exam cram Flashcards
1
Q
10Base-T (IEEE 802.3)
A
The 802.3i specification for running Ethernet at 10 Mbps over twisted-pair cabling. The maximum length is 100 meters
2
Q
10GBASE-T
A
10 Gbps connections over unshielded or shielded twisted-pair cables. Distance =100 meters. CAT 6a (category 6 can reach 55 meters).
3
Q
1000BASE-LX
A
A standard for Gigabit Ethernet intended for use with long-wavelength (LX) transmissions over long cable runs of fiber-optic cabling.
4
Q
1000BASE-T
A
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.
5
Q
APIPA (Automatic Private IP Addressing)
A
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.
6
Q
attenuation
A
The loss of signal experienced as data transmits over distance and across the network medium.
7
Q
BCP (business continuity plan)
A
The strategy for addressing potential threats to a company and creation of systems to aid in the prevention of threats and recovery from problems.
8
Q
Broadcast
A
A packet-delivery system in which a copy of a packet is transmitted to all hosts attached to the network.
9
Q
cable modem
A
A device that provides Internet access over cable television lines.
10
Q
cable tester
A
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.
11
Q
CDMA (code-division multiple access)
A
A multiple-access channel method used to provide bandwidth sharing.
12
Q
Client
A
A node that uses the services from another node on a network.
13
Q
CNAME (canonical name)
A
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).
14
Q
coaxial cable
A
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.
15
Q
cold site
A
A disaster recovery site that provides office space, but the customer provides and installs all the equipment needed to continue operations.
16
Q
Collision
A
The result of two frames simultaneously transmitting on an Ethernet network and colliding, thereby destroying both frames.
17
Q
CRC (cyclic redundancy check)
A
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.
18
Q
crossover cable
A
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.
19
Q
CSMA/CD (Carrier Sense Multiple Access with Collision Detection)
A
A contention media access method that uses collision-detection and retransmission techniques.
20
Q
100BASE-T
A
The IEEE 802.3 specification for running Ethernet at 100 Mbps over twisted-pair cabling. The maximum length is 100 meters
21
Q
1000BASE-SX
A
A fiber-optic Gigabit Ethernet standard for operation over multimode fiber.
22
Q
AAA
A
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.
23
Q
access control vestibule
A
A physical security access control system that requires one set of doors to close before the second set opens. Previously known as a mantrap.
24
Q
access point (AP)
A
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.
25
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.
26
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.
27
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.
28
application layer
Layer 7 of the OSI model, which provides support for end users and for application programs using network resources.
29
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.
30
AUP (acceptable use policy)
A policy created by an organization defining what is acceptable on their resources (network, computers, and so on).
31
Backbone
A network segment that acts as a trunk between other network segments. Backbones typically are high-bandwidth implementations, such as fiber-optic cable.
32
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.
33
Baseline
A measurement of the performance of a device or system for the purposes of future comparison. Baselining is a common server administration task.
34
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.
35
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.
36
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.
37
broadcast storm
An undesirable condition in which broadcasts become so numerous that they bog down the flow of data across the network.
38
bus topology
A linear LAN architecture in which all devices connect to a common cable, called a bus or backbone.
39
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.
40
cable stripper
A tool used to strip the sheathing from copper cabling.
41
CAN (campus-area network)
A wide-area network (WAN) created to service a campus area.
42
Cat 5
Data-grade cable that typically was used with Fast Ethernet operating at 100 Mbps with a transmission range of 100 meters.
43
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.
44
Cat 6
High-performance UTP cable that can transmit data up to 10 Gbps.
45
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.
46
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.
47
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.
48
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.
49
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).
50
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.
51
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.
52
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.
53
DDoS (distributed denial-of-service) attack
A DoS attack that utilizes more than one computer in the attack.
54
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.
55
demarcation point
The point at which communication lines enter a customer's premises. Sometimes shortened to simply demarc.
56
DHCP (Dynamic Host Configuration Protocol)
A protocol that provides dynamic IP addressing to DHCP-enabled workstations on the network.
57
Dig
A command used on a Linux, UNIX, or macOS system to perform manual DNS lookups.
58
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.
59
DLP (data loss prevention)
A system designed to detect and respond to potential breaches.
60
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.
61
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.
62
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.
63
DSL (digital subscriber line)
A public network technology that delivers high bandwidth over conventional copper wiring over limited distances.
64
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.
65
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.
66
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.
67
EIA/TIA
The Electronic Industries Alliance/Telecommunications Industry Association is a trade organization responsible for a number of communications standards.
68
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.
69
EIRP (Effective Isotropic Radiated Power)
A measure of the radiated power of an antenna in a specific direction.
70
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.
71
ESP (Encapsulating Security Payload)
One of the two separate protocols IPSec consists of (the other being AH). ESP provides encryption services.
72
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.
73
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.
74
EUI (extended unique identifier)
A naming convention for MAC addresses.
75
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.
76
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.
77
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.
78
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.
79
flow control
A method of controlling the amount of data transmitted within a given period of time. Different types of flow control exist.
80
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.
81
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.
82
GBIC (gigabit interface converter)
A Gigabit Ethernet and Fibre Channel transceiver standard.
83
GRE (Generic Routing Encapsulation)
A routing encapsulation method that comes in a plain wrapper.
84
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.
85
HA (high availability)
A system goal/ attribute aimed at ensuring operational uptime higher than normal.
86
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.
87
hot site
A disaster recovery site, or alternative site, that can be immediately functional in the event of a disaster at the primary site.
88
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.
89
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.
90
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.
91
HVAC (heating, ventilation, and air conditioning)
A self-defining acronym.
92
IaaS (Infrastructure as a Service)
The most basic method of cloud service computing; the users install everything from the operating system up.
93
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.
94
ICS (industrial control system)
A general term used to describe industrial control systems such as supervisory control and data acquisition (SCADA) systems.
95
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.
96
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.
97
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.
98
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.
99
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.
100
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.
101
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.
102
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.
103
ifconfig
A command used on Linux- and UNIX-based systems to obtain configuration for and configure network interfaces.
104
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.
105
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.
106
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.
107
IPS (intrusion prevention system)
A network device that continually scans the network, looking for inappropriate activity.
108
ipconfig
A Windows command that provides information about the configuration of the TCP/IP parameters, including the IP address.
109
IPSec (IP Security)
A protocol used to provide strong security standards for encryption and authentication on virtual private networks.
110
IPv4 (Internet Protocol version 4)
A suite of protocols used for communication on a local-area network and for accessing the Internet.
111
IPv6 (Internet Protocol version 6)
The newer version of IP, which has a larger range of usable addresses than IPv4, and enhanced security.
112
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.
113
jumbo frame
An Ethernet frame with a payload greater than the standard maximum transmission unit (MTU) of 1500 bytes.
114
Kerberos
A network authentication protocol designed to ensure that the data sent across networks is encrypted and safe from attack. Its primary purpose is to provide authentication for client/server applications.
115
LACP (Link Aggregation Control Protocol)
An IEEE specification that provides a control method of bundling several physical ports into one single channel.
116
Latency
The delay induced by a piece of equipment or device used to transfer data.
117
LC (local connector)
A media connector used with fiber-optic cabling.
118
LDAP (Lightweight Directory Access Protocol)
A protocol used to access and query compliant directory services systems, such as Microsoft Active Directory.
119
LDAPS (Lightweight Directory Access Protocol over SSL)
A protocol that uses SSL, and port 636, to add additional security to LDAP.
120
Linux
A UNIX-like operating system kernel created by Linus Torvalds. Linux is distributed under an open-source license agreement, as are many of the applications and services that run on it.
121
logical topology
The appearance of the network to the devices that use it, even if in physical terms the layout of the network is different.
122
LTE (Long-Term Evolution)
A wireless communication standard more commonly referred to as 4G LTE.
123
MAN (metropolitan-area network)
A network that spans a defined geographic location, such as a city or suburb.
124
MDF (main distribution frame)
A type of wiring closet known as the main distribution frame. The primary wiring closet for a network typically holds the majority of the network gear, including routers, switches, wiring, servers, and more. This is also typically the wiring closet where outside lines run into the network. One of the key components in the MDF is a primary patch panel. The network connector jacks attached to this patch panel lead out of the building for network connections.
125
media converter
A device used to interconnect different types of cables within an existing network. For example, the media converter can be used to connect newer Gigabit Ethernet technologies with older 100BASE-T networks.
126
Mesh
A type of network topology in which each node connects to every other node. The mesh network provides a high level of redundancy because it provides alternative routes for data to travel should a single route become unavailable.
127
mGRE (Multipoint Generic Routing Encapsulation)
A tunneling protocol that can encapsulate other network layer protocols inside multipoint links to increase security over an IP network.
128
MIB (Management Information Base)
A data set that defines the criteria that can be retrieved and set on a device using SNMP.
129
MIMO (multiple input, multiple output)
The use of multiple antennas— often at both the transmitter and receiver—to improve communications in IEEE 802.11n and 802.11ac Wi-Fi networks.
130
MMF (multimode fiber)
A type of fiber in which many beams of light travel through the cable, bouncing off the cable walls. This strategy actually weakens the signal, reducing the length and speed at which the data signal can travel.
131
MOU (memorandum of understanding)
132
MPLS (multiprotocol label switching)
133
MTBF (mean time between failure)
The predicted time between inherent failures of a system.
134
MTTR (mean time to repair)
The average time that a device will take to recover from a failure.
135
MTU (maximum transmission unit)
The largest data size that a protocol/ layer can transmit.
136
Multicast
A single-packet transmission from one sender to a specific group of destination nodes.
137
Multimeter
A tool used to measure voltage, current, and resistance.
138
MU-MIMO (multiuser multiple input, multiple output)
A set of advanced MIMO technologies included with IEEE 802.11ac and 802.11ax that dramatically enhances wireless throughput.
139
MX (Mail Exchange)
A DNS record entry used to identify the mail server.
140
NAC (network access control)
A computer networking security solution that uses a set of network protocols with the goal to unify endpoint security solutions such as antivirus, vulnerability assessment, and authentication. Also known as network admission control.
141
name server
A server that contains a database of name resolution information used to resolve network names to network addresses.
142
NAS (network-attached storage)
An array of disks providing network storage capacity to the users on the network. It is a specialized file level computer storage device connected to a network.
143
NAT (Network Address Translation)
A standard that enables the translation of IP addresses used on one network to a different IP address that is acceptable for use on another network. This translation enables multiple systems to access an external network, such as the Internet, through a single IP address.
144
NDA (nondisclosure agreement)
A document agreeing that information shared will not be shared further with other parties.
145
Netstat
A Windows operating system command-line utility that displays protocol statistics and current TCP/IP network connections.
146
network layer
Layer 3 of the OSI model, which is where routing based on node addresses (IP addresses) occurs.
147
NFV (Network Function Virtualization)
A network architecture in which virtualization technologies are used to connect/create communication services.
148
NGFW (next-generation firewall)
A traditional firewall combined with any other network device (such as an intrusion prevention system) to get additional functionalities.
149
NIC (network interface card)
A hardware component that serves as the interface, or connecting component, between a network and the node. It has a transceiver, a MAC address, and a physical connector for the network cable. Also called a network adapter or network card.
150
NS (name server)
A type of DNS record used to identify the name servers responsible for the DNS zone. A DNS name server stores DNS address records such as A and AAAA and also stores mail exchange (MX) records for a domain.
151
Nslookup
Windows and Linux/UNIX command-line utility used to query Domain Name System (DNS) servers and clients to obtain DNS information.
152
NTP (Network Time Protocol)
A protocol used to communicate time synchronization information between devices on the network. NTP is part of the TCP/IP suite. NTP uses port 123.
153
OID (object identifier)
An ITU identifier employed for naming any object with a globally unambiguous persistent name.
154
on-path attack
An attack in which a party between the sender and receiver intercepts data between the two and then uses it for malicious intent. Previously known as a manin- the-middle attack.
155
OSI (Open Systems Interconnection) reference model
A seven-layer model created by the ISO to standardize and explain the interactions of networking protocols.
156
OSPF (Open Shortest Path First)
A link-state routing protocol used on TCP/IP networks. Compare with distance-vector routing.
157
OTDR (optical time-domain reflectometer)
A tool used to locate problems with optical media, such as cable breaks.
158
PaaS (Platform as a Service)
A cloud computing service model in which the provider supplies the operating system and the user is responsible for the stack above it.
159
PAN (personal-area network)
A network layout whereby devices work together in close proximity to share information and services, commonly using technologies such as Bluetooth or infrared.
160
PAT (Port Address Translation)
A variation on NAT (Network Address Translation). With PAT, all systems on the LAN are translated into the same IP address, but with a different port number assignment.
161
Patch
A fix for a bug in a software application. Patches can be downloaded from the Internet to correct errors or security problems in software applications.
162
patch cable
A cable, normally twisted pair, used to connect two devices. Strictly speaking, a patch cable is the cable that connects a port on a hub or switch to the patch panel, but today people commonly use the term to refer to any cable connection.
163
patch panel
A device in which the cables used in coaxial or twisted-pair networks converge and are connected. The patch panel is usually in a central location.
164
PDU (power distribution unit)
A device fitted with multiple outputs designed to distribute electric power, especially to racks of computers and networking equipment.
165
peer-to-peer networking
A network environment that does not have dedicated servers, where communication occurs between similarly capable network nodes that act as both clients and servers.
166
physical layer
Layer 1 of the OSI model, where all physical connectivity is defined.
167
physical network diagram
A diagram that displays the physical layout of a network, including placement of systems and all network cabling.
168
physical topology
The actual physical layout of the network. Common physical topologies include star, bus, mesh, and ring.
169
Ping
A TCP/IP stack utility that works with ICMP and that uses echo requests
170
Plenum
The space between the structural ceiling and a drop-down ceiling. It is commonly used for heating, ventilation, and air-conditioning systems and to run network cables.
171
PoE (Power over Ethernet)
A technology that enables electrical power to be transmitted over twisted-pair Ethernet cable. The power is transferred, along with data, to provide power to remote devices.
172
PoE+ (Power over Ethernet plus)
A technology that provides more power than PoE (increasing from 12.95W to 25.5W) and raising the maximum current (from 350mA to 600mA).
173
POP3 (Post Office Protocol version 3)
A protocol that is part of the TCP/IP suite used to retrieve mail stored on a remote server. The most commonly used version of POP is POP3. POP3 is an application layer protocol that runs unsecured over port 110 by default. POP3S uses secure port 995.
174
port mirroring
A process by which two ports on a device, such as a switch, are configured to receive the same information. Port mirroring is useful in troubleshooting scenarios.
175
presentation layer
Layer 6 of the OSI model, which prepares information to be used by the application layer.
176
private network
A network to which access is limited, restricted, or controlled. Most corporate networks are private networks. Compare with public network.
177
protocol analyzer
Hardware- or software-based tools, with their primary function being to analyze network protocols such as TCP, UDP, HTTP, FTP, and more.
178
proxy server
A server that acts as a go-between for a workstation and the Internet. A proxy server typically provides an increased level of security, caching, NAT, and administrative control.
179
PSK (preshared key)
A value (key) shared with another party so that they can encrypt messages to then be securely sent.
180
PTR (pointer)
A DNS record used to map an IP address to a hostname.
181
public network
A network, such as the Internet, to which anyone can connect with the most minimal of restrictions. Compare with private network.
182
punchdown block
A device used to connect network cables from equipment closets or rooms to other parts of a building. Connections to networking equipment such as hubs or switches are established from the punchdown block. Also used in telecommunications wiring to distribute phone cables to their respective locations throughout the building.
183
punchdown tool
A hand tool that enables the connection of twisted-pair wires to wiring equipment such as a patch panel.
184
QoS (quality of service)
The strategies used to manage and increase the flow of network traffic. QoS features enable administrators to predict bandwidth use, monitor that use, and control it to ensure that bandwidth is available to the applications that need it.
185
QSFP (Quad Small Form-factor Pluggable)
A compact, hot-pluggable transceiver used for data communications.
186
RA (router advertisement)
An ICMPv6 packet type used by routers to advertise their presence periodically (or in response to a solicitation message).
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RADIUS (Remote Authentication Dial-In User Service)
A security standard that employs a client/server model to authenticate remote network users. Remote users are authenticated using a challenge-and-response mechanism between the remote-access server and the RADIUS server.
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RAID (Redundant Array of Inexpensive/Independent Disks)
Any of many methods of storing data on multiple drives and enabling the overlapping of I/O operations. The various RAID levels offer either fault-tolerance or performance advantages.
189
RDP (Remote Desktop Protocol)
A presentation layer protocol that supports a Remote Desktop Connection between an RDP client (formerly known as Windows Terminal Client) and a server.
190
Repeater
A device that regenerates and retransmits signals on a network. Repeaters usually are used to strengthen signals going long distances.
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RF (radio frequency)
A rate of oscillation used by radio waves and radio signals.
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RFC (Request For Comments)
The process by which standards relating to the Internet, the TCP/IP suite, and associated technologies are created, commented on, and approved.
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RG (Radio Guide)
A specification commonly used with connection types. More frequently used as Radio Grade.
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RG-6/59
Designations for the coaxial cable used in thin coaxial networks that operate on the Ethernet standard.
195
RJ (Registered Jack)
A specification for a family of cable connectors.
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RJ-11 connector
A connector used with telephone systems. It can have up to six conductors.
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RJ-45 connector
A connector used with twisted-pair cable. It can support eight conductors for four pairs of wires.
198
Route
The entire path between two nodes on a network.
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Router
A device that works at the network layer of the OSI model to control the flow of data between two or more network segments.
200
RPO (recovery point objective)
The maximum acceptable period in which data might be lost from a major incident.
201
RSSI (Received Signal Strength Indication)
A measurement of the power present in a received radio signal.
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RTO (recovery time objective)
The acceptable duration of time within which a business process must be restored after a disaster to avoid unacceptable consequences associated with a break in business continuity.
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RTSP (Real-Time Streaming Protocol)
A protocol used for establishing and maintaining communications with a media server.
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runt
A packet too small for an Ethernet network.
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SaaS (Software as a Service)
A cloud computing service model in which a user runs everything supplied by the provider.
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SAN (storage-area network)
A network that provides access to consolidated, block-level data storage. It is usually found on high- speed networks and shared by all servers on a network.
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SC (standard connector)
A type of connector used with fiber cabling.
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SCADA (supervisory control and data acquisition)
A system operating with coded signals to remotely control a device or equipment.
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screened subnet
An area for placing web and other servers that serve the general public outside the firewall, thereby isolating them from internal network access. Previously known as a demilitarized zone, or DMZ.
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SDN (software-defined network)
An approach to networking that allows network administrators to programmatically manage network behavior dynamically via open interfaces and provide abstraction of lower-level functionality.
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SDWAN (software-defined WAN)
A wide-area network in which the networking hardware has been decoupled from the control mechanism.
212
Server
A network node that fulfills service requests for clients. Usually referred to by the type of service it performs, such as file server, communications server, or print server.
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session layer
Layer 5 of the OSI model, which establishes, manages, and terminates sessions between applications on different nodes.
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SFP (small form-factor pluggable)
A line of small optical transceivers that have recently become available.
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SFTP (Secure File Transfer Protocol)
An implementation of File Transfer Protocol (FTP) that uses Secure Shell (SSH) technology to provide additional authentication and encryption services for file transfers.
216
SIEM (security information and event management)
Any of a family of products that combine security information management and event management to achieve a more holistic approach to security.
217
SIP (Session Initiation Protocol)
An application layer protocol designed to establish and maintain multimedia sessions such as Internet telephony calls.
218
SLA (service-level agreement)
An agreement between a customer and provider detailing the level of service to be provided on a regular basis and in the event of problems.
219
SLAAC (Stateless Address Auto Configuration)
A feature of IPv6 networks that allows devices to connect to the Internet without requiring any intermediate IP support from a DHCP server.
220
SMB (Server Message Block)
An application-layer network protocol used primarily for providing shared access to files, printers, and ports as well as miscellaneous communications between nodes.
221
SMF (single-mode fiber)
A type of fiber that uses a single direct beam of light, thus allowing for greater distances and increased transfer speeds.
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SMTP (Simple Mail Transfer Protocol)
An Internet protocol used for the transfer of email messages and attachments.
223
SNMP (Simple Network Management Protocol)
A protocol that provides network devices with a method to monitor and control network devices; manage configurations, statistics collection, performance, and security; and report network management information to a management console. SNMP runs over port 161 and is part of the TCP/IP suite.
224
SOA (Start of Authority)
A record of information containing data on DNS zones and other DNS records. A DNS zone is the part of a domain for which an individual DNS server is responsible. Each zone contains a single SOA record.
225
SOHO (small office/home office)
A small network typically serving 1 to 10 users.
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SOP (standard operating procedure)
The normal, accepted way that business is conducted.
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SQL (Structured Query Language)
The language designed for working with, and managing, data in a relational database management system.
228
SRV (service record)
Within DNS, a record used to identify computers that host specific services.
229
SSD (solid-state drive)
An alternative to physical drives, such as traditional hard drives, a solid-state storage drive/device uses integrated circuits to store data persistently (usually with flash memory).
230
SSH (Secure Shell)
An application, such as Telnet, that enables a session to be opened on a remote host. SSH differs from Telnet in that it provides additional authentication methods and encryption for data as it traverses the network. SSH uses TCP/IP port 22.
231
SSID (service set identifier)
A unique client identifier sent over the WLAN that acts as a simple password used for authentication between a wireless client and an access point. The SSID is used to differentiate between networks. Therefore, the client system and the AP must use the same SSID.
232
SSL (Secure Sockets Layer)
A method of securely transmitting information to and receiving information from a remote website. SSL is implemented through HTTPS. SSL operates at the presentation layer of the OSI model and uses TCP/IP port 443. SSL has been succeeded by TLS.
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SSO (single sign-on)
A method of access in which users are given access to all the applications and systems they need when they initially log on.
234
ST (straight tip or snap twist)
A type of connector used with cabling.
235
Star
A type of physical network design in which all nodes connect to a centralized device—in most cases a network switch.
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static routing
A routing method in which all routes must be entered into a device manually and in which no route information is exchanged between routing devices on the network. Compare with dynamic routing.
237
STP (Spanning Tree Protocol)
A protocol developed to eliminate the loops caused by the multiple paths in an internetwork. STP is defined in IEEE 802.1.
238
Subnetting
The process of using parts of the node portion of an assigned IP address to create more network IDs. Although subnetting increases the number of network IDs, it decreases the number of node addresses available for each network ID.
239
Switch
A Layer 2 networking device that forwards frames based on destination addresses.
240
syslog (system logging protocol)
A standard used to send log messages (system or event) to a syslog server. These events include driver failures, device conflicts, read/write errors, timeouts, and bad block errors.
241
TACACS+ (Terminal Access Controller Access Control System Plus)
A Cisco security protocol designed to provide centralized validation of users who are attempting to gain access to a router or network access server (NAS). TACACS+ is a set of security protocols designed to provide authentication, authorization, and accounting (AAA) of remote users. TACACS+ uses TCP port 49 by default.
242
TCP (Transmission Control Protocol)
A connection-oriented, reliable data transmission communication service that operates at the transport layer of the OSI model. TCP is part of the TCP/IP suite.
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TCP/IP (Transmission Control Protocol/Internet Protocol)
A suite of protocols that includes TCP and IP. TCP/IP was originally designed for use on large internetworks but has now become the de facto protocol for networks of all sizes.
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telco (telephone company)
A slang term for the telephone provider in question.
245
Telnet
A standard terminal emulation protocol in the TCP/IP stack. Telnet is used to perform terminal emulation over TCP/IP via remote terminal connections, enabling users to log in to remote systems and use resources as if they were connected to a local system. Telnet has been replaced in most instances by the more secure SSH.
246
TFTP (Trivial File Transfer Protocol)
A simplified version of FTP that enables file transfers but does not offer any security or file management capabilities. TFTP uses TCP/IP port 69.
247
throughput tester
A device used to test the actual data throughput of a network cable.
248
TKIP (Temporal Key Integrity Protocol)
A encryption protocol designed to address the shortcomings of the WEP security protocol. It is defined in IEEE 802.11i.
249
TLS (Transport Layer Security)
A security protocol designed to ensure privacy between communicating client/server applications. When a server and client communicate, TLS ensures that no one can eavesdrop and intercept or otherwise tamper with the data message. TLS is the successor to SSL.
250
tone generator
A device used with a tone locator to locate and diagnose problems with twisted-pair cabling. Commonly referred to as fox and hound.
251
Topology
The shape or layout of a physical network and the flow of data through the network. See also logical topology and physical topology.
252
trace route
A function of the TCP/IP suite, implemented in utilities such as traceroute and tracert, which enables the entire path of a packet to be tracked between source and destination hosts. It is used as a troubleshooting tool.
253
Tracert
A Windows command-line utility used to track the route a data packet takes to get to its destination.
254
transport layer
Layer 4 of the OSI model. Protocols at this layer perform functions such as segmenting data so that it can be sent over the network and then reassembling the segmented data on the receiving end. The transport layer also deals with some of the errors that can occur in a stream of data, such as dropped and duplicated packets.
255
TTL (time to live)
A value assigned to a packet of data to prevent it from moving around the network indefinitely. The TTL value is decremented each time the packet crosses a router, until it reaches 0, at which point it is removed from the network.
256
TX/RX (transmit and receive)
The commonly used abbreviations for transmit and receive. These can refer to wiring, physical switches, buffers, or any other element.
257
UDP (User Datagram Protocol)
A communications protocol that provides connectionless, unreliable communication services and operates at the transport layer of the OSI model. It requires a network layer protocol such as IP to guide it to the destination host.
258
Unicast
Communication that takes place over a network between a single sender and a single receiver.
259
UPC (ultra-polished connector)
A type of connector used with fiber networks.
260
UPS (uninterruptible power supply)
A system that provides protection against power surges and power outages. During blackouts, a UPS gives you time to shut down systems or devices on the network before the temporary power interruption becomes permanent. A UPS is also called battery backup.
261
Uptime
The length of time a device has been on and operating.
262
URL (Uniform Resource Locator)
A name used to identify a website and a page on the Internet. An example of a URL is www.quepublishing.com/products.
263
USB (universal serial bus)
A type of interface between a computer system and peripheral devices. The USB interface enables you to add or remove devices without shutting down the computer. USB supports up to 127 devices. USB also supports autodetection and plug and play.
264
UTP (unshielded twisted-pair)
A type of cable that uses multiple twisted pairs of copper wire in a casing that does not provide much protection from EMI. The most common network cable in Ethernet networks, UTP is rated in categories including Category 1 through Category 8, as well as Category 5e, Category 6a, and Category 7a.
265
VIP (virtual IP)
An IP address that does not correspond, one-to-one, to an actual physical network interface.
266
VLAN (virtual LAN)
A group of devices located on one or more LAN segments, whose configuration is based on logical instead of physical connections. This enables the devices to operate as if they were connected to the same physical switch, regardless of whether they are connected to the same switch.
267
VM (virtual machine)
Any emulation of a computer system.
268
VNC (virtual network computing)
A process that involves enabling a remote login, in which clients can access their own desktops while physically away from their computers. Also known as virtual network connection.
269
vNIC (virtual network interface card)
Any abstract emulation of a network interface card (NIC). The vNIC may, or may not, correspond directly to a physical network interface controller.
270
VoIP (Voice over IP)
Any of a number of technologies that enable voice communication across the Internet Protocol.
271
VPN (virtual private network)
A network that uses a public network such as the Internet as a backbone to connect two or more private networks. A VPN provides users with the equivalent of a private network in terms of security. VPNs can also be used as a means of establishing secure remote connectivity between a remote system and another network.
272
VRRP (Virtual Router Redundancy Protocol)
An IP-based routing protocol that automatically assigns available routers to participating hosts.
273
WAN (wide-area network)
A data communications network that serves users across a broad geographic area. WANs often use transmission devices such as modems or CSUs/ DSUs to carry signals over leased lines or common carrier lines.
274
warm site
A disaster recovery site offering most equipment and applications. Compare to a cold site that refers to a disaster recovery site with limited hardware and typically only a reserved location. A hot site is one with duplicate hardware and software and can be operational within minutes of a disaster.
275
WDM (wavelength division multiplexing)
A fiber transmission method that uses multiple light wavelengths to send data over the same medium.
276
WLAN (wireless LAN)
A local-area network created using wireless transmission methods, such as radio or infrared, rather than traditional wired solutions.
277
WPA (Wi-Fi Protected Access)
A data encryption method used on 802.11 wireless LANs. WPA is an industry-supported standard designed to address WEP’s security shortcomings.
278
WPA2 (Wi-Fi Protected Access v2)
A secure wireless data encryption method based on 802.11i that replaces WPA.
279
zero-day vulnerability
A newly discovered vulnerability for which a patch or fix has not yet been issued.
280
zone transfer
The passing of DNS information from one name server to a secondary name server.
