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||A measure of the degree to which signals from a nominally closed coaxial cable system are transmitted through the air. Also known as Signal Leakage. The FCC requires that egress be monitored and controlled by CATV system operators.
||Electronic Industries Association. A trade organization in Washington representing manufacturers of electronic equipment in the United States.
||EIRP (effective isotropically radiated power) - the arithmetic product of (a) the power supplied to an antenna and (b) its gain.
||EIRP (equivalent isotropically radiated power) is a measure of the total effective transmitting power of radio including adding gains from an antenna and subtracting losses from an antenna cable.
In 802.11x Wi-Fi networks, from the viewpoint of US FCC regulations for Point to Multi-Point, you are allowed only 36 dBm (4 Watts) EIRP. This is 30 dBm (1 watt) into a 6 dBi antenna. Point-to-point systems allow for higher EIRP.
||EMI (Electromagnetic Induction/Interference) is a term used to describe disturbances to electrical signals that can arise from a wide range of sources. EMI can affect all types of copper communications cables. Optical fiber is completely immune to EMI.
||The process of putting data inside a larger "package" (or packet, transmission unit) that includes a header and possibly an end-of-packet identifier. The encapsulation may be thought of as putting a letter in an envelope for transport to another location.
||The process of rendering a digital signal unintelligible to any receiver that doesn't have some unique piece of information needed to recover that signal.
||ESSID (Extended Service Set Identifier) is a unique identifier which is attached to the header of packets sent over a WLAN. The ESSID differentiates one WLAN from another, so all access points and all devices attempting to connect to a specific WLAN must use the same ESSID. A device will not be permitted to join the network group unless it can provide the same unique ESSID. An ESSID is also referred to as a Network Name because essentially it is a name that identifies a wireless network. The ESSID is a 32-character maximum string and is case-sensitive.
See aslso: SSID
||Ethernet is an IEEE data communications protocol originally developed for premises and local access networks (IEEE 802.3). It was originally developed for peer-to-peer communications using shared media over relatively short distances. Ethernet has been substantially improved over the years and now operates in a wide variety of settings. Ethernet is currently the most widely deployed LAN protocol in the world.
Some of the newer variants of the standard include;
Fast Ethernet - Ethernet at 100 Megabits per second.
Gigabit Ethernet (Gig-E) - Ethernet at 1000 Megabits per second.
||European Telecommunications Standards Institute (ETSI) is an independent, non-profit organization that produces telecommunications standards.
ETSI is officially responsible for standardization of Information and Communication Technologies (ICT) within Europe. These technologies include telecommunications, broadcasting and related areas.
||EUI (Extended Unique Identifier) allows a network interface to assign itself a unique 64-bit IPv6 address (EUI-64). This feature is a key benefit over IPv4 as it eliminates the need of manual IP address configuration, or DHCP.
The IPv6 EUI-64 format address is obtained from the 48-bit MAC address. The MAC address of network interfaces consists of two 24-bit parts, with one being OUI (Organizationally Unique Identifier) and the other being a unique NIC specific number. The EUI is constructed by splitting the MAC address in its two parts, inserting "FFFE" in between the two poeces, and inverting the 7th bit (called the "universal unique bit"). See: [RFC2373] [RFC3513]
Linux/MAC uses the EUI to automatically assign IPv6 addresses. Windows Vista/7/8/10/Server 2008 create random interface ids instead of using EUI-64.
||In wireless networking, an extender (wireless range extender, a.k.a wireless repeater) takes an existing signal from a wireless router or access point and rebroadcasts it to/from wireless clients to extend the range of the network. It differs from access points in that it connects wirelessly to all devices on both ends of the connection.
In contrast, an access point only connects wirelessly to clients, however, it uses wired networking to connect to the main router (and possibly the internet).
||The Federal Communications Commission (FCC) is an independent US federal government regulatory agency responsible for regulating interstate and international communications by radio, television, wire, satellite and cable in all U.S. territories.
The FCC is directly overseen by the US Congress, and is the US primary authority for communications law, regulation and "technological innovation". The agency is directed by five commissioners who are appointed by the President of the United States and confirmed by the U.S. Senate. The FCC's rules and regulations are in Title 47 of the Code of Federal Regulations (CFR)
||FDDI (Fiber Distributed Data Interface) is a high-speed data transmission protocol over fiber optic lines. FDDI is based on the token ring protocol and frequently used on backbones for a WAN (wide area network) due to its speed and reliability.
||FDM (Frequency Division Multiplexing) refers to the multiplexing technique that uses different frequencies to combine multiple streams of data for transmission over a communications medium. FDM uses a different frequency to each data stream. For example, cable television uses FDM to broadcast a number of channels in the same transmission.
See also: WDM, TDM.
||FHSS (frequency-hopping spread spectrum) is a modulation technology used in wireless netwok transmissions. It also is known as frequency-hopping code division multiple access (FH-CDMA).
In FHSS, the data signal "hops" between available frequencies several times per second, according to a specified algorighm. The transmission is synchronized between the sender and the receiver.
Benefits include improved privacy, decreased narrowband interference, and increased signal capacity.
See also: DSSS
||FIPS (Federal Information Processing Standard) refers to US Government technical standards published by the NIST (National Institute of Standards and Technology).
NIST develops FIPS when there are compelling Federal government requirements such as for security and interoperability but no acceptable industry standards or solutions. Computer-related products bought by the US Government must conform to FIPS.
||Firewall is a system designed to prevent unauthorized acess to or from an internal private network. Firewalls can be implemented in hardware, software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet. All traffic entering or leaving the private network (or a particular PC) passes through the firewall, which examines and blocks traffic that does not meet some specified security criteria. Firewalls are a vital part of securing a system/network.
||firmware refers to the programming that runs the device, oftern loaded into programmable read-only memory (PROM).
||FITL (Fiber in the Loop) - used by the telephone industry to describe the deployment of fiber on the subscriber side of class 5 telephone switches.
||Framework defines the technological basis, or the underlying structure supporting or containing something.
||FTF (Fiber to the Feeder) is a term typically used to describe CATV Fiber to the Node (FTTN) networks. Coaxial cables are normally used for the terminal network segment (from the node to the end-user).
||FTP (File Transfer Protocol) is a standard client/server protocol used for transfering files that operates over TCP/IP networks (such as the Internet).
An FTP server accepts commands from systems running FTP client software that allows them to download/upload files from the server. FTP is popular on the Internet because it allows for fast transfer of large files, as well as some advanced features, such as resuming interrupted uploads/downloads.
||FTTC (Fiber To The Curb) refers to the installation of optical fiber from a telephone switch to within 1,000 feet of a home or enterprise. An optical to electrical (O/E) conversion takes place somewhere near the end-user. The terminal network segment of a FTTC network is usually twisted copper pairs or coaxial cable. The final optical receiver in a FTTC network typically serves several customers.
||FTTH (Fiber To The Home) - the installation of optical fiber from a telephone switch directly into the subscriber's home.
||FTTN (Fiber to the Node) refers to an access network in which fiber is used for part, but not all of the link from the OLT to the end-user. An optical to electrical (O/E) conversion takes place at an active device called a Node. This Node typically serves a neighborhood or geographically similar area, which is larger than the typical service area in an FTTC deployment. The terminal network segment is usually twisted copper pairs or coaxial cable. Most current CATV and Telephony networks have FTTN architectures.
||FTTP (Fiber to the Premises)- refers to a telecommunications system, replacing the last mile of copper to homes/businesses with fiber optic cables for delivery of broadband service. Same as FTTH (Fiber to the Home).
||For What It's Worth
||A system (hardware-software combination) that links otherwise incompatible networks to communicate with one another.
The term often refers to the server computer, or device (NAT router,cable/dsl modem) that links a LAN to the Internet.
||Gbps (Gigabits per second, not to be confused with GBps) stands for billions of bits per second or gigabits per second and is a measure of bandwidth (the total information flow over a given time) on a communications medium.
A gigabit is a billion bits (binary pulses), or 1,000,000,000 (10^9) bits. Bits in data communications are discrete signal pulses and have historically been counted using the decimal number system.
See also: Bits/Bytes conversion calculator
||Geo-synchronous Orbit Satellites
||Gig-E (Gigabit Ethernet) refers to Ethernet at 1000 Megabits per second.
See also: Ethernet.
||General Routing Encapsulation
||Hacker, in general computing terms means to cleverly solve programming problems. It is not necessarily associated with intruders breaking into remote computer systems via communication networks (a.k.a. crackers), even though it is sometimes used in that context by journalists.
Following are definitions of the different contexts/subcultures of the term:
hacker (computer security context) is someone who seeks and exploits weaknesses in a computer system or computer network, debugging, or fixing security problems.
hacker (programmer) is a person who enjoys the intellectual challenge of creatively overcoming and circumventing limitations of programming systems, trying to extend their capabilities.
hacker (hobbyist) is a person who enjoys exploring the limits of what is possible, building, rebuilding, and modifying to make software/hardware better or faster.
||HDCP (High-bandwidth Digital Content Protection) is a form of Digital Rights Management (DRM) developed by Intel to control digital audio and video content as it travels across DVI or HDMI connections.
The specification is proprietary, and creating an implementation of HDCP requires a license by Digital Content Protection, an Intel subsidiary.
||HDSL (High-data-rate Digital Subscriber Line, High-speed DSL).
One of the older DSL implementations, providing equal upstream and downstream traffic. HDSL requires minimum two twisted pairs and offers data rates up to 2,048 Kbps.
||HDTV (High Definition television) is a term describing television with significantly more picture information (resolution) than that provided by a good NTSC or PAL television signal. The specific resolution (or definition) of HDTV can vary according to specifications, however it is typically about twice the resolution of standard signals in both the horizontal and vertical direction. HDTV often has a wider aspect ratio. To transfer the required additional resolution data through the narrow frequency TV channels, frames are digitized and compressed before they are transmitted, and then decompressed when they reach the TV.
||headend is a general term that refers to the point at which all cable television programming is collected and formatted for placement on the cable system.
The headend master facility is typically a secure building (or PLC substation) housing several large satellite dishes for reception of cable/satellite TV networks, antennae, and/or fiber optics, as well as electronic equipment used to receive, process and re-transmit video and data over the local cable infrastructure.
||header refers to the first part of a data cell or packet, containing such information as source and destination addresses, and instructions on how the telecommunications network is to handle the data. The header is part of the overhead in a data transmission protocol.
For typical TCP/IP transmissions (most Internet traffic), the header is usually 40 bytes of each packet (20-byte TCP and 20-byte IP headers). Note TCP and IP headers can be larger than 20 bytes if "options" are enabled. ICMP headers (as in pings) are 28 bytes. UDP headers are 8 bytes.
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