Infoarch Network Terminology


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Networking Terms

Amplifier	A network component, also known as repeater. Amplifiers increase the power of a signal when it is lost due to attenuation. They allow signals to cover greater distances in a LAN environment.
Application Layer	The seventh layer in the OSI model. The Application layer defines program to program communication, or how applications access network services. Services defined by the Application layer include file transfer, job transfer and terminal emulation
ATM	Borad bandwith (155Mb), ATM can be implemented either as a backbone solution or as an entire network solution. In the backbone scenario, ATM is used to connect departments, floors, or any part of the organization that is distant from the main server center. In the network scenario, ATM is used as the entire LAN, WAN, MAN. LAN Emulation (LANE) is used in these types of networks to give an Ethernet feel to the network. This emulation is easier to implement than IP emulation over ATM and is much more popular.
Bandwidth	The amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second or bytes per second. For analog devices, the bandwidth is expressed in cycles per second, or Hertz (Hz)
Bridge	A network component that connects two LANs, thus extending the range of the network. Bridges check data and forward them across LANs.
Broadband	A single wire or network pipe that has sufficient bandwidth to carry large amount of data simultaneously
Broadcast	When data is sent simultaneously to all stations on a network
Brouter	A network component that serves as both a Bridge and a Router
Buffer	Space allocated on a system's Random Access Memory (RAM) where data is stored temporarily until it is transferred to another part of the system
Bus Topology	A LAN network structure in which all stations (nodes) are connected to the same cable. Data is transmitted up and down this single cable
Cable Modem	A modem that connects home networking systems (computer + TV) to cable TV networks, and by so doing bypasses traditional phone networks. Cable TV networks use a coaxial cable or HFC infrastructure
Circuit Switching	A communication technology in which a dedicated channel (circuit) is established for the duration of a transmission
Collisions	In an Ethernet network, every host connected to the network can transmit at any time. This may result in two hosts transmitting at the same time. If a collision between packets is sensed by both hosts, their NICs (Network Interface Cards) perform a Back Off - a transmission time-out. Since the length of the back-off is randomly determined, in most cases when the time-out has elapsed both NICs will be able to re-transmit without interfering with each other. There is always a change that another host will try to send a packet, causing the back-off procedure to start again
Coaxial Cable	Copper cable that consists of a central wire surrounded by insulation and then a grounded shield of braided wire. Coaxial wire is widely used by the cable television industries. It is less prone to interference than regular wire cables. Most older Ethernet network also use coaxial cable
Connectionless vs Connection-oriented Protocols	When using a connectionless protocol, hosts send data without establishing a connection with the recipient. The host does not know if the data arrives at its destination or not. In contrast, connection-oriented protocols require a designated path to be established between the sender and receiver before any messages are transmitted
Dial-Up Access	When computer devices hook up to a network via modem and public phone system on a pay-per-time basis. Usually dial-up connections offer limited bandwidths. The alternative is a leased line that offers continuous access at a constant bandwidth to a network
DSL (Digital Subscriber Lines)	A general acronym relating to Digital Subscriber Lines. The two main types are ADSL (Asynchronous) and SDSL (Synchronous). DSL modulate data over copper wires. Also known as 'last mile' technologies because they are used to connect only between telephone switching stations to a home or office, not between switching stations
E1/T1	In the United States, A T1 service is a framed communication protocol that delivers a two-way connection at 1.544 Mbits/s each way. In manay other countries, the equivalent of T1 is a service called E1 - a two way connection at 2.048 Mbit/s
FDDI (Fiber Distributed Data Interface)	A set of ANSI protocols for sending digital data over fiber optic cable. FDDI networks are token-passing networks. They support data rates of up to 100 Mbps. FDDI networks usually serve as backbones for wide-area network. FDDI-2 is an extension of FDDI that supports the tranmission of voice and video too
FTP (File Transfer Protocol)	A protocol that defines the transfer of files over the Internet
Hub	A networking component that enables the common connection of devices to a network. Hubs are usually used to connect nodes in local area networks. Active hubs can regenerate data over the network, wheras passive hubs only transfer information
Jitter	Data packets, in general, are not sensitive to how long it takes for them to arrive or when they arrive in relation to the preceding or subsequent packets. The delay added by the network is called latency. The difference over time between the latencies of different packets is called jutter
IP (Internet Protocol)	The protocol that defines how packets are formated and addressed when sending data over the Internet. The IP frame header contains routing information and control information associated with datagram delivery. IP is part of the TCP/IP group of protocols
IP Multicast	To send information over the Internet to a group of computers that share the same IP address
Local Area Networks (LAN)	A network that covers a small geographical area
Latency	The amount of time it takes a packet to travel from source to destination. Together, latency and bandwidth define the speed and capacity of a network
Leased Line	A permanent connection to a network that guarantees constant bandwidth and network access. Leased lines cost a fixed monthly fee
Modem	A network interface device that allows computers to send and receive data over telephone lines
Quality of Service (QoS)	Quality of Service refers to the way data is transmitted between two hosts on a network. Networking protocols that offer QoS make sure that when information needs to be communicated, the sender requests a designated path with the network for a connection to the destination. The sender specifies the type, speed and other attributes of the call, which determine and guarantee the end-to-end quality of service
Packet Switching	A networking technology in which messages are devided into packets before they are sent. Each packet is transmitted individually and can even follow different routes to its destination. Once all the packets forming a message arrive at the destination, they are recompiled into the original message. Packet switching is more efficient and robust for data that can withstand some delays in transmission, such as e-mail messages and Web pages
Router	A networking device that connects different types of networks. Routers know how to direct data between networks that use different architectures and protocols
RTP (Real-Time Transport Protocol)	An Internet protocol that defines the transmission of real-time data, for example audio and video. RTP provides mechanisms for the sending (server) and receiving applications to support streaming data. RTP usually runs on top of the UDP protocol
Star Topology	A local-area network (LAN) in which all nodes (stations) are connected to a central device
Streaming	A technique for transferring data so that it is received as a continuous real-time stream
TCP (Transmission Control Protocol)	TCP is one of the main protocols in TCP/IP networks. TCP defines the way two hosts establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent
TCP/IP	A set of protocols designed by the US Department of Defense for transferring data between networks
UDP (Universal Data Protocol)	A transfer protocol that allows any station on a network that possesses a standard network card to transmit or receive information, without the need for a special interface card. UDP is mainly used to broadcast messages over a network
Virtual Private Network (VPN)	A network dedicated to a specific user or graoup of users that is part of a public network. For example, there are a number of systems that enable users to create dedicated networks using the Internet as the backbone for transporting data
VLANS	Virtual Local Area Networks are networks that allow any user, no matter where they are, to log on to their home network
WAP (Wireless Application Protocol)	A protocol that defines delivery and access of information to wireless devices
Wide Area Network (WAN)	A network that covers large geographical areas by connecting many local area networks together

Disclaimers

This section is intended as a quick reference for those with technical background only. Advice posted in this area may be simplified; certain key steps may be neglected with the assumption that you know what you are doing. If you don't, please consult your Infoarch representative.