S - Definitions
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S
SD-branch
SD-branch is a single, automated, centrally managed software-centric platform that replaces or supplements an existing branch network architecture.
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SDN controller (software-defined networking controller)
A software-defined networking controller is an application in SDN architecture that manages flow control for improved network management and application performance.
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secure access service edge (SASE)
Secure access service edge, also known as SASE and pronounced sassy, is a cloud architecture model that bundles network and cloud-native security technologies together and delivers them as a single cloud service.
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Seebeck effect
The Seebeck effect is a phenomenon in which a temperature difference between two dissimilar electrical conductors or semiconductors produces a voltage difference between the two substances.
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serial digital interface (SDI)
Serial digital interface (SDI) is a standard for digital video and audio transmission over coaxial or fiber optic cabling.
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Server Message Block protocol (SMB protocol)
The Server Message Block protocol (SMB protocol) is a client-server communication protocol used for sharing access to files, printers, serial ports and other resources on a network.
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Service Profile Identifier (SPID)
In telecommunications, a Service Profile Identifier (SPID) is a number assigned by a phone company to a terminal on an Integrated Services Digital Network (ISDN) B-channel.
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session border controller (SBC)
A session border controller (SBC) is a dedicated hardware device or software application that governs the manner in which phone calls are initiated, conducted and terminated on a voice over Internet Protocol (VoIP) network.
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session layer
The session layer is Layer 5 of the OSI communications model. It is the long-lived logical connection that persists between endpoints over time.
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shielded twisted pair (STP)
Shielded twisted pair (STP) is a special kind of copper telephone and local area network (LAN) wiring used in some business installations.
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signal-to-noise ratio (S/N or SNR)
In analog and digital communications, a signal-to-noise ratio, often written S/N or SNR, is a measure of the strength of the desired signal relative to background noise (undesired signal).
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Signaling System 7 (SS7)
Signaling System 7 (SS7) is an international telecommunication protocol standard that defines how the network elements in a public switched telephone network (PSTN) exchange information and control signals.
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Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP) is an application-layer protocol for monitoring and managing network devices on a local area network (LAN) or wide area network (WAN).
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single-user multiple input, multiple output (SU-MIMO)
Single-user multiple input, multiple output (SU-MIMO) is a multitransmitter and receiver technology that lets a wireless access point send multiple, simultaneous data streams to one compatible endpoint at a time.
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sliding window (windowing)
The sliding window (windowing) technique is used by Transmission Control Protocol (TCP) to manage the flow of packets between two computers or network hosts.
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small cell
A small cell is an umbrella term used to describe a miniature radio access point or wireless network base station with a low radio frequency power output, footprint and range.
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Snort
Snort is an open source network intrusion detection system (NIDS) created by Sourcefire founder and former CTO Martin Roesch.
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software-defined networking (SDN)
Software-defined networking (SDN) is an architecture that abstracts different, distinguishable layers of a network to make networks agile and flexible.
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software-defined networking monitoring application (SDN monitoring application)
An SDN monitoring application is a software program that oversees the traffic in a software-defined network (SDN) as a component of network management.
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Spanning Tree Protocol (STP)
Spanning Tree Protocol (STP) is a Layer 2 network protocol used to prevent looping within a network topology.
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spectrum analyzer
A spectrum analyzer is a device that measures and displays signal amplitude (strength) as it varies by frequency within its frequency range (spectrum).
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split horizon
Split horizon is a method used by distance vector protocols to prevent network routing loops.
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star network
A star network is a local area network (LAN) topology in which all nodes -- personal computers (PCs), workstations or other devices -- are directly connected to a common central computer that is often referred to as a hub.
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stateful inspection
Stateful inspection, also known as dynamic packet filtering, is a firewall technology that monitors the state of active connections and uses this information to determine which network packets to allow through the firewall.
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Stream Control Transmission Protocol (SCTP)
Stream Control Transmission Protocol (SCTP) is a connection-oriented network protocol for transmitting multiple streams of data simultaneously between two endpoints that have established a connection in a network.
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streaming network telemetry
Streaming network telemetry is a real-time data collection service in which network devices, such as routers, switches and firewalls, continuously push data related to the network's health to a centralized location.
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subcarrier
A subcarrier is a secondary modulated signal frequency modulated into the main frequency (the carrier) to provide an additional channel of transmission.
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subnet (subnetwork)
A subnet, or subnetwork, is a segmented piece of a larger network.
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Switched Multimegabit Data Service (SMDS)
Switched Multimegabit Data Service (SMDS) is a public, packet-switched service aimed at enterprises that need to exchange large amounts of data with other enterprises over the wide area network on a nonconstant or bursty basis.
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SYN scanning
SYN scanning is a tactic that a malicious hacker can use to determine the state of a communications port without establishing a full connection.
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Synchronous Data Link Control (SDLC)
Synchronous Data Link Control (SDLC) is a transmission protocol used to synchronously transfer code-transparent, serial-by-bit data over a communications channel.
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Synchronous Digital Hierarchy (SDH)
Synchronous Digital Hierarchy (SDH) is a group of fiber optic transmission rates that transport digital signals with different capacities.
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Synchronous Optical Network (SONET)
Synchronous Optical Network (SONET) is a North American standard for synchronous data transmission over optical fibers.
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system administrator (sysadmin)
A system administrator (sysadmin) is an information technolog professional who supports a multiuser computing environment and ensures continuous, optimal performance of IT services and support systems.
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What is SD-WAN (software-defined WAN)? Ultimate guide
Software-defined WAN is a technology that uses software-defined networking concepts to distribute network traffic across a wide area network, or WAN.