Glossary of Terms Flashcards
10Base2
The last true bus-standard network where nodes connected to a common, shared length of coaxial cable
10BaseFL
Fiber-optic implementation of Ethernet that runs at 10 Mbps using baseband signaling. Maximum segment length is 2 km
10BaseT
An Ethernet LAN designed to run on UTP cabling. Runs at 10 Mbps and uses baseband signaling. Maximum length for the cabling between the NIC and the hub (or the switch, the repeater, and so forth) is 100 m.
10GBaseER/10GBaseEW
A 10 GbE standard using 1550-nm single-mode fiber. Maximum cable length up to 40 km
10GBaseLR/10GBaseLW
A 10 GbE standard using 1310-nm single-mode fiber. Maximum cable length up to 10 km.
10GBaseSR/10GBaseSW
A 10 GbE standard using 850-nm multimode fiber. Maximum cable length up to 300 m.
10GBaseT
A 10 GbE standard designed to run on CAT 6a UTP cabling. Maximum cable length of 100 m.
10 Gigabit Ethernet (10 GbE)
Currently (2015) the fastest Ethernet designation available, with a number of fiber-optic and copper standards.
100BaseFX
An Ethernet LAN designed to run on fiber-optic cabling. Runs at 100 Mbps and uses baseband signaling. Maximum cable length is 400 m for half-duplex and 2 km for full-duplex
100BaseT
An Ethernet LAN designed to run on UTP cabling. Runs at 100 Mbps, uses baseband signaling, and uses two pairs of wires on CAT 5 or better cabling.
100BaseT4
An Ethernet LAN designed to run on UTP cabling. Runs at 100 Mbps and uses four-pair CAT 3 or better cabling. Made obsolete by 100BaseT.
100BaseTX
The technically accurate but little-used name for 100BaseT
110 Block
Also known as a 110-punchdown block, a connection gridwork used to link UTP and STP cables behind an RJ-45 patch panel.
110-Punchdown Block
The most common connection used on the back of an RJ-45 jack and patch panels.
802 Committee
The IEEE committee responsible for all Ethernet standards.
802.1X
A port-authentication network access control mechanism for networks.
802.3 (Ethernet)
See Ethernet: Name coined by Xerox for the first standard of network cabling and protocols. Ethernet is based on a bus topology. The IEEE 802.3 subcommittee defines the current Ethernet specifications.
802.3ab
The IEEE standard for 1000BaseT.
802.3z
The umbrella IEEE standard for all versions of Gigabit Ethernet other than 1000BaseT.
802.11
See IEEE 802.11.
802.11a
A wireless standard that operates in the frequency range of 5 GHz and offers throughput of up to 54 Mbps.
802.11a-ht
802.11a-ht, and the corresponding 802.11g-ht standard, are technical terms for mixed mode 802.11a/802.11g operation. In mixed mode, both technologies are simultaneously supported
802.11b
The first popular wireless standard, operates in the frequency range of 2.4 GHz and offers throughput of up to 11 Mbps.
802.11g
Currently (2015) the wireless standard with the widest use, operates on the 2.4-GHz band with a maximum throughput of 54 Mbps
802.11g-ht
802.11g-ht, and the corresponding 802.11a-ht standard, are technical terms for mixed mode 802.11a/802.11g operation. In mixed mode, both technologies are simultaneously supported
802.11i
A wireless standard that added security features.
802.11n
An updated 802.11 standard that increases transfer speeds and adds support for multiple in/multiple out (MIMO) by using multiple antennas. 802.11n can operate on either the 2.4- or 5-GHz frequency band and has a maximum throughput of 400 Mbps.
802.16
A wireless standard (also known as WiMAX) with a range of up to 30 miles.
1000BaseCX
A Gigabit Ethernet standard using unique copper cabling, with a 25-m maximum cable distance.
1000BaseLX
A Gigabit Ethernet standard using single-mode fiber cabling, with a 5-km maximum cable distance.
1000BaseSX
A Gigabit Ethernet standard using multimode fiber cabling, with a 220- to 500-m maximum cable distance
1000BaseT
A Gigabit Ethernet standard using CAT 5e/6 UTP cabling, with a 100-m maximum cable distance
1000BaseTX
Short-lived gigabit-over-UTP standard from TIA/EIA. Considered a competitor to 1000BaseT, it was simpler to implement but required the use of CAT 6 cable
1000BaseX
An umbrella Gigabit Ethernet standard. Also known as 802.3z. Comprises all Gigabit standards with the exception of 1000BaseT, which is under the 802.3ab standard.
A Records
A list of the IP addresses and names of all the systems on a DNS server domain.
AAA
(Authentication, Authorization, and Accounting) A security philosophy wherein a computer trying to connect to a network must first present some form of credential in order to be authenticated and then must have limitable permissions within the network. The authenticating server should also record session information about the client.
Acceptable Use Policy
A document that defines what a person may and may not do on an organization’s computers and networks.
Access Control
All-encompassing term that defines the degree of permission granted to use a particular resource. That resource may be anything from a switch port to a particular file to a physical door within a building.
A clearly defined list of permissions that specifies what actions an authenticated user may perform on a shared resource
Access Control Server (ACS)
Cisco program/process/server that makes the decision to admit or deny a node based on posture assessment. From there, the ACS directs the edge access device to allow a connection or to implement a denial or redirect.
Access Port
Regular port in a switch that has been configured as part of a VLAN. Access ports are ports that hosts connect to. They are the opposite of a trunk port, which is only connected to a trunk port on another switch.
Active Directory
A form of directory service used in networks with Windows servers. Creates an organization of related computers that share one or more Windows domains.
Activity Light
An LED on a NIC, hub, or switch that blinks rapidly to show data transfers over the network
Ad Hoc Mode
A wireless networking mode where each node is in direct contact with every other node in a decentralized free-for-all. Ad hoc mode is similar to the mesh topology
Address Resolution Protocol (ARP)
A protocol in the TCP/IP suite used with the command-line utility of the same name to determine the MAC address that corresponds to a particular IP address.
Used to resolve ip addresses into MAC addresses
Administrative Accounts
pecialized user accounts that have been granted sufficient access rights and authority to manage specified administrative tasks. Some administrative accounts exist as a default of the system and have all authority throughout the system. Others must be explicitly assigned the necessary powers to administer given resources.
ADSL (Asymmetric Digital Subscriber Line)
Advanced Encryption Standard (AES)
A block cipher created in the late 1990s that uses a 128-bit block size and a 128-, 192-, or 256-bit key size. Practically uncrackable.
Adware
A program that monitors the types of Web sites you frequent and uses that information to generate targeted advertisements, usually pop-up windows
Agent
In terms of posture assessment, refers to software that runs within a client and reports the client’s security characteristics to an access control server to be approved or denied entry to a system.
Aggregation
A router hierarchy in which every router underneath a higher router always uses a subnet of that router’s existing routes
Air Gap
The act of physically separating a network from every other network.
Amplification
The aspect of a DoS attack that makes a server do a lot of processing and responding.
Angled Physical Contact (APC)
Fiber-optic connector that makes physical contact between two fiber-optic cables. It specifies an 8-degree angle to the curved end, lowering signal loss. APC connectors have less connection degradation from multiple insertions compared to other connectors.
Anti-Malware Program
Software that attempts to block several types of threats to a client including viruses, Trojan horses, worms, and other unapproved software installation and execution.
Antivirus
Software that attempts to prevent viruses from installing or executing on a client. Some antivirus software may also attempt to remove the virus or eradicate the effects of a virus after an infection.
Anycast
A method of addressing groups of computers as though they were a single computer. Anycasting starts by giving a number of computers (or clusters of computers) the same IP address. Advanced routers then send incoming packets to the closest of the computers.
Application Layer
Application/Context Aware
Advanced feature of some stateful firewalls where the content of the data is inspected to ensure it comes from, or is destined for, an appropriate application. Context-aware firewalls look both deeply and more broadly to ensure that the data content and other aspects of the packet are appropriate to the data transfer being conducted. Packets that fall outside these awareness criteria are denied by the firewall
Application Programming Interface (API)
Shared functions, subroutines, and libraries that allow programs on a machine to communicate with the OS and other programs.
Approval Process
One or more decision makers consider a proposed change and the impact of the change, including funding. If the change, the impact, and the funding are acceptable, the change is permitted.
Archive
The creation and storage of retrievable copies of electronic data for legal and functional purposes.
Area ID
Address assigned to routers in an OSPF network to prevent flooding beyond the routers in that particular network. See also Open Shortest Path First (OSPF).
Groups of logically associated OSPF routers designed to maximize routing efficiency while keeping the amount of broadcast traffic well managed. Areas are assigned a 32-bit value that manifests as an integer between 0 and 4294967295 or can take a form similar to an IP address, for example, “0.0.0.0.”
ARP
ARP Cache Poisoning
A man-in-the-middle attack, where the attacker associates his MAC address with someone else’s IP address (almost always the router), so all traffic will be sent to him first. The attacker sends out unsolicited ARPs, which can either be requests or replies
arping
A command used to discover hosts on a network, similar to ping, but that relies on ARP rather than ICMP. The arping command won’t cross any routers, so it will only work within a broadcast domain. See also Address Resolution Protocol (ARP) and ping.
Asset Management
Managing each aspect of a network, from documentation to performance to hardware.
Asymmetric Digital Subscriber Line (ADSL)
A fully digital, dedicated connection to the telephone system that provides download speeds of up to 9 Mbps and upload speeds of up to 1 Mbps.
Asymmetric-Key Algorithm
An encryption method in which the key used to encrypt a message and the key used to decrypt it are different, or asymmetrical
Asynchronous Transfer Mode (ATM)
A network technology that runs at speeds between 25 and 622 Mbps using fiber-optic cabling or CAT 5 or better UTP
Attenuation
The degradation of signal over distance for a networking cable.
Authentication
A process that proves good data traffic truly came from where it says it originated by verifying the sending and receiving users and computers
Authentication Server (AS)
In Kerberos, a system that hands out Ticket-Granting Tickets to clients after comparing the client hash to its own
Authoritative DNS Servers
DNS servers that hold the IP addresses and names of systems for a particular domain or domains in special storage areas called forward lookup zones. They also have reverse lookup zones.
Authoritative Name Servers
Another name for authoritative DNS servers. DNS servers that hold the IP addresses and names of systems for a particular domain or domains in special storage areas called forward lookup zones. They also have reverse lookup zones.
Authorization
A step in the AAA philosophy during which a client’s permissions are decided upon
Automatic Private IP Addressing (APIPA
A networking feature in operating systems that enables DHCP clients to self-configure an IP address and subnet mask automatically when a DHCP server isn’t available
Autonomous System (AS)
One or more networks that are governed by a single protocol, which provides routing for the Internet backbone
Backup Designated Router (BDR)
A second router set to take over if the designated router fails.
Bandwidth
A piece of the spectrum occupied by some form of signal, whether it is television, voice, fax data, and so forth. Signals require a certain size and location of bandwidth to be transmitted. The higher the bandwidth, the faster the signal transmission, thus allowing for a more complex signal such as audio or video. Because bandwidth is a limited space, when one user is occupying it, others must wait their turn. Bandwidth is also the capacity of a network to transmit a given amount of data during a given period.
Bandwidth Saturation
When the frequency of a band is filled to capacity due to the large number of devices using the same bandwidth.
Banner Grabbing
When a malicious user gains access to an open port and uses it to probe a host to gain information and access, as well as learn details about running services
Baseband
Digital signaling that has only one signal (a single signal) on the cable at a time. The signals must be in one of three states: one, zero, or idle
Baseline
Static image of a system’s (or network’s) performance when all elements are known to be working properly
Basic NAT
A simple form of NAT that translates a computer’s private or internal IP address to a global IP address on a one-to-one basis
Basic Rate Interface (BRI)
The basic ISDN configuration, which consists of two B channels (which can carry voice or data at a rate of 64 Kbps) and one D channel (which carries setup and configuration information, as well as data, at 16 Kbps)
Basic Service Set (BSS
In wireless networking, a single access point servicing a given area
Basic Service Set Identifier (BSSID
Naming scheme in wireless networks
Baud
One analog cycle on a telephone line
Baud Rate
The number of bauds per second. In the early days of telephone data transmission, the baud rate was often analogous to bits per second. Due to advanced modulation of baud cycles as well as data compression, this is no longer true.
Bearer Channel (B Channel)
A type of ISDN channel that carries data and voice information using standard DS0 channels at 64 Kbps.
Biometric
Human physical characteristic that can be measured and saved to be compared as authentication in granting the user access to a network or resource. Common biometrics include fingerprints, facial scans, retinal scans, voice pattern recognition, and others.
Bit Error Rate Test (BERT)
An end-to-end test that verifies a T-carrier connection
Block
Access that is denied through to or from a resource. A block may be implemented in a firewall, access control server, or other secure gateway
Blocks
Contiguous ranges of IP addresses that are assigned to organizations and end users by IANA. Also called network blocks.
Block Cipher
An encryption algorithm in which data is encrypted in “chunks” of a certain length at a time. Popular in wired networks
BNC Connector
A connector used for 10Base2 coaxial cable. All BNC connectors have to be locked into place by turning the locking ring 90 degrees
BNC Coupler
Passive connector used to join two segments of coaxial cables that are terminated with BNC connectors
Bonding
Two or more NICs in a system working together to act as a single NIC to increase performance
Bootstrap Protocol (BOOTP)
A component of TCP/IP that allows computers to discover and receive an IP address from a DHCP server prior to booting the OS. Other items that may be discovered during the BOOTP process are the IP address of the default gateway for the subnet and the IP addresses of any name servers.
Border Gateway Protocol (BGP-4)
An exterior gateway routing protocol that enables groups of routers to share routing information so that efficient, loop-free routes can be established
Botnet
A group of computers under the control of one operator, used for malicious purposes.
Bps (Bits Per Second)
A measurement of how fast data is moved across a transmission medium. A Gigabit Ethernet connection moves 1,000,000,000 bps
Bridge
A device that connects two networks and passes traffic between them based only on the node address, so that traffic between nodes on one network does not appear on the other network. For example, an Ethernet bridge only looks at the MAC address. Bridges filter and forward frames based on MAC addresses and operate at Layer 2 (Data Link layer) of the OSI seven-layer model.
Bridge Loop
A negative situation in which bridging devices (usually switches) are installed in a loop configuration, causing frames to loop continuously. Switches using Spanning Tree Protocol (STP) prevent bridge loops by automatically turning off looping ports
Bridged Connection
An early type of DSL connection that made the DSL line function the same as if you snapped an Ethernet cable into your NIC
Bridging Loop
A physical wiring of a circuitous path between two or more switches, causing frames to loop continuously. Implementing Spanning Tree Protocol (STP) in these devices will discover and block looped paths
BYOD
Bring Your Own Device A trend wherein users bring their own network-enabled devices to the work environment. These cell phones, tablets, notebooks, and other mobile devices must be easily and securely integrated and released from corporate network environments using on-boarding and off-boarding technologies.
Broadband
Analog signaling that sends multiple signals over the cable at the same time. The best example of broadband signaling is cable television. The zero, one, and idle states exist on multiple channels on the same cable
Broadcast
A frame or packet addressed to all machines, almost always limited to a broadcast domain
Broadcast Address
The address a NIC attaches to a frame when it wants every other NIC on the network to read it. In TCP/IP, the general broadcast address is 255.255.255.255. In Ethernet, the broadcast MAC address is FF-FF-FF-FF-FF-FF.
Broadcast Domain
A network of computers that will hear each other’s broadcasts. The older term collision domain is the same but rarely used today
Broadcast Storm
The result of one or more devices sending a nonstop flurry of broadcast frames on the network.
Brute Force
A type of attack wherein every permutation of some form of data is tried in an attempt to discover protected information. Most commonly used on password cracking.
Bus Topology
A network topology that uses a single bus cable that connects all of the computers in a line. Bus topology networks must be terminated to prevent signal reflection.
BCP
Business Continuity Planning The process of defining the steps to be taken in the event of a physical corporate crisis to continue operations. Includes the creation of documents to specify facilities, equipment, resources, personnel, and their roles.
Butt Set
Device that can tap into a 66- or 110-punchdown block to see if a particular line is working
Byte
Eight contiguous bits, the fundamental data unit of personal computers. Storing the equivalent of one character, the byte is also the basic unit of measurement for computer storage. Bytes are counted in powers of two.
CAB Files
Short for “cabinet files.” These files are compressed and most commonly used during Microsoft operating system installation to store many smaller files, such as device drivers.
Cable Certifier
A very powerful cable testing device used by professional installers to test the electrical characteristics of a cable and then generate a certification report, proving that cable runs pass TIA/EIA standards
Cable Drop
Location where the cable comes out of the wall at the workstation location
Cable Modem
A bridge device that interconnects the cable company’s DOCSIS service to the user’s Ethernet network. In most locations, the cable modem is the demarc
Cable Stripper
Device that enables the creation of UTP cables