S- Tag

Service VLAN Tag

The IEEE standard 802.1ad provides for double-tagging by service providers so that they can use VLANs allocated internally together with traffic already tagged as VLANs by service provider customers.
 
In this double tagging, the S-Tag comes first followed by the C-Tag (customer tag). The standard 802.1ad specifies a TPID of 0x88a8 for the outer S-Tag.

SAAL

Signalling ATM Adaptation Layer

In ATM (Asynchronous Transfer Mode), the SAAL (ATM Adaptation Layer for Signalling) provides reliable transport of signalling messages between peer entities. These signalling messages are carried over a PVC (Permanent Virtual Circuit).

SaaS

Software As A Service

Software as a service is a software licensing and delivery model in which software is licensed on a subscription basis and is centrally hosted. It is sometimes referred to as "on-demand software". SaaS is typically accessed by users using a thin client, e.g. via a web browser.
 

 

 

 

SaaS

Software as a Service

Software as a service (SaaS /sæs/) is a software licensing and delivery model in which software is licensed on a subscription basis and is centrally hosted. It is sometimes referred to as "on-demand software", and was formerly referred to as "software plus services" by Microsoft. SaaS is typically accessed by users using a thin client via a web browser. SaaS has become a common delivery model for many business applications, including office software, messaging software, payroll processing software, DBMS software, management software, CAD software, development software, gamification, virtualization, accounting, collaboration, customer relationship management (CRM), Management Information Systems (MIS), enterprise resource planning (ERP), invoicing, human resource management (HRM), talent acquisition, learning management systems, content management (CM), and service desk management. SaaS has been incorporated into the strategy of nearly all leading enterprise software companies

SAE

System Architecture Evolution

System Architecture Evolution (SAE) is the core network architecture of 3GPP's LTE wireless communication standard.
 
SAE is the evolution of the GPRS Core Network, with some differences:

• simplified architecture

• all-IP Network (AIPN)

• support for higher throughput and lower latency radio access networks (RANs)

• support for, and mobility between, multiple heterogeneous access networks, including E-UTRA (LTE and LTE Advanced air interface), 3GPP legacy systems (for example GERAN or UTRAN, air interfaces of GPRS and UMTS respectively), but also non-3GPP systems (for example WiFi, WiMAX or cdma2000)
  
  

  
   

SAFe

scaled agile framework enterprise

agile methodology used for software development.

SBC

Session Border Controller

A session border controller (SBC) is a device regularly deployed in Voice over Internet Protocol (VoIP) networks to exert control over the signalling and usually also the media streams involved in setting up, conducting, and tearing down telephone calls or other interactive media communications.

 

Scala

Scala is a general-purpose programming language providing support for functional programming and a strong static type system. Designed to be concise, many of Scala's design decisions aimed to address criticisms of Java.
 
Scala source code is intended to be compiled to Java bytecode, so that the resulting executable code runs on a Java virtual machine. Scala provides language interoperability with Java, so that libraries written in both languages may be referenced directly in Scala or Java code. Like Java, Scala is object-oriented, and uses a curly-brace syntax reminiscent of the C programming language. Unlike Java, Scala has many features of functional programming languages like Scheme, Standard ML and Haskell, including currying, type inference, immutability, lazy evaluation, and pattern matching. It also has an advanced type system supporting algebraic data types, covariance and contravariance, higher-order types (but not higher-rank types), and anonymous types. Other features of Scala not present in Java include operator overloading, optional parameters, named parameters, and raw strings. Conversely, a feature of Java not in Scala is checked exceptions, which have proved controversial.

Scaled Agile

agile scaled up to large projects or programmes, for example by having multiple sub-projects, creating tranches of projects, etc.

SCCP

Signalling Connection Control Part

The (SCCP) is a network layer protocol that provides extended routing, flow control, segmentation, connection-orientation, and error correction facilities in Signaling System 7 telecommunications networks. SCCP relies on the services of MTP for basic routing and error detection.

Scenario

A narrative description of an activity or activities which take the form of a story

SC-FDMA

Single-carrier FDMA

Single-carrier FDMA (SC-FDMA) is a frequency-division multiple access scheme. It is also called Linearly precoded OFDMA (LP-OFDMA). Like other multiple access schemes (TDMA, FDMA, CDMA, OFDMA), it deals with the assignment of multiple users to a shared communication resource. SC-FDMA can be interpreted as a linearly precoded OFDMA scheme, in the sense that it has an additional DFT processing step preceding the conventional OFDMA processing.
SC-FDMA has drawn great attention as an attractive alternative to OFDMA, especially in the uplink communications where lower peak-to-average power ratio (PAPR) greatly benefits the mobile terminal in terms of transmit power efficiency and reduced cost of the power amplifier. It has been adopted as the uplink multiple access scheme in 3GPP Long Term Evolution (LTE), or Evolved UTRA (E-UTRA).

Schedule

General term for a plan that defines calendar timing, resources, dependencies, and other details for tasks necessary to complete a project or part of a project. CxOne defines two major classes of schedules, business schedules and detailed schedules.

Scheduler

In computing, scheduling is the method by which work specified by some means is assigned to resources that complete the work. The work may be virtual computation elements such as threads, processes or data flows, which are in turn scheduled onto hardware resources such as processors, network links or expansion cards.
 
A scheduler is what carries out the scheduling activity. Schedulers are often implemented so they keep all computer resources busy (as in load balancing), allow multiple users to share system resources effectively, or to achieve a target quality of service. Scheduling is fundamental to computation itself, and an intrinsic part of the execution model of a computer system; the concept of scheduling makes it possible to have computer multitasking with a single central processing unit (CPU).
 
A scheduler may aim at one or more of many goals, for example: maximizing throughput (the total amount of work completed per time unit); minimizing wait time (time from work becoming enabled until the first point it begins execution on resources); minimizing latency or response time (time from work becoming enabled until it is finished in case of batch activity, or until the system responds and hands the first output to the user in case of interactive activity); or maximizing fairness (equal CPU time to each process, or more generally appropriate times according to the priority and workload of each process). In practice, these goals often conflict (e.g. throughput versus latency), thus a scheduler will implement a suitable compromise. Preference is measured by any one of the concerns mentioned above, depending upon the user's needs and objectives.
 
In real-time environments, such as embedded systems for automatic control in industry (for example robotics), the scheduler also must ensure that processes can meet deadlines; this is crucial for keeping the system stable. Scheduled tasks can also be distributed to remote devices across a network and managed through an administrative back end.

SCM

software configuration management

In software engineering, software configuration management (SCM or S/W CM) is the task of tracking and controlling changes in the software, part of the larger cross-disciplinary field of configuration management.[2] SCM practices include revision control and the establishment of baselines. If something goes wrong, SCM can determine what was changed and who changed it. If a configuration is working well, SCM can determine how to replicate it across many hosts.

Scratch

Scratch is a visual programming language and online community targeted primarily at children. Using Scratch, users can create online projects and develop them into almost anything by using a simple block-like interface. When they are ready, they then share, and also discuss their creations with each other. Developed by the Lifelong Kindergarten group at the MIT Media Lab, the service is designed to help children (ages 8 and up) learn to utilize their imaginations, practice common sense, and, most importantly, to interact with computers.

Scribe

Records issues during an inspection or other formal meeting.

Scrum

Scrum is a process framework used to manage product development and other knowledge work.

Scrum Master

The scrum master is responsible for ensuring the team lives agile values and principles and follows the practices that the team agreed they would use.

Scrum of Scrums

A technique to scale Scrum up to large groups (over a dozen people), consisting of dividing the groups into Agile teams of 5-10.

SCTP

Stream Control Transmission Protocol

The (SCTP) is a computer networking communications protocol which operates at the transport layer and serves a role similar to the popular protocols TCP and UDP. It is standardized by IETF in RFC 4960.
 
SCTP provides some of the features of both UDP and TCP: it is message-oriented like UDP and ensures reliable, in-sequence transport of messages with congestion control like TCP. It differs from those protocols by providing multi-homing and redundant paths to increase resilience and reliability.

SDES

Session Description protocol Security

SDES (Session Description Protocol Security Descriptions) for Media Streams is a way to negotiate the key for Secure Real-time Transport Protocol.

SDH

Synchronous Digital Hierarchy

Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diodes (LEDs). At low transmission rates data can also be transferred via an electrical interface. The method was developed to replace the plesiochronous digital hierarchy (PDH) system for transporting large amounts of telephone calls and data traffic over the same fiber without synchronization problems.
 
SONET and SDH, which are essentially the same, were originally designed to transport circuit mode communications (e.g., DS1, DS3) from a variety of different sources, but they were primarily designed to support real-time, uncompressed, circuit-switched voice encoded in PCM format.[1] The primary difficulty in doing this prior to SONET/SDH was that the synchronization sources of these various circuits were different. This meant that each circuit was actually operating at a slightly different rate and with different phase. SONET/SDH allowed for the simultaneous transport of many different circuits of differing origin within a single framing protocol. SONET/SDH is not a communications protocol in itself, but a transport protocol.
 
Due to SONET/SDH's essential protocol neutrality and transport-oriented features, SONET/SDH was the obvious choice for transporting the fixed length Asynchronous Transfer Mode (ATM) frames also known as cells. It quickly evolved mapping structures and concatenated payload containers to transport ATM connections. In other words, for ATM (and eventually other protocols such as Ethernet), the internal complex structure previously used to transport circuit-oriented connections was removed and replaced with a large and concatenated frame (such as STS-3c) into which ATM cells, IP packets, or Ethernet frames are placed.

SDK

Software Development Kit

a set of programs used by a computer programmer to write application programs.

SDLC

Synchronous Data Link Control

Synchronous Data Link Control (SDLC) is a computer communications protocol. It is the layer 2 protocol for IBM's Systems Network Architecture (SNA). SDLC supports multipoint links as well as error correction. It also runs under the assumption that an SNA header is present after the SDLC header.[1] SDLC was mainly used by IBM mainframe and midrange systems; however, implementations exist on many platforms from many vendors. The use of SDLC (and SNA) is becoming more and more rare, mostly replaced by IP-based protocols or being tunnelled through IP (using AnyNet or other technologies)

SDLC

systems development life cycle model

one of a number of structured approaches to information system development, created to guide all the processes involved, from an initial feasibility study through maintenance of the completed application. Models include the waterfall model; rapid application development (RAD); joint application development (JAD); the fountain model; the spiral model; build and fix; and synchronize-and-stabilize.

SDMA

Space-division multiple access

Space-division multiple access (SDMA) is a channel access method based on creating parallel spatial pipes[clarification needed] next to higher capacity pipes through spatial multiplexing and/or diversity, by which it is able to offer superior performance in radio multiple access communication systems.[clarification needed] In traditional mobile cellular network systems, the base station has no information on the position of the mobile units within the cell and radiates the signal in all directions within the cell in order to provide radio coverage. This results in wasting power on transmissions when there are no mobile units to reach, in addition to causing interference for adjacent cells using the same frequency, so called co-channel cells. Likewise, in reception, the antenna receives signals coming from all directions including noise and interference signals. By using smart antenna technology and differing spatial locations of mobile units within the cell, space-division multiple access techniques offer attractive performance enhancements. The radiation pattern of the base station, both in transmission and reception, is adapted to each user to obtain highest gain in the direction of that user. This is often done using phased array techniques.
 
In GSM cellular networks, the base station is aware of the distance (but not direction) of a mobile phone by use of a technique called "timing advance" (TA). The base transceiver station (BTS) can determine how far the mobile station (MS) is by interpreting the reported TA. This information, along with other parameters, can then be used to power down the BTS or MS, if a power control feature is implemented in the network. The power control in either BTS or MS is implemented in most modern networks, especially on the MS, as this ensures a better battery life for the MS. This is also why having a BTS close to the user results in less exposure to electromagnetic radiation.

SDN

Software Defined Network

Software-defined networking (SDN) technology is an approach to cloud computing that facilitates network management and enables programmatically efficient network configuration in order to improve network performance and monitoring. SDN is meant to address the fact that the static architecture of traditional networks is decentralized and complex while current networks require more flexibility and easy troubleshooting. SDN suggests to centralize network intelligence in one network component by disassociating the forwarding process of network packets (data plane) from the routing process (control plane). The control plane consists of one or more controllers which are considered as the brain of SDN network where the whole intelligence is incorporated. However, the intelligence centralization has its own drawbacks when it comes to security, scalability and elasticity and this is the main issue of SDN

SDP

Session Description Protocol

The Session Description Protocol (SDP) is a format for describing streaming media communications parameters. The IETF published the original specification as an IETF Proposed Standard in April 1998, and subsequently published a revised specification as an IETF Proposed Standard as RFC 4566 in July 2006.
 
SDP is used for describing multimedia communication sessions for the purposes of session announcement, session invitation, and parameter negotiation. SDP does not deliver any media by itself but is used between endpoints for negotiation of media type, format, and all associated properties. The set of properties and parameters are often called a session profile.
 
SDP is designed to be extensible to support new media types and formats. SDP started off as a component of the Session Announcement Protocol (SAP), but found other uses in conjunction with Real-time Transport Protocol (RTP), Real-time Streaming Protocol (RTSP), Session Initiation Protocol (SIP) and even as a standalone format for describing multicast sessions.

SDSL

Symmetrical Digital Subscriber Line

A symmetric digital subscriber line (SDSL) is a digital subscriber line (DSL) that transmits digital data over the copper wires of the telephone network, where the bandwidth in the downstream direction, from the network to the subscriber, is identical to the bandwidth in the upstream direction, from the subscriber to the network. This symmetric bandwidth can be considered to be the opposite of the asymmetric bandwidth offered by asymmetric digital subscriber line (ADSL) technologies, where the upstream bandwidth is lower than the downstream bandwidth. SDSL is generally marketed at business customers, while ADSL is marketed at private as well as business customers.
 
More specifically, SDSL can be understood as:

• in the wider sense, an umbrella term for all DSL variant which offer symmetric bandwidth, including IDSL, which offers 144 kbit/s, HDSL, HDSL2, G.SHDSL, which offers up to 22.784 Mbit/s over four pairs of copper wires, as well as the SDSL variant below

• in the narrow sense, a particular proprietary and non-standardized DSL variant for operation at 1.544 Mbit/s or 2.048 Mbit/s over a single pair of copper wires, without support for analog calls on the same line

• a term used by ETSI to refer to G.SHDSL

Sed

sed (stream editor) is a Unix utility that parses and transforms text, using a simple, compact programming language. sed was developed from 1973 to 1974 by Lee E. McMahon of Bell Labs, and is available today for most operating systems. sed was based on the scripting features of the interactive editor ed ("editor", 1971) and the earlier qed ("quick editor", 1965–66). sed was one of the earliest tools to support regular expressions, and remains in use for text processing, most notably with the substitution command. Popular alternative tools for plaintext string manipulation and "stream editing" include AWK and Perl.

Semaphore

In computer science, a semaphore is a variable or abstract data type used to control access to a common resource by multiple processes in a concurrent system such as a multitasking operating system. Semaphore is simply a variable. This variable is used to solve critical section problems and to achieve process synchronization in the multi processing environment.
 
A trivial semaphore is a plain variable that is changed (for example, incremented or decremented, or toggled) depending on programmer-defined conditions.
 
A useful way to think of a semaphore as used in the real-world systems is as a record of how many units of a particular resource are available, coupled with operations to adjust that record safely (i.e. to avoid race conditions) as units are required or become free, and, if necessary, wait until a unit of the resource becomes available.
 
Semaphores are a useful tool in the prevention of race conditions; however, their use is by no means a guarantee that a program is free from these problems. Semaphores which allow an arbitrary resource count are called counting semaphores, while semaphores which are restricted to the values 0 and 1 (or locked/unlocked, unavailable/available) are called binary semaphores and are used to implement locks.

Sematic Versioning

Given a version number MAJOR.MINOR.PATCH, increment the:

1. MAJOR version when you make incompatible API changes,

2. MINOR version when you add functionality in a backwards compatible manner, and

3. PATCH version when you make backwards compatible bug fixes.

Additional labels for pre-release and build metadata are available as extensions to the MAJOR.MINOR.PATCH format.

<valid semver> ::= <version core>
                 | <version core> "-" <pre-release>
                 | <version core> "+" <build>
                 | <version core> "-" <pre-release> "+" <build>

<version core> ::= <major> "." <minor> "." <patch>

<major> ::= <numeric identifier>

<minor> ::= <numeric identifier>

<patch> ::= <numeric identifier>

<pre-release> ::= <dot-separated pre-release identifiers>

<dot-separated pre-release identifiers> ::= <pre-release identifier>
                                          | <pre-release identifier> "." <dot-separated pre-release identifiers>

<build> ::= <dot-separated build identifiers>

<dot-separated build identifiers> ::= <build identifier>
                                    | <build identifier> "." <dot-separated build identifiers>

<pre-release identifier> ::= <alphanumeric identifier>
                           | <numeric identifier>

<build identifier> ::= <alphanumeric identifier>
                     | <digits>

<alphanumeric identifier> ::= <non-digit>
                            | <non-digit> <identifier characters>
                            | <identifier characters> <non-digit>
                            | <identifier characters> <non-digit> <identifier characters>

<numeric identifier> ::= "0"
                       | <positive digit>
                       | <positive digit> <digits>

<identifier characters> ::= <identifier character>
                          | <identifier character> <identifier characters>

<identifier character> ::= <digit>
                         | <non-digit>

<non-digit> ::= <letter>
              | "-"

<digits> ::= <digit>
           | <digit> <digits>

<digit> ::= "0"
          | <positive digit>

<positive digit> ::= "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"

<letter> ::= "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J"
           | "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" | "S" | "T"
           | "U" | "V" | "W" | "X" | "Y" | "Z" | "a" | "b" | "c" | "d"
           | "e" | "f" | "g" | "h" | "i" | "j" | "k" | "l" | "m" | "n"
           | "o" | "p" | "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x"
           | "y" | "z"

Sequence Model

Specifies the set of object roles and their interactions by showing and describing the messages exchanged. The focus is on the timing of messages.

SF

Super Frame

In telecommunications, superframe (SF) is a T1 framing standard. In the 1970s it replaced the original T1/D1 framing scheme of the 1960s in which the framing bit simply alternated between 0 and 1.

SFTP

Secure File Transfer Protocol

In computing, the SSH File Transfer Protocol (also Secure File Transfer Protocol, or SFTP) is a network protocol that provides file access, file transfer, and file management over any reliable data stream. It was designed by the Internet Engineering Task Force (IETF) as an extension of the Secure Shell protocol (SSH) version 2.0 to provide secure file transfer capabilities. The IETF Internet Draft states that, even though this protocol is described in the context of the SSH-2 protocol, it could be used in a number of different applications, such as secure file transfer over Transport Layer Security (TLS) and transfer of management information in VPN applications.
 
This protocol assumes that it is run over a secure channel, such as SSH, that the server has already authenticated the client, and that the identity of the client user is available to the protocol.

SGML

Standard Generalized Markup Language

The Standard Generalized Markup Language (SGML; ISO 8879:1986) is a standard for defining generalized markup languages for documents. ISO 8879 Annex A.1 defines generalized markup:
 
Generalized markup is based on two postulates:

• Markup should be declarative: it should describe a document's structure and other attributes, rather than specify the processing to be performed on it. Declarative markup is less likely to conflict with unforeseen future processing needs and techniques.
  Markup should be rigorous so that the techniques available for processing rigorously-defined objects like programs and databases can be used for processing documents as well.

<!-- Lunch at the steakhouse -->

<!ELEMENT  lunch (meal)+   -- one meal per person -->

<!ELEMENT  meal  (appetiz?, steak, dessert?, 
                     custname, whopays)     +(drink) >

<!-- The plus sign after the content model followed by 
one or more elements within parentheses declares an 
"inclusion". An inclusion indicates that the elements 
can appear anywhere in the element to which they are 
attached and in any of its subelements. You can have 
one or more DRINK elements any time during MEAL. -->

<!ELEMENT  appetiz  (soup | salad) >

<!ELEMENT  soup     EMPTY      --soup of the day -->

<!ELEMENT  salad    EMPTY>

<!ATTLIST  salad  kind   NAME   #REQUIRED 
               dressing (french | 1000isl | bluechse) #REQUIRED>

<!-- The declared value for the attribute DRESSING is 
called a "name token group", a series of values separated 
by a vertical bar (|). They represent the only possible 
values for the attribute. the declared value NAME requires 
a value usually comprising up to 8 letters and numbers. 
REQUIRED means that one value must be specified for the 
attribute. -->

<!ELEMENT steak   EMPTY>

<!ATTLIST steak cook (rare|medrare|medium) "medrare"
              side  (potato|fries|rice) "fries">

<!--The value between quotes is used to force a default 
value in case no value is specified for the attribute. -->

<!ELEMENT  dessert             (cake|applepie)>

<!ELEMENT  (cake|applepie)      EMPTY>

<!ATTLIST   cake    kind    CDATA  #REQUIRED>

<!-- CDATA means any letters, numbers, punctuation, 
spaces, or other special characters. This gives you 
the possibility of creating long and unique values 
for an attribute. This means you can ask for any 
cake you want; if the system doesn't recognize the 
name, you may not get it. -->

<!ATTLIST applepie    hot    (hot|warm|cool) #IMPLIED
                  icecream   (yes|no)        #IMPLIED

<!--   IMPLIED is an equivalent for optional. The 
APPLEPIE comes the way the waiter or waitress prefers 
unless you specify otherwise. -->

<!ELEMENT  drink     (water|beer|cola)>

<!ELEMENT  (water|beer|cola)     EMPTY>

<!ATTLIST  water   kind  (tap)    #FIXED    tap>

<!-- The declared value for WATER is fixed by the 
system. You can order any kind of fancy water you 
want, but all they've got here is tap water. -->

<!ATTLIST beer   number  NUMBER        #REQUIRED>

<!ATTLIST cola   type    (regular | diet) #CURRENT>

<!-- Beer is ordered by NUMBER from the beer list. 
The Default Value CURRENT says that the first time 
the element COLA appears, a type must be specified. 
That value will be used for the next occurrences 
unless you specify another. In other words, you 
don't have to re-specify the type of COLA every 
time you ask for a refill.-->

<!ELEMENT  (custname | whopays)        (#PCDATA)   >

<!ATTLIST  custname      account    ID       #IMPLIED>

<!ATTLIST  whopays       charge     IDREF   #REQUIRED>

<!-- The customer's name is not critical data within 
the content of the element CUSTNAME: The cashier could 
make a typo or use a nickname and the computer would 
have difficulty tracking the charge. Instead a unique 
identifier is requested - but only if the customer has 
an account. However, WHOPAYS has a required IDREF. The 
system knows that WHOPAYS may have the same value for 
many people's meals (when someone buys for the whole 
table) but each CUSTNAME will have a unique ID. The 
system will check that the value of the IDREF will be 
a legitimate ID. The example below illustrates only 
one of several MEALS in the LUNCH. A separate MEAL in 
the same LUNCH must include a CUSTNAME with an 
ACCOUNTID of "ALEXF" for the CHARGE IDREF to work -->

SGSN

Serving GPRS support node

The Serving GPRS Support Node (SGSN) is the node that is serving the MS/UE. The SGSN supports GPRS and/or UMTS. The SGSN keeps track of the location of an individual MS/UE and performs security functions and access control. The SGSN is connected to the GERAN base station system through the Gb or Iu interface and/or to the UTRAN through the Iu interface. A SGSN is responsible for the delivery of data packets from and to the mobile stations within its geographical service area. Its tasks include packet routing and transfer, mobility management (attach/detach and location management), logical link management, and authentication and charging functions. The location register of the SGSN stores location information (e.g., current cell, current VLR) and user profiles (e.g., IMSI, address(es) used in the packet data network) of all GPRS users registered with it.

SGW

signalling gateway

A signalling gateway (SGW) interfaces with the signalling plane of the CS. It transforms lower layer protocols as Stream Control Transmission Protocol (SCTP, an IP protocol) into Message Transfer Part (MTP, an Signalling System 7 (SS7) protocol), to pass ISDN User Part (ISUP) from the MGCF to the CS network.

S-GW

Serving Gateway

The SGW routes and forwards user data packets, while also acting as the mobility anchor for the user plane during inter-eNodeB handovers and as the anchor for mobility between LTE and other 3GPP technologies (terminating S4 interface and relaying the traffic between 2G/3G systems and PGW). For idle state UEs, the SGW terminates the downlink data path and triggers paging when downlink data arrives for the UE. It manages and stores UE contexts, e.g. parameters of the IP bearer service, network internal routing information. It also performs replication of the user traffic in case of lawful interception.

Sh

The Bourne shell (sh) is a shell, or command-line interpreter, for computer operating systems.
 
The Bourne shell was the default shell for Version 7 Unix. Most Unix-like systems continue to have /bin/sh—which will be the Bourne shell, or a symbolic link or hard link to a compatible shell—even when other shells are used by most users.

SHA

Secure Hash Algorithm

The Secure Hash Algorithms are a family of cryptographic hash functions published by the National Institute of Standards and Technology (NIST) as a U.S. Federal Information Processing Standard (FIPS), including:
 

• SHA-0: A retronym applied to the original version of the 160-bit hash function published in 1993 under the name "SHA". It was withdrawn shortly after publication due to an undisclosed "significant flaw" and replaced by the slightly revised version SHA-1.

• SHA-1: A 160-bit hash function which resembles the earlier MD5 algorithm. This was designed by the National Security Agency (NSA) to be part of the Digital Signature Algorithm. Cryptographic weaknesses were discovered in SHA-1, and the standard was no longer approved for most cryptographic uses after 2010.

• SHA-2: A family of two similar hash functions, with different block sizes, known as SHA-256 and SHA-512. They differ in the word size; SHA-256 uses 32-bit words where SHA-512 uses 64-bit words. There are also truncated versions of each standard, known as SHA-224, SHA-384, SHA-512/224 and SHA-512/256. These were also designed by the NSA.

• SHA-3: A hash function formerly called Keccak, chosen in 2012 after a public competition among non-NSA designers. It supports the same hash lengths as SHA-2, and its internal structure differs significantly from the rest of the SHA family.
  The corresponding standards are FIPS PUB 180 (original SHA), FIPS PUB 180-1 (SHA-1), FIPS PUB 180-2 (SHA-1, SHA-256, SHA-384, and SHA-512). NIST has updated Draft FIPS Publication 202, SHA-3 Standard separate from the Secure Hash Standard (SHS).

Shell Scripting

A shell script is a computer program designed to be run by the Unix shell, a command-line interpreter. The various dialects of shell scripts are considered to be scripting languages. Typical operations performed by shell scripts include file manipulation, program execution, and printing text. A script which sets up the environment, runs the program, and does any necessary cleanup, logging, etc. is called a wrapper.
 
The term is also used more generally to mean the automated mode of running an operating system shell; in specific operating systems they are called other things such as batch files (MSDos-Win95 stream, OS/2), command procedures (VMS), and shell scripts (Windows NT stream and third-party derivatives like 4NT—article is at cmd.exe), and mainframe operating systems are associated with a number of terms.

Sidetone

Sidetone is audible feedback to someone speaking when using a handset or headset as an indication of an active transmission. The term is often used in the telecommunication field.

Sign Up

for Tasks Members of an Agile development team normally choose which tasks to work on, rather than being assigned work by a manager. (see more

SIM

Subscriber Identity Module

A subscriber identity module or subscriber identification module (SIM), widely known as a SIM card, is an integrated circuit that is intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers). It is also possible to store contact information on many SIM cards. SIM cards are always used on GSM phones; for CDMA phones, they are only needed for newer LTE-capable handsets. SIM cards can also be used in satellite phones, smart watches, computers, or cameras.
 
The SIM circuit is part of the function of a universal integrated circuit card (UICC) physical smart card, which is usually made of PVC with embedded contacts and semiconductors. SIM cards are transferable between different mobile devices. The first UICC smart cards were the size of credit and bank cards; sizes were reduced several times over the years, usually keeping electrical contacts the same, so that a larger card could be cut down to a smaller size.
 
A SIM card contains its unique serial number (ICCID), international mobile subscriber identity (IMSI) number, security authentication and ciphering information, temporary information related to the local network, a list of the services the user has access to, and two passwords: a personal identification number (PIN) for ordinary use, and a personal unblocking code (PUC) for PIN unlocking.
 
SIM cards have been made smaller over the years; functionality is independent of format. Full-size SIM were followed by mini-SIM, micro-SIM, and nano-SIM. SIM cards are also made to embed in devices.
 

 

 

SIMPLE

Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions

SIMPLE, the Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions, is an instant messaging (IM) and presence protocol suite based on Session Initiation Protocol (SIP) managed by the Internet Engineering Task Force. Contrary to the vast majority of IM and presence protocols used by software deployed today, SIMPLE is an open standard like XMPP.

Simple Design

A team adopting the "simple design" practice bases its software design strategy on a set of "simple design" principles.

Simplex

Simplex communication is a communication channel that sends information in one direction only.
 
The International Telecommunication Union definition is a communications channel that operates in one direction at a time, but that may be reversible; this is termed half duplex in other contexts. A duplex communication channel requires two simplex channels operating in opposite directions.
 


 

Single Step Test

Test conducted in a debugging environment by stepping through the source code while executing.

SIP

Session Initiation Protocol

The Session Initiation Protocol (SIP) is a communications protocol for signaling and controlling multimedia communication sessions in applications of Internet telephony for voice and video calls, in private IP telephone systems, as well as in instant messaging over Internet Protocol (IP) networks.
 
The protocol defines the specific format of messages exchanged and the sequence of communications for cooperation of the participants. SIP is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP).[1] A call established with SIP may consist of multiple media streams, but no separate streams are required for applications, such as text messaging, that exchange data as payload in the SIP message.
 
SIP works in conjunction with several other protocols that specify and carry the session media. Media type and parameter negotiation and media setup is performed with the Session Description Protocol (SDP), which is carried as payload in SIP messages. SIP is designed to be independent of the underlying transport layer protocol, and can be used with the User Datagram Protocol (UDP), the Transmission Control Protocol (TCP), and the Stream Control Transmission Protocol (SCTP). For the transmission of media streams (voice, video) SIP typically employs the Real-time Transport Protocol (RTP) or the Secure Real-time Transport Protocol (SRTP). For secure transmissions of SIP messages over insecure network links, the protocol may be encrypted with Transport Layer Security (TLS)


 
 

SIP Trunk

SIP trunking enables the end point's PBX (Phone Exchange System) to send and receive calls via Internet. As SIP is applied for the signalling protocol for multiple real-time application, SIP trunk is able to control voice, video and messaging applications.
It is also a voice over Internet Protocol (VoIP) technology and streaming media service based on the Session Initiation Protocol (SIP) by which Internet telephony service providers (ITSPs) deliver telephone services and unified communications to customers equipped with SIP-based private branch exchange (IP-PBX) and unified communications facilities.

SISO

single-input and single-output

A single-input and single-output (SISO) system is a simple single variable control system with one input and one output. In radio it is the use of only one antenna both in the transmitter and receiver.

Skew

Clock skew (sometimes called timing skew) is a phenomenon in synchronous digital circuit systems (such as computer systems) in which the same sourced clock signal arrives at different components at different times i.e. the instantaneous difference between the readings of any two clocks is called their skew.

SLA

Service Level Agreement

A service-level agreement (SLA) is a commitment between a service provider and a client. Particular aspects of the service – quality, availability, responsibilities – are agreed between the service provider and the service user. The most common component of SLA is that the services should be provided to the customer as agreed upon in the contract. As an example, Internet service providers and telcos will commonly include service level agreements within the terms of their contracts with customers to define the level(s) of service being sold in plain language terms. In this case the SLA will typically have a technical definition in mean time between failures (MTBF), mean time to repair or mean time to recovery (MTTR); identifying which party is responsible for reporting faults or paying fees; responsibility for various data rates; throughput; jitter; or similar measurable details.

SLIP

Serial Line Interface Protocol

The Serial Line Internet Protocol (also SLIP) is an encapsulation of the Internet Protocol designed to work over serial ports and modem connections. It is documented in RFC 1055. On personal computers, SLIP has been largely replaced by the Point-to-Point Protocol (PPP), which is better engineered, has more features and does not require its IP address configuration to be set before it is established. On microcontrollers, however, SLIP is still the preferred way of encapsulating IP packets due to its very small overhead.

SME

Subject Matter Expert

A subject-matter expert (SME) or domain expert is a person who is an authority in a particular area or topic. The term domain expert is frequently used in expert systems software development, and there the term always refers to the domain other than the software domain. A domain expert is a person with special knowledge or skills in a particular area of endeavour (e.g. an accountant is an expert in the domain of accountancy). The development of accounting software requires knowledge in two different domains: accounting and software. Some of the development workers may be experts in one domain and not the other.

Smoke Test

Test conducted to prove a build.

smoke testing

non-exhaustive software testing, ascertaining that the most crucial functions of a prog

SMP

Symmetric Multiprocessing

Symmetric multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all input and output devices, and are controlled by a single operating system instance that treats all processors equally, reserving none for special purposes. Most multiprocessor systems today use an SMP architecture. In the case of multi-core processors, the SMP architecture applies to the cores, treating them as separate processors.
 
Professor John D. Kubiatowicz considers traditionally SMP systems to contain processors without caches. Culler and Pal-Singh in their 1998 book "Parallel Computer Architecture: A Hardware/Software Approach" mention: "The term SMP is widely used but causes a bit of confusion. [...] The more precise description of what is intended by SMP is a shared memory multiprocessor where the cost of accessing a memory location is the same for all processors; that is, it has uniform access costs when the access actually is to memory. If the location is cached, the access will be faster. but cache access times and memory access times are the same on all processors."
 
SMP systems are tightly coupled multiprocessor systems with a pool of homogeneous processors running independently of each other. Each processor, executing different programs and working on different sets of data, has the capability of sharing common resources (memory, I/O device, interrupt system and so on) that are connected using a system bus or a crossbar.
 

 

SMPF

Shared Metallic Path Facility

A copper pair to the exchange that goes to two telcos, one for telephone service and one for broadband. Normally this means telephone from BT, and can mean broadband from BT or from another provider.

SMSC

Short Message service center

A Short Message Service Center (SMSC) is a network element in the mobile telephone network. Its purpose is to store, forward, convert and deliver Short Message Service (SMS) messages.
 
The full designation of an SMSC according to 3GPP is Short Message Service - Service Center (SMS-SC).
 
Basic Trajectories of SMS are

1. From mobile to another mobile - referred to as MO-MT (Mobile Originated - Mobile Terminated)

2. From mobile to a content provider (also known as Large Account / ESME) - referred to as MO-AT (Mobile Originated - Application Terminated)

3. From application to a mobile - referred to as AO-MT (Application Originated - Mobile Terminated)

Snake Case

Snake case (or snake_case) is the practice of writing compound words or phrases in which the elements are separated with one underscore character (_) and no spaces, with each element's initial letter usually lowercased within the compound and the first letter either upper- or lowercase—as in "foo_bar" and "Hello_world". It is commonly used in computer code for variable names, and function names, and sometimes computer filenames.

SNMP

Simple Network Management Protocol

Simple Network Management Protocol (SNMP) is an Internet Standard protocol for collecting and organizing information about managed devices on IP networks and for modifying that information to change device behavior. Devices that typically support SNMP include cable modems, routers, switches, servers, workstations, printers, and more.
 
SNMP is widely used in network management for network monitoring. SNMP exposes management data in the form of variables on the managed systems organized in a management information base (MIB) which describe the system status and configuration. These variables can then be remotely queried (and, in some circumstances, manipulated) by managing applications.
 
Three significant versions of SNMP have been developed and deployed. SNMPv1 is the original version of the protocol. More recent versions, SNMPv2c and SNMPv3, feature improvements in performance, flexibility and security.
 
SNMP is a component of the Internet Protocol Suite as defined by the Internet Engineering Task Force (IETF). It consists of a set of standards for network management, including an application layer protocol, a database schema, and a set of data objects.
 

 

SNTP

Simple Network time Protocol

A less complex implementation of NTP, using the same protocol but without requiring the storage of state over extended periods of time, is known as the Simple Network Time Protocol (SNTP). It is used in some embedded devices and in applications where full NTP capability is not required.

SOA

Service-oriented architecture

Service-oriented architecture (SOA) is a style of software design where services are provided to the other components by application components, through a communication protocol over a network. The basic principles of service-oriented architecture are independent of vendors, products and technologies. A service is a discrete unit of functionality that can be accessed remotely and acted upon and updated independently, such as retrieving a credit card statement online.
 
A service has four properties according to one of many definitions of SOA:

1. It logically represents a business activity with a specified outcome.

2. It is self-contained.

3. It is a black box for its consumers.

4. It may consist of other underlying services.
   
    
   Different services can be used in conjunction to provide the functionality of a large software application, a principle SOA shares with modular programming. Service-oriented architecture integrates distributed, separately-maintained and -deployed software components. It is enabled by technologies and standards that facilitate components' communication and cooperation over a network, especially over an IP network.

SOAP

Simple Object Access Protocol

SOAP (originally Simple Object Access Protocol) is a messaging protocol specification for exchanging structured information in the implementation of web services in computer networks. Its purpose is to induce extensibility, neutrality and independence. It uses XML Information Set for its message format, and relies on application layer protocols, most often Hypertext Transfer Protocol (HTTP) or Simple Mail Transfer Protocol (SMTP), for message negotiation and transmission.
 
SOAP allows processes running on disparate operating systems (such as Windows and Linux) to communicate using Extensible Markup Language (XML). Since Web protocols like HTTP are installed and running on all operating systems, SOAP allows clients to invoke web services and receive responses independent of language and platforms.

 

Softswitch

A softswitch (software switch) is a central device in a telecommunications network which connects telephone calls from one phone line to another, across a telecommunication network or the public Internet, entirely by means of software running on a general-purpose computer system. Most landline calls are routed by purpose-built electronic hardware; however, soft switches using general purpose servers and VoIP technology are becoming more popular.[1]
 
Many telecommunications networks now make use of combinations of softswitches and more traditional purpose-built hardware.
 
Although the term softswitch technically refers to any such device, it is more conventionally applied to a device that handles IP-to-IP phone calls, while the phrase "access server" or "media gateway" is used to refer to devices that either originate or terminate traditional "land line" (hard wired) phone calls. In practice, such devices can often do both. As a practical distinction, a Skype-to-Skype phone call is entirely IP (internet) based, and so uses a softswitch somewhere in the middle connecting the calling party with the called party. In contrast, access servers might take a mobile call or a call originating from a traditional phone line, convert it to IP traffic, then send it over the internet to another such device, which terminates the call by reversing the process and converting the Voice over IP call back to older circuit switched digital systems using traditional digital ISDN / PSTN protocols that transmit voice traffic using non-IP systems.
 
The Call Agent takes care of functions such as billing, call routing, signaling, call services and the like, supplying the functional logic to accomplish these telephony meta-tasks. A call agent may control several different media gateways in geographically dispersed areas via a TCP/IP link. It is also used to control the functions of media gateway, in order to connect with media as well as other interfaces. This procedure is utilized to keep the interfaces clear as crystal for receiving calls from any phone lines.[2]
 
The softswitch generally resides in a building owned by the telephone company called a telephone exchange (UK/IRL/AUS/NZ) or central office (US/CAN). The central office or telephone exchange has high capacity connections to carry calls to other offices owned by the telecommunication company and to other telecommunication companies via the PSTN.
 
Looking towards the end users from the switch, the softswitch may be connected to several access devices via TCP/IP network. These access devices can range from small and large Analog Telephone Adaptors (ATA) which provide from one to hundreds of Telephone Pairs to an Integrated Access Device (IAD), eMTA s (embedded Multimedia Terminal Adapters) using MGCP/NCS protocol over cable (VoCable) or PBX which may provide several hundred telephone connections
 
Note here that Analogue (ATA), PSTN telephone devices can only be reached by a softswitch that has embedded SS7 or SIGTRAN cards, software in terms of signalling AND Trunking Gateway for Voice traffic IP/TDM, TDM/IP, TDM/TDM functions.
 
Typically the larger access devices will be located in a building owned by the telecommunication company near to the customers they serve. Each end user can be connected to the IAD by a simple pair of copper wires.
 
The medium-sized devices and PBXs are most commonly used by business that locate them on their own premises, and single-line devices are mostly found at private residences.
 
At the turn of the 21st century with IP Multimedia Subsystem (or IMS), the Softswitch element is represented by the Media Gateway Controller (MGC) element, and the term "Softswitch" is rarely used in the IMS context. Rather, it is called an AGCF (Access Gateway Control Function).

Software Change Request

SCR

See change request.

Software Configuration Management

SCM

See configuration management.

Software Development Plan

SDP

Sometimes used as a synonym for project plan on software focused projects.

Software Engineering Body of Knowledge

SWEBOK

IEEE led industry effort to define a body of knowledge for software engineering. Is intended to support defining software engineering as a profession. CxOne bases its top-level organization on SWEBOK.
www.swebok.org

Software Engineering Lab

SEL

NASA lab developed to improving the software process used to develop systems at Goddard.

Software Engineering Process Group

SEPG

Provides experienced and objective technical oversight from individuals who are not directly involved in the project. Also provides process improvement input for projects and the organization.

Software Requirements Specification

SRS

A text based document that captures the requirements for a software system. Often used in conjunction with other requirements techniques such as modeling and prototyping to provide a complete view of system requirements.

SoGEA

Single Order Generic Ethernet Access
 

• Single order Generic Ethernet Access.
• Copper bearer to the cabinet and IP FTTC service delivered in a single order.
• No voice service services provided on copper bearer.
 

 

 

SONET

Synchronous Optical Network

Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diodes (LEDs). At low transmission rates data can also be transferred via an electrical interface. The method was developed to replace the plesiochronous digital hierarchy (PDH) system for transporting large amounts of telephone calls and data traffic over the same fiber without synchronization problems.
 
SONET and SDH, which are essentially the same, were originally designed to transport circuit mode communications (e.g., DS1, DS3) from a variety of different sources, but they were primarily designed to support real-time, uncompressed, circuit-switched voice encoded in PCM format.[1] The primary difficulty in doing this prior to SONET/SDH was that the synchronization sources of these various circuits were different. This meant that each circuit was actually operating at a slightly different rate and with different phase. SONET/SDH allowed for the simultaneous transport of many different circuits of differing origin within a single framing protocol. SONET/SDH is not a communications protocol in itself, but a transport protocol.
 
Due to SONET/SDH's essential protocol neutrality and transport-oriented features, SONET/SDH was the obvious choice for transporting the fixed length Asynchronous Transfer Mode (ATM) frames also known as cells. It quickly evolved mapping structures and concatenated payload containers to transport ATM connections. In other words, for ATM (and eventually other protocols such as Ethernet), the internal complex structure previously used to transport circuit-oriented connections was removed and replaced with a large and concatenated frame (such as STS-3c) into which ATM cells, IP packets, or Ethernet frames are placed.

Source Code

In computing, source code is any collection of code, possibly with comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source code. The source code is often transformed by an assembler or compiler into binary machine code understood by the computer. The machine code might then be stored for execution at a later time. Alternatively, source code may be interpreted and thus immediately executed.
 
Most application software is distributed in a form that includes only executable files. If the source code were included it would be useful to a user, programmer or a system administrator, any of whom might wish to study or modify the program.

SPEEX

Speex is an audio compression format specifically tuned for the reproduction of human speech and also a free software speech codec that may be used on VoIP applications and podcasts. It is based on the CELP speech coding algorithm. Speex claims to be free of any patent restrictions and is licensed under the revised (3-clause) BSD license. It may be used with the Ogg container format or directly transmitted over UDP/RTP. It may also be used with the FLV container format.
 
The Speex designers see their project as complementary to the Vorbis general-purpose audio compression project.
 
Speex is a lossy format, i.e. quality is permanently degraded to reduce file size.
 
The Speex project was created on February 13, 2002. The first development versions of Speex were released under LGPL license, but as of version 1.0 beta 1, Speex is released under Xiph's version of the (revised) BSD license. Speex 1.0 was announced on March 24, 2003, after a year of development. The last stable version of Speex encoder and decoder is 1.2.0.
 
Xiph.Org now considers Speex obsolete; its successor is the more modern Opus codec, which surpasses its performance in all areas.

Spiral Lifecycle

A set of mini-projects cumulating in final delivery. Each mini-project focuses on addressing the current major project risk(s).

Sponsor

Synonym for project sponsor.

Sprial Model

The spiral model is a risk-driven process model generator for software projects. Based on the unique risk patterns of a given project, the spiral model guides a team to adopt elements of one or more process models, such as incremental, waterfall, or evolutionary prototyping.

 

Sprint Planning

Sprint planning is an event that occurs at the beginning of a sprint where the team determines the product backlog items they will work on during that sprint.

Sprint retrospective

a review of a Sprint providing lessons learned with the aim of promoting continuous improvement.

Sprints

a short development phase within a larger project defined by available time ('timeboxes') and resources.

SQL

SQL is a domain-specific language used in programming and designed for managing data held in a relational database management system (RDBMS), or for stream processing in a relational data stream management system (RDSMS). It is particularly useful in handling structured data where there are relations between different entities/variables of the data. SQL offers two main advantages over older read/write APIs like ISAM or VSAM: first, it introduced the concept of accessing many records with one single command; and second, it eliminates the need to specify how to reach a record, e.g. with or without an index.
 
Originally based upon relational algebra and tuple relational calculus, SQL consists of many types of statements, which may be informally classed as sublanguages, commonly: a data query language (DQL), a data definition language (DDL), a data control language (DCL), and a data manipulation language (DML). The scope of SQL includes data query, data manipulation (insert, update and delete), data definition (schema creation and modification), and data access control. Although SQL is often described as, and to a great extent is, a declarative language (4GL), it also includes procedural elements.

SS7

Signaling System 7

Signaling System No. 7 (SS7) is a set of telephony signaling protocols developed in 1975, which is used to set up and tear down most of the world's public switched telephone network (PSTN) telephone calls. It also performs number translation, local number portability, prepaid billing, Short Message Service (SMS), and other mass market services.
 
In North America it is often referred to as CCSS7, abbreviated for Common Channel Signaling System 7. In the United Kingdom, it is called C7 (CCITT number 7), number 7 and CCIS7 (Common Channel Interoffice Signaling 7). In Germany, it is often called ZZK-7 (Zentraler ZeichengabeKanal Nummer 7).
 
The only international SS7 protocol is defined by ITU-T's Q.700-series recommendations in 1988.[1] Of the many national variants of the SS7 protocols, most are based on variants of the international protocol as standardized by ANSI and ETSI. National variants with striking characteristics are the Chinese and Japanese (TTC) national variants.
 
The Internet Engineering Task Force (IETF) has defined the SIGTRAN protocol suite that impinaplements levels 2, 3, and 4 protocols compatible with SS7. Sometimes also called Pseudo SS7, it is layered on the Stream Control Transmission Protocol (SCTP) transport mechanism.
 
SS7 protocol suite
 
The SS7 protocol stack may be partially mapped to the OSI Model of a packetized digital protocol stack. OSI layers 1 to 3 are provided by the Message Transfer Part (MTP) and the Signalling Connection Control Part (SCCP) of the SS7 protocol (together referred to as the Network Service Part (NSP)); for circuit related signaling, such as the BT IUP, Telephone User Part (TUP), or the ISDN User Part (ISUP), the User Part provides layer 7. Currently there are no protocol components that provide OSI layers 4 through 6.[1] The Transaction Capabilities Application Part (TCAP) is the primary SCCP User in the Core Network, using SCCP in connectionless mode. SCCP in connection oriented mode provides transport layer for air interface protocols such as BSSAP and RANAP. TCAP provides transaction capabilities to its Users (TC-Users), such as the Mobile Application Part, the Intelligent Network Application Part and the CAMEL Application Part.[citation needed]
 

 
 
The Message Transfer Part (MTP) covers a portion of the functions of the OSI network layer including: network interface, information transfer, message handling and routing to the higher levels. Signaling Connection Control Part (SCCP) is at functional Level 4. Together with MTP Level 3 it is called the Network Service Part (NSP). SCCP completes the functions of the OSI network layer: end-to-end addressing and routing, connectionless messages (UDTs), and management services for users of the Network Service Part (NSP).[12] Telephone User Part (TUP) is a link-by-link signaling system used to connect calls. ISUP is the key user part, providing a circuit-based protocol to establish, maintain, and end the connections for calls. Transaction Capabilities Application Part (TCAP) is used to create database queries and invoke advanced network functionality, or links to Intelligent Network Application Part (INAP) for intelligent networks, or Mobile Application Part (MAP) for mobile services.
 
 

SSADM

Structured Systems Analysis & Design Method

a widely-used computer application development method in the UK that divides an application development project into modules, stages, steps, and tasks, and provides a framework for describing projects in a fashion suited to managing the project.

SSH

Secure Shell

Secure Shell (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network. The best known example application is for remote login to computer systems by users.
 
SSH provides a secure channel over an unsecured network in a client-server architecture, connecting an SSH client application with an SSH server. Common applications include remote command-line login and remote command execution, but any network service can be secured with SSH. The protocol specification distinguishes between two major versions, referred to as SSH-1 and SSH-2.

SSID

Service Set Identifier

Logical wireless networks (including extended service sets) are identified by SSIDs, which serve as "network names" and are typically natural language labels.

SSIS

SQL Server Integration Services

SQL Server Integration Services (SSIS) is a component of the Microsoft SQL Server database software that can be used to perform a broad range of data migration tasks.
 
SSIS is a platform for data integration and workflow applications. It features a data warehousing tool used for data extraction, transformation, and loading (ETL). The tool may also be used to automate maintenance of SQL Server databases and updates to multidimensional cube data

SSL

Secure Sockets Layer

See TLS

Stack

The protocol stack or network stack is an implementation of a computer networking protocol suite or protocol family. The terms are often used interchangeably; strictly speaking, the suite is the definition of the Communications protocols, and the stack is the software implementation of them.
 
Individual protocols within a suite are often designed with a single purpose in mind. This modularization makes design and evaluation easier. Because each protocol module usually communicates with two others, they are commonly imagined as layers in a stack of protocols. The lowest protocol always deals with low-level interaction with the communications hardware. Every higher layer adds more features and capability. User applications usually deal only with the topmost layers (see also OSI model)

 

Staff Days

A measure of effort indicating how much work needs to take place on an activity or artifact. Is often used to differentiate from calendar days. Also applies to other units of time.

Stage

Often used as a synonym for phase. May be more precisely used to define groupings of milestones, in terms of a hierarchy with phases that are made up of stages.

Staged Delivery Lifecycle

Project development occurs in stages, where the most critical functionality is delivered first

Stakeholder

Individuals or entities with significant investment in the outcome of a project. Normally includes clients, customers, internal/external organizations affected by the project, etc.

Standard

CxStand

CxOne standard material type. Defined terminology, processes, policies, knowledge, and/or guidelines. See CxOneOverview for description.

Statistical Estimation

Estimation techniques that utilize historical data coupled with a statistically derived model to provide output estimates based on input characteristics. Most often use size as an input to predict effort and time. Works best when calibrated with relevant historical data and influence modifiers.

STB

Set Top Box

A set-top box (STB) or set-top unit (STU) (one type also colloquially known as a cable box) is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of signal, turning the source signal into content in a form that then be displayed on the television screen or other display device. They are used in cable television, satellite television, and over-the-air television systems, as well as other uses.

Story Mapping

Story mapping consists of ordering user stories along two independent dimensions.

Story Splitting

Splitting consists of breaking up one user story into smaller ones, while preserving the property that each user story separately has measurable business value.

Storyboard

A sequence of images which depict a scenario or use case.

STP

Spanning Tree Protocol

The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree also allows a network design to include backup links to provide fault tolerance if an active link fails.
 
As the name suggests, STP creates a spanning tree within a network of connected layer-2 bridges, and disables those links that are not part of the spanning tree, leaving a single active path between any two network nodes. STP is based on an algorithm that was invented by Radia Perlman while she was working for Digital Equipment Corporation.
 
In 2001, the IEEE introduced Rapid Spanning Tree Protocol (RSTP) as 802.1w. RSTP provides significantly faster recovery in response to network changes or failures, introducing new convergence behaviors and bridge port roles to do this. RSTP was designed to be backwards-compatible with standard STP.

Strategy

The way a problem or issue is approached.

STUN

Session Traversal Utilities for NAT

(STUN) is a standardized set of methods, including a network protocol, for traversal of network address translator (NAT) gateways in applications of real-time voice, video, messaging, and other interactive communications.
 
STUN is a tool used by other protocols, such as Interactive Connectivity Establishment (ICE), the Session Initiation Protocol (SIP), or WebRTC. It provides a tool for hosts to discover the presence of a network address translator, and to discover the mapped, usually public, Internet Protocol (IP) address and port number that the NAT has allocated for the application's User Datagram Protocol (UDP) flows to remote hosts. The protocol requires assistance from a third-party network server (STUN server) located on the opposing (public) side of the NAT, usually the public Internet.
 
Originally, STUN was an acronym for Simple Traversal of User Datagram Protocol (UDP) through Network Address Translators, but this title was changed in a specification of an updated set of methods published as RFC 5389, retaining the same acronym

Subversion

Apache Subversion (often abbreviated SVN, after its command name svn) is a software versioning and revision control system distributed as open source under the Apache License. Software developers use Subversion to maintain current and historical versions of files such as source code, web pages, and documentation. Its goal is to be a mostly compatible successor to the widely used Concurrent Versions System (CVS).

Sustainable Pace

The team aims for a work pace that they would be able to sustain indefinitely.

SVC

Soft Virtual Service

Switched virtual circuits (SVCs) are generally set up on a per-call basis and are disconnected when the call is terminated; however, a permanent virtual circuit (PVC) can be established as an option to provide a dedicated circuit link between two facilities. PVC configuration is usually preconfigured by the service provider. Unlike SVCs, PVC are usually very seldom broken/disconnected.
 
A switched virtual circuit (SVC) is a virtual circuit that is dynamically established on demand and is torn down when transmission is complete, for example after a phone call or a file download. SVCs are used in situations where data transmission is sporadic and/or not always between the same data terminal equipment (DTE) endpoints.

Swift

Swift is a general-purpose, multi-paradigm, compiled programming language developed by Apple Inc. for iOS, macOS, watchOS, tvOS, and Linux. Swift is designed to work with Apple's Cocoa and Cocoa Touch frameworks and the large body of existing Objective-C (ObjC) code written for Apple products. It is built with the open source LLVM compiler framework and has been included in Xcode since version 6. On platforms other than Linux, it uses the Objective-C runtime library which allows C, Objective-C, C++ and Swift code to run within one program

Switch

A network switch (also called switching hub, bridging hub, officially MAC bridge) is a computer networking device that connects devices together on a computer network by using packet switching to receive, process, and forward data to the destination device.
 
A network switch is a multiport network bridge that uses hardware addresses to process and forward data at the data link layer (layer 2) of the OSI model. Some switches can also process data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches.
 
Switches for Ethernet are the most common form of network switch. The first Ethernet switch was introduced by Kalpana in 1990. Switches also exist for other types of networks including Fibre Channel, Asynchronous Transfer Mode, and InfiniBand.
 
Unlike less advanced repeater hubs, which broadcast the same data out of each of its ports and let the devices decide what data they need, a network switch forwards data only to the devices that need to receive it

System

A functional entity, normally composed of software, hardware, and closely related operational processes.
In CxOne, system is often used to refer to the software portions of a system.
Also used in CxOne to refer to the end output of a project, i.e., the system a project was chartered to create. This is useful when discussing attributes of a the system separate from attributes of the project.

System Test

Test focused on verifying operational behavior of the entire system, using a project build and the system test environment.

System Test Environment

Environment that simulates operational environment and conditions as closely as possible.

SystemX

2nd national digital telephone exchange system to be used in the United Kingdom.

System X was developed by the UK Post Office (later to become British Telecom), GEC, Plessey (later to be Marconi), and Standard Telephones and Cables (STC).
 
System X covers three main types of telephone switching equipment. Many of these switches reside all over the United Kingdom. Concentrators are usually kept in local telephone exchanges but can be housed remotely in less populated areas. DLEs and DMSUs operate in major towns and cities and provide call routing functions.
 
Concentrator unit
The concentrator unit consists of four main sub-systems, line modules, digital concentrator switch, digital line termination (DLT) units and control unit. Its purpose is to convert speech from analogue signals to digital format and concentrate the traffic for onward transmission to the digital local exchange (DLE). It also receives dialled information from the subscriber and passes this to the DLE, so that the call can be routed to its destination. In normal circumstances, it does not switch signals between subscriber lines but has limited capacity to do this if the connection to the DLE is lost.
 
Digital local exchange
The Digital Local Exchange (DLE) connects to the concentrator and routes calls to different DLEs or DMSUs depending on the destination of the call. The heart of the DLE is the Digital Subscriber Switching Subsystem (DSSS) which consists of Time Switches and a Space Switch. Incoming traffic on the 30 channel PCM highways from the Concentrator Units is connected to Time Switches. The purpose of these is to take any incoming individual Time Slot and connect it to an outgoing Time Slot and so perform a switching and routing function.
 
Digital main switching unit
The Digital Main Switching Unit (DMSU) deals with calls that have been routed by DLEs or another DMSU and is a 'trunk switch', i.e. it is not connected to any concentrators. As with DLEs, DMSUs are made up of a Digital Switching Subsystem and a Processor Utility Subsystem, amongst other things. In the British PSTN network, each DMSU is connected to every other DMSU in the country, enabling almost congestion-proof connectivity for calls through the network.
 
Replacement system
Many of the switches installed during the 1980s are near to or over 30 years old and still in use within local exchanges, giving an idea of their reliability.
 
System X was scheduled for replacement with Next Generation softswitch equipment as part of the BT 21st Century Network (21CN) programme. Some other users of System X – in particular Jersey Telecom and Kingston Communications – replaced their circuit switched System X equipment with Marconi XCD5000 softswitches (which are the NGN replacement for System X) and Access Hub multiservice access nodes. However, the omission of Marconi from the BT 21CN supplier list, the lack of a suitable replacement softswitch to match System X reliability, and the shift in focus away from telephony onto broadband – all led to much of the System X estate being maintained.