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Troubleshooting Wireless Networks
10BASE-T
10BASE-T, one of several physical media specified in the IEEE 802.3 standard for Ethernet local area networks (LANs), is ordinary telephone twisted pair wire. Continue Reading
100BASE-T
In 100 Mbps (megabits per second) Ethernet (known as Fast Ethernet), there are three types of physical wiring that can carry signals: 100BASE-T4 (four pairs of telephone twisted pair wire) 100BASE-TX (two pairs of data grade twisted-pair wire) ... Continue Reading
high-speed dialup
High-speed dialup, sometimes advertised as broadband dialup, is an Internet service provider (ISP) feature that speeds up data transfer by using a special server, called an acceleration server, to act as a bridge between the user's dialup connection... Continue Reading
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Asynchronous Pulsed Radiated Incident Light
Asynchronous Pulsed Radiated Incident Light is a multi-duplicitous communication protocol (MDCP) used to configure wireless local area networks (WLANs) on the fly. Continue Reading
32-bit IP addressing
32-bit IP addressing is the
IP address scheme used in Internet Protocol 4 (IPv6 uses a 128-bit system)... (Continued) Continue Readinggraceful degradation
Graceful degradation is the ability of a computer, machine, electronic system or network to maintain limited functionality even when a large portion of it has been destroyed or rendered inoperative. The purpose of graceful degradation is to prevent ...Continue Reading
bottleneck
A bottleneck is a stage in a process that causes the entire process to slow down or stop. In a communications context, a bottleneck is a point in the enterprise where the flow of data is impaired or stopped entirely... (Continued)Continue Reading
TCP/IP troubleshooting: A structured approach -- Introduction
This tip from WindowsNetworking.com describes a structured approach for troubleshooting connectivity problems with TCP/IP networks. This is the first of a series of articles on TCP/IP troubleshootingContinue Reading
CompTIA Security+ exam overview
An overview of the CompTIA Security+ exam overview including some basic facts about the exam and some analysis and perspectives of the exam.Continue Reading
disruption-tolerant network (DTN)
A disruption-tolerant network (DTN) is a network designed so that temporary or intermittent communications problems, limitations and anomalies have the least possible adverse impact... (Continued)Continue Reading
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Wireless network security best practices
Don't let your wireless LAN (WLAN) jeopardize your corporate networks, servers and data. In this guide, you'll discover how to mitigate the risks WLAN pose and learn how to perform vulnerability assessments to manage potential risks.Continue Reading
star network
A star network is a local area network (LAN) in which all nodes (workstations or other devices) are directly connected to a common central computer.Continue Reading
email response management service (ERMS)
An email response management service (ERMS) is a set of programs that automatically handles email messages and attachments according to user-defined rules... (Continued)Continue Reading
Introduction -- Chapter 1 of 'Network Analysis, Architecture and Design'
This chapter introduces the analysis, architecture, and design processes. Described are the fundamental concepts of the processes of network analysis, architecture, and design; systems and services; as well as their characteristics and prepares the ...Continue Reading
wideband
Wideband is a transmission medium or channel that has a wider bandwidth than one voice channel (with a carrier wave of a certain modulated frequency).Continue Reading
WATS (wide-area telephone service)
WATS (wide-area telephone service) is a specialized form of fixed-rate long-distance telecommunication service.Continue Reading
TDMA (time division multiple access)
TDMA (time division multiple access) is a technology used in digital cellular telephone communication that divides each cellular channel into three time slots in order to increase the amount of data that can be carried. (Continued...)Continue Reading
out-of-band signaling
Out-of-band signaling is telecommunication signaling (exchange of information in order to control a telephone call) that is done on a channel that is dedicated for the purpose and separate from the channels used for the telephone call.Continue Reading
digital loop carrier (DLC)
DLC also is an abbreviation for Data Link Control.Continue Reading
E-carrier system
To see the relationship between the E-carrier system, the T-carrier system, and DS0 multiples, see digital signal X. E1 (or E- is a European digital transmission format devised by the ITU-TS and given the name by the Conference of European Postal ...Continue Reading
committed information rate (CIR)
committed information rateContinue Reading
carrier-to-noise ratio (CNR or C/N)
In communications, the carrier-to-noise ratio, often written CNR or C/N, is a measure of the received carrier strength relative to the strength of the received noise.Continue Reading
microwave
The term microwave refers to electromagnetic energy having a frequency higher than 1 gigahertz (billions of cycles per second), corresponding to wavelength shorter than 30 centimeters.Continue Reading
in-band signaling
In the public switched telephone network, (PSTN), in-band signaling is the exchange of signaling (call control) information on the same channel that the telephone call itself is using.Continue Reading
baseband
Describes a telecommunication system in which information is carried in digital form on a single unmultiplexed signal channel on the transmission medium.Continue Reading
band
In telecommunication, a band - sometimes called a frequency band - is a specific range of frequencies in the radio frequency (RF) spectrum, which is divided among ranges from very low frequencies (vlf) to extremely high frequencies (ehf).Continue Reading
broadband voice gateway
A broadband voice gateway is a device that allows you to make telephone calls over a high-speed Internet connection rather than through a regular telephone outlet without having to go through your computer.Continue Reading
attenuation-to-crosstalk ratio (ACR) or headroom
Attenuation-to-crosstalk ratio (ACR), also called headroom, is the difference, expressed as a figure in decibels (dB), between the signal attenuation produced by a wire or cable transmission medium and the near-end crosstalk (NEXT).Continue Reading
ADSL (Asymmetric Digital Subscriber Line)
Also see Fast Guide to DSL. ADSL (Asymmetric Digital Subscriber Line) is a technology for transmitting digital information at a high bandwidth on existing phone lines to homes and businesses.Continue Reading
four-way server
A four-way server is a server that incorporates a multi-core processor for increased performance... (Continued)Continue Reading
ARCNET
ARCNET is a widely-installed local area network (LAN) technology that uses a token-bus scheme for managing line sharing among the workstations and other devices connected on the LAN.Continue Reading
STUN (Simple Traversal of UDP through NAT)
Simple Traversal of UDP through NAT (STUN) is a protocol that governs the exchange of data over a User Datagram Protocol (UDP) connection by communications devices operating behind a Network Address Translator (NAT) or firewall... (Continued)Continue Reading
CCNA exam preparation guide
A learning guide for CCNA exam preparation with book chapters, expert advice and quiz.Continue Reading
predictive dialer
A predictive dialer is a telephone control system that automatically calls a list of telephone numbers in sequence, screening out no-answers, busy signals, answering machines and disconnected numbers while predicting at what point a human caller ...Continue Reading
V.90
V.90 is a A Tour of the Internet, Who Runs It, Standards Org, approved by the International Telecommunications Union (ITU-TS), for transmitting data downstream to modems at 56 Kbps (thousand bits per second).Continue Reading
spread spectrum
Spread spectrum is a form of wireless communications in which the frequency of the transmitted signal is deliberately varied.Continue Reading
Nessus
Nessus is an open-source network vulnerability scanner that uses the Common Vulnerabilities and Exposures architecture for easy cross-linking between compliant security tools.Continue Reading
layer 2
Layer 2 refers to the Data Link layer of the commonly-referenced multilayered communication model, Open Systems Interconnection (OSI).Continue Reading
Local Number Portability (LNP)
Local Number Portability (LNP) is the ability of a telephone customer in the U.S. to retain their local phone number if they switch to another local telephone service provider.Continue Reading
PCS (personal communications service)
PCS (personal communications service) is a wireless phone service similar to cellular telephone service but emphasizing personal service and extended mobility. (Continued...)Continue Reading
two-tiered Internet
Two-tiered Internet refers to proposed changes in Internet architecture that would give priority to the traffic of those who have paid for premium service.Continue Reading
virtual circuit
A virtual circuit is a circuit or path between points in a network that appears to be a discrete, physical path but is actually a managed pool of circuit resources from which specific circuits are allocated as needed to meet traffic requirements.Continue Reading
permanent virtual circuit (PVC)
A permanent virtual circuit (PVC) is a software-defined logical connection in a network such as a frame relay network.Continue Reading
switched virtual circuit (SVC)
In a network, a switched virtual circuit (SVC) is a temporary virtual circuit that is established and maintained only for the duration of a data transfer session.Continue Reading
Network+ certification: Where does CompTIA Network+ take you? Part 3
Network+ certification: Where does CompTIA Network+ take you?Continue Reading
network access control (NAC)
Network access control (NAC), also called network admission control, is a method of bolstering the security of a proprietary network by restricting the availability of network resources to endpoint devices that comply with a defined security policy....Continue Reading
maximum transmission unit (MTU)
A maximum transmission unit (MTU) is the largest size packet or frame, specified in octets (eight-bit bytes), that can be sent in a packet- or frame-based network such as the Internet.Continue Reading
maximum segment size (MSS)
The maximum segment size (MSS) is the largest amount of data, specified in bytes, that a computer or communications device can handle in a single, unfragmented piece.Continue Reading
master
A master, in a technological context, is a device that controls one or more other devices.Continue Reading
network analyzer (protocol analyzer or packet analyzer)
A network analyzer is a combination of hardware and programming, or in some cases a stand-alone hardware device, that can be installed in a computer or network to enhance protection against malicious activity... (Continued)Continue Reading
FTAM (File Transfer Access Method)
File Transfer Access Method (FTAM), also known as File Transfer Access and Management or Electronic File Transfer Access Method (EFTAM), is an ISO standard that specifies methods of transfering files between networked computers... (Continued)Continue Reading
asymmetric communications
In telecommunications, the term asymmetric (also asymmetrical or non-symmetrical) refers to any system in which the data speed or quantity differs in one direction as compared with the other direction, averaged over time.Continue Reading
DARPANET
DARPANET (or DARPANet) is a term sometimes used for the ARPANET, the early network from which today's Internet evolved.Continue Reading
Appleshare
The AppleShare protocol is a communications protocol from Apple Computer that allows client applications in a computer to exchange files with and request services from server programs in a computer network.Continue Reading
APPC (Advanced Program-to-Program Communication or LU 6.2)
APPC (Advanced Program-to-Program Communication, sometimes called LU 6.2) is a communication protocol and programming interface standard that operates in the presentation layer and the session layer of the Open Systems Interconnection (OSI) ...Continue Reading
anycast
In Internet Protocol Version 6 (IPv6), anycast is communication between a single sender and the nearest of several receivers in a group. The term exists in contradistinction to multicast, communication between a single sender and multiple receivers...Continue Reading
mail user agent (MUA)
A mail user agent (MUA) is a program that allows you to receive and send e-mail messages; it's usually just called an e-mail program.Continue Reading
MAE
A MAE (pronounced MAY), originally an abbreviation for Metropolitan Area Exchange and now a service mark of MCI WorldCom, is a major center in the United States for interconnecting traffic between Internet service providers (ISPs).Continue Reading
Logical Link Control layer (LCL layer)
The Logical Link Control (LCL) layer is one of two sublayers of the Data-Link layer in the Open Systems Interconnection (OSI) model of communication. The LCL layer is concerned with managing traffic (flow and error control) over the physical medium.Continue Reading
collision
In a half duplex Ethernet network, a collision is the result of two devices on the same network attempting to transmit data at exactly the same time.Continue Reading
wire speed
Wire speed refers to the rate of data transfer a given telecommunication technology provides at the physical wire level.Continue Reading
network computer (NC)
A network computer (NC) is a concept from Oracle and Sun Microsystems that describes a low-cost personal computer for business networks that, like the NetPC, would be configured with only essential equipment (including CD-ROM players, diskette ...Continue Reading
acoustic coupler
An acoustic coupler is a hardware device that enables a modem (a device that converts signals from analog to digital and from digital back to analog) to connect to a voice circuit.Continue Reading
ACK
In some digital communication protocols, ACK is the name of a signal that data has been received successfully (for example, with an acceptable number of errors).Continue Reading
BOOTP (Bootstrap Protocol)
BOOTP (Bootstrap Protocol) is a protocol that lets a network user be automatically configured (receive an IP address) and have an operating system booted (initiated) without user involvement.Continue Reading
Jini
Jini (pronounced "GEE-nee" like the Arabic word for "magician") is a network architecture concept that Sun Microsystems calls "spontaneous networking." Using Jini, users will be able to plug printers, storage devices, speakers or any kind of device...Continue Reading
jam
In an Ethernet network, a jam is a signal from one device to all other devices that a collision has occurred. Specifically, the device was trying to send a frame while another device was also trying to put a frame on the line.Continue Reading
jabber (in networks)
In networks, a jabber is any device that is handling electrical signals improperly, usually with negative results for the rest of the network.Continue Reading
Jabber
Jabber is an initiative to produce an open source, XML-based instant messaging platform.Continue Reading
call failure rate (CFR)
The call failure rate (CFR) is the percentage of calls to an ISP or any network provider that fail to get through. The CFR is commonly used as a statistical measure in assessing Internet service providers.Continue Reading
weighted fair queueing (WFQ)
Weighted fair queueing (WFQ) is a method of automatically smoothing out the flow of data in packet-switched communication networks by sorting packets to minimize the average latency and prevent exaggerated discrepancies between the transmission ...Continue Reading
10-high-day busy period (10HD busy period)
In designing and assessing networks, the peak load is sometimes measured using the 10HD (10-high-day) busy period method.Continue Reading
1000BASE-T
1000BASE-T is Gigabit Ethernet (1 gigabit is 1000 megabits per second) on copper cables, using four pairs of Category 5 unshielded twisted pair to achieve the gigabit data rate.Continue Reading
OpenNMS (Open Network Management System)
OpenNMS (Open Network Management System) is the first enterprise-grade network management platform developed under the open source model.Continue Reading
Novell Directory Services (NDS)
Novell Directory Services (NDS) is a popular software product for managing access to computer resources and keeping track of the users of a
network , such as a company'sintranet , from a single point of administration.Continue Readingnetwork operations center (NOC)
A network operations center (NOC) is a place from which administrators supervise, monitor and maintain a telecommunications network.Continue Reading
network access server (NAS)
A network access server (NAS) is a computer server that enables an independent service provider (ISP) to provide connected customers with Internet access.Continue Reading
NetWare
NetWare, made by Novell, is a widely-installed network server operating system.Continue Reading
N1
N1 is Sun Microsystems' strategy for making a network environment as easy to manage as a single machine.Continue Reading
multistation access unit (MSAU)
A multistation access unit (MSAU) is a hub or concentrator that connects a group of computers ('nodes' in network terminology) to a token ring local area network.Continue Reading
loopback test
A loopback test is a test in which a signal in sent from a communications device and returned (looped back) to it as a way to determine whether the device is working right or as a way to pin down a failing node in a network.Continue Reading
loopback
In telephone systems, a loopback is a test signal sent to a network destination that is returned as received to the originator. The returned signal may help diagnose a problem.Continue Reading
Kbps (kilobits per second)
In the U.S., Kbps stands for kilobits per second (thousands of bits per second) and is a measure of bandwidth (the amount of data that can flow in a given time) on a data transmission medium.Continue Reading
null modem
A null modem cable allows you to connect your PC to another nearby PC or serial device using its modem protocol.Continue Reading
forest-and-tree model
The forest-and-tree model is a logical structure for interconnecting multiple network domains in Windows 2000 and later operating systems.Continue Reading
VRRP (Virtual Router Redundancy Protocol)
VRRP (Virtual Router Redundancy Protocol) is an Internet protocol that provides a way to have one or more backup routers when using a statically configured router on a local area network (LAN).Continue Reading
virtual network computing (VNC)
Virtual network computing (VNC) is a type of remote-control software that makes it possible to control another computer over a network connection...Continue Reading
terminal emulation
Terminal emulation is the ability to make one computer terminal, typically a PC, appear to look like another, usually older type of terminal so that a user can access programs originally written to communicate with the other terminal type.Continue Reading
port number
A port number is a way to identify a specific process to which an Internet or other network message is to be forwarded when it arrives at a server.Continue Reading
network tracking tool (network device management program)
A network tracking tool, also called a network device management program, is a program that helps a network administrator keep track of moves, additions, and changes (known as MACs) to the hardware infrastructure of a network.Continue Reading
audible ring
In a telephone system, an audible ring is the tone that is returned from the called party's switching device and heard by the caller. This tone indicates to the caller that the desired party is being rung.Continue Reading
Guide to network security
This guide introduces you to the main components in whole network security. You'll find articles, tutorials, tips, tools, white papers and more to pump up your network security quickly.Continue Reading
Network Virtualization, Chapter 3: A basic virtualized enterprise
In this excerpt from Network Virtualization by Victor Moreno and Kumar Reddy, learn the technical requirements posed by the need to virtualize the network, as well as an architectural framework comprised of the functional areas necessary to ...Continue Reading
terminal proxy server (TPS)
A terminal proxy server (TPS) is a program that acts as an interface for voice over Internet Protocol (VoIP) telephone sets... (Continued)Continue Reading
Open source network tools
Some of the most commonly used, enterprise-ready open source tools are used for networking applications; likewise, many networking tasks can be accomplished quickly and cheaply using open source tools. In this guide, we present advice and resources ...Continue Reading
Manufacturing Message Specification (MMS)
The Manufacturing Message Specification (MMS) is an international standard that defines the ways in which control information is transferred among intelligent devices and systems such as computers and robots... (Continued)Continue Reading
branch office box (BOB)
A Branch Office Box (BOB) is a server appliance that has been optimized to provide distributed support for simple utility functions that are required locally but are difficult to provide over a WAN... (Continued)Continue Reading
VPN appliance
A VPN (virtual private network) appliance is a network device equipped with enhanced security features... (Continued)Continue Reading
common channel signaling (CCS)
Common channel signaling (CCS) is signaling (for example, in a T-carrier system line) in which a group of voice-and-data channels share a separate channel that is used only for control signals.Continue Reading
channel-associated signaling (CAS)
Channel-associated signaling (CAS) is signaling (for example, in a T-carrier system line) in which control signals, such as those for synchronizing and bounding frames, are carried in the same channels as voice and data signals... (Continued)Continue Reading