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• AAUI (Apple attachment unit interface)

  An AAUI (Apple attachment unit interface) is the 14- or 15-pin port or connection interface on earlier models of Macintosh computers that allowed it to be connected by a short interface cable (or "transceiver") to an Ethernet cable. Continue Reading

• average bouncing busy hour (ABBH)

  In designing and assessing telephone networks, one approach is to measure the average bouncing busy hour (ABBH) traffic in various network trunks or trunk groups of the network. Continue Reading

• modem lights (AA)

  This page provides a description of the abbreviations and meanings of each of the lights that describe the "handshaking" between a computer modem and the UART chip in a computer. Continue Reading

• Multichannel Multipoint Distribution Service (MMDS)

  Multichannel Multipoint Distribution Service (MMDS) is a broadcasting and communications service that operates in the ultra-high-frequency (UHF) portion of the radio spectrum between 2.1 and 2.7 GHz. Continue Reading

• plain old telephone service (POTS)

  POTS is a term sometimes used in discussion of new telephone technologies in which the question of whether and how existing voice transmission for ordinary phone communication can be accommodated. Continue Reading

• Definitions to Get Started

  • TCP (Transmission Control Protocol)
  • wavelength
  • subnet (subnetwork)
  • UDP (User Datagram Protocol)

  • Telnet
  • VPN (virtual private network)
  • CIDR (Classless Inter-Domain Routing or supernetting)
  • Ethernet

  View All Definitions

• software-defined radio (SDR)

  Software-defined radio (SDR), sometimes shortened to software radio (SR), refers to wireless communication in which the transmitter modulation is generated or defined by a computer, and the receiver uses a computer to recover the signal intelligence.Continue Reading

• WiMAX (Worldwide Interoperability for Microwave Access)

  WiMAX is a wireless industry coalition whose members organized to advance IEEE 802.16 standards for broadband wireless access (BWA) networks...(Continued)Continue Reading

• Classes of MPLS services: Find the best MPLS/VPN service for your WAN

  Despite the many names given to MPLS/VPNs by marketers, there are only three classes of MPLS-based VPN services with very distinct characteristics. If you’re able to map their service descriptions into one of these classes, you’ll immediately ...Continue Reading

• fiber to the x (FTTx)

  Fiber to the x (FTTx) is a collective term for various optical fiber delivery topologies that are categorized according to where the fiber terminatesContinue Reading

• 802.11s

  802.11s is a proposed amendment to the 802.11 wireless networking standards that will provide a vendor-neutral way to build wireless mesh networks over wireless LAN (WLAN) products.Continue Reading

• I/O Virtualization and Converged I/O: Understanding the basics

  I/O virtualization and converged I/O are crucial to enabling converged data center networks and avoiding the bottlenecking that arises in virtualized environments. In this primer, learn about I/O virtualization appliances and software, as well as ...Continue Reading

• Virtualization networking guide: Managing virtualization

  Networking professionals must understand how server virtualization affects the network. This virtualization networking guide examines capacity planning for virtual server networking, managing virtual networks through distributed virtual switching, ...Continue Reading

• MPLS VPN basics

  In this review of MPLS VPN basics, discover the differences between MPLS VPN and traditional virtual private networks, as well as the advantages and disadvantages of this newer service provider offering.Continue Reading

• What's the value of ITIL foundation certification?

  The ITIL foundation certification sets the baseline for understanding the move to an IT service management model. Whether it is required by your organization, for personal resume enhancement, or even to move into another type of IT role, an ITIL ...Continue Reading

• Primer: Multi-tenant network for the private cloud

  The push for private cloud computing networks is creating new security and management challenges for network managers. The first step is to build a multi-tenant network to isolate applications and data; next come application-aware networks.Continue Reading

• How to apply network virtualization to a wide area network (WAN)

  How can you apply network virtualization technology to an enterprise wide area network (WAN)? Allocating bandwidth and improving network management and performance are just a sampling of what WAN managers can do better. In this primer, discover ...Continue Reading

• throttled data transfer

  Throttled data transfer, also known as data transfer throttling or lean data transfer, is the deliberate regulation of the data transfer rate in a communications system... (Continued)Continue Reading

• WAN bandwidth optimization tools and techniques

  WAN bandwidth optimization tools and techniques are explained in this primer on getting the most out of your business wide area network links. This introduction to WAN technologies discusses methods and products that accelerate traffic so that your ...Continue Reading

• Wide Area Ethernet (WAE)

  Wide Area Ethernet (WAE) or Ethernet WAN (also sometimes referred to as fiber or LAN extension service ) is a network carrier service that delivers high-speed wide area network (WAN) connectivity, utilizing Ethernet as the connection method. ...Continue Reading

• CCNA quiz: Test your skills from routing configuration to VLANs

  In this CCNA quiz, you can test yourself on a number of skills found in the CCNA certification study guide, ranging from Cisco IOS router configuration to setting up VLANs with Cisco switches and monitoring spanning tree protocol operation.Continue Reading

• Wireshark filter tutorial: A Wireshark guide from Laura Chappell

  This Wireshark guide from Laura Chappell examines the open source network monitoring tool and its many uses. Use this Wireshark filter tutorial to find out what the network analyzer can do for your network.Continue Reading

• Smart grid tutorial: What IT managers should know

  This smart grid tutorial explains what enterprise IT managers should know about the technology and how it will be applied to your business's wide area network (WAN).Continue Reading

• 100 Gigabit Ethernet (100GbE)

  100 Gigabit Ethernet (100GbE) is a standard in development that will enable the transfer of Ethernet frames at 100 gigabits per second (gp/s). The 100GbE standard is for core switching. A 40GbE standard, in development simultaneously, is designed ...Continue Reading

• Internet Group Management Protocol (IGMP)

  The Internet Group Management Protocol (IGMP) is an Internet protocol that provides a way for an Internet computer to report its multicast group membership to adjacent routers.Continue Reading

• How do I...choose a VPN for my small business?

  A virtual private network (VPN)is a way to use a public telecommunication infrastructure, such as the Internet,to provide remote offices or individual users with secure access to their organization's network.Continue Reading

• device relationship management (DRM)

  Device relationship management (DRM) is enterprise software that enables the monitoring, managing, and servicing of intelligent devices over the Internet.Continue Reading

• Web SSL VPN introduction

  This Web SSL VPN introduction answers the question "What is a Web SSL VPN?" and explains SSL VPN advantages in remote access environments. Understand how they evolved from their lesser IPsec VPN counterparts, how they protect against hackers, how ...Continue Reading

• wireless WAN (Wireless Wide Area Network)

  A wireless WAN is a wide area network in which separate areas of coverage or cells are connected wirelessly to provide service to a large geographic area.Continue Reading

• What is a sensor network?

  This technology overview answers the question "What is a sensor network?" It defines the term and explains why network managers need to know about it in the enterprise space, especially IT professionals dealing with wide areaContinue Reading

• Using LAN edge switch security features for network defense-in-depth

  Enterprises are turning their focus to the largely unused LAN edge switch security features that can enable the use of ACLs and VLANs for port management and traffic monitoring. LAN edge switches also support network access authentication and can be...Continue Reading

• Types of cloud computing services WAN managers should consider

  WAN managers can benefit greatly from understanding the different types of cloud computing services available to them. Understand how SaaS, PaaS, IaaS, security, network, systems, and project planning services can be used to benefit your enterprise ...Continue Reading

• frequency-shift keying (FSK)

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

• frequency modulation (FM)

  Also see modulation and frequency-shift keying (FSK).Continue Reading

• fiber to the home (FTTH)

  Fiber to the home (FTTH), also called fiber to the premises (FTTP), is the installation and use of optical fiber from a central point directly to individual buildings such as residences, apartment buildings and businesses to provide unprecedented ...Continue Reading

• fiber to the curb (FTTC)

  Fiber to the curb (FTTC) refers to the installation and use of optical fiber cable directly to the curbs near homes or any business environment as a replacement for "plain old telephone service" (POTS).Continue Reading

• Digital Powerline (DPL)

  Digital Powerline (DPL) technology provides the transmission of data to users over the same lines that bring electric power to homes and businesses.Continue Reading

• cyclic redundancy checking

  Cyclic redundancy checking is a method of checking for errors in data that has been transmitted on a communications link.Continue Reading

• customer premises equipment (CPE)

  Customer premises equipment (CPE) is telephone or other service provider equipment that is located on the customer's premises (physical location) rather than on the provider's premises or in between.Continue Reading

• Broadband over Power Line (BPL)

  Broadband over Power Line (BPL) is a technology that allows Internet data to be transmitted over utility power lines.Continue Reading

• baud

  Baud was the prevalent measure for data transmission speed until replaced by a more accurate term, bps (bits per second).Continue Reading

• bits per second (bps or bit/sec)

  In data communications, bits per second (abbreviated bps or bit/sec) is a common measure of data speed for computer modems and transmission carriers.Continue Reading

• Cloud computing network primer

  Cloud computing network architecture is moving toward a flat, leaf-spine topology, enabling reduced latency and balancing bandwidth, providing any-to-any connectivity within and between servers. Learn more in this primer.Continue Reading

• VLAN guide for networking professionals

  Virtual LANs (VLANs) are LANs with definitions that map workstations based on anything except for geographic location. In this VLAN guide, you will learn about VLANs as they relate to server virtualization and WLANs and find VLAN configuration tips ...Continue Reading

• Evaluating Citrix Branch Repeater for WAN optimization

  Citrix's product for WAN optimization is the Citrix Branch Repeater. This family of products integrates network optimization with application, desktop and server virtualization.Continue Reading

• Evaluating Blue Coat Systems' WAN optimization

  Blue Coat Systems distinguishes itself as a WAN optimization vendor with strengths in security and application visibility. Learn important facts about Blue Coat's ProxySG and PacketShaper products.Continue Reading

• Evaluating Silver Peak Systems for WAN optimization

  Silver Peak Systems' WAN optimization product line addresses problems typically seen in the data center, including accelerating data backup, server and storage centralization, and real-time collaboration and virtual desktop infrastructure (VDI).Continue Reading

• Evaluating Ipanema Technologies' WAN optimization

  Ipanema Technologies provides WAN optimization to system integrators, VARs, and service providers. It offers extensive performance management in addition to acceleration and optimization technology.Continue Reading

• WAN optimization vendors: Comparison methodology and snapshot

  We polled the major WAN optimization vendors for product information and compiled it to help you make a vendor comparison. Here we list the main differences between WOC providers, in brief.Continue Reading

• Evaluating Expand Networks accelerators for WAN optimization

  Expand Networks' accelerators help WAN optimization by supporting branch office server consolidation, server-based computing and virtualization technologies, as well as low-bandwidth, high-latency links.Continue Reading

• Evaluating Cisco WAAS WAN optimization

  Cisco WAAS is a family of WAN optimization products that integrate well into the network environment and offers broad application support through Cisco's partnerships.Continue Reading

• Evaluating Riverbed Steelhead WAN optimization

  Riverbed Steelhead appliances for WAN optimization are focused on specific enterprise applications -- such as rich media, thin clients, Web apps and disaster recovery -- scalability and ease of installation.Continue Reading

• Regional Internet Registry (RIR)

  A Regional Internet Registry (RIR) is a not-for-profit organization that oversees Internet Protocol (IP) address space and the Autonomous System (AS) numbers within a specific geographical region. Each RIR is tasked with creating local policy for ...Continue Reading

• Bandwidth measurement and management guide

  Today's enterprise applications are demanding more and more network bandwidth. How do you ensure you have enough bandwidth and manage it well? Find out with the resources in our bandwidth measurement and management guide.Continue Reading

• IP network design guide: Managing an IP-based network

  Network design underlies the performance of your enterprise IP network. This four part guide by Cormac Long offers you a comprehensive roadmap to designing IP-based networks, from the basic principles involved to the more complex finishing touches.Continue Reading

• logical network

  A logical network is one that appears to the user as a single, separate entity although it might in fact be either just a part of a larger network or an entity connecting multiple networks. A logical network is defined by its IP addressing scheme.Continue Reading

• WAN accelerator

  A WAN accelerator is an appliance that improves the end user's experience on a wide area network (WAN).Continue Reading

• chatty protocol

  A chatty protocol is an application or routing protocol that requires a client or server to wait for an acknowledgement before it can transmit again.Continue Reading

• Packet Order Correction (POC)

  Packet Order Correction (POC) is a technique for dealing with out-of-order packet delivery.Continue Reading

• transparent addressing

  On a wide area network (WAN), transparent addressing is a method of network addressing in which all intermediate node addresses are spoofed, so the client and server see each other's addresses and port configurations as if there were no intermediate...Continue Reading

• Port Address Translation (PAT)

  Port Address Translation (PAT), is an extension to network address translation (NAT) that permits multiple devices on a local area network (LAN) to be mapped to a single public IP address. The goal of PAT is to conserve IP addresses.Continue Reading

• wireless mesh network (WMN)

  A wireless mesh network (WMN) is a mesh network created through the connection of wireless access points installed at each network user's locale.Continue Reading

• WAN clustering (geoclustering, high-availability clustering or remote clustering)

  WAN clustering, also called geoclustering, high-availability clustering or remote clustering, is the use of multiple redundant computing resources located in different geographical locations to form what appears to be a single highly-available ...Continue Reading

• stateful inspection

  Stateful inspection 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. Stateful inspection is also known as dynamic packet filtering.Continue Reading

• green networking

  Green networking is the practice of selecting energy-efficient networking technologies and products, and minimizing resource use whenever possible.Continue Reading

• beamforming

  Beamforming is a type of RF (radio frequency) management in which an access point uses multiple antennas to send out the same signal.Continue Reading

• Network change and configuration management primer

  With network change and configuration management (NCCM), enterprises aim to standardize the way they implement network change without disturbing existing systems. That often means using NCCM tools to map and archive the entire network and its ...Continue Reading

• WAN optimization lifecycle: Planning, executing and maintaining

  Developing an effective and flexible WAN strategy doesn't end with selecting the right optimization solution and putting it in place across your network. The next step is to plan for the future.

  For the most part, this means continually ...Continue Reading

• 10 Gigabit Ethernet tutorial: Connecting data centers, storage, LAN and beyond

  As IT teams build 10 Gigabit Ethernet networks, they'll have to choose the right 10 Gigabit Ethernet cabling and components in order to ensure data center optimization and prevent latency in the network. They''ll also need to be sure their networks ...Continue Reading

• passive optical network (PON)

  A passive optical network (PON) is a system that brings optical fiber cabling and signals all or most of the way to the end user.Continue Reading

• Metro Ethernet

  Metro Ethernet is the use of Carrier Ethernet technology in metropolitan area networks (MANs)... (Continued)Continue Reading

• 3G (third generation of mobile telephony)

  3G refers to the third generation of mobile telephony (that is, cellular) technology. The third generation, as the name suggests, follows two earlier generations. (Continued....)Continue Reading

• 6to4

  6to4 is a tunneling mechanism used to transfer IPv6 (Internet Protocol version 6) packets over an IPv4 infrastructure, typically the IPv4 Internet. The 6to4 mechanism was created to support coexistence of both versions during the transition to IPv6,...Continue Reading

• Choosing WAN connectivity and services wisely

  This guide explores the evolution of the wide area network and the WAN connectivity services being developed to improve remote connections, including the use of services like MPLS, Ethernet, and the Internet.Continue Reading

• WAN performance: More than meeting the need for network speed

  WAN performance and measurement, as well as overall network design and capabilities, are being impacted as enterprises increasingly rely on mobile workforces and remote locations to grow and compete in a global marketplace.Continue Reading

• Citrix Access Gateway

  Access Gateway is a secure application access solution that provides administrators application-level control allowing users application access from anywhere.Continue Reading

• Enterprise wireless LAN security: 802.11 and seamless wireless roaming

  Learn how to secure your enterprise wireless local area network (LAN) in this guide of industry best practices. Wireless networking expert Lisa Phifer explains how network security is improved by the wireless IEEE 802.11n protocol; how to secure ...Continue Reading

• location-based service (LBS)

  A location-based service (LBS) is a software application for a mobile device that requires knowledge about where the mobile device is located.Continue Reading

• Cisco Network Analysis Module (NAM)

  As enterprises are faced with the challenge of delivering applications and services in complex IT environments, Cisco NAM provides comprehensive network and application visibility to reduce management complexity, optimize usage of network resources ...Continue Reading

• NetQoS ReporterAnalyzer 8.1

  NetQoS ReporterAnalyzer, the network traffic analysis module of the NetQoS Performance Center, captures a rich set of traffic statistics from Cisco IOS® NetFlow or other IPFIX-enabled routers and switches to identify which applications and users...Continue Reading

• Citrix Branch Repeater 5

  Citrix Branch Repeater is a branch optimization solution that accelerates application delivery for remote users, reducing bandwidth costs and simplifying infrastructure.Continue Reading

• Cisco Application Extension Platform v1.1

  Cisco AXP is an open network module that facilitates development and hosting of branch applications directly onto the router platform.Continue Reading

• Modeling can be key to capacity planning

  Planning for the future of your network sometimes requires rigorous planning and modeling. In this tip, Ed Tittel shows how a free modeling tool just may come to your rescue.Continue Reading

• Introduction to IPv6 -- 'IPv6 Security,' Chapter 1

  Learn what the Internet Protocol version 6 (IPv6) is, know who has adopted it, understand the vulnerabilities causing security concerns, and learn methods used to protect networks against hacker attacks and tools.Continue Reading

• How does a firewall work?

  A firewall is a set of related programs, located at a network gateway server, that protects the resources of a private network from users from other networks. An enterprise with an intranet that allows its workers access to the wider Internet ...Continue Reading

• ping

  Ping is a basic Internet program that allows a user to verify that a particular IP address exists and can accept requests. The verb "ping" means the act of using the ping utility or command.Continue Reading

• Seebeck effect

  The Seebeck effect describes the generation of electricity following the connection of two dissimilar electrical conductors or semiconductors that illustrates the thermoelectric effect. Continue Reading

• WAN technologies summarized

  This excerpt from 'The Shortcut Guide to Optimizing WAN Application Delivery' introduces current and existing WAN environments and technologies. Topics include point-to-point links, circuit and packet switching methodologies, virtual circuits, ...Continue Reading

• port interface card (PIC)

  A port interface card (PIC) is a computer circuit board that provides multiple, diverse interfaces for connections to external networks. In effect, a PIC is an enhanced network interface card (NIC)... (Continued)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 (for example, e-mail, streaming video, voice, large document file transfer) together and treating each type as a class with its own level of ...Continue Reading

• Internet Routing in Space (IRIS)

  Internet Routing in Space in Space, also known as (IRIS), is a project being conducted by the U.S. Department of Defense to place an IP (Internet protocol) router on a geostationary satellite... (Continued)Continue Reading

• Trouble connecting to the VPN: Static and dynamic IP address issues

  For mobile or remote employees, a corporate VPN promises simple, secure access to privileged data and resources. But when that access fails, troubleshooting VPN connectivity issues can be frustrating for the end user and networking staff alike. In ...Continue Reading

• phase-change cooling (vapor cooling)

  Phase-change cooling, also called vapor cooling, is a microprocessor-cooling technology that works according to the same principles as a conventional refrigerator, freezer or air conditioner. The principal components of a phase-change cooling system...Continue Reading

• Best practices for securing your wireless LAN

  Perhaps the biggest network security concern for many enterprises is securing a wireless local area network (WLAN). This three-part expert lesson provides best practices for securing a WLAN in the enterprise. Lesson 1 focuses on methods of ...Continue Reading

• cognitive radio (CR)

  Cognitive radio (CR) is a form of wireless communication in which a transceiver can intelligently detect which communication channels are in use and which are not, and instantly move into vacant channels while avoiding occupied ones... (Continued)Continue Reading

• Peltier effect

  The Peltier effect is a temperature difference created by applying a voltage between two electrodes connected to a sample of semiconductor material. This phenomenon can be useful when it is necessary to transfer heat from one medium to another on a ...Continue Reading

• thermoelectric cooling

  Thermoelectric cooling is a way to remove thermal energy from a medium, device or component by applying a voltage of constant polarity to a junction between dissimilar electrical conductors or semiconductors...(continued)Continue Reading

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

  MDI/MDIX is a type of Ethernet port connection using twisted pair cabling.Continue Reading

• master/slave

  In computer networking, master/slave is a model for a communication protocol in which one device or process (known as the master) controls one or more other devices or processes (known as slaves).Continue Reading

• FECN/BECN (forward explicit congestion notification/backward explicit congestion notification)

  In a frame relay network, FECN (forward explicit congestion notification) is a header bit transmitted by the source (sending) terminal requesting that the destination (receiving) terminal slow down its requests for data.Continue Reading

• Carrier Sense Multiple Access/Collision Detect (CSMA/CD)

  Carrier Sense Multiple Access/Collision Detect (CSMA/CD) is the protocol for carrier transmission access in Ethernet networks.Continue Reading