition that encompasses everything or entity that can be identified, named, addressed, or handled, in any way whatsoever, on the web. In a RESTful web service, requests made to a resource's URI will elicit a response that may be in HTML, XML, JSON, or some other format. The response may confirm that some alteration has been made to the stored resource, and the response may provide hypertext links to other related resources or collections of resources. When HTTP is used, as is most common, the operations available are GET, POST, PUT, DELETE, and other predefined CRUD HTTP methods.
 
By using a stateless protocol and standard operations, REST systems aim for fast performance, reliability, and the ability to grow, by re-using components that can be managed and updated without affecting the system as a whole, even while it is running.
 

 

Review

A defined process in which people who are not the author of an artifact look over it with the intent of finding issues. Reviews range in formality from desk checks to inspections.

Reviewer

A person who participates in a review to identify issues in an artifact

Revision

An instance of a specific artifact, generally as noted by an automated system.

Revision Control

RC

The identification, storage, and management of projects artifacts and the revisions over time of those artifacts. Usually performed to artifacts stored in electronic form, through an automated system.

Rework

Any unforeseen or unplanned activity necessary to bring an artifact into conformance with project needs. Compare to update.

RFC

RF connector

A coaxial RF connector (radio frequency connector) is an electrical connector designed to work at radio frequencies in the multi-megahertz range. RF connectors are typically used with coaxial cables and are designed to maintain the shielding that the coaxial design offers. Better models also minimize the change in transmission line impedance at the connection in order to reduce signal reflection and power loss. As the frequency increases, transmission line effects become more important, with small impedance variations from connectors causing the signal to reflect rather than pass through. An RF connector must not allow external signals into the circuit through electromagnetic interference and capacitive pickup.
 
Mechanically, RF connectors may provide a fastening mechanism (thread, bayonet, braces, blind mate) and springs for a low ohmic electric contact while sparing the gold surface, thus allowing very high mating cycles and reducing the insertion force. Research activity in the area of radio-frequency (RF) circuit design has surged in the 2000s in direct response to the enormous market demand for inexpensive, high-data-rate wireless transceivers.

RFC

Request For Comment

A Request for Comments (RFC) is a formal document drafted by the Internet Engineering Task Force (IETF) that describes the specifications for a particular technology. When an RFC is ratified, it becomes a formal standards document.

RIP

Routing Information Protocol

The Routing Information Protocol (RIP) is one of the oldest distance-vector routing protocols which employ the hop count as a routing metric. RIP prevents routing loops by implementing a limit on the number of hops allowed in a path from source to destination. The largest number of hops allowed for RIP is 15, which limits the size of networks that RIP can support.
 
RIP implements the split horizon, route poisoning and holddown mechanisms to prevent incorrect routing information from being propagated.
 
In RIPv1 router broadcast updates with their routing table every 30 seconds. In the early deployments, routing tables were small enough that the traffic was not significant. As networks grew in size, however, it became evident there could be a massive traffic burst every 30 seconds, even if the routers had been initialized at random times.
 
In most networking environments, RIP is not the preferred choice for routing as its time to converge and scalability are poor compared to EIGRP, OSPF, or IS-IS. However, it is easy to configure, because RIP does not require any parameters unlike other protocols.
 
RIP uses the User Datagram Protocol (UDP) as its transport protocol, and is assigned the reserved port number 520.

Risk

An undesirable outcome.
Risks on projects generally refer to the captured representation of a possible future negative impact to a project's feature, budget, schedule, or quality. Risks are a type of corrective activity management item.

Risk Analysis

Assesses risks for the likelihood and impact of occurrence.

Risk Identification

The elicitation and determination of current risks.

Risk List

A technique for extrinsic risk management that documents current and previous risks. Normally includes analysis information and mitigation plans.

Risk Management

A process or activity involving formal or informal means of identification, control, and elimination of project risk. Risk management may be explicit, or may be implicit in other activities (see intrinsic and extrinsic risk management). Managing identified risks is part of corrective activity management.

Risk Mitigation

The planning or steps taken to minimize either the probability or impact of a risk.

Risk Reward Matric

A risk-reward analysis is a very simple tool which can help you assess the risk and reward profile of completely different options. It works in the same way as a risk-return analysis which you may already be familiar with.
It can be applied at any level, for example:

• by a CEO for comparing different strategic directions for the company.
  
• by a program manager deciding which projects to keep within the program and which to discard.
  
• by a project manager deciding how to sequence tasks
  
• or simply by an individual team member deciding how best to spend their day.
  
  The template works by having risk plotted along one axis and reward along the other. In the diagram below I've divided the template into four sections to show you how to interpret the information.
  
  
  The four categories from the diagram above are as follows:
  
  Equal Low: where risk and reward are both proportional and low.
  Equal High: where risk and reward are both proportional and high.
  Positive: represents a positive risk-reward balance, where a higher return can be achieved with limited risk.
  Negative: represents a negative risk-reward balance, where a low return is the reward for taking on a relatively high risk.
  How to Use it
  First, you need to create a list of all the different options and their possible rewards. This can done quickly and roughly, or can involve serious effort (market research, scenario development etc) – the effort you put in will depend on the size of the decision you are making. Examples of some options might include: outsourcing non-core activities, stop investing in poorly performing product lines, invest in new products, or investing to move into new markets. Once you have all the options and their potential reward, they should be plotted on the risk-reward chart:
  
  At this stage some options will appear to have a more favourable risk-reward profile than others, such as outsourcing in the above example, but it is work taking the time to investigate whether any options can have their risks mitigated, or if there are options that can have their rewards boosted, before making a final decision on which option to go with. In the above example, if the risk of developing new products could be mitigated somehow then that option would become more favourable than outsourcing.
  
  Finally, for an even more complete picture to further aid our decision making, we can add resources to the risk-reward template. In the diagram below, the bigger the bubble the more resources are required to execute that option.
  
  With risk, reward, and resources all plotted, we are able to trade them against one another to find the best option for us. From the diagram above you can see that outsourcing is probably the most favourable option, providing plenty of upside reward but requiring minimal resource and having little risk. Additionally, with so few resources engaged in making the outsourcing happen, perhaps some investigative work can start on the new product development option with some of the spare resource.

RNC

Radio Network Controller

The Radio Network Controller (or RNC) is a governing element in the UMTS radio access network (UTRAN) and is responsible for controlling the Node Bs that are connected to it. The RNC carries out radio resource management, some of the mobility management functions and is the point where encryption is done before user data is sent to and from the mobile. The RNC connects to the Circuit Switched Core Network through Media Gateway (MGW) and to the SGSN (Serving GPRS Support Node) in the Packet Switched Core Network.
Interfaces
 
RNC Interfaces
The logical connections between the network elements are known as interfaces. The interface between the RNC and the Circuit Switched Core Network (CS-CN) is called Iu-CS and between the RNC and the Packet Switched Core Network is called Iu-PS. Other interfaces include Iub (between the RNC and the Node B) and Iur (between RNCs in the same network). Iu interfaces carry user traffic (such as voice or data) as well as control information (see Protocols), and Iur interface is mainly needed for soft handovers involving 2 RNCs though not required as the absence of Iur will cause these handovers to become hard handovers.

 
Protocols
Iub, Iu and Iur protocols all carry both user data and signalling (that is, control plane).

• Signalling protocol responsible for the control of the Node B by the RNC is called NBAP (Node-B Application Part). NBAP is subdivided into Common and Dedicated NBAP (C-NBAP and D-NBAP), where Common NBAP controls overall Node B functionality and Dedicated NBAP controls separate cells or sectors of the Node B. NBAP is carried over Iub. In order for NBAP to handle common and dedicated procedures, it is divided into: NodeB Control Port (NCP) which handles common NBAP procedures and Communication Control Port (CCP) which handles dedicated NBAP procedures.
  
• Control plane protocol for the transport layer is called ALCAP (Access Link Control Application Protocol). Basic functionality of ALCAP is multiplexing of different users onto one AAL2 transmission path using channel IDs (CIDs). ALCAP is carried over Iub and Iu-CS interfaces.
  
• Signalling protocol responsible for communication between RNC and the core network is called RANAP (Radio Access Network Application Part), and is carried over Iu interface.
  
• Signalling protocol responsible for communications between RNCs is called RNSAP (Radio Network Subsystem Application Part) and is carried on the Iur interface.
   

RNSAP

Radio Network Subsystem Application Part

RNSAP (Radio Network Subsystem Application Part) is a 3GPP signalling protocol responsible for communications between RNCs Radio Network Controllers defined in 3GPP specification TS 25.423.[1] It is carried on the lur interface and provides functionality needed for soft handovers and SRNS (Serving Radio Network Subsystem) relocation (handoff between RNCs).It defines signalling between RNCs, including SRNC(Serving RNC) and DRNC(drift RNC).
 
SRNC

DRNC

IUR

RNSAP

RNSAP

Converge protol

Converge protol
 

AAL 5

AAL5
ATM

ATM
Physical links------→→→ Physical links
 
RNSAP Layer Architecture

Role-feature-reason

The "role-feature-reason" template is one of the most commonly recommended aids to write user stories: As a ... I want ... So that ...

Rolling Wave Planning

Planning a project, often with an iterative lifecycle, with a sliding window of visibility. Items closer to the present are planned and tracked with greater detail than items further in the future. See project headlights.

Round Robin

Round-robin (RR) is one of the algorithms employed by process and network schedulers in computing. As the term is generally used, time slices (also known as time quanta) are assigned to each process in equal portions and in circular order, handling all processes without priority (also known as cyclic executive). Round-robin scheduling is simple, easy to implement, and starvation-free. Round-robin scheduling can also be applied to other scheduling problems, such as data packet scheduling in computer networks. It is an operating system concept.
 
The name of the algorithm comes from the round-robin principle known from other fields, where each person takes an equal share of something in turn.

 

Router

A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. Data sent through the internet, such as a web page or email, is in the form of data packets. A packet is typically forwarded from one router to another router through the networks that constitute an internetwork until it reaches its destination node.
 
A router is connected to two or more data lines from different networks. When a data packet comes in on one of the lines, the router reads the network address information in the packet to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey.
 
The most familiar type of routers are home and small office routers that simply forward IP packets between the home computers and the Internet. An example of a router would be the owner's cable or DSL router, which connects to the Internet through an Internet service provider (ISP). More sophisticated routers, such as enterprise routers, connect large business or ISP networks up to the powerful core routers that forward data at high speed along the optical fiber lines of the Internet backbone. Though routers are typically dedicated hardware devices, software-based routers also exist

RPC

In distributed computing, a remote procedure call (RPC) is when a computer program causes a procedure (subroutine) to execute in a different address space (commonly on another computer on a shared network), which is coded as if it were a normal (local) procedure call, without the programmer explicitly coding the details for the remote interaction. That is, the programmer writes essentially the same code whether the subroutine is local to the executing program, or remote. This is a form of client–server interaction (caller is client, executor is server), typically implemented via a request–response message-passing system. In the object-oriented programming paradigm, RPC calls are represented by remote method invocation (RMI). The RPC model implies a level of location transparency, namely that calling procedures is largely the same whether it is local or remote, but usually they are not identical, so local calls can be distinguished from remote calls. Remote calls are usually orders of magnitude slower and less reliable than local calls, so distinguishing them is important.
 
RPCs are a form of inter-process communication (IPC), in that different processes have different address spaces: if on the same host machine, they have distinct virtual address spaces, even though the physical address space is the same; while if they are on different hosts, the physical address space is different. Many different (often incompatible) technologies have been used to implement the concept.

RRC

Radio Resource Control

The Radio Resource Control (RRC) protocol is used in UMTS and LTE on the Air interface. It is a layer that exists between UE and eNB and exists at the IP level. This protocol is specified by 3GPP in TS 25.331 for UMTS and in TS 36.331 for LTE. RRC messages are transported via the PDCP-Protocol.
 
The major functions of the RRC protocol include connection establishment and release functions, broadcast of system information, radio bearer establishment, reconfiguration and release, RRC connection mobility procedures, paging notification and release and outer loop power control. By means of the signalling functions the RRC configures the user and control planes according to the network status and allows for Radio Resource Management strategies to be implemented.
 
The operation of the RRC is guided by a state machine which defines certain specific states that a UE may be present in. The different states in this state machine have different amounts of radio resources associated with them and these are the resources that the UE may use when it is present in a given specific state. Since different amounts of resources are available at different states the quality of the service that the user experiences and the energy consumption of the UE are influenced by this state machine.
 
In order to comprehend the Radio Resource Control (RRC) state machine, we should study the architecture of the third generation mobile cellular system, the Universal Mobile Telecommunications System (UMTS). The UMTS is composed by two subsystems, the UTRAN (Umts Terrestrial Radio Access Network) and CN (core network) :

 
The RNC is responsible for the packet scheduling, radio resource control and handover control.
Unlike other wireless technologies like WIFI in which clients concurrently send packets and collisions occur (and backoff algorithms), in the UMTS there is a centralized entity that schedules resources to each client. In order to manage the UE access to radio resources, the UMTS introduces a radio resource control protocol (RRC) that attributes each UE a specific state machine (based on radio resource usage). This state machine is dependent on the 3G provider and can have different states and/or transitions. According to the reference paper – Characterizing Radio Resource Allocation for 3G Networks – the studied networks were composed by three states: IDLE, CELL_FACH and CELL_DCH.
In truth other states can actually be observed in some operators before going into a disconnected mode. For example the PCH states – URA_PCH and CELL_PCH – are states in which the user equipment has no transport channels allocated but has to monitor the cell/UTRAN it is currently connected to in order to send CELL_UPDATES to the RCN (just in case it actually changes). This update implies temporarily changing the state to a CELL_FACH in order to be able to send data. The change from CELL_PCH, in which the UE is known at a cell level, to URA_PCH, in which the user is known at UTRAN level, may be due to an increasing number of CELL_UPDATES (e.g. travelling fast). This is useful in order to speed up incoming connections since it might take around 0.9 seconds to establish it against the 2.5s delay if the UE is on the IDLE state.
Below is a diagram that represents the six most common states – CELL_DCH, CELL_FACH, CELL_PCH, URA_PCH, IDLE, DISCONNECT – and some of the possible transitions.

 

RSTP

Rapid Spanning Tree Protocol

In 2001, the IEEE introduced Rapid Spanning Tree Protocol (RSTP) as 802.1w. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. RSTP was designed to be backwards-compatible with standard STP.
 
While STP can take 30 to 50 seconds to respond to a topology change, RSTP is typically able to respond to changes within 3 × Hello times (default: 3 times 2 seconds) or within a few milliseconds of a physical link failure. The Hello time is an important and configurable time interval that is used by RSTP for several purposes; its default value is 2 seconds.
 
Standard IEEE 802.1D-2004 incorporates RSTP and obsoletes the original STP standard.

RSVP

Resource Reservation Protocol

The Resource Reservation Protocol (RSVP) is a transport layer protocol designed to reserve resources across a network for quality of service (QoS) using the integrated services model. RSVP operates over an IPv4 or IPv6 and provides receiver-initiated setup of resource reservations for multicast or unicast data flows. It does not transport application data but is similar to a control protocol, like Internet Control Message Protocol (ICMP) or Internet Group Management Protocol (IGMP). RSVP is described in RFC 2205.
 
RSVP can be used by hosts and routers to request or deliver specific levels of QoS for application data streams or flows. RSVP defines how applications place reservations and how they can relinquish the reserved resources once no longer required. RSVP operation will generally result in resources being reserved in each node along a path. RSVP is not a routing protocol and was designed to interoperate with current and future routing protocols.
 
RSVP by itself is rarely deployed in telecommunications networks today[citation needed] but, as of February 2003, the traffic engineering extension of RSVP, or RSVP-TE, is becoming more widely accepted nowadays in many QoS-oriented networks. Next Steps in Signaling (NSIS) is a proposed replacement for RSVP.

RTCP

Real-Time Control Protocol

The RTP Control Protocol (RTCP) is a sister protocol of the Real-time Transport Protocol (RTP). Its basic functionality and packet structure is defined in RFC 3550. RTCP provides out-of-band statistics and control information for an RTP session. It partners with RTP in the delivery and packaging of multimedia data, but does not transport any media data itself.
 
The primary function of RTCP is to provide feedback on the quality of service (QoS) in media distribution by periodically sending statistics information such as transmitted octet and packet counts, packet loss, packet delay variation, and round-trip delay time to participants in a streaming multimedia session. An application may use this information to control quality of service parameters, perhaps by limiting flow, or using a different codec.

RTOS

A real-time operating system (RTOS) is an operating system (OS) intended to serve real-time applications that process data as it comes in, typically without buffer delays. Processing time requirements (including any OS delay) are measured in tenths of seconds or shorter increments of time. A real time system is a time bound system which has well defined fixed time constraints. Processing must be done within the defined constraints or the system will fail. They either are event driven or time sharing. Event driven systems switch between tasks based on their priorities while time sharing systems switch the task based on clock interrupts. Most RTOS's use a pre-emptive scheduling algorithm.
 
A key characteristic of an RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task; the variability is jitter. A hard real-time operating system has less jitter than a soft real-time operating system. The chief design goal is not high throughput, but rather a guarantee of a soft or hard performance category. An RTOS that can usually or generally meet a deadline is a soft real-time OS, but if it can meet a deadline deterministically it is a hard real-time OS.
 
An RTOS has an advanced algorithm for scheduling. Scheduler flexibility enables a wider, computer-system orchestration of process priorities, but a real-time OS is more frequently dedicated to a narrow set of applications. Key factors in a real-time OS are minimal interrupt latency and minimal thread switching latency; a real-time OS is valued more for how quickly or how predictably it can respond than for the amount of work it can perform in a given period of time.

RTP

Real-time Protocol

The Real-time Transport Protocol (RTP) is a network protocol for delivering audio and video over IP networks. RTP is used extensively in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications including WebRTC, television services and web-based push-to-talk features.
 
RTP typically runs over User Datagram Protocol (UDP). RTP is used in conjunction with the RTP Control Protocol (RTCP). While RTP carries the media streams (e.g., audio and video), RTCP is used to monitor transmission statistics and quality of service (QoS) and aids synchronization of multiple streams. RTP is one of the technical foundations of Voice over IP and in this context is often used in conjunction with a signalling protocol such as the Session Initiation Protocol (SIP) which establishes connections across the network.

RTSP

Real Time Streaming Protocol

The Real Time Streaming Protocol (RTSP) is a network control protocol designed for use in entertainment and communications systems to control streaming media servers. The protocol is used for establishing and controlling media sessions between end points. Clients of media servers issue VCR-style commands, such as play, record and pause, to facilitate real-time control of the media streaming from the server to a client (Video On Demand) or from a client to the server (Voice Recording).
 
The transmission of streaming data itself is not a task of RTSP. Most RTSP servers use the Real-time Transport Protocol (RTP) in conjunction with Real-time Control Protocol (RTCP) for media stream delivery.

Ruby

Ruby is a dynamic, interpreted, reflective, object-oriented, general-purpose programming language. It was designed and developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan.
 
According to the creator, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, and Lisp. It supports multiple programming paradigms, including functional, object-oriented, and imperative. It also has a dynamic type system and automatic memory management.

Ruby on rails

Ruby on Rails, or Rails, is a server-side web application framework written in Ruby under the MIT License. Rails is a model–view–controller (MVC) framework, providing default structures for a database, a web service, and web pages. It encourages and facilitates the use of web standards such as JSON or XML for data transfer, and HTML, CSS and JavaScript for display and user interfacing. In addition to MVC, Rails emphasizes the use of other well-known software engineering patterns and paradigms, including convention over configuration (CoC), don't repeat yourself (DRY), and the active record pattern.

Rule of Simplicity

Rules of Simplicity is a set of criteria, in priority order, proposed by Kent Beck to judge whether some source code is "simple enough."

RUP

Rational Unified Process

an object-oriented and Web-enabled program development methodology that is said to be like an online mentor that provides guidelines, templates, and examples for all aspects and stages of program development.