exam cram Flashcards
10Base-T (IEEE 802.3)
The 802.3i specification for running Ethernet at 10 Mbps over twisted-pair cabling. The maximum length is 100 meters
10GBASE-T
10 Gbps connections over unshielded or shielded twisted-pair cables. Distance =100 meters. CAT 6a (category 6 can reach 55 meters).
1000BASE-LX
A standard for Gigabit Ethernet intended for use with long-wavelength (LX) transmissions over long cable runs of fiber-optic cabling.
1000BASE-T
An IEEE 802.3ab standard that specifies Gigabit Ethernet over Category 5 or better UTP cable. The standard allows for full-duplex transmission using four pairs of twisted cables up to 100 meters.
APIPA (Automatic Private IP Addressing)
A technology implemented on certain Windows platforms through which a system assigns itself an IP address in the absence of a DHCP server. Addresses are assigned from the 169.254.x.x address range.
attenuation
The loss of signal experienced as data transmits over distance and across the network medium.
BCP (business continuity plan)
The strategy for addressing potential threats to a company and creation of systems to aid in the prevention of threats and recovery from problems.
Broadcast
A packet-delivery system in which a copy of a packet is transmitted to all hosts attached to the network.
cable modem
A device that provides Internet access over cable television lines.
cable tester
A device used to check for electrical continuity along a length of cable. Cable tester is a generic term that can be applied to devices such as volt/ohm meters and TDRs.
CDMA (code-division multiple access)
A multiple-access channel method used to provide bandwidth sharing.
Client
A node that uses the services from another node on a network.
CNAME (canonical name)
An alias or nickname for a canonical hostname record in a Domain Name System (DNS) database. CNAME records are used to give a single computer multiple names (aliases).
coaxial cable
A data cable, commonly referred to as coax, that is made of a solid copper core insulated and surrounded by braided metal and covered with a thick plastic or rubber covering. Coax is the standard cable used in cable television and in older bus topology networks.
cold site
A disaster recovery site that provides office space, but the customer provides and installs all the equipment needed to continue operations.
Collision
The result of two frames simultaneously transmitting on an Ethernet network and colliding, thereby destroying both frames.
CRC (cyclic redundancy check)
A method used to check for errors in packets that have been transferred across a network. A computation bit is added to the packet and recalculated at the destination to determine whether the entire content of the packet has been correctly transferred.
crossover cable
A cable that can be used to directly connect two devices—such as two computer systems—or as a means to expand networks that use devices such as hubs or switches. A traditional crossover cable is a UTP cable in which the wires are crossed for the purposes of placing the transmit line of one device on the receive line of the other. A T1 crossover is used to connect two T1 CSU/DSU devices in a back-to back configuration.
CSMA/CD (Carrier Sense Multiple Access with Collision Detection)
A contention media access method that uses collision-detection and retransmission techniques.
100BASE-T
The IEEE 802.3 specification for running Ethernet at 100 Mbps over twisted-pair cabling. The maximum length is 100 meters
1000BASE-SX
A fiber-optic Gigabit Ethernet standard for operation over multimode fiber.
AAA
Authentication, authorization, and accounting. Authentication is the process to determine whether someone is authorized to use the network—if the person can log on to the network. Authorization refers to identifying the resources a user can access after the user is authenticated. Accounting refers to the tracking methods used to identify who uses the network and what they do on the network.
access control vestibule
A physical security access control system that requires one set of doors to close before the second set opens. Previously known as a mantrap.
access point (AP)
A transmitter and receiver (transceiver) device is commonly used to facilitate communication between a wireless client and a wired network. Wireless APs (or WAPs) are used with the wireless infrastructure network topology to provide a connection point between WLANs and a wired Ethernet LAN.
ACL (access control list)
The list of trustees assigned to a file or directory. A trustee can be any object available to the security subsystem. The term ACL is also used with routers and firewall systems to refer to the list of permitted computers or users.
AES (Advanced Encryption Standard)
An encryption algorithm for securing sensitive networks used by U.S. government agencies. It has become the encryption standard for corporate networks.
APC (angle physical contact)
A connector is commonly used with fiber cables—usually single mode— to keep the signal from bouncing back down the line.
application layer
Layer 7 of the OSI model, which provides support for end users and for application programs using network resources.
ARP (Address Resolution Protocol)
A protocol in the TCP/ IP suite used to resolve IP addresses to MAC addresses. Specifically, the ARP command returns a Layer 2 address for a Layer 3 address.
AUP (acceptable use policy)
A policy created by an organization defining what is acceptable on their resources (network, computers, and so on).
Backbone
A network segment that acts as a trunk between other network segments. Backbones typically are high-bandwidth implementations, such as fiber-optic cable.
Bandwidth
The width of the range of electrical frequencies, or how many channels the medium can support. Bandwidth correlates to the amount of data that can traverse the medium at one time, but other factors determine the maximum speed supported by a cable.
Baseline
A measurement of the performance of a device or system for the purposes of future comparison. Baselining is a common server administration task.
BGP (Border Gateway Protocol)
A protocol used between gateway hosts on the Internet. BGP examines the routing table, which 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. BGP communicates between the routers using TCP.
Bluetooth
A low-cost, short-range RF technology designed to replace many of the cords used to connect devices. Bluetooth uses 2.4 GHz RF and provides transmission speeds up to 2 Mbps.
Bridge
A device that connects and passes packets between two network segments that use the same communications protocol. Bridges operate at the data link layer of the OSI model. A bridge filters, forwards, or floods an incoming frame based on the packet’s MAC address.
broadcast storm
An undesirable condition in which broadcasts become so numerous that they bog down the flow of data across the network.
bus topology
A linear LAN architecture in which all devices connect to a common cable, called a bus or backbone.
BYOD (bring your own device)
A policy governing employees bringing personally owned devices (laptops, smartphones, and the like) to the workplace and the use of those devices to access company data.
cable stripper
A tool used to strip the sheathing from copper cabling.
CAN (campus-area network)
A wide-area network (WAN) created to service a campus area.
Cat 5
Data-grade cable that typically was used with Fast Ethernet operating at 100 Mbps with a transmission range of 100 meters.
Cat 5e
Data-grade cable used on networks that run at 10/100 Mbps and even up to 1000 Mbps. Category 5e cabling can be used up to 100 meters, depending on the implementation and standard used. Category 5e cable provides a minimum of 100 MHz of bandwidth.
Cat 6
High-performance UTP cable that can transmit data up to 10 Gbps.
Cat 6a
Cable that offers improvements over Category 6 by offering a minimum of 500 MHz of bandwidth. It specifies transmission distances up to 100 meters with 10 Gbps networking speeds. Also called augmented 6.
Cat 7
Cable that offers improvements over Category 6a by offering 600 MHz of bandwidth and improved crosstalk suppression. It specifies transmission distances up to 100 meters with 10 Gbps networking speeds.
Cat 8
Twisted-pair cabling that offers improvement in speed over Cat 7, but it is intended only for short distances (such as between switches and servers in a datacenter). It offers 2000 MHz of bandwidth and specifies distances up to 30 meters with 40 Gbps networking speeds.
CIDR (classless interdomain routing)
An IP addressing scheme that enables a single IP address to designate many unique IP addresses. CIDR addressing uses an IP address followed by a / and the IP network prefix. An example of a CIDR address is 192.168.100.0/16. CIDR is sometimes called supernetting.
WAP (wireless access point)
A protocol for wireless mobile access (now outdated) and the devices that make it possible for hosts to connect (widely used).
CWDM (coarse wavelength-division multiplexing)
A method of multiplexing in which different signals operate at different speeds. The best example of this is cable modems, allowing for different speeds of uploading and downloading.
DaaS (Desktop as a Service)
Software that separates the desktop environment and associated application software from the physical client device that is used to access it.
data link layer
Layer 2 of the OSI model, which is above the physical layer. Data comes off the cable, goes through the physical layer, and goes into the data link layer. The data link layer has two distinct sublayers: MAC and LLC.
DDoS (distributed denial-of-service) attack
A DoS attack that utilizes more than one computer in the attack.
default gateway
Normally, a router or a multihomed computer to which packets are sent when they are destined for a host on a different network.
demarcation point
The point at which communication lines enter a customer’s premises. Sometimes shortened to simply demarc.
DHCP (Dynamic Host Configuration Protocol)
A protocol that provides dynamic IP addressing to DHCP-enabled workstations on the network.
Dig
A command used on a Linux, UNIX, or macOS system to perform manual DNS lookups.
disaster recovery plan
A plan for implementing duplicate computer services if a natural disaster, a human-made disaster, or another catastrophe occurs. A disaster recovery plan includes offsite backups and procedures to activate information systems in alternative locations.
DLP (data loss prevention)
A system designed to detect and respond to potential breaches.
DNS (Domain Name Service)
A service/system/server used to translate domain names, such as www.quepublishing.com, into IP addresses, such as 165.193.123.44. DNS uses a hierarchical namespace that enables the database of hostname- to-IP address mappings to be distributed across multiple servers.
DoS (denial-of-service) attack
A type of hacking attack in which the target system is overwhelmed with requests for service, which keeps it from servicing any requests—legitimate or otherwise.
Downtime
A period of time during which a computer system or network is unavailable. This may be due to scheduled maintenance or hardware or software failure.
DSL (digital subscriber line)
A public network technology that delivers high bandwidth over conventional copper wiring over limited distances.
DWDM (dense wavelength-division multiplexing)
A form of multiplexing optical signals that replaces SONET/SDH regenerators with erbium-doped fiber amplifiers (EDFAs) and can also amplify the signal and allow it to travel a greater distance. The main components of a DWDM system include a terminal multiplexer, line repeaters, and a terminal demultiplexer.
dynamic routing
A routing system that enables routing information to be communicated between devices automatically and that can recognize changes in the network topology and update routing tables accordingly. Compare with static routing.
EAP (Extensible Authentication Protocol)
An extension of PPP that supports authentication methods more secure than a standard username and password combination. EAP is commonly used as an authentication protocol for token cards, smartcards, and digital certificates.
EIA/TIA
The Electronic Industries Alliance/Telecommunications Industry Association is a trade organization responsible for a number of communications standards.
EIGRP (Enhanced Interior Gateway Routing Protocol)
A protocol that enables routers to exchange information more efficiently than earlier network protocols. Routers configured to use EIGRP keep copies of their neighbors’ routing information and query these tables to help find the best possible route for transmissions to follow.
EIRP (Effective Isotropic Radiated Power)
A measure of the radiated power of an antenna in a specific direction.
Encapsulation
A technique used by protocols in which header and trailer information is added to the protocol data unit as it is passed down through the protocol stack on a sending system. The reverse process, decapsulation, is performed at the receiving system as the packet travels up through the protocol suite.
ESP (Encapsulating Security Payload)
One of the two separate protocols IPSec consists of (the other being AH). ESP provides encryption services.
ESS (extended service set)
Two or more basic service sets (BSS) that are connected, therefore using multiple APs. An ESS is used to create WLANs or larger wireless networks and is a collection of APs and clients.
Ethernet
The most common LAN technology. Ethernet can be implemented using coaxial, twisted-pair, or fiber optic cable. Ethernet typically uses the CSMA/CD media access method and has various implementation standards.
EUI (extended unique identifier)
A naming convention for MAC addresses.
FCoE (Fibre Channel over Ethernet)
A technology that encapsulates Fibre Channel frames over Ethernet networks allowing FC to use 10 Gigabit Ethernet networks (or higher) while preserving the Fibre Channel protocol.
FHRP (First Hop Redundancy Protocol)
A redundancy protocol designed to protect a subnet’s default gateway by allowing one or more additional routers to provide backup for that address.
Fibre Channel
A technology that defines full gigabit-per-second (commonly runs at 2-, 4-, 8-, and 16-gigabit per second data rates) data transfer over fiber-optic cable. Commonly used with storage-area network (SAN) implementations.
Firewall
A program, system, device, or group of devices acting as a barrier between one network and another. Firewalls are configured to enable certain types of traffic to pass while blocking others.
flow control
A method of controlling the amount of data transmitted within a given period of time. Different types of flow control exist.
FTP (File Transfer Protocol)
A protocol that provides for the transfer of files between two systems. FTP users authenticate using clear-text sign-in procedures, making FTP an unsecure protocol. FTP is part of the TCP/IP suite and operates at Layer 7 of the OSI model.
F-type connecter
A screw-type connector used with coaxial cable. In computing environments, it is most commonly used to connect cable modems to ISP equipment or incoming cable feeds.
GBIC (gigabit interface converter)
A Gigabit Ethernet and Fibre Channel transceiver standard.
GRE (Generic Routing Encapsulation)
A routing encapsulation method that comes in a plain wrapper.
GSM (Global System for Mobile Communications)
A standard created by the European Telecommunications Standards Institute (ETSI) used to describe communication protocols for second-generation (2G) cellular networks and devices. It has now become the default global standard for mobile communications in more than 219 countries and territories.
HA (high availability)
A system goal/ attribute aimed at ensuring operational uptime higher than normal.
Hostname
A name assigned to a system for the purposes of identifying it on the network in a more user-friendly manner than by the network address.
hot site
A disaster recovery site, or alternative site, that can be immediately functional in the event of a disaster at the primary site.
HTTP (Hypertext Transfer Protocol)
protocol used by web browsers over port 80 to transfer pages, links, and graphics from the remote node to the user’s computer.
HTTPS (Hypertext Transfer Protocol Secure)
A protocol that performs the same function as HTTP but does so over an encrypted link over port 443, ensuring the confidentiality of any data that is uploaded or downloaded. Also referred to as S-HTTP.
Hub
A largely obsolete hardware device that acts as a connection point on a network that uses twisted-pair cable. It operates at the physical layer of the OSI model and forwards signals to all ports. Also known as a concentrator or a multiport repeater.
HVAC (heating, ventilation, and air conditioning)
A self-defining acronym.
IaaS (Infrastructure as a Service)
The most basic method of cloud service computing; the users install everything from the operating system up.
ICMP (Internet Control Message Protocol)
A network layer Internet protocol documented in RFC 792 that reports errors and provides other information relevant to IP packet processing. Utilities such as ping and tracert use functionality provided by ICMP.
ICS (industrial control system)
A general term used to describe industrial control systems such as supervisory control and data acquisition (SCADA) systems.
IDF (intermediate distribution frame)
A secondary wiring closet in a network using multiple wiring closets. A wiring closet known as the main distribution frame (MDF) connects to secondary wiring closets.
IDS (intrusion detection system)
A software application or hardware device that monitors a network or system for malicious or non policy-related activity and reports to a centralized management system.
802.11a
A wireless networking standard operating in the 5 GHz band. 802.11a supports a maximum theoretical data rate of 54 Mbps. Depending on interference, 802.11a could have a range of 150 feet at the lowest speed setting. Higher-speed transmissions would see a lower range. 802.11a uses the CSMA/CA media access method and is incompatible with 802.11b and 802.11g.
IEEE 802.11ac
A wireless standard that provides even higher throughput for WLANs on the 5 GHz frequency range. The specification’s goal is at least 1 gigabit per second throughput for multistation WLANs and a single station link throughput of at least 500 Mbps. It supports MIMO spatial streams as well as the newer MU-MIMO technology. 802.11ac is backward compatible with 802.11b, g, and n.
IEEE 802.11ax
A wireless standard (Wi-Fi 6) that succeeds the previous standards. It works over both the 2.4 GHz and 5 GHz bands and also works with the 6 GHz band. It provides a number of performance benefits, including the capability to avoid interference with other nearby networks.
802.11b
A commonly deployed IEEE wireless standard that uses the 2.4 GHz RF range and offers speeds up to 11 Mbps. Under ideal conditions, the transmission range can be as far as 75 meters.
802.11g
An IEEE wireless standard that is backward compatible with 802.11b. 802.11g offers a data rate of 54 Mbps. Like 802.11b, 802.11g uses the 2.4 GHz RF range.
802.11n
A wireless standard that significantly increased throughput in both the 2.4 GHz and 5 GHz frequency range. The baseline goal of the standard reaches speeds of 100 Mbps, but given the right conditions, 802.11n speeds can reach 600 Mbps. 802.11n is backward compatible with 802.11b and g.
ifconfig
A command used on Linux- and UNIX-based systems to obtain configuration for and configure network interfaces.
Interference
Anything that can compromise a signal’s quality. On bound media, crosstalk and EMI are examples of interference. In wireless environments, atmospheric conditions that degrade a signal’s quality would be considered interference.
IoT (Internet of Things)
A network of physical devices embedded with software, sensors, actuators, and network connectivity that enable these objects to collect and exchange data.
IP (Internet Protocol)
A network layer protocol, documented in RFC 791, that offers a connectionless internetwork service. IP provides features for addressing, packet fragmentation and reassembly, type-ofservice specification, and security.
IPS (intrusion prevention system)
A network device that continually scans the network, looking for inappropriate activity.
ipconfig
A Windows command that provides information about the configuration of the TCP/IP parameters, including the IP address.
IPSec (IP Security)
A protocol used to provide strong security standards for encryption and authentication on virtual private networks.
IPv4 (Internet Protocol version 4)
A suite of protocols used for communication on a local-area network and for accessing the Internet.
IPv6 (Internet Protocol version 6)
The newer version of IP, which has a larger range of usable addresses than IPv4, and enhanced security.
iSCSI (Internet Small Computer Systems Interface)
An IP-based networking storage standard for linking and managing data storage facilities. iSCSI allows SCSI commands to be sent over IP networks, including LANs, WANs, and the Internet.