Comptia Network+ 2017 Acronyms W/ Definitions

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A

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Address

An A and AAAA record are actually primary DNS records. They associate a domain name with a specific IP address, so that when a user types in a web address, such as "www.rackspace.com" their browser knows where to go for the actual website.The difference between A and AAAA is this: A is IPv4 and AAAA is the current IPv6 record. Beyond that, there is no difference. Later on, IPv6 records will be changed to A6 records.

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AAA pronounced "triple-A"

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Authentication, Authorization and Acounting:

An AAA server is a server program that handles user requests for access to computer resources and, for an enterprise, provides authentication, authorization, and accounting (AAA)services. The AAA server typically interacts with network access and gateway servers and with databases and directories containing user information. The current standard by which devices or applications communicate with an AAA server is the Remote Authentication Dial-In User Service (RADIUS).

the AAA chain (that is, client to PEP, PEP to PDP, etc.), has a protocol that deals with communication from the client to the PDP directly: the Extensible Authentication Protocol (EAP)

Core Components of triple-A
Client: The client is the device attempting to access the network. The client either authenticates itself, or it acts as a proxy to authenticate the user.Policy Enforcement Point (Authenticator): The Policy Enforcement Point (PEP) is some­times called the authenticator or dial-in server, VPN concentrator, firewall, gateway General Packet Radio Service(GPRS) support node, Ethernet switch, wireless access point, or an inline security gateway. The PEP is responsible for enforcing the terms of a client's access. This enforcement varies based on the capabilities of the PEP and is discussed later in this article.Policy Information Point: The Policy Information Point (PIP) is a repository of information to help make the access decision. It could be a database of device IDs, a user directory such as the Lightweight Directory Access Protocol (LDAP), a one-time password (OTP) token server, or any other system that houses data relevant to a device or user access request.Policy Decision Point (AAA Server): The Policy Decision Point (PDP) is the brain of the AAA decision. It collects the access request from the client through the PEP. It also queries any relevant PIPs to gather the information it needs to make the access decision. The PDP, as its name implies, is the entity that makes the final decision around network access. It also can send specific authorizations back to the PEP that apply settings or constraints to the client's network traffic.Accounting and Reporting System: Whether on a dedicated system or built as part of a PDP, tracking use of the network with accounting is one of the best features of AAA. With all forms of network access now offering controlled access, the AAA service can tell you who got on the network, from where, and what that person was granted access to.It is important to note that the preceding categories are logical containers of functions and not necessarily dedicated physical devices. Often elements are combined, such as PEP with PDP, and PDP with PIP.

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AAAA

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Authentication, Authorization, Accounting and Address

AAAA record, also known as "IPv6 address record", maps a hostname to a 128-bit IPv6 address in the Domain Name System (DNS)

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ABR

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Area Border Router

An area border router (ABR) is a kind of router that is located near the border between one or more Open Shortest Path First (OSPF) areas. It is used to establish a connection between backbone networks and the OSPF areas. It is a member of both the main backbone network and the specific areas to which it connects, so it stores and maintains separate routing information or routing tables regarding the backbone and the topologies of the area to which it is connected.

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ACL, aka Ackle

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Access Control List

A network access control list (ACL) is an optional layer of security for your VPC that acts as a firewall for controlling traffic in and out of one or more subnets. You might set up network ACLs with rules similar to your security groups in order to add an additional layer of security to your VPC

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AD

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Active Directory

is a directory service that Microsoft developed for Windows domain networks. It is included in most Windows Server operating systems as a set of processes and services. Initially, Active Directory was only in charge of centralized domain management.

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ADSL

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Asymmetric Digital Subscriber Line

) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide.

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AES

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Advanced Encryption Standard

is a symmetric block cipher chosen by the U.S. government to protect classified information and is implemented in software and hardware throughout the world to encrypt sensitive data.

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AH

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Authentication Header

is a protocol and part of the Internet Protocol Security (IPsec) protocol suite, which authenticates the origin of IP packets (datagrams) and guarantees the integrity of the data.

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AP

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Access Point

In a wireless local area network (WLAN), an access point is a station that transmits and receives data (sometimes referred to as a transceiver). An access pointconnects users to other users within the network and also can serve as the point of interconnection between the WLAN and a fixed wire network.

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APC

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Angle Polished Connector is a type of fiber connector that minimizes backreflection due to a 5° to 15° angle-polish applied to end faces

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APIPA

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Automatic Private Internet Protocol Addressing

(Automatic Private IP Addressing) The Windows function that provides DHCP autoconfiguration addressing. APIPA assigns a class B IP address from 169.254.0.0 to 169.254.255.255 to the client when a DHCP server is either permanently or temporarily unavailable. Designed for small non-routable networks, if a DHCP server becomes available later, the APIPA address is replaced with one from the DHCP server. For example, when a Windows Vista machine starts up, it waits only six seconds to find a DHCP server before assigning an IP from the APIPA range. It then continues to look for a DHCP server. Previous versions of Windows looked for a DHCP server for up to three minutes. See DHCP autoconfiguration addressing, DHCP and private IP address.An IP Assigned by APIPAThis IP address was assigned by APIPA, and the IPCONFIG utility reports the IP as an "Autoconfiguration IP address." See IPCONFIG

Definition of: APIPA

APIPA

(Automatic Private IP Addressing) The Windows function that provides DHCP autoconfiguration addressing. APIPA assigns a class B IP address from 169.254.0.0 to 169.254.255.255 to the client when a DHCP server is either permanently or temporarily unavailable. Designed for small non-routable networks, if a DHCP server becomes available later, the APIPA address is replaced with one from the DHCP server.

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APT

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Advanced Persistent Threat

is a network attack in which an unauthorized person gains access to a network and stays there undetected for a long period of time. The intention of an APT attack is to steal data rather than to cause damage to the network or organization.

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AS

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Autonomous System

Within the Internet, an autonomous system (AS) is a collection of connected Internet Protocol (IP) routing prefixes under the control of one or more network operators on behalf of a single administrative entity or domain that presents a common, clearly defined routing policy to the Internet.

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ASIC

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Application Specific Integrated Circuit

, is an integrated circuit (IC) customized for a particular use, rather than intended for general-purpose use. For example, a chip designed to run in a digital voice recorder or a high-efficiency Bitcoin miner is an ASIC.

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ASP

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Application Service Provder

(ASP) is a company that offers individuals or enterprises access over the Internet to applications and related services that would otherwise have to be located in their own personal or enterprise computers

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ATM

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Asynchronous Transfer Mode

is a switching technique used by telecommunication networks that uses asynchronous time-division multiplexing to encode data into small, fixed-sized cells. This is different from Ethernet or internet, which use variable packet sizes for data or frames.

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AUI

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Attachment Unit Interface

The AUI (attachment unit interface) is the 15-pin physical connector interface between a computer's network interface card (NIC) and an Ethernet cable. On10Base-5 ("thicknet") Ethernet, a short cable is used to connect the AUI on the computer with a transceiver on the main cable.

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AUP

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Acceptable Use Policy

is a document stipulating constraints and practices that a user must agree to for access to a corporate network or the Internet. Many businesses and educational facilities require that employees or students sign anacceptable use policy before being granted a network ID.

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BCP

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Business Continuity Plan

deals with keeping a company and business after a disaster has been experienced and takes a lot more into account than just technology.

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BCS

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Business Connectivity Services

infrastructure that is on your corporate network. Information workers who access the Business Connectivity Services solution are on your corporate network. External content that is surfaced in SharePoint as an external list.

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BDR

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Backup Designated Router

Designated router and backup designated router. Based on the network type, OSPF router can elect one router to be a designated router (DR) and one router to be a backup designated router (BDR). For example, onmultiaccess broadcast networks (such as LANs) routers defaults to elect a DR and BDR.

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BERT

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Bit Error Rate Test

is a procedure or device thatmeasures the bit error rate of a transmission to determine if errors are introduced into the system when data is transmitted.

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BGP

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Border Gateway Protocol

is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet. Theprotocol is often classified as a path vector protocolbut is sometimes also classed as a distance-vector routing protocol.

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BL

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Bluetooth Low Energy

is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet. The protocol is often classified as a path vector protocol but is sometimes also classed as a distance-vector routing protocol.

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BNC

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British Naval Connector or Bayonet Naval Connector

is used to connect a computer to a coaxial cable in a 10BASE-2 Ethernet network. ... The BNC connector in particular is generally easier to install and less expensive than other coaxial connectors.

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BootP

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Boot Protocol or 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.

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BPDU

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Bridge Protocol Data Unit

is a data message transmitted across a local area network to detect loops in network topologies. A BPDU contains information regarding ports, switches, port priority and addresses. BPDUs contain the information necessary to configure and maintain spanning tree topology.

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BRI

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Basic Rate Interface

is one of the two levels of services provided by Integrated Services Digital Network (ISDN). BRI is made for home and small-scale enterprise use. It consists of two bearer channels (B channels) and one data channel (D channel) for transmission of data. The B channel carries data, voice, and other services, while the D channel carries controlling and signaling data.

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BSSID

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Basic Service Set Identifier

is the MAC address of the wireless access point (WAP) generated by combining the 24 bit Organization Unique Identifier (the manufacturer's identity) and the manufacturer's assigned 24-bit identifier for the radio chipset in the WAP.

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BYOD

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Bring Your Own Device

Bring your own device (BYOD)—also called bring your own technology (BYOT), bring your own phone (BYOP), and bring your own personal computer (BYOPC)—refers to the policy of permitting employees to bring personally owned devices (laptops, tablets, and smart phones) to their workplace, and to use those devices to access privileged company information and applications.[1] The phenomenon is commonly referred to as IT consumerization

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CAM

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Channel Access Method

=

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CAN

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Campus Area Network

is a computer networkthat links the buildings and consists of two or more local area networks (LANs) within the limited geographical area. It can be the college campus, enterprise campus, office buildings, military base, industrial complex.

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CARP

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Common Address Redundancy Protocol

is a computer networking protocol which allows multiple hosts on the same local area network to share a setof IP addresses. Its primary purpose is to provide failover redundancy, especially when used with firewalls and routers.

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CAT

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Computer And Telephone

Category 5 cable is used in structured cabling for computer networks such as Ethernet over twisted pair. The cable standard provides performance of up to 100 MHz and is suitable for 10BASE-T, 100BASE-TX (Fast Ethernet), and 1000BASE-T (Gigabit Ethernet).

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CCTV

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Closed Circuit TV

is a TV system in which signals are not publicly distributed but are monitored, primarily for surveillance and security purposes. CCTV relies on strategic placement of cameras and private observation of the camera's input on monitors.

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CDMA

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Code Division Multiple Access

is a channelaccess method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel.

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CDMA/CD

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Carrier Sense Multiple Access/Collision Detection

is the protocol forcarrier transmission access in Ethernet networks. On Ethernet, any device can try to send a frame at any time. Each device senses whether the line is idle and therefore available to be used.

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CIDR

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Classless Inter-Domain Routing

is a set of Internet protocol (IP) standards that is used to create unique identifiers for networks and individual devices. ... That system is known as CIDR notation. CIDR IP addresses consist of two groups of numbers, which are also referred to as groups of bits.

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CHAP

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Challenge Handshake Authentication Protocol

In computing, the Challenge-Handshake Authentication Protocol (CHAP) authenticatesa user or network host to an authenticating entity. That entity may be, for example, an Internet service provider. CHAP is specified in RFC 1994.CHAP provides protection against replay attacks by the peer through the use of an incrementally changing identifier and of a variable challenge-value. CHAP requires that both the client and server know the plaintext of the secret, although it is never sent over the network. Thus, CHAP provides better security as compared to Password Authentication Protocol (PAP) which is vulnerable for both these reasons. The MS-CHAPvariant does not require either peer to know the plaintext and does not transmit it, but has been broken.[1]

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CIFS

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Common Internet File System/Services

Common Internet File SystemThe Common Internet File System (CIFS) is the standard way that computer users share files across corporate intranets and the Internet. An enhanced version of the Microsoft open, cross-platform Server Message Block (SMB) protocol, CIFS is a native file-sharing protocol in Windows 2000.CIFS defines a series of commands used to pass information between networked computers. The redirector packages requests meant for remote computers in a CIFS structure. CIFS can be sent over a network to remote devices. The redirector also uses CIFS to make requests to the protocol stack of the local computer.

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CLI

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Command Line Interface

A CLI (command line interface) is a user interface to a computer's operating system or an application in which the user responds to a visual prompt by typing in a command on a specified line, receives a response back from the system, and then enters another command, and so forth.

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CNAME

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Canonical Name

A Canonical Name record (abbreviated as CNAME record) is a type of resource recordin the Domain Name System (DNS) used to specify that a domain name is an alias for another domain (the 'canonical' domain).This can prove convenient when running multiple services (like an FTP server and a webserver; each running on different ports) from a single IP address. One can, for example, point ftp.example.com and www.example.com to the DNS entry for example.com, which in turn has an A record which points to the IP address. Then, if the IP address ever changes, one only has to record the change in one place within the network: in the DNS A record for example.com.CNAME records must always point to another domain name, never directly to an IP address.

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COOP

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Concurrent Object-Oriented Programming

While numerous programming languages, such as Java, combine OOP withconcurrency mechanisms like threads, the phrase "concurrent object-oriented programming" primarily refers to systems where objects themselves are aconcurrency primitive, such as when objects are combined with the actor model.

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COS

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Class of Service

is a parameter used in data and voice protocols to differentiate the types of payloads contained in the packet being transmitted. The objective of such differentiation is generally associated with assigning priorities to the data payload or access levels to the telephone call.

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CPU

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Central Processing Unit

A central processing unit (CPU) is the electronic circuitrywithin a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. The computer industry has used the term "central processing unit" at least since the early 1960s.[1] Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memoryand I/O circuitry.[2]The form, design, and implementation of CPUs have changed over the course of their history, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the fetching (from memory) and execution of instructions by directing the coordinated operations of the ALU, registers and other components.

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CRAM

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Challenge-Response Authentication Mechanism-Message Digest 5

In cryptography, CRAM-MD5 is a challenge-response authentication mechanism (CRAM) based on the HMAC-MD5 algorithm. As one of the mechanisms supported by the Simple Authentication and Security Layer (SASL), it is often used in email software as part of SMTP Authentication and for the authentication of POP and IMAP users, as well as in applications implementing LDAP, XMPP, BEEP, and other protocols.When such software requires authentication over unencrypted connections, CRAM-MD5 is preferred over mechanisms that transmit passwords "in the clear," such as LOGIN and PLAIN. However, it can't prevent derivation of a password through a brute-force attack, so it is less effective than alternative mechanisms that avoid passwords or that use connections encrypted with Transport Layer Security (TLS).

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CRC

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Cyclic Redundancy Checking

A cyclic redundancy check (CRC) is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to raw data. Blocks of data entering these systems get a short check value attached, based on the remainder of a polynomial division of their contents. On retrieval, the calculation is repeated and, in the event the check values do not match, corrective action can be taken against data corruption. CRCs can be used for error correction (see bitfilters).[1]CRCs are so called because the check (data verification) value is a redundancy (it expands the message without adding information) and the algorithm is based on cycliccodes. CRCs are popular because they are simple to implement in binary hardware, easy to analyze mathematically, and particularly good at detecting common errors caused by noise in transmission channels. Because the check value has a fixed length, the functionthat generates it is occasionally used as a hash function.The CRC was invented by W. Wesley Peterson in 1961; the 32-bit CRC function of Ethernet and many other standards is the work of several researchers and was published in 1975.

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CSMA/CA

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Carrier Sense Multiple Access/ Collision Avoidance

Carrier-sense multiple access with collision avoidance (CSMA/CA) in computer networking, is a network multiple access method in which carrier sensing is used, but nodes attempt to avoid collisions by transmitting only when the channel is sensed to be "idle".[1][2] When they do transmit, nodes transmit their packet data in its entirety.It is particularly important for wireless networks, where the collision detection of the alternative CSMA/CD is unreliable due to the hidden node problem.[3][4]CSMA/CA is a protocol that operates in the Data Link Layer (Layer 2) of the OSI model.

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CSU

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Channel Service Unit

In telecommunications, a channel service unit (CSU) is a line Bridging device for use with T-carrier that:is used to perform loopback testing,may perform bit stuffing,may also provide a framing and formatting pattern compatible with the network,provides a barrier for electrical interference from either side of the unit, andis the last signal regeneration point, on the loop side, coming from the central office, before the regenerated signal reaches a multiplexer or data terminal equipment (DTE).

A CSU/DSU (Channel Service Unit/Data Service Unit) is a digital-interface device used to connect data terminal equipment (DTE), such as a router, to a digital circuit, such as a Digital Signal 1 (DS1) T1 line. The CSU/DSU implements two different functions. The channel service unit (CSU) is responsible for the connection to the telecommunicationnetwork, while the data service unit (DSU) is responsible for managing the interface with the DTE.DSL and cable modems are CSU/DSUs because they convert from one type of digital signal to another. A CSU/DSU is the equivalent of the modem for an entire LAN.[1]WAN interface[edit]The WAN Interface Card (WIC) may contain an integrated CSU/DSU that can be inserted into a router slot. An example of a WIC is the 1-port 56/64-kbit/s DSU/CSU WIC (WIC-1DSU-56K4) by Cisco Systems.

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CWDM

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Course Wave Division Multiplexing

in fiber-optic communications, wavelength-division multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light. This technique enables bidirectional communications over one strand of fiber, as well as multiplication of capacity.The term wavelength-division multiplexing is commonly applied to an optical carrier, which is typically described by its wavelength, whereas frequency-division multiplexing typically applies to a radio carrier which is more often described by frequency. This is purely convention because wavelength and frequency communicate the same information.

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db

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Decibels

The decibel (symbol: dB) is a logarithmic unit used to express the ratio of one value of a physical property to another, and may be used to express a change in value (e.g., +1 dB or -1 dB) or an absolute value. In the latter case, it expresses the ratio of a value to a reference value; when used in this way, the decibel symbol should be appended with a suffix that indicates the reference value or some other property. For example, if the reference value is 1 volt, then the suffix is "V" (i.e., "20 dBV"), and if the reference value is one milliwatt, then the suffix is "m" (i.e., "20 dBm").[1] However, sound pressure level is referenced to the "threshold of hearing" (generally given as 20 micropascals at 1 kHz), and the suffix is "SPL" (i.e., "60 dB SPL").[2]There are two different scales used when expressing a ratio in decibels depending on the nature of the quantities: field, power, and root-power. When expressing power quantities, the number of decibels is ten times the logarithm to base 10 of the ratio of two power quantities.[3] That is, a change in power by a factor of 10 corresponds to a 10 dB change in level. When expressing field quantities, a change in amplitude by a factor of 10 corresponds to a 20 dB change in level. The extra factor of two is due to the logarithm of the quadratic relationship between power and amplitude. The decibel scales differ so that direct comparisons can be made between related power and field quantities when they are expressed in decibels.The definition of the decibel is based on the measurement of power in telephony of the early 20th century in the Bell System in the United States. One decibel is one tenth (deci-) of one bel, named in honor of Alexander Graham Bell; however, the bel is seldom used. Today, the decibel is used for a wide variety of measurements in science and engineering, most prominently in acoustics, electronics, and control theory. In electronics, the gains of amplifiers, attenuation of signals, and signal-to-noise ratios are often expressed in decibels.In the International System of Quantities, the decibel is defined as a unit of measurementfor quantities of type level or level difference, which are defined as the logarithm of the ratio of power- or field-type quantities.[4]

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DCS

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Distributed Computer System

Distributed networking is a distributed computing network system, said to be distributed when the computer programming and the data to be worked on are spread out across more than one computer. Usually, this is implemented over a computer network.Prior to the emergence of low-cost desktop computer power, computing was generally centralized to one computer. Although such centers still exist, distribution networking applications and data operate more efficiently over a mix of desktop workstations, local area network servers, regional servers, Web servers, and other servers.One popular trend is client/server computing. This is the principle that a client computer can provide certain capabilities for a user and request others from other computers that provide services for the clients. (The Web's Hypertext Transfer Protocol is an example of this idea.)Enterprises that have grown in scale over the years and those that are continuing to grow are finding it extremely challenging to manage their distributed network in the traditional client/server computing model. The recent developments in the field of cloud computing has opened up new possibilities. Cloud-based networking vendors have started to sprout offering solutions for enterprise distributed networking needs. Whether it turns out to revolutionize the distributed networking space or turns out to be another craze remains to be seen.

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DDoS

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Distributed Denial of Service In computing, a denial-of-service attack (DoS attack) is a cyber-attack where the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to the Internet. Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled.[1]In a distributed denial-of-service attack (DDoS attack), the incoming traffic flooding the victim originates from many different sources. This effectively makes it impossible to stop the attack simply by blocking a single source.A DoS or DDoS attack is analogous to a group of people crowding the entry door or gate to a shop or business, and not letting legitimate parties enter into the shop or business, disrupting normal operations.Criminal perpetrators of DoS attacks often target sites or services hosted on high-profile web servers such as banks or credit card payment gateways. Revenge, blackmail[2][3][4]and activism[5] can motivate these attacks.

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DHCP

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Dynamic Host Configuration Protocol

The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on TCP/IP networks whereby a DHCP server dynamically assigns an IP address and other network configuration parameters to each device on a network so they can communicate with other IP networks.[1] A DHCP server enables computers to request IP addresses and networking parameters automatically from the Internet service provider (ISP), reducing the need for a network administrator or a user to manually assign IP addresses to all network devices.[1] In the absence of a DHCP server, a computer or other device on the network needs to be manually assigned an IP address.DHCP can be implemented on networks ranging in size from home networks to large campus networks and regional Internet service provider networks small local networks as well as large enterprise networks.[2] A router or a residential gateway can be enabled to act as a DHCP server. Most residential network routers receive a globally unique IP address within the ISP network. Within a local network, a DHCP server assigns a local IP address to each device connected to the network.

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DLC

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Data Link Control

In the OSI networking model, Data Link Control (DLC) is the service provided by the data link layer. Network interface cards have a DLC address that identifies each card; for instance, Ethernet and other types of cards have a 48-bit MAC address built into the cards' firmware when they are manufactured.There is also a network protocol with the name Data Link Control. It is comparable to better-known protocols such as TCP/IP or AppleTalk. DLC is a transport protocol used by IBM SNA mainframe computers and peripherals and compatible equipment. In computer networking, it is typically used for communications between network-attached printers, computers and servers, for example by HP in their JetDirect print servers. While it was widely used up until the time of Windows 2000, versions from Windows XP onward do not include support for DLC.[1]

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DLP

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Data Leak Prevention

data loss prevention software detects potential data breaches/data ex-filtration transmissions and prevents them by monitoring, detecting and blocking sensitive data while in-use (endpoint actions), in-motion (network traffic), and at-rest (data storage).The terms "data loss" and "data leak" are related and are often used interchangeably.[1]Data loss incidents turn into data leak incidents in cases where media containing sensitive information is lost and subsequently acquired by an unauthorized party. However, a data leak is possible without losing the data on the originating side. Other terms associated with data leakage prevention are information leak detection and prevention (ILDP), information leak prevention (ILP), content monitoring and filtering (CMF), information protection and control (IPC) and extrusion prevention system (EPS), as opposed to

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DLR

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Device Level Ring

The Device Level Ring Protocol (DLR) is a redundancy protocol for EtherNet/IP and operates on OSI Layer 2. It can detect bus faults in a single line topology. This bus fault can be compensated by activating a redundant communication path. Thus DLR allows to build fast recovering and redundant network topologies that do not influence the controlling applications. The DLR stack requires port’s GOAL (Generic OS Abstraction Layer). A DLR participant always has two external Ethernet ports. Thus it requires an Embedded 3-port-switch. Furthermore Beacon-based Ring Nodes or DLR Supervisors need additional hardware support to process and generate Beacon frames at a high level of speed

The Ring Supervisor controls the DLR network. It must be able to send out and process Beacon Frames and Announce Frames within the specified time intervals. A Beacon Frame interval of at least 400 microseconds must be supported. The Ring Supervisor also opens and closes the ring. In Normal State Forwarding between its external Ethernet ports is disabled, i.e. the ring is open. If a fault is detected somewhere in the network, the Ring Supervisor enables Forwarding between its ports and the ring is closed. As a result the line topology is restored and the network fault does not interfere with the logical communication channels.

The DLR stack by port requires GOAL (Generic OS Abstraction Layer). Every platform that is supported by GOAL is also supported by the DLR stack. However the hardware requires a 3-port switch. Announce-based Ring Nodes can run on any platform with a 3-port switch. However Beaconbased Ring Nodes require special hardware support and a special GOAL driver. Currently the following platforms are supporded for Beacon-based Ring Nodes:

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DMZ

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Demilitarized Zone

In computer security, a DMZ or demilitarized zone (sometimes referred to as a perimeter network) is a physical or logical subnetwork that contains and exposes an organization's external-facing services to an untrusted network, usually a larger network such as the Internet. The purpose of a DMZ is to add an additional layer of security to an organization's local area network (LAN); an external network node can access only what is exposed in the DMZ, while the rest of the organization's network is firewalled. The DMZ functions as a small, isolated network positioned between the Internet and the private network.The name is derived from the term "demilitarized zone", an area between nation states in which military operation is not permitted.

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DNAT

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Destination Network Address Translation

Destination network address translation (DNAT) is most often used to redirect packets destined for a particular IP address, or a specific port on an IP address, on one host to a different address and/or port, possibly on a different host.

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DNS

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Domain Name Service or Domain Name Server or Domain Name System

The main function of DNS is to translate domain names into IP Addresses, which computers can understand. It also provides a list of mail servers which accept Emails for each domain name.

Domain Name Servers (DNS) are the Internet's equivalent of a phone book. They maintain a directory of domain names and translate them to Internet Protocol (IP) addresses. This is necessary because, although domain names are easy for people to remember, computers or machines, access websites based on IP addresses

(Domain Name System) The Internet's system for converting alphabetic names into numeric IP addresses. For example, when a Web address (URL) is typed into a browser, DNS servers return the IP address of the Web server associated with that name.

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DOCSIS

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Data-Over-Cable Service Interface Specification

is an international telecommunications standard that permits the addition of high-bandwidth data transfer to an existing cable TV (CATV) system. It is employed by many cable television operators to provide Internet access (see cable Internet) over their existing hybrid fiber-coaxial (HFC) infrastructure. The version numbers are sometimes prefixed with simply "D" instead of "DOCSIS" (e.g. D3 for DOCSIS 3).

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DoS

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Denial of Service

In computing, a denial-of-service attack (DoS attack) is a cyber-attack where the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to the Internet. Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled.[1]In a distributed denial-of-service attack (DDoS attack), the incoming traffic flooding the victim originates from many different sources. This effectively makes it impossible to stop the attack simply by blocking a single source.A DoS or DDoS attack is analogous to a group of people crowding the entry door or gate to a shop or business, and not letting legitimate parties enter into the shop or business, disrupting normal operations.Criminal perpetrators of DoS attacks often target sites or services hosted on high-profile web servers such as banks or credit card payment gateways. Revenge, blackmail[2][3][4]and activism[5] can motivate these attacks.

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DR

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Designated Router is a hardware piece playing a particular role in wireless networking. It is most frequently used as part of an Open Shortest Path First or OSPF link-state routing protocol for IP networks.

systems like OSPF involve a designated router or DR and designated backup router or BDR. Experts describe the designated router as the chosen path for multiple routers on a multi-access network segment. Using testing processes like a neighbor discovery process and various types of IP messaging, a designated router can be chosen.Elaborate systems for link-state routing will help to identify which types of routers can be designated or backup-designated, and which routers may not receive a designation. OSPF is a very common type of implementation for quick network convergence. It competes with other models such as IS-IS, or Intermediate System to Intermediate System, a routing protocol for a set of physically connected hardware.

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DSCP

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Differentiated Services Code Point

Differentiated Services Code Point (DSCP) is a means of classifying and managing network traffic and of providing quality of service (QoS) in modern Layer 3 IP networks. It uses the 6-bit Differentiated Services (DS) field in the IP header for the purpose of packet classification. Differentiated services (DiffServ) is a computer networking architecture that specifies a simple and scalable mechanism for classifying and managing network traffic and providing quality of service (QoS) on modern IP networks.

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DSL

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Digital Subscriber Line

Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric digital subscriber line (ADSL), the most commonly installed DSL technology, for Internet access. DSL service can be delivered simultaneously with wired telephone service on the same telephone line since DSL uses higher frequency bands for data. On the customer premises, a DSL filter on each non-DSL outlet blocks any high-frequency interference to enable simultaneous use of the voice and DSL services.The bit rate of consumer DSL services typically ranges from 256 kbit/s to over 100 Mbit/s in the direction to the customer (downstream), depending on DSL technology, line conditions, and service-level implementation. Bit rates of 1 Gbit/s have been reached in trials,[1] but most homes are likely to be limited to 500-800 Mbit/s. In ADSL, the data throughput in the upstream direction (the direction to the service provider) is lower, hence the designation of asymmetric service. In symmetric digital subscriber line (SDSL) services, the downstream and upstream data rates are equal. Researchers at Bell Labs have reached speeds of 10 Gbit/s, while delivering 1 Gbit/s symmetrical broadband access services using traditional copper telephone lines. These higher speeds are lab results, however.[2][3] A 2012 survey found that "DSL continues to be the dominant technology for broadband access" with 365.1 million subscribers worldwide.

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DSSS

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Direct Sequence Spread Spectrum

In telecommunications, direct-sequence spread spectrum (DSSS) is a spread spectrum modulation technique used to reduce overall signal interference. The spreading of this signal makes the resulting wideband channel more noisy, allowing for greater resistance to unintentional and intentional interference.[1]A method of achieving the spreading of a given signal is provided by the modulation scheme. With DSSS, the message signal is used to modulate a bit sequence known as a Pseudo Noise (PN) code; this PN code consists of a radio pulse that is much shorter in duration (larger bandwidth) than the original message signal. This modulation of the message signal scrambles and spreads the pieces of data, and thereby resulting in a bandwidth size nearly identical to that of the PN sequence.[1] In this context, the duration of the radio pulse for the PN code is referred to as the chip duration. The smaller this duration, the larger the bandwidth of the resulting DSSS signal; more bandwidth multiplexed to the message signal results in better resistance against interference.[1][2]Some practical and effective uses of DSSS include the Code Division Multiple Access (CDMA) channel access methodand the IEEE 802.11b specification used in Wi-Fi networks.[3][4]

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DSU

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Data Service Unit

A data service unit, sometimes called a digital service unit, is a piece of telecommunications circuit terminating equipment that transforms digital data between telephone company lines and local equipment. The device converts bipolar digital signals coming ultimately from a digital circuit and directly from a Channel service unit(CSU), into a format (e.g. RS- 530) compatible with the piece of data terminal equipment (DTE) (e.g. a router) to which the data is sent. The DSU also performs a similar process in reverse for data heading from the DTE toward the circuit. The telecommunications service a DSU supports can be a point-to-point or multipoint operation in a digital data network.A DSU is a two or more port device; one port is called the WAN (Wide Area Network) port and the other is called a DTE port. The purpose of the DSU is to transfer serial data synchronously between the WAN port and the DTE ports. If more than one DTE port is used, the DSU assigns the DTE data according to time slots (channels) on the WAN side.On the WAN side, the DSU, via a CSU, interfaces with a digital carrier such as DS1 or DS3 or a low speed Digital Data Service. On the DTE side, the DSU provides control lines, timing lines and appropriate physical and electrical interface. To maintain the synchronous relationship between the ports, the DSU manages timing by slaving ports to the bit rate of another or to its internal clock. Typically, the DTE port provides timing to the data terminal equipment while the WAN port dictates the rate.DSUs usually include some maintenance capabilities. At minimum, they can loop data back at either the WAN or DTE ports, or at both. When only one port is looped back, the data received at that port is simultaneously sent back toward the port and passed in normal fashion to the other port. Most DSUs also allow various data patterns to be generated and monitored to measure error rate of the communication link. A DSU may be a separate piece of equipment, or may be combined in a CSU/DSU.

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E1

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E-Carrier Level 1

The E-carrier is a member of the series of carrier systems developed for digital transmission of many simultaneous telephone calls by time-division multiplexing. The European Conference of Postal and Telecommunications Administrations (CEPT) originally standardized the E-carrier system, which revised and improved the earlier American T-carrier technology, and this has now been adopted by the International Telecommunication Union Telecommunication Standardization Sector (ITU-T). It was widely adopted in almost all countries outside the US, Canada, and Japan. E-carrier deployments have steadily been replaced by Ethernet as telecommunication networks transitions towards all IP.

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EAP

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Extensible Authentication Protocol

Extensible Authentication Protocol, or EAP, is an authentication framework frequently used in wireless networks and point-to-point connections. It is defined in RFC 3748, which made RFC 2284 obsolete, and is updated by RFC 5247.EAP is an authentication framework for providing the transport and usage of keying material and parameters generated by EAP methods.[1] There are many methods defined by RFCs and a number of vendor specific methods and new proposals exist. EAP is not a wire protocol; instead it only defines message formats. Each protocol that uses EAP defines a way to encapsulate EAP messages within that protocol's messages.EAP is in wide use. For example, in IEEE 802.11 (WiFi) the WPA and WPA2 standards have adopted IEEE 802.1X with one hundred EAP Types as the official authentication mechanisms.

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EDNS

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Extension Mechanisms for DNS

Extension mechanisms for DNS (EDNS) is a specification for expanding the size of several parameters of the Domain Name System (DNS) protocol which had size restrictions that the Internet engineering community deemed too limited for increasing functionality of the protocol. The first set of extensions was published in 1999 by the Internet Engineering Task Force as RFC 2671, also known as EDNS0.[1]

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EGP

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Exterior Gateway Protocol

Exterior Gateway Protocol (EGP) is a protocol for exchanging routing information between two neighbor gateway hosts (each with its own router) in a network of autonomous systems. EGP is commonly used between hosts on the Internet to exchange routing table information. The routing table contains a list of known routers, the addresses they can reach, and a cost metric associated with the path to each router so that the best available route is chosen. Each router polls its neighbor at intervals between 120 to 480 seconds and the neighbor responds by sending its complete routing table. EGP-2 is the latest version of EGP.A more recent exterior gateway protocol, the Border Gateway Protocol (BGP), provides additional capabilities.Also see Interior Gateway Protocol (IGP).

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EIGRP

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Enhanced Interior Gateway Routing Protocol Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced distance-vector routing protocol that is used on a computer network for automating routing decisions and configuration. The protocol was designed by Cisco Systems as a proprietary protocol, available only on Cisco routers. Partial functionality of EIGRP was converted to an open standard in 2013[1] and was published with informational status as RFC 7868 in 2016.EIGRP is used on a router to share routes with other routers within the same autonomous system. Unlike other well known routing protocols, such as RIP, EIGRP only sends incremental updates, reducing the workload on the router and the amount of data that needs to be transmitted.EIGRP replaced the Interior Gateway Routing Protocol (IGRP) in 1993. One of the major reasons for this was the change to classless IPv4 addresses in the Internet Protocol, which IGRP could not support.

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EMI

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Electromagnetic Interference

Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction.[1] The disturbance may degrade the performance of the circuit or even stop it from functioning. In the case of a data path, these effects can range from an increase in error rate to a total loss of the data.[2] Both man-made and natural sources generate changing electrical currents and voltages that can cause EMI: ignition systems, cellular network of mobile phones, lightning, solar flares, and auroras(Northern/Southern Lights). EMI frequently affects AM radios. It can also affect mobile phones, FM radios, and televisions, as well as observations for radio astronomy.EMI can be used intentionally for radio jamming, as in electronic warfare.

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ESD

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Electrostatic Discharge Electrostatic discharge (ESD) is the sudden flow of electricity between two electrically charged objects caused by contact, an electrical short, or dielectric breakdown. A buildup of static electricity can be caused by tribocharging or by electrostatic induction. The ESD occurs when differently-charged objects are brought close together or when the dielectricbetween them breaks down, often creating a visible spark.ESD can create spectacular electric sparks (lightning, with the accompanying sound of thunder, is a large-scale ESD event), but also less dramatic forms which may be neither seen nor heard, yet still be large enough to cause damage to sensitive electronic devices. Electric sparks require a field strength above approximately 40 kV/cm in air, as notably occurs in lightning strikes. Other forms of ESD include corona dischargefrom sharp electrodes and brush discharge from blunt electrodes.ESD can cause a range of harmful effects of importance in industry, including gas, fuel vapour and coal dust explosions, as well as failure of solid state electronics components such as integrated circuits. These can suffer permanent damage when subjected to high voltages. Electronics manufacturers therefore establish electrostatic protective areas free of static, using measures to prevent charging, such as avoiding highly charging materials and measures to remove static such as grounding human workers, providing antistatic devices, and controlling humidity.ESD simulators may be used to test electronic devices, for example with a human body model or a charged device model.

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ESP

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Encapsulated Security Packets In computing, Internet Protocol Security(IPsec) is a network protocol suite that authenticates and encrypts the packets of data sent over a network. IPsec includes protocols for establishing mutual authentication between agents at the beginning of the session and negotiation of cryptographic keys to use during the session. IPsec can protect data flows between a pair of hosts (host-to-host), between a pair of security gateways (network-to-network), or between a security gateway and a host (network-to-host).[1]Internet Protocol security (IPsec) uses cryptographic security services to protect communications over Internet Protocol (IP) networks. IPsec supports network-level peer authentication, data-origin authentication, data integrity, data confidentiality (encryption), and replay protection.IPsec is an end-to-end security scheme operating in the Internet Layer of the Internet Protocol Suite, while some other Internet security systems in widespread use, such as Transport Layer Security (TLS) and Secure Shell (SSH), operate in the upper layers at the Transport Layer (TLS) and the Application layer (SSH). IPsec can automatically secure applications at the IP layer.

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ESSID

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Extended Service Set Identifier An extended service set (ESS) is a set of one or more infrastructure basic service sets on a common logical network segment (i.e. same IP subnet and VLAN).[7] Key to the concept is that the participating basic service sets appear as a single network to the logical link control layer.[7][8] Thus, from the perspective of the logical link control layer, stations within an ESS may communicate with one another, and mobile stations may move transparently from one participating BSS to another (within the same ESS).[8] Extended service sets make possible distribution services such as centralized authentication and seamless roaming between infrastructure-BSSs. From the perspective of the link layer, all stations within an ESS are all on the same link, and transfer from one BSS to another is transparent to logical link control.[9]The basic service sets formed in wireless ad hoc networks are, by definition, independent from other BSSs, and an independent-BSS cannot therefore be part of an extended infrastructure.[10] In that formal sense an independent-BSS has no extended service set. However, the network packets of both independent-BSSs and infrastructure-BSSs have a logical network service set identifier (described below), and the logical link control does not distinguish between the use of that field to name an ESS network, and the use of that field to name a peer-to-peer ad hoc network. The two are effectively indistinguishable at the logical link control layer level.[9]There is formally no such thing as an 'ESSID' in 802.11 standards.[11]cf. [12] In 802.11 standard documents, the logical network (ESS or independent-BSS) service set identifier is simply abbreviated 'SSID',[13]) irrespective of whether a SSID identifies an infrastructure-BSS's ESS, or the peer-to-peer network of an independent-BSS. Unlike basic service set identifiers, SSIDs are usually customizable.[14] These SSIDs can be zero to 32 octets (32 bytes) long,[13] and are for convenience usually in a natural language, such as English. The 802.11 standards prior to the 2012 edition did not define any particular encoding/representation for SSIDs, which were expected be treated and handled as an arbitrary sequence of 0–32 octets that are not limited to printable characters. The 2012 edition of the 802.11 standard defines a simplified variant of UTF-8for encoding and interpreting non-ISO basic Latin characters in SSID labels, but wireless network stacks must still be prepared to handle arbitrary values in the SSID field.Since the contents of an SSID field are arbitrary, the 802.11 standard permits devices to advertise the presence of a wireless network with beacon packets in which the SSID field is set to null.[15][n 1] A null SSID (the SSID element's 'length' field is set to zero[13]) is called a "wildcard SSID" in IEEE 802.11 standards documents,[16] and as a "no broadcast SSID" or "hidden SSID" in the context of beacon announcements,[15][17] and can be used, for example, in enterprise and mesh networks to steer a client to a particular (e.g. less utilized) access point.[15] A station may also likewise transmit packets in which the SSID field is set to null; this prompts an associated access point to send the station a list of supported SSIDs.[18]

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EUI

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Extended Unique Identifier Extended Unique Identifier (EUI), as per RFC2373, allows a host to assign iteslf a unique 64-Bit IP Version 6 interface identifier (EUI-64). This feature is a key benefit over IPv4 as it eliminates the need of manual configuration or DHCP as in the world of IPv4. The IPv6 EUI-64 format address is obtained through the 48-bit MAC address. The MAC address is first separated into two 24-bits, with one being OUI (Organizationally Unique Identifier) and the other being NIC specific. The 16-bit 0xFFFE is then inserted between these two 24-bits for the 64-bit EUI address. IEEE has chosen FFFE as a reserved value which can only appear in EUI-64 generated from the an EUI-48 MAC address.

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FC

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Fibre Channel Fibre Channel, or FC, is a high-speed network technology (commonly running at 1, 2, 4, 8, 16, 32, and 128 gigabit per second rates) primarily used to connect computer data storage to servers.[1][2] Fibre Channel is mainly used in storage area networks (SAN) in commercial data centers. Fibre Channel networks form a switched fabric because they operate in unison as one big switch. Fibre Channel typically runs on optical fiber cables within and between data centers, but can also run on copper cabling.[1][2]Most block storage runs over Fibre Channel Fabrics and supports many upper level protocols. Fibre Channel Protocol (FCP) is a transport protocol that predominantly transports SCSI commands over Fibre Channel networks.[1][2] Mainframe computers run the FICON command set over Fibre Channel because of its high reliability and throughput. Fibre Channel can be used to transport data from storage systems that use solid-state flash memory storage medium by transporting NVMe protocol commands.

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FCS

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Frame Check SequenceA frame check sequence (FCS) refers to the extra error-detecting code added to a frame in a communications protocol. Frames are used to send upper-layer data and ultimately the application data from a source to a destination.The detection does not imply error recovery; for example, Ethernet specifies that a damaged frame should be discarded, but at the same time does not specify any action to cause the frame to be retransmitted. Other protocols, notably the Transmission Control Protocol (TCP), can notice the data loss and initiate error recovery.[2]Overview[edit]All frames and the bits, bytes, and fields contained within them, are susceptible to errors from a variety of sources. The FCS field contains a number that is calculated by the source node based on the data in the frame. This number is added to the end of a frame that is sent. When the destination node receives the frame the FCS number is recalculated and compared with the FCS number included in the frame. If the two numbers are different, an error is assumed and the frame is discarded.The FCS is often transmitted in such a way that the receiver can compute a running sum over the entire frame, together with the trailing FCS, expecting to see a fixed result (such as zero) when it is correct. For Ethernet and other IEEE 802 protocols, this fixed result, also known as the magic number or CRC32 residue, is 0xC704DD7B.[3] When transmitted and used in this way, FCS generally appears immediately before the frame-ending delimiter.By far the most popular FCS algorithm is a cyclic redundancy check (CRC), used in Ethernet and other IEEE 802 protocols with 32 bits, in X.25 with 16 or 32 bits, in HDLCwith 16 or 32 bits, in Frame Relay with 16 bits,[4] in Point-to-Point Protocol (PPP) with 16 or 32 bits, and in other data link layer protocols.

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FDDI

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Fiber Distributed Data InterfaceFiber Distributed Data Interface (FDDI) is a standard for data transmission in a local area network. It uses optical fiber as its standard underlying physical medium, although it was also later specified to use copper cable, in which case it may be called CDDI (Copper Distributed Data Interface), standardized as TP-PMD (Twisted-Pair Physical Medium-Dependent), also referred to as TP-DDI (Twisted-Pair Distributed Data Interface). Frequency Hopping Spread Spectrum FDDI provides a 100 Mbit/s optical standard for data transmission in local area networkthat can extend in range up to 200 kilometers (120 mi). Although FDDI logical topology is a ring-based token network, it did not use the IEEE 802.5 token ring protocol as its basis; instead, its protocol was derived from the IEEE 802.4 token bus timed token protocol. In addition to covering large geographical areas, FDDI local area networks can support thousands of users. FDDI offers both a Dual-Attached Station (DAS), counter-rotating token ring topology and a Single-Attached Station (SAS), token bus passing ring topology.[1]FDDI, as a product of American National Standards Institute X3T9.5 (now X3T12), conforms to the Open Systems Interconnection (OSI) model of functional layering using other protocols. The standards process started in the mid 1980s.[2] FDDI-II, a version of FDDI described in 1989, added circuit-switched service capability to the network so that it could also handle voice and video signals.[3] Work started to connect FDDI networks to synchronous optical networking (SONET) technology.A FDDI network contains two rings, one as a secondary backup in case the primary ring fails. The primary ring offers up to 100 Mbit/s capacity. When a network has no requirement for the secondary ring to do backup, it can also carry data, extending capacity to 200 Mbit/s. The single ring can extend the maximum distance; a dual ring can extend 100 km (62 mi). FDDI had a larger maximum-frame size (4,352 bytes) than the standard Ethernet family, which only supports a maximum-frame size of 1,500 bytes,[a] allowing better effective data rates in some cases

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FDM

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In telecommunications, frequency-division multiplexing (FDM) is a technique by which the total bandwidth available in a communication medium is divided into a series of non-overlapping frequency bands, each of which is used to carry a separate signal. This allows a single transmission medium such as a cable or optical fiber to be shared by multiple independent signals. Another use is to carry separate serial bits or segments of a higher rate signal in parallel.The most natural example of frequency-division multiplexing is radio and television broadcasting, in which multiple radio signals at different frequencies pass through the air at the same time. Another example is cable television, in which many television channels are carried simultaneously on a single cable. FDM is also used by telephone systems to transmit multiple telephone calls through high capacity trunklines, communications satellites to transmit multiple channels of data on uplink and downlink radio beams, and broadband DSL modems to transmit large amounts of computer data through twisted pairtelephone lines, among many other uses.An analogous technique called wavelength division multiplexing is used in fiber-optic communication, in which multiple channels of data are transmitted over a single optical fiber using different wavelengths (frequencies) of light. The multiple separate information (modulation) signals that are sent over an FDM system, such as the video signals of the television channels that are sent over a cable TV system, are called baseband signals. At the source end, for each frequency channel, an electronic oscillator generates a carrier signal, a steady oscillating waveform at a single frequency that serves to "carry" information. The carrier is much higher in frequency than the baseband signal. The carrier signal and the baseband signal are combined in a modulator circuit. The modulator alters some aspect of the carrier signal, such as its amplitude, frequency, or phase, with the baseband signal, "piggybacking" the data onto the carrier.The result of modulating (mixing) the carrier with the baseband signal is to generate sub-frequencies near the carrier frequency, at the sum (fC + fB) and difference (fC − fB) of the frequencies. The information from the modulated signal is carried in sidebands on each side of the carrier frequency. Therefore, all the information carried by the channel is in a narrow band of frequencies clustered around the carrier frequency, this is called the passband of the channel.Similarly, additional baseband signals are used to modulate carriers at other frequencies, creating other channels of information. The carriers are spaced far enough apart in frequency that the band of frequencies occupied by each channel, the passbands of the separate channels, do not overlap. All the channels are sent through the transmission medium, such as a coaxial cable, optical fiber, or through the air using a radio transmitter. As long as the channel frequencies are spaced far enough apart that none of the passbands overlap, the separate channels will not interfere with each other. Thus the available bandwidth is divided into "slots" or channels, each of which can carry a separate modulated signal.For example, the coaxial cable used by cable television systems has a bandwidth of about 1000 MHz, but the passband of each television channel is only 6 MHz wide, so there is room for many channels on the cable (in modern digital cable systems each channel in turn is subdivided into subchannels and can carry up to 10 digital television channels).At the destination end of the cable or fiber, or the radio receiver, for each channel a local oscillator produces a signal at the carrier frequency of that channel, that is mixed with the incoming modulated signal. The frequencies subtract, producing the baseband signal for that channel again. This is called demodulation. The resulting baseband signal is filtered out of the other frequencies and output to the user.

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FIPS

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Federal Information Processing Standard Federal Information Processing Standards (FIPS) are publicly announced standardsdeveloped by the United States federal government for use in computer systems by non-military government agencies and government contractors.[1]FIPS standards are issued to establish requirements for various purposes such as ensuring computer security and interoperability, and are intended for cases in which suitable industry standards do not already exist.[1] Many FIPS specifications are modified versions of standards used in the technical communities, such as the American National Standards Institute (ANSI), the Institute of Electrical and Electronics Engineers (IEEE), and the International Organization for Standardization (ISO). The U.S. government has developed various FIPS specifications to standardize a number of topics including:Codes: for instance, standards for encoding data (such as FIPS county codes or codes to indicate weather conditions or emergency indications). In 1994 NOAA began broadcasting coded signals called FIPS codes along with their standard weather broadcasts from local stations. These codes identify the type of emergency and the specific geographic area, such as a county, affected by the emergency.Encryption standards, such as the Data Encryption Standard (FIPS 46-3[2]) and the Advanced Encryption Standard (FIPS 197[3])

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FM

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Frequency Modulation In telecommunications and signal processing, frequency modulation (FM) is the encoding of information in a carrier waveby varying the instantaneous frequency of the wave.In analog frequency modulation, such as FM radio broadcasting of an audio signal representing voice or music, the instantaneous frequency deviation, the difference between the frequency of the carrier and its center frequency, is proportional to the modulating signal.Digital data can be encoded and transmitted via FM by shifting the carrier's frequency among a predefined set of frequencies representing digits - for example one frequency can represent a binary 1 and a second can represent binary 0. This modulation technique is known as frequency-shift keying (FSK). FSK is widely used in modems and fax modems, and can also be used to send Morse code.[1] Radioteletype also uses FSK.[2]Frequency modulation is widely used for FM radiobroadcasting. It is also used in telemetry, radar, seismic prospecting, and monitoring newborns for seizures via EEG,[3] two-way radio systems, music synthesis, magnetic tape-recording systems and some video-transmission systems. In radio transmission, an advantage of frequency modulation is that it has a larger signal-to-noise ratio and therefore rejects radio frequency interference better than an equal power amplitude modulation (AM) signal. For this reason, most music is broadcast over FM radio.Frequency modulation and phase modulationare the two complementary principle methods of angle modulation; phase modulation is often used as an intermediate step to achieve frequency modulation. These methods contrast with amplitude modulation, in which the amplitude of the carrier wave varies, while the frequency and phase remain constant.

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FQDN

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Fully Qualified Domain Name A fully qualified domain name (FQDN), sometimes also referred to as an absolute domain name,[1] is a domain name that specifies its exact location in the tree hierarchy of the Domain Name System(DNS). It specifies all domain levels, including the top-level domain and the root zone.[2] A fully qualified domain name is distinguished by its lack of ambiguity: it can be interpreted only in one way.The DNS root domain is unnamed which is expressed by having an empty label in the DNS hierarchy, resulting in a fully qualified domain name ending with the top-level domain. However, in some cases the full stop (period) character is required at the end of the fully qualified domain name.In contrast to a domain name that is fully specified, a domain name that does not include the full path of labels up to the DNS root is often called a partially qualified domain name. A fully qualified domain name consists of a list of domain labels representing the hierarchy from the lowest relevant level in the DNS to the top-level domain (TLD). The domain labels are concatenated using the full stop (dot, period) character as separator between labels.The DNS root is unnamed, expressed as the empty label terminated by the dot. This is most notable in DNS zone files in which a fully qualified domain name must be specified with a trailing dot. For example, somehost.example.com. explicitly specifies an absolute domain name that ends with the empty top level domain label.[3]Example[edit]A device with the hostname myhost in the parent domain example.com has the fully qualified domain name myhost.example.com. The FQDN uniquely distinguishes the device from any other hosts called myhost in other domains.

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FTP

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File Transfer Protocol The File Transfer Protocol (FTP) is the standard network protocol used for the transfer of computer files between a client and server on a computer network.FTP is built on a client-server model architecture and uses separate control and data connections between the client and the server.[1] FTP users may authenticate themselves with a clear-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission that protects the username and password, and encrypts the content, FTP is often secured with SSL/TLS(FTPS). SSH File Transfer Protocol (SFTP) is sometimes also used instead; it is technologically different.The first FTP client applications were command-line programs developed before operating systems had graphical user interfaces, and are still shipped with most Windows, Unix, and Linux operating systems.[2][3] Many FTP clients and automation utilities have since been developed for desktops, servers, mobile devices, and hardware, and FTP has been incorporated into productivity applications, such as web page editors. The original specification for the File Transfer Protocol was written by Abhay Bhushan and published as RFC 114 on 16 April 1971. Until 1980, FTP ran on NCP, the predecessor of TCP/IP.[2] The protocol was later replaced by a TCP/IP version, RFC 765 (June 1980) and RFC 959 (October 1985), the current specification. Several proposed standards amend RFC 959, for example RFC 1579 (February 1994) enables Firewall-Friendly FTP (passive mode), RFC 2228 (June 1997) proposes security extensions, RFC 2428(September 1998) adds support for IPv6 and defines a new type of passive mode.[4]

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FTPS

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File Transfer Protocol SecuritySecure File Transfer Protocol (SFTP), also called SSH File Transfer Protocol, is a network protocol for accessing, transferring and managing files on remote systems.The term secure file transfer protocol or secure FTP may refer to:Network protocolsSSH File Transfer Protocol — a file transfer protocol specifically developed by the IETF to run over secure shell connectionsFTP over SSH, also known as "secure FTP" — the practice of using SSH to tunnel the older, well-known File Transfer Protocol (FTP)Computer programsSecure file transfer program, usually known as "sftp" — a well-known command-line program, common in Unix, for using SSH File Transfer ProtocolSecure FTP (software) — a software package, by Glub Tech, for using FTPS (traditional FTP over SSL/TLS)

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GBIC

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Gigabit Interface Converterfibre channel in the 2000s.[citation needed] By offering a standard, hot swappable electrical interface, one gigabit port can support a wide range of physical media, from copper to long-wave single-mode optical fiber, at lengths of hundreds of kilometers.A variation of the GBIC called the small form-factor pluggable transceiver (SFP), also known as mini-GBIC, has the same functionality but in a smaller form factor.[1] Announced in 2001, it largely made the GBIC obsolete.

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Gbps

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Gigabits per second Gbps stands for billions of bits per second and is a measure of bandwidth on a digital data transmission medium such as optical fiber . With slower media and protocols, bandwidth may be in the Mbps (millions of bits or megabits per second) or the Kbps (thousands of bits or kilobits per second) range.

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GLBP

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Gateway Load Balancing Protocol Gateway Load Balancing Protocol (GLBP) is a Cisco proprietary protocol that attempts to overcome the limitations of existing redundant router protocols by adding basic load balancing functionality.In addition to being able to set priorities on different gateway routers, GLBP allows a weighting parameter to be set. Based on this weighting (compared to others in the same virtual router group), ARP requests will be answered with MAC addresses pointing to different routers. Thus, by default, load balancing is not based on traffic load, but rather on the number of hosts that will use each gateway router. By default GLBP load balances in round-robin fashion.GLBP elects one AVG (Active Virtual Gateway) for each group. Other group members act as backup in case of AVG failure. In case there are more than two members, the second best AVG is placed in the Standby state and all other members are placed in the Listening state. This is monitored using hello and holdtime timers, which are 3 and 10 seconds by default. The elected AVG then assigns a virtual MAC address to each member of the GLBP group, including itself, thus enabling AVFs (Active Virtual Forwarders). Each AVF assumes responsibility for forwarding packets sent to its virtual MAC address. There could be up to four AVFs at the same time.By default, GLBP routers use the local multicast address 224.0.0.102 to send hello packets to their peers every 3 seconds over UDP 3222 (source and destination).Cisco implemented IPv6 support for GLBP in IOS release 12.2(33)SXI.[1]

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GPG

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GNU Privacy Guard

GNU Privacy Guard (GnuPG or GPG) is a free software replacement for Symantec's PGP cryptographic software suite.[4] GnuPG is compliant with RFC 4880, which is the IETF standards track specification of OpenPGP. Modern versions of PGP are interoperable with GnuPG and other OpenPGP-compliant systems.GnuPG is part of the GNU Project, and has received major funding from the German government.[5]

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GPRS

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General Packet Radio Service

General Packet Radio Service (GPRS) is a packet oriented mobile data service on the 2G and 3G cellular communication system's global system for mobile communications(GSM). GPRS was originally standardized by European Telecommunications Standards Institute (ETSI) in response to the earlier CDPD and i-mode packet-switched cellular technologies. It is now maintained by the 3rd Generation Partnership Project (3GPP).[1][2]GPRS usage is typically charged based on volume of data transferred, contrasting with circuit switched data, which is usually billed per minute of connection time. Sometimes billing time is broken down to every third of a minute. Usage above the bundle cap is charged per megabyte, speed limited, or disallowed.GPRS is a best-effort service, implying variable throughput and latency that depend on the number of other users sharing the service concurrently, as opposed to circuit switching, where a certain quality of service (QoS) is guaranteed during the connection. In 2G systems, GPRS provides data rates of 56–114 kbit/second.[3] 2G cellular technology combined with GPRS is sometimes described as 2.5G, that is, a technology between the second (2G) and third (3G) generations of mobile telephony.[4] It provides moderate-speed data transfer, by using unused time division multiple access (TDMA) channels in, for example, the GSM system. GPRS is integrated into GSM Release 97 and newer releases.

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GRE

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Generic Routing EncapsulationGeneric Routing Encapsulation (GRE) is a tunneling protocol developed by Cisco Systems that can encapsulate a wide variety of network layer protocols inside virtual point-to-point links over an Internet Protocol network.

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GSM

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Global System for Mobile communications GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation digital cellular networks used by mobile devices such as tablets, first deployed in Finland in December 1991.[2] As of 2014, it has become the global standard for mobile communications – with over 90% market share, operating in over 193 countries and territories.[3]2G networks developed as a replacement for first generation (1G) analog cellular networks, and the GSM standard originally described as a digital, circuit-switched network optimized for full duplexvoice telephony. This expanded over time to include data communications, first by circuit-switched transport, then by packet data transport via GPRS (General Packet Radio Services) and EDGE (Enhanced Data rates for GSM Evolution, or EGPRS).Subsequently, the 3GPP developed third-generation (3G) UMTS standards, followed by fourth-generation (4G) LTE Advanced standards, which do not form part of the ETSI GSM standard."GSM" is a trademark owned by the GSM Association. It may also refer to the (initially) most common voice codec used, Full Rate.

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HBA

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Host Bus Adapter

In computer hardware, a host controller, host adapter, or host bus adapter (HBA) connects a computer, which acts as the host system, to other network and storage devices. The terms are primarily used to refer to devices for connecting SCSI, Fibre Channel and SATA devices. Devices for connecting to IDE, Ethernet, FireWire, USB and other systems may also be called host adapters.The term network interface controller (NIC) is more often used for devices connecting to computer networks, while the term converged network adapter can be applied when protocols such as iSCSI or Fibre Channel over Ethernet allow storage and network functionality over the same physical connection. These can include TCP offload engines.

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HDLC

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High-level Data Link Control

High-Level Data Link Control (HDLC) is a bit-oriented code-transparent synchronousdata link layer protocol developed by the International Organization for Standardization (ISO). The original ISO standards for HDLC are as follows:ISO 3309 – Frame StructureISO 4335 – Elements of ProcedureISO 6159 – Unbalanced Classes of ProcedureISO 6256 – Balanced Classes of ProcedureThe current standard for HDLC is ISO/IEC 13239:2002, which replaces all of those standards.HDLC provides both connection-oriented and connectionless service.HDLC can be used for point-to-multipoint connections, but is now used almost exclusively to connect one device to another, using Asynchronous Balanced Mode (ABM). The original master-slave modes Normal Response Mode (NRM) and Asynchronous Response Mode (ARM) are rarely used.

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HDMI

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High Definition Multimedia Interface

HDMI (High-Definition Multimedia Interface) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device.[4] HDMI is a digital replacement for analog video standards.HDMI implements the EIA/CEA-861standards, which define video formats and waveforms, transport of compressed, uncompressed, and LPCM audio, auxiliary data, and implementations of the VESA EDID.[5][6](p. III) CEA-861 signals carried by HDMI are electrically compatible with the CEA-861 signals used by the digital visual interface (DVI). No signal conversion is necessary, nor is there a loss of video quality when a DVI-to-HDMI adapter is used.[6](§C) The CEC (Consumer Electronics Control) capability allows HDMI devices to control each other when necessary and allows the user to operate multiple devices with one handheld remote controldevice.[6](§6.3)Several versions of HDMI have been developed and deployed since initial release of the technology but all use the same cable and connector. Other than improved audio and video capacity, performance, resolution and color spaces, newer versions have optional advanced features such as 3D, Ethernet data connection, and CEC (Consumer Electronics Control) extensions.Production of consumer HDMI products started in late 2003.[7] In Europe either DVI-HDCP or HDMI is included in the HD readyin-store labeling specification for TV sets for HDTV, formulated by EICTA with SES Astrain 2005. HDMI began to appear on consumer HDTVs in 2004 and camcordersand digital still cameras in 2006.[8][9] As of January 6, 2015 (twelve years after the release of the first HDMI specification), over 4 billion HDMI devices have been sold.[10]

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HIDS

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Host Intrusion Detection System

A host-based intrusion detection system (HIDS) is an intrusion detection system that is capable of monitoring and analyzing the internals of a computing system as well as the network packets on its network interfaces, similar to the way a network-based intrusion detection system (NIDS) operates.[1] This was the first type of intrusion detection software to have been designed, with the original target system being the mainframe computerwhere outside interaction was infrequent.[2] A host-based IDS is capable of monitoring all or parts of the dynamic behavior and the state of a computer system, based on how it is configured. Besides such activities as dynamically inspecting network packets targeted at this specific host (optional component with most software solutions commercially available), a HIDS might detect which program accesses what resources and discover that, for example, a word-processor has suddenly and inexplicably started modifying the system password database. Similarly a HIDS might look at the state of a system, its stored information, whether in RAM, in the file system, log files or elsewhere; and check that the contents of these appear as expected, e.g. have not been changed by intruders.[3]One can think of a HIDS as an agent that monitors whether anything or anyone, whether internal or external, has circumvented the system's security policy.

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HIPS

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Host Intrusion Prevention System

Definition - What does Host-Based Intrusion Prevention System (HIPS) mean?A host-based intrusion prevention system (HIPS) is a system or a program employed to protect critical computer systems containing crucial data against viruses and other Internet malware. Starting from the network layer all the way up to the application layer, HIPS protects from known and unknown malicious attacks. HIPS regularly checks the characteristics of a single host and the various events that occur within the host for suspicious activities.HIPS can be implemented on various types of machines, including servers, workstations, and computers.

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HSPA

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High-Speed Packet Access

High Speed Packet Access (HSPA)[1] is an amalgamation of two mobile protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performance of existing 3G mobile telecommunication networks using the WCDMA protocols. A further improved 3GPPstandard, Evolved High Speed Packet Access (also known as HSPA+), was released late in 2008 with subsequent worldwide adoption beginning in 2010. The newer standard allows bit-rates to reach as high as 337 Mbit/s in the downlink and 34 Mbit/s in the uplink. However, these speeds are rarely achieved in practice.[2] The first HSPA specifications supported increased peak data rates of up to 14 Mbit/s in the downlink and 5.76 Mbit/s in the uplink. It also reduced latency and provided up to five times more system capacity in the downlink and up to twice as much system capacity in the uplink compared with original WCDMA protocol.

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HSRP

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Hot Standby Router Protocol

in computer networking, the Hot Standby Router Protocol (HSRP) is a Cisco proprietaryredundancy protocol for establishing a fault-tolerant default gateway. Version 1 of the protocol was described in RFC 2281. There is no RFC for version 2 of the protocol.The protocol establishes a framework between network routers in order to achieve default gateway failover if the primary gateway becomes inaccessible, in close association with a rapid-converging routing protocol like EIGRP or OSPF. HSRP routers send multicast Hellomessages to other routers to notify them of their priorities (which router is preferred) and current status (Active or Standby).The primary router with the highest configured priority will act as a virtual router with a pre-defined gateway IP address and will respond to the ARP / ND request from machines connected to the LAN with a virtual MAC address. If the primary router should fail, the router with the next-highest priority would take over the gateway IP address and answer ARP requests with the same MAC address, thus achieving transparent default gateway failover.

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HT

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High Throughput

There are many differences between high-throughput computing, high-performance computing (HPC), and many-task computing (MTC).HPC tasks are characterized as needing large amounts of computing power for short periods of time, whereas HTC tasks also require large amounts of computing, but for much longer times (months and years, rather than hours and days).[1] HPC environments are often measured in terms of FLOPS.The HTC community, however, is not concerned about operations per second, but rather operations per month or per year. Therefore, the HTC field is more interested in how many jobs can be completed over a long period of time instead of how fast.As an alternative definition, the European Grid Infrastructure defines HTC as “a computing paradigm that focuses on the efficient execution of a large number of loosely-coupled tasks”,[2] while HPC systems tend to focus on tightly coupled parallel jobs, and as such they must execute within a particular site with low-latency interconnects. Conversely, HTC systems are independent, sequential jobs that can be individually scheduled on many different computing resources across multiple administrative boundaries. HTC systems achieve this using various grid computing technologies and techniques.MTC aims to bridge the gap between HTC and HPC. MTC is reminiscent of HTC, but it differs in the emphasis of using many computing resources over short periods of time to accomplish many computational tasks (i.e. including both dependent and independent tasks), where the primary metrics are measured in seconds (e.g. FLOPS, tasks/s, MB/s I/O rates), as opposed to operations (e.g. jobs) per month. MTC denotes high-performance computations comprising multiple distinct activities, coupled via file system operations.

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HTTP

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Hypertext Transfer Protocol

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HTTPS

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Hypertext Transfer Protocol Secure The Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, and hypermedia information systems.[1] HTTP is the foundation of data communication for the World Wide Web.Hypertext is structured text that uses logical links (hyperlinks) between nodes containing text. HTTP is the protocol to exchange or transfer hypertext.Development of HTTP was initiated by Tim Berners-Lee at CERN in 1989. Standards development of HTTP was coordinated by the Internet Engineering Task Force (IETF) and the World Wide Web Consortium(W3C), culminating in the publication of a series of Requests for Comments (RFCs). The first definition of HTTP/1.1, the version of HTTP in common use, occurred in RFC 2068 in 1997, although this was made obsolete by RFC 2616 in 1999 and then again by the RFC 7230 family of RFCs in 2014.A later version, the successor HTTP/2, was standardized in 2015, and is now supported by major web servers and browsers over TLS using ALPN extension[2] where TLS 1.2 or newer is required.[3]

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HVAC

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Heating, Ventilation and Air Conditioning

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Hz

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Hertz

The hertz (symbol: Hz) is the derived unit of frequency in the International System of Units (SI) and is defined as one cycle per second.[1] It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (103 Hz, kHz), megahertz (106 Hz, MHz), gigahertz (109 Hz, GHz), and terahertz (1012 Hz, THz).Some of the unit's most common uses are in the description of sine waves and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the speeds at which computers and other electronics are driven.

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Iaas

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Infrastructure as a Service Infrastructure as a service (IaaS) refers to online services that provide high-level APIsused to dereference various low-level details of underlying network infrastructure like physical computing resources, location, data partitioning, scaling, security, backup etc. A hypervisor, such as Xen, Oracle VirtualBox, Oracle VM, KVM, VMware ESX/ESXi, or Hyper-V, LXD, runs the virtual machines as guests. Pools of hypervisors within the cloud operational system can support large numbers of virtual machines and the ability to scale services up and down according to customers' varying requirements. Linux containers run in isolated partitions of a single Linux kernel running directly on the physical hardware. Linux cgroups and namespaces are the underlying Linux kernel technologies used to isolate, secure and manage the containers. Containerisation offers higher performance than virtualization, because there is no hypervisor overhead. Also, container capacity auto-scales dynamically with computing load, which eliminates the problem of over-provisioning and enables usage-based billing.[1] IaaS clouds often offer additional resources such as a virtual-machine disk-image library, raw block storage, file or object storage, firewalls, load balancers, IP addresses, virtual local area networks (VLANs), and software bundles.[2]The NIST's definition of cloud computing defines Infrastructure as a Service as:[3]The capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications; and possibly limited control of select networking components (e.g., host firewalls).According to the Internet Engineering Task Force (IETF), the most basic cloud-service model is that of providers offering IT infrastructure — virtual machines and other resources — as a service to subscribers.IaaS-cloud providers supply these resources on-demand from their large pools of equipment installed in data centers. For wide-area connectivity, customers can use either the Internet or carrier clouds (dedicated virtual private networks). To deploy their applications, cloud users install operating-system images and their application software on the cloud infrastructure.[4][unreliable source?] In this model, the cloud user patches and maintains the operating systems and the application software. Cloud providers typically bill IaaS services on a utility computing basis: cost reflects the amount of resources allocated and consumed.[5][6][7][8]

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IANA

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Internet Assigned Numbers AuthorityThe Internet Assigned Numbers Authority(IANA) is a department of ICANN, a nonprofit private American corporation that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System (DNS), media types, and other Internet Protocol-related symbols and Internet numbers.[1][2]Before ICANN was established primarily for this purpose in 1998, IANA was administered principally by Jon Postel at the Information Sciences Institute (ISI) of the University of Southern California (USC) situated at Marina Del Rey (Los Angeles), under a contract USC/ISI had with the United States Department of Defense, until ICANN was created to assume the responsibility under a United States Department of Commerce contract. Following ICANN's transition to a global multistakeholder governance model, the IANA functions were transferred to Public Technical Identifiers, an affiliate of ICANN.[3]In addition, five regional Internet registries delegate number resources to their customers, local Internet registries, Internet service providers, and end-user organizations. A local Internet registry is an organization that assigns parts of its allocation from a regional Internet registry to other customers. Most local Internet registries are also Internet service providers.

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ICA

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Independent Computer Architecture Independent Computing Architecture (ICA) is a proprietary protocol for an application server system, designed by Citrix Systems. The protocol lays down a specification for passing data between server and clients, but is not bound to any one platform. Citrix's ICA is an alternative to Microsoft's Remote Desktop Protocol (RDP).Practical products conforming to ICA are Citrix's WinFrame, Citrix XenApp (formerly called MetaFrame/Presentation Server), and Citrix XenDesktop products. These permit ordinary Windows applications to be run on a suitable Windows server, and for any supported client to gain access to those applications. Besides Windows, ICA is also supported on a number of Unix server platforms and can be used to deliver access to applications running on these platforms. The client platforms need not run Windows; for example, there are clients for Mac, Unix, Linux, and various smartphones. ICA client software is also built into various thin client platforms.ICA is broadly similar in purpose to window servers such as the X Window System. It also provides for the feedback of user input from the client to the server, and a variety of means for the server to send graphical output, as well as other media such as audio, from the running application to the client.Key challenges of such an architecture are network latency and performance—a graphically intensive application (as most are when presented using a GUI) being served over a slow or bandwidth-restricted network connection requires considerable compression and optimization to render the application usable by the client. The client machine may be a different platform, and may not have the same GUI routines available locally—in this case the server may need to send the actual bitmap data over the connection. Depending on the client's capabilities, servers may also off-load part of the graphical processing to the client, e.g. to render multimedia content. ICA runs natively over TCP port 1494 or may be encapsulated in Common Gateway Protocol (CGP) on TCP 2598. ICA supports the concept of channels at a session layer to encapsulate rich media redirection or USB extension within ICA.

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ICANN

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Internet Corporation for Assigned Names and Numbers

The Internet Corporation for Assigned Names and Numbers (ICANN /ˈaɪkæn/EYE-kan) is a nonprofit organizationresponsible for coordinating the maintenance and procedures of several databases related to the namespaces of the Internet, ensuring the network's stable and secure operation.[1] ICANN performs the actual technical maintenance work of the Central Internet Address pools and DNS root zone registries pursuant to the Internet Assigned Numbers Authority (IANA) function contract. The contract regarding the IANA stewardship functions between ICANN and the National Telecommunications and Information Administration (NTIA) of the United States Department of Commerceended on October 1, 2016, formally transitioning the functions to the global multistakeholder community.[2][3][4][5]Much of its work has concerned the Internet's global Domain Name System(DNS), including policy development for internationalization of the DNS system, introduction of new generic top-level domains (TLDs), and the operation of root name servers. The numbering facilities ICANN manages include the Internet Protocol address spaces for IPv4 and IPv6, and assignment of address blocks to regional Internet registries. ICANN also maintains registries of Internet Protocol identifiers.ICANN's primary principles of operation have been described as helping preserve the operational stability of the Internet; to promote competition; to achieve broad representation of the global Internet community; and to develop policies appropriate to its mission through bottom-up, consensus-based processes.[6]ICANN was created on September 18, 1998, and incorporated on September 30, 1998, in the U.S. state of California.[7] It is headquartered in the Playa Vistaneighborhood of Los Angeles.

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ICMP

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Internet Control Message ProtocolThe Internet Control Message Protocol (ICMP) is a supporting protocol in the Internet protocol suite. It is used by network devices, including routers, to send error messages and operational information indicating, for example, that a requested service is not available or that a host or router could not be reached.[1] ICMP differs from transport protocols such as TCP and UDP in that it is not typically used to exchange data between systems, nor is it regularly employed by end-user network applications (with the exception of some diagnostic tools like ping and traceroute)

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ICS

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Internet Connection Sharing OR Industrial Control SystemInternet Connection Sharing (ICS) is a Windows service that enables one Internet-connected computer to share its Internet connection with other computers on a local area network (LAN). The computer that shares its Internet connection serves a gateway device, meaning that all traffic between other computers and the Internet go through this computer. ICS provides Dynamic Host Configuration Protocol(DHCP) and network address translation(NAT) services for the LAN computers.ICS was a feature of Windows 98 SE and all versions of Windows released for personal computers thereafter.

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IDF

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Intermediate Distribution Frame

An intermediate distribution frame (IDF) is a distribution frame in a central office or customer premises, which cross-connects the user cable media to individual user line circuits and may serve as a distribution point for multipair cables from the main distribution frame (MDF) or combined distribution frame (CDF) to individual cables connected to equipment in areas remote from these frames.IDFs are used for telephone exchange central office, customer-premises equipment, wide area network (WAN), and local area network (LAN) environments, among others.In central office environments the IDF may contain circuit termination equipment from various auxiliary components. In WAN and LAN environments IDFs can hold devices of different types including backup systems (hard drives or other media as self-contained, or as RAIDs, CD-ROMs, etc.), networking (switches, hubs, routers), and connections (fiber optics, coaxial, category cables) and so on.

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IDS

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Intrusion Detection System An intrusion detection system (IDS) is a device or software application that monitors a network or systems for malicious activity or policy violations. Any detected activity or violation is typically reported either to an administrator or collected centrally using a security information and event management(SIEM) system. A SIEM system combines outputs from multiple sources, and uses alarm filtering techniques to distinguish malicious activity from false alarms.There is a wide spectrum of IDS, varying from antivirus software to hierarchical systems that monitor the traffic of an entire backbone network.[citation needed] The most common classifications are network intrusion detection systems (NIDS) and host-based intrusion detection systems(HIDS). A system that monitors important operating system files is an example of a HIDS, while a system that analyzes incoming network traffic is an example of a NIDS. It is also possible to classify IDS by detection approach: the most well-known variants are signature-based detection (recognizing bad patterns, such as malware) and anomaly-based detection (detecting deviations from a model of "good" traffic, which often relies on machine learning). Some IDS have the ability to respond to detected intrusions. Systems with response capabilities are typically referred to as an intrusion prevention system.

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IEEE

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Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a professional association with its corporate office in New York City and its operations center in Piscataway, New Jersey. It was formed in 1963 from the amalgamation of the American Institute of Electrical Engineersand the Institute of Radio Engineers. Today, it is the world's largest association of technical professionals with more than 420,000 members in over 160 countries around the world. Its objectives are the educational and technical advancement of electrical and electronic engineering, telecommunications, computer engineeringand allied disciplines.[2]

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IGMP

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Internet Group Multicast Protocol The Internet Group Management Protocol (IGMP) is a communications protocol used by hosts and adjacent routers on IPv4 networks to establish multicast group memberships. IGMP is an integral part of IP multicast.IGMP can be used for one-to-many networking applications such as online streaming video and gaming, and allows more efficient use of resources when supporting these types of applications.IGMP is used on IPv4 networks. Multicast management on IPv6 networks is handled by Multicast Listener Discovery (MLD) which is a part of ICMPv6 in contrast to IGMP's bare IP encapsulation.

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IGP

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Interior Gateway Protocol

An IGP (Interior Gateway Protocol) is a protocol for exchanging routing information between gateways (hosts with routers) within an autonomous network (for example, a system of corporate local area networks). The routing information can then be used by the Internet Protocol (IP) or other network protocols to specify how to route transmissions.There are two commonly used IGPs: the Routing Information Protocol (RIP) and the Open Shortest Path First (OSPF) protocol.Also see the Exterior Gateway Protocol (EGP)

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IGRP

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Interior Gateway Routing ProtocolInterior Gateway Routing Protocol (IGRP) is a distance vector interior gateway protocol (IGP) developed by Cisco. It is used by routers to exchange routing data within an autonomous system.IGRP is a proprietary protocol. IGRP was created in part to overcome the limitations of RIP (maximum hop count of only 15, and a single routing metric) when used within large networks. IGRP supports multiple metrics for each route, including bandwidth, delay, load, and reliability; to compare two routes these metrics are combined together into a single metric, using a formula which can be adjusted through the use of pre-set constants. By default, the IGRP composite metric is a sum of the segment delays and the lowest segment bandwidth. The maximum configurable hop count of IGRP-routed packets is 255 (default 100), and routing updates are broadcast every 90 seconds (by default).[1]IGRP uses protocol number 9 for communication.[2]IGRP is considered a classful routing protocol. Because the protocol has no field for a subnet mask, the router assumes that all subnetwork addresses within the same Class A, Class B, or Class C network have the same subnet mask as the subnet mask configured for the interfaces in question. This contrasts with classless routing protocols that can use variable length subnet masks. Classful protocols have become less popular as they are wasteful of IP address space.Advancement[edit]In order to address the issues of address space and other factors, Cisco created EIGRP(Enhanced Interior Gateway Routing Protocol). EIGRP adds support for VLSM (variable length subnet mask) and adds the Diffusing Update Algorithm (DUAL) in order to improve routing and provide a loopless environment. EIGRP has completely replaced IGRP, making IGRP an obsolete routing protocol. In Cisco IOS versions 12.3 and greater, IGRP is completely unsupported. In the new Cisco CCNA curriculum (version 4), IGRP is mentioned only briefly, as an "obsolete protocol".

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IKE

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Internet Key ExchangeIn computing, Internet Key Exchange (IKE, sometimes IKEv1 or IKEv2, depending on version) is the protocol used to set up a security association (SA) in the IPsec protocol suite. IKE builds upon the Oakley protocol and ISAKMP.[1] IKE uses X.509 certificates for authentication ‒ either pre-shared or distributed using DNS (preferably with DNSSEC) and a Diffie–Hellman key exchange ‒ to set up a shared session secret from which cryptographic keys are derived.[2][3] In addition, a security policy for every peer which will connect must be manually maintained.[

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IMAP4

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Internet Message Access Protocol Version 4

In computing, the Internet Message Access Protocol (IMAP) is an Internet standard protocol used by e-mail clients to retrieve e-mail messages from a mail serverover a TCP/IP connection.[1] IMAP is defined by RFC 3501.IMAP was designed with the goal of permitting complete management of an email box by multiple email clients, therefore clients generally leave messages on the server until the user explicitly deletes them. An IMAP server typically listens on port number 143. IMAP over SSL (IMAPS) is assigned the port number 993.Virtually all modern e-mail clients and servers support IMAP. IMAP and the earlier POP3 (Post Office Protocol) are the two most prevalent standard protocols for email retrieval,[2] with many webmail service providers such as Gmail, Outlook.com and Yahoo! Mail also providing support for either IMAP or POP3.

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InterNIC

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Internet Network Information Center

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IO

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Input/Output

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IP

Back 123

Internet Protocol

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IPS

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Intrusion Prevention System

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IPSec

Back 125

Internet Protocol Security

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IPv4

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Internet Protocol version 4

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IPv6

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Internet Protocol version 6

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IR

Back 128

Infrared

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ISAKMP

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Internet Security Association and Key Management Protocol

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iSCSI

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Internet Small Computer System

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ISDN

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Integrated Services Digital Network

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IS-IS

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Intermediate System to Intermediate System

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ISP

Back 133

Internet Service Provider

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IT

Back 134

Information Technology

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ITS

Back 135

Intelligent Transportation System

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IV

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Initialization Vector

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Kbps

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Kilobits per second

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KVM

Back 138

Keyboard Video Mouse

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L2F

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Layer 2 Forwarding

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L2TP

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Layer 2 Tunneling Protocol

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LACP

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Link Aggregation Control Protocol

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LAN

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Local Area Network

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LC

Back 143

Local Connector

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LDAP

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Lightweight Directory Access Protocol

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LEC

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Local Exchange Carrier

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LED

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Light Emitting Diode

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LLC

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Logical Link Control

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LSA

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Link State Advertisement

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LTE

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Long Term Evolution

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LWAPP

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Light Weight Access Point Protocol

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MAC

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Media Access Control or Medium Access

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MAN

Back 152

Metropolitan Area Network

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Mbps

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Megabits per second

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MBps

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Megabytes per second

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MDF

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Main Distribtution Frame

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MDI

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Media Dependent Interface

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MDIX

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Media Dependent Interface Crossover

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MGCP

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Media Gateway Control Protocol

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MIB

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Management Information Base

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MIBS

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Management Information Bases

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MIMO

Back 161

Multiple Input, Multiple Output

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MLA

Back 162

Master License Agreement

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MLA

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Multilateral License Agreement

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MMF

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Multimode Fiber

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MOA

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Memorandum Of Understanding

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MPLS

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Multi-Protocol Label Switching

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MS-CHAP

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Microsoft Challenge Handshake Authentication Protocol

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MSA

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Master Service agreement

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MSDS

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Material Safety Data Sheet

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MT-RJ

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Mechanical Transfer-Registered Jack

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MTU

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Maximum Transmission Unit

Front 172

MUMIMO

Back 172

Multiuser Multiple Input, Multiple Output

Front 173

MX

Back 173

Mail Exchanger

Front 174

NAC

Back 174

Network Access Control

is an approach to computer security that attempts to unify endpoint security technology (such as antivirus, host intrusion prevention, and vulnerability assessment), user or system authentication and network security enforcement.

Front 175

NAS

Back 175

Network Attached Storage

Front 176

NAT

Back 176

Network Address Translation

Front 177

NCP

Back 177

Network Contol Protocol

Front 178

NDR

Back 178

Non-Delivery Receipt

Front 179

NetBEUI

Back 179

Network Basic Input/Output Extended User Interface

Front 180

NFC

Back 180

Network Control Protocol

Front 181

NFS

Back 181

Network File Service

Front 182

NIC

Back 182

Network Interface Card

Front 183

NIDS

Back 183

Network Intrusion Detection System

Front 184

NIPS

Back 184

Network Intrusion Prevention System

Front 185

NIST

Back 185

Network Information Security & Technology

Front 186

NIU

Back 186

Network Interface Unit

Front 187

nm

Back 187

Nanometer

Front 188

NMS

Back 188

Network Management System

Front 189

NNTP

Back 189

Network News Transport Protocol

Front 190

NTP

Back 190

Network Time Protocol

Front 191

OCx

Back 191

Optical Carrier

Front 192

OS

Back 192

Operation System

Front 193

OSI

Back 193

Open Systems Interconnect

Front 194

OSPF

Back 194

Open Shortest Path First

Front 195

OTDR

Back 195

Optical Time Domain Reflectometer

Front 196

OUI

Back 196

Organizationally Unique Indetifier

Front 197

P2P

Back 197

Peer-to-Peer

Front 198

PaaS

Back 198

Platform as a Service

Front 199

PAN

Back 199

Personal Area Network

Front 200

PAP

Back 200

Password Authentication Protocol

Front 201

PAT

Back 201

Port Address Translation

Front 202

PBX

Back 202

Private Branch Exchange

Front 203

PC

Back 203

Personal Computer

Front 204

PCM

Back 204

Phase Change Memory

Front 205

PDU

Back 205

Protocol Data Unit

Front 206

PGP

Back 206

Pretty Good Privacy

Front 207

PKI

Back 207

Public Key Infrastructure

Front 208

PLC

Back 208

Programmable Logic Controller

Front 209

PoE

Back 209

Power over Ethernet

Front 210

POP

Back 210

Post Office Protocol

Front 211

POP3

Back 211

Post Office Protocol version 3

Front 212

POTS

Back 212

Plain Old Telephone System

Front 213

PPP

Back 213

Point-to-Point Protocol

Front 214

PPPoE

Back 214

Point-to-Point over Ethernet

Front 215

PPTP

Back 215

Point-to-Point Tunneling Protocol

Front 216

PRI

Back 216

Primary Rate Interface

Front 217

PSK

Back 217

Pre-Shared Key

Front 218

PSTN

Back 218

Public Switched Telephone Network

Front 219

PTP

Back 219

Point-to-Point

Front 220

PTR

Back 220

Pointer

Front 221

PVC

Back 221

Permanent Virtual Circuit

Front 222

QAM

Back 222

Quadrature Amplitude Modulation

Front 223

QoS

Back 223

Quality of Service

Front 224

RADIUS

Back 224

Remote Authentication Dial-In User Service

Front 225

RARP

Back 225

Reverse Address Resolution Protocol

Front 226

RAS

Back 226

Remote Access Service

Front 227

RDP

Back 227

Remote Desktop Protocol

Front 228

RDS

Back 228

Radio Data System

Front 229

RF

Back 229

Radio Frequency

Front 230

RFI

Back 230

Radio Frequency Interference

Front 231

RFID

Back 231

Radio Frequency Identification/or Identify

Front 232

RG

Back 232

Radio Guide

Front 233

RIP

Back 233

Routing Internet Protocol

Front 234

RJ

Back 234

Registered Jack

Front 235

RPO

Back 235

Recovery Point Objective

Front 236

RSA

Back 236

Rivest, Shamir, Adelman

Front 237

RSH

Back 237

Remote Shell

Front 238

RTP

Back 238

Real-Time Protocol

Front 239

RTS/CTS

Back 239

Request to Send/Clear to Send

Front 240

RTT

Back 240

Round-Trip Time or Real Transfer Time

Front 241

SA

Back 241

Security Association

Front 242

SaaS

Back 242

Software as a Service

Front 243

SAN

Back 243

Storage Area Network

Front 244

SATA

Back 244

Serial Advanced Technology Attachment

Front 245

SC

Back 245

Standard Connector or Subscriber Connector

Front 246

SCADA

Back 246

Supervisory Control And Data Acquisition

Front 247

SCP

Back 247

Secure Copy Protocol

Front 248

SDLC

Back 248

Software Development Life Cycle

Front 249

SDP

Back 249

Sesssion Description Protocol

Front 250

SDSL

Back 250

Symmetrical Digital Subscriber Line

Front 251

SFP

Back 251

Small Form-factor Protocol

Front 252

SHA

Back 252

Secure Hash Algorithm

Front 253

SIEM

Back 253

Security Information and Event Management

Front 254

SIP

Back 254

Session Initiation Protocol

Front 255

SLA

Back 255

Service Level Agreement

Front 256

SLAAC

Back 256

Stateless Address Auto Configuration

Front 257

SLIP

Back 257

Serial Line Internet Protocol

Front 258

SMB

Back 258

Server Message Block

Front 259

SMF

Back 259

Single-Mode Fiber

Front 260

S/MIME

Back 260

Secure/Multipurpose Internet Email Extensions

Front 261

SMS

Back 261

Short Message Service

Front 262

SMTP

Back 262

Simple Mail Transfer Protocol

Front 263

SNAT

Back 263

Static Network Address Translation or Source Network Address Translation

Front 264

SNMP

Back 264

Simple Network Management Protocol

Front 265

SNTP

Back 265

Simple Network time Protocol

Front 266

SOA

Back 266

Start Of Authority

Front 267

SOHO

Back 267

Small Office, Home Office

Front 268

SONET

Back 268

Syncrhonous Optical Network

Front 269

SOW

Back 269

Statement Of Work

Front 270

SPB

Back 270

Shortet Path Bridging

Front 271

SPI

Back 271

Stateful Packet Inspection

Front 272

SPS

Back 272

Standby Power Supply

Front 273

SQL

Back 273

Search and Query Language

Front 274

SSH

Back 274

Secure Shell

Front 275

SSID

Back 275

Service Sete Identifier

Front 276

SSL

Back 276

Secure Sockets Layer

Front 277

ST

Back 277

Straight Tip or Snap Twist

Front 278

STP

Back 278

Spanning Tree Protocol or Shielded Twisted Pair

Front 279

SVC

Back 279

Switched Virtual Circuit

Front 280

SYSLOG

Back 280

System Log

Front 281

T1

Back 281

Terrestrial Carrier Level 1

Front 282

TA

Back 282

Terminal Adapter

Front 283

TACACS

Back 283

Terminal Access Control Access Control System

Front 284

TACACS+

Back 284

Terminal Access Control Access Control System

Front 285

TCP

Back 285

Transmission Control Protocol

Front 286

TCP/IP

Back 286

Transmission Control Protocol / Internet Protocol

Front 287

TDM

Back 287

Time Division Multiplexing

Front 288

TDR

Back 288

Time Domain Reflectometer

Front 289

Telco

Back 289

Telephone Company

Front 290

TFTP

Back 290

Trivial File Transfer Protocol

Front 291

TKIP

Back 291

Temporal Key Integrity Protocol

Front 292

TLS

Back 292

Transport Layer Security

Front 293

TMS

Back 293

Transportation Management System

Front 294

TOS

Back 294

Type Of Service

Front 295

TTL

Back 295

Time To Live

Front 296

TTLS

Back 296

Tunneled Transport Layer Security

Front 297

UC

Back 297

Unified Communications

Front 298

UDP

Back 298

User Datagram Protocol

Front 299

UNC

Back 299

Universal Naming Convention

Front 300

UPC

Back 300

Universal Polished Connector

Front 301

UPS

Back 301

Uninterruptible Power Supply

Front 302

URL

Back 302

Uniform Resource Locator

Front 303

USB

Back 303

Universal Serial Bus

Front 304

UTM

Back 304

Unified Threat Management

Front 305

UTP

Back 305

Unshielded Twisted Pair

Front 306

VDI

Back 306

Video Device Interface

Front 307

VDSL

Back 307

Virtual Digital Subscriber Line

Front 308

VLAN

Back 308

Virtual Local Area Network

Front 309

VNC

Back 309

Virtual Network Connection

Front 310

VoIP

Back 310

Voice over IP

Front 311

VPN

Back 311

Virtual Private Network

Front 312

VRF

Back 312

Virtual Routing Forwarding

Front 313

VRRP

Back 313

Virtual Router Redundancy Protocol

Front 314

VTC

Back 314

Video Teleconference

Front 315

VTP

Back 315

VLAN Trunk Protocol

Front 316

WAN

Back 316

Wide Area Network

Front 317

WAP

Back 317

Wireless Application Protocol or Wireless Access Point

Front 318

WEP

Back 318

Wired Equivalent Privacy

Front 319

WINS

Back 319

Window Internet Name Service

Front 320

WLAN

Back 320

Wireless Local Area Network

Front 321

WMS

Back 321

Warehouse Management System

Front 322

WPA

Back 322

WiFi Protected Access

Front 323

WPS

Back 323

WiFi Protected Setup

Front 324

WWN

Back 324

World Wide Name

Front 325

WWW

Back 325

World Wide Web

Front 326

XDSL

Back 326

Extended Digital Subscriber Line

Front 327

XML

Back 327

Extensible Markup Language

Front 328

ZEROCONF

Back 328

Zero configuration

Front 329

Optical and copper patch panels

Front 330

Pubchdown blocks (110)

Front 331

Layer 3 switch/router

Front 332

Layer 2 switch/router

Front 333

Firewall

Front 334

VPN concentrator

Front 335

DHCP Server

Front 336

DNS Server

Front 337

IDS/IPS

Front 338

Wireless access point

Front 339

Two basic PCs

Front 340

Media converters

Front 341

Configuration terminal (with Telnet and SSH)

Front 342

VoIP (including a phone)

Front 343

KVM switch

Front 344

Spare Hardware

Front 345

NICs

Front 346

Power Supplies

Front 347

GBICs

Front 348

SFPs

Front 349

Switch

Front 350

Hub

Front 351

Wireless Access Point

Front 352

UPS

Front 353

Spare Parts

Back 353

Spare Parts

Front 354

Patch cables

Front 355

Rj-45 connectors, modular jacks

Front 356

RJ-11 connectors

Front 357

Cable spool

Front 358

Coaxial cable spool

Front 359

F-connectors

Back 359

Fiber connectors

Front 360

Antennas

Front 361

Bluetooth/wireless adapters

Front 362

Console Cables

Front 363

Tools

Back 363

Tools

Front 364

Telco/network crimper

Front 365

Cable tester

Front 366

Punchdown tool

Front 367

Cable Stripper

Front 368

Coaxial crimper

Front 369

Wire cutter

Front 370

Tone generator

Front 371

Fiber termination kit

Front 372

Snips

Front 373

Butt set

Front 374

Optical power meter

Front 375

Software

Back 375

Software

Front 376

Packet sniffer

Back 376

Proto

Front 377

Protocol analyzer

Front 378

Terminal emulation software

Front 379

Linux/ Window OSs

Front 380

Software firewall

Front 381

Software IDS/IPS

Front 382

Network mapper

Front 383

Virtual network enviroment

Front 384

Wifi analyzer

Front 385

Spectrum analyzer

Front 386

Anti-malware software

Front 387

Network monitoring software

Front 388

Other

Back 388

Other

Front 389

Sample network documentation

Front 390

Sample logs

Front 391

Defective cables

Front 392

Sample malware/viruses

Back 392

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