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• access control list (ACL)

  An access control list (ACL) is a list of rules that specifies which users or systems are granted or denied access to a particular object or system resource. Continue Reading

• Point-to-Point Protocol (PPP)

  Point-to-Point Protocol (PPP) refers to a suite of computer communication protocols that provide a standard way to transport multiprotocol data over point-to-point links. Continue Reading

• Intro to encapsulation and decapsulation in networking

  Encapsulation adds information to a packet as it travels to its destination. Decapsulation reverses the process by removing the info, so a destination device can read the original data. Continue Reading

• What's happening with standalone 5G?

  Standalone 5G is the next major update for 5G technology. Learn about the benefits SA 5G will bring and find out when operators will begin deploying it worldwide. Continue Reading

• Network engineer vs. network administrator: What's the difference?

  The difference between a network engineer and network administrator is an engineer is focused on network design, while an administrator is more focused on operations. Continue Reading

• Definitions to Get Started

  • What is Cisco Certified Internetwork Expert (CCIE) certification?
  • What is Cisco Performance Routing (PfR)?
  • What is a MAC address and how do I find it?
  • What is cloud networking?

  • What is IPv6 (Internet Protocol version 6)?
  • What is TCP/IP?
  • What is ICMP (Internet Control Message Protocol)?
  • What is asynchronous?

  View All Definitions

• What are the different types of network switches?

  Some of the different types of network switches include managed, modular, unmanaged and stackable. Find out how different network switches dovetail and differ.Continue Reading

• Reverse Address Resolution Protocol (RARP)

  Reverse Address Resolution Protocol (RARP) is a protocol a physical machine in a local area network (LAN) can use to request its IP address.Continue Reading

• MDI/MDIX (medium-dependent interface/MDI crossover)

  MDI/MDIX is a type of Ethernet port connection that uses twisted-pair cabling to link two networked devices.Continue Reading

• DHCP client configuration for Linux, Windows and macOS

  Network and system admins can use command-line and GUI tools to configure DHCP clients in Linux, Windows and macOS. Here's a breakdown of which commands to use for each OS.Continue Reading

• 9 wireless questions for Cisco's CCT, CCNA exams

  Those looking to pass the Cisco CCT and CCNA certification exams will need to understand how wireless networking works. This practice quiz covers the basics of wireless networking.Continue Reading

• Guide on wireless networking concepts for CCT, CCNA exams

  Cisco's CCT and CCNA exams include wireless networking questions. Use this excerpt from Glen Clarke's 'CCT/CCNA Routing and Switching All-in-One Exam Guide' as a tool to prepare.Continue Reading

• Learn the basics of wireless networking for exam prep

  In this Q&A, author Glen Clarke introduces readers to wireless networking and outlines what CCT and CCNA test-takers should study when prepping for their exams.Continue Reading

• patch panel

  A patch panel in a local area network (LAN) is a mounted hardware assembly that contains ports that are used to connect and manage incoming and outgoing LAN cables.Continue Reading

• chatty protocol

  A chatty protocol is an application or routing protocol requiring a client or server to wait for an acknowledgment before transmitting data again.Continue Reading

• 4 ideas for network cable management best practices

  When organizing cable clutter, network engineers should follow some common best practices, including the use of cable labels, cable ties and proper documentation.Continue Reading

• downloading

  Downloading is the transmission of a file or data from one computer to another over a network, usually from a larger server to a user device.Continue Reading

• IDSL

  IDSL is a hybrid of a digital subscriber line (DSL) and integrated services digital network (ISDN) technology that transmits data slightly faster than ISDN but much slower than most DSL services.Continue Reading

• ARPANET

  The U.S. Advanced Research Projects Agency Network (ARPANET) was the first public packet-switched computer network.Continue Reading

• HELLO packet

  A HELLO packet is a special data packet (message) that is sent out periodically from a router to establish and confirm network adjacency relationships to other routers in the Open Shortest Path First (OSPF) communications protocol.Continue Reading

• full-duplex

  Full-duplex data transmission means that data can be transmitted in both directions on a signal carrier at the same time.Continue Reading

• route summarization (route aggregation)

  Route summarization -- also known as route aggregation -- is a method to minimize the number of routing tables in an Internet Protocol (IP) network.Continue Reading

• What are the different types of network cables?

  The main types of network cables are coax, fiber optics, and shielded and unshielded twisted pair. As enterprises deploy new technologies, it's critical to select the right cables.Continue Reading

• Variable Length Subnet Mask (VLSM)

  Variable Length Subnet Mask (VLSM) is a subnet -- a segmented piece of a larger network -- design strategy where all subnet masks can have varying sizes.Continue Reading

• network node

  A computer network is a system of computers and computing devices that are connected via communication links.Continue Reading

• 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.Continue Reading

• dynamic multipoint VPN (DMVPN)

  A dynamic multipoint virtual private network (DMVPN) is a secure network that exchanges data between sites/routers without passing traffic through an organization's virtual private network (VPN) server or router located at its headquarters.Continue Reading

• delay-tolerant network (DTN)

  A delay-tolerant network (DTN) is a network that's designed to operate effectively in extreme conditions and over very large distances, such as with space communications.Continue Reading

• NBMA (non-broadcast multiple access)

  Non-broadcast multiple access (NBMA) is one of four network types in the Open Shortest Path First (OSPF) communications protocol.Continue Reading

• CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance)

  CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) is a protocol for carrier transmission in 802.11 networks.Continue Reading

• fixed-length subnet mask (FLSM)

  A fixed-length subnet mask (FLSM) refers to a type of enterprise or provider networking where a block of IP addresses is divided into multiple subnets of equal length (i.e., an equal number of IP addresses).Continue Reading

• virtual network adapter

  A virtual network adapter is software that operates like a physical network adapter within the host operating system (OS) or through an application installed on the endpoint or server.Continue Reading

• network analyzer (protocol analyzer or packet analyzer)

  A network analyzer -- also called a network protocol analyzer or packet analyzer -- is a software application, dedicated appliance or feature set within a network component used in network performance troubleshooting or to enhance protection against...Continue Reading

• flow routing

  Flow routing is a network routing technology that takes variations in the flow of data into account to increase routing efficiency.Continue Reading

• GMPLS (Generalized Multiprotocol Label Switching or Multiprotocol Lambda Switching)

  GMPLS (Generalized Multiprotocol Label Switching) is a networking technology that enables fast and reliable network switching of data flows on any type of network infrastructure.Continue Reading

• computer hardware

  Computer hardware is a collective term used to describe any of the physical components of an analog or digital computer.Continue Reading

• What's the difference between internet and Ethernet?

  Internet and Ethernet are two technologies that sound similar and provide connectivity, but the methods of providing connectivity differ significantly.Continue Reading

• Layer Two Tunneling Protocol (L2TP)

  Layer Two Tunneling Protocol (L2TP) is an extension of the Point-to-Point Tunneling Protocol (PPTP) used by an internet service provider (ISP) to enable the operation of a virtual private network (VPN) over the internet.Continue Reading

• Remote access vs. site-to-site VPN: What's the difference?

  A remote access VPN connects remote users from any location to a corporate network. A site-to-site VPN, meanwhile, connects individual networks to each other.Continue Reading

• Class of Service (CoS)

  Class of Service (CoS) is a way of managing traffic in a network by grouping similar types of traffic -- such as email, streaming video, voice over IP and large document file transfer -- together and treating each type as a class with its own level ...Continue Reading

• What is modulation?

  Modulation is the process of converting data into radio waves by adding information to an electronic or optical carrier signal.Continue Reading

• 10BASE-T

  10BASE-T is an Ethernet standard for local area networks and one of several physical media specified in the Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard.Continue Reading

• frequency-shift keying (FSK)

  Frequency-shift keying (FSK) is a method of transmitting digital signals using discrete signals.Continue Reading

• subcarrier

  A subcarrier is a secondary modulated signal frequency modulated into the main frequency (the carrier) to provide an additional channel of transmission.Continue Reading

• internet metering

  Internet metering is a service model in which an internet service provider (ISP) keeps track of bandwidth use and charges users accordingly.Continue Reading

• bottleneck

  A bottleneck, in a communications context, is a point in the enterprise where the flow of data is impaired or stopped entirely.Continue Reading

• CDN vs. cloud computing: What's the difference?

  Content delivery networks and cloud computing architectures may appear to serve the same function. But each has a specific role to play when distributing content.Continue Reading

• circuit switching

  Circuit switching is a type of network configuration in which a physical path is obtained and dedicated to a single connection between two endpoints in the network for the duration of a dedicated connection.Continue Reading

• What is a thin client (lean client)?

  A thin client (or lean client) is a virtual desktop computing model that runs on the resources stores on a central server instead of a computer's resources.Continue Reading

• frame relay

  Frame relay is a packet-switching telecommunications service designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between endpoints in wide area networks (WANs).Continue Reading

• Ways to speed up white box networking adoption

  Most organizations are slow to deploy new techniques, white box networking included. Experts explain why and offer advice on how to speed up adoption across enterprises.Continue Reading

• What is the Universal Service Fund (USF)?

  The Universal Service Fund (USF) is a United States government program that supports telecommunications access and affordability in rural and low-income communities.Continue Reading

• 100 Gigabit Ethernet (100 GbE)

  100 Gigabit Ethernet (100 GbE) is an Ethernet standard that supports data speeds of up to 100 billion bits (gigabits) per second (Gbps).Continue Reading

• transceiver

  A transceiver is a combination transmitter/receiver in a single package.Continue Reading

• Next Hop Resolution Protocol (NHRP)

  Next Hop Resolution Protocol (NHRP) is an automated configuration technology that routes data on a distributed network by discovering the best routing path between endpoints.Continue Reading

• What is an edge router?

  An edge router is a specialized router located at a network boundary that enables an internal network to connect to external networks.Continue Reading

• What is PSTN (public switched telephone network)?

  The public switched telephone network, or PSTN, is the world's collection of interconnected voice-oriented public telephone networks.Continue Reading

• runbook

  Runbooks are a set of standardized written procedures for completing repetitive IT processes within a company.Continue Reading

• network visibility

  Network visibility is an awareness of the components and data within an enterprise computer network.Continue Reading

• Joint Academic Network (JANET)

  The Joint Academic Network (JANET) is an internal, high-speed computer network that links the U.K. education and research community.Continue Reading

• visitor-based networking (visitor-based network)

  Visitor-based networking (VBN) is a computer network with high-speed internet access provided by an organization for temporary use by visitors, guests or other users in a public area.Continue Reading

• 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.Continue Reading

• deep packet inspection (DPI)

  Deep packet inspection (DPI) is an advanced method of examining and managing network traffic.Continue Reading

• The role of smartNICs in modern enterprise networks

  This chapter excerpt from 'Building a Future-Proof Cloud Infrastructure' looks at how smartNICs can support distributed services platforms for both cloud providers and enterprises.Continue Reading

• How smartNIC architecture supports scalable infrastructure

  In this Q&A, author Silvano Gai discusses how smartNICs can benefit enterprises by providing more granular telemetry and supporting distributed cloud infrastructure.Continue Reading

• GVRP (GARP VLAN Registration Protocol or Generic VLAN Registration Protocol)

  GVRP (GARP VLAN Registration Protocol or Generic VLAN Registration Protocol) is a standards-based protocol that facilitates control of virtual local area networks (VLANs) within a larger network.Continue Reading

• Gigabit Ethernet (GbE)

  Gigabit Ethernet (GbE), a transmission technology based on the Ethernet frame format and protocol used in local area networks (LANs), provides a data rate of 1 billion bits per second, or 1 gigabit (Gb).Continue Reading

• trunk (trunking)

  A network trunk is a communications line or link designed to carry multiple signals simultaneously to provide network access between two points.Continue Reading

• serial digital interface (SDI)

  Serial digital interface (SDI) is a standard for digital video and audio transmission over coaxial or fiber optic cabling.Continue Reading

• Point-to-Point Protocol over Ethernet (PPPoE)

  Point-to-Point Protocol over Ethernet (PPPoE) is a network protocol that facilitates communication between network endpoints.Continue Reading

• 1000BASE-T (Gigabit Ethernet)

  1000BASE-T is Gigabit Ethernet -- 1 gigabit is 1,000 megabits per second (Mbps) on copper cables, using four pairs of Category 5 (Cat5) unshielded twisted pair (UTP) to achieve the gigabit data rate.Continue Reading

• 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.Continue Reading

• customer proprietary network information (CPNI)

  Customer proprietary network information (CPNI) in the United States is information that telecommunications services -- such as local, long-distance and wireless telephone companies -- acquire about their subscribers.Continue Reading

• dynamic port numbers

  Dynamic port numbers, also known as private port numbers, are the port numbers that are available for use by any application to use in communicating with any other application, using the internet's Transmission Control Protocol (TCP) or User ...Continue Reading

• autonomous system (AS)

  An autonomous system (AS) in networking is a collection of one or more associated Internet Protocol (IP) prefixes with a clearly defined routing policy that governs how the AS exchanges routing information with other autonomous systems.Continue Reading

• CompTIA Cloud+ tips to troubleshoot cloud networks

  The CompTIA Cloud+ exam covers a range of topics, including how to secure and troubleshoot cloud networks. Some of the first steps: Start simple, and isolate the problem.Continue Reading

• 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.Continue Reading

• domain name system (DNS)

  The domain name system (DNS) is a naming database in which internet domain names are located and translated into Internet Protocol (IP) addresses.Continue Reading

• Real-time Transport Protocol (RTP)

  Real-time Transport Protocol (RTP) is a network standard designed for transmitting audio or video data that is optimized for consistent delivery of live data.Continue Reading

• NACK (NAK, negative acknowledgment, not acknowledged)

  NACK, or NAK, an abbreviation for negative acknowledgment or not acknowledged, is a signal used by computers or other devices to indicate that data transmitted over a network was received with errors or was otherwise unreadable.Continue Reading

• 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.Continue Reading

• multiplexing

  Multiplexing, or muxing, is a way of sending multiple signals or streams of information over a communications link at the same time in the form of a single, complex signal.Continue Reading

• 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).Continue Reading

• Synchronous Digital Hierarchy (SDH)

  Synchronous Digital Hierarchy (SDH) is a group of fiber optic transmission rates that transport digital signals with different capacities.Continue Reading

• Explore virtualization study topics for CCNP, CCIE exams

  Aspiring CCNPs and CCIEs will need to grasp one of networking's most important topics: virtualization. 'Day 7' from Patrick Gargano's '31 Days' explains the subject in detail.Continue Reading

• Virtualization concepts to study for CCNP and CCIE exams

  In this Q&A, author Patrick Gargano discusses the importance of virtualization in networking and offers studying advice for aspiring CCNPs and CCIEs in preparation for the exams.Continue Reading

• bit stuffing

  Bit stuffing refers to the insertion of one or more bits into a data transmission as a way to provide signaling information to a receiver.Continue Reading

• Power over Ethernet (PoE)

  Power over Ethernet (PoE) is a technology for implementing wired Ethernet local area networks (LANs) that enables the electrical current necessary for operating each device to be carried by Ethernet data cables instead of standard electrical power ...Continue Reading

• Plain Old Telephone Service (POTS)

  Plain Old Telephone Service (POTS) refers to the traditional, analog voice transmission phone system implemented over physical copper wires (twisted pair).Continue Reading

• file server

  A file server is a computer responsible for the storage and management of data files so that other computers on the same network can access the files.Continue Reading

• How to set up a VLAN for enterprise networks

  VLANs can secure and prioritize network traffic. To set up VLANs correctly, teams should understand concepts like VLAN tagging and subnets.Continue Reading

• connectionless

  In telecommunications, connectionless describes communication between two network endpoints in which a message can be sent from one endpoint to another without prior arrangement.Continue Reading

• QAM (quadrature amplitude modulation)

  QAM (quadrature amplitude modulation) is a method of combining two amplitude modulation (AM) signals into a single channel.Continue Reading

• network operations center (NOC)

  A network operations center (NOC) is a centralized place from which enterprise information technology (IT) administrators -- either internal or third party -- supervise, monitor and maintain a telecommunications network.Continue Reading

• conductance

  Conductance is an expression of the ease with which electric current flows through materials like metals and nonmetals.Continue Reading

• 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.Continue Reading

• dense wavelength-division multiplexing (DWDM)

  Dense wavelength-division multiplexing (DWDM) is an optical fiber multiplexing technology that is used to increase the bandwidth of existing fiber networks.Continue Reading

• IPTV (Internet Protocol television)

  IPTV (Internet Protocol television) is a service that provides television programming and other video content using the Transmission Control Protocol/Internet Protocol (TCP/IP) suite, as opposed to broadcast TV, cable TV or satellite signals.Continue Reading

• packet loss

  Packet loss is when one or more transmitted data packets fail to arrive at their destination.Continue Reading

• carrier-to-noise ratio

  In communications, the carrier-to-noise ratio, often written as CNR or C/N, is a measure of the received carrier strength relative to the strength of the received noise.Continue Reading

• split horizon

  Split horizon is a method used by distance vector protocols to prevent network routing loops.Continue Reading