Vocabulary Flashcards
10BASE-T
The 10-Mbps baseband Ethernet specification using two pairs of twisted pair cabling (CAT III IV or V). One pair transmits data and the other receives data. 10BASE-T, which is part of the IEEE 802.3 specification, has a distance limit of approximately 100m per segment.
100BASE-T
A name for the IEEE Fast Ethernet standard that used two-pair copper cabling, a speed of 100 Mbps, and a maximum cable length of 100 m.
1000BASE-T
A name for the IEEE Gigabit Ethernet standard that uses four-pair copper cabling, a speed of 1000 Mbps (1 Gbps), and a maximum cable length of 100 m.
802.1Q
The IEEE standardized protocol for VLAN trunking.
802.11a
The IEEE standard for wireless LANs using the U-NII spectrum, OFDM encoding, at speeds up to 54 Mbps
802.11b
The IEEE standard for wireless LANs using the ISM spectrum, DSSS encoding, and speeds up to 11 Mbps
802.11g
The IEEE standard for wireless LANs using the ISM spectrum, OFDM or DSSS encoding and speeds of up to 54 Mbps.
802.11n
The IEEE standard for wireless LANs using the ISM spectrum, OFDM encoding, and multiple antennas for single-stream speeds up to 150 Mbps.
AAA
Authentication, authorization and accounting. Authentication confirms the identity of the user or device. Authorization determines what the user or device is allowed to do. Accounting records information about access attempts, including inappropriate requests.
Access Interface
A LAN network design term that refers to a switch interface connected to end-user devices, configured so that it does not use VLAN trunking.
Access Link
In Frame Relay, the physical serial link that connects a Frame Relay DTE device, usaully at router, to a Frame Relay switch. The access link uses the same physical layer standards as do point-to-point leased lines.
Access Point
a wireless LAN device that provides a means for wireless clients to send data to each other and to the rest of a wired network, with the AP connecting to both the wireless LAN and the wired Ethernet LAN.
Accounting
In security, the recording of access attempts. See AAA.
Address Block
In both IPv4 and IPv6, a set of consecutive addresses. This term is typically used for public addresses, assigned by some numbering authority (IANA/ICANN, an RIR, or an ISP).
Adjacent-Layer Interaction
The general topic of how on one computer, two adjacent layers in a networking architectural model work together, with the lower layer providing services to the higher layer.
Administrative Distance
In Cisco routers, a means for one router to chose between multiple routes to reach the same subnet when those routes were learned by different routing protocols. The lower the administrative distance, the better the source of the routing information.
ADSL
Asymmetric digital subscriber line. One of many DSL technologies, ADSL is designed to deliver more bandwidth down-stream (from the central office to the customer site) than upstream.
All-Nodes Multicast Address
A specific IPv6 multicast address, FF02::1, with link-local scope, used to send packets to all devices on the link that support IPv6.
All-Routers Mulitcast Address
A specific IPv6 multicast address, FF02::2, with a link-local scope, used to send packets to all devices that act as IPv6 routers on the local link.
Anti-X
The term used by Cisco to refer to a variety of security tools that help prevent various attacks, including antivirus, antiphishing, and antispam.
Area Border Router (ABR)
A router using OSPF in which the router has interfaces in multiple OSPF areas
ARP
Address Resolution Protocol. An Internet protocol used to map an IP address to a MAC address. Defined in RFC 826.
ARP table
A list of IP addresses of neighbors on the same VLAN, along with their MAC addresses, as kept in memory by hosts and routers.
ARPANET
The first packet-switched network, first created around 1970, which served as the predecessor to the Internet.
Asymmetric
A feature of many Internet access technologies, including DSL, cable, and modems, in which the downstream transmission rate is higher than the upstream transmission rate.
Asynchronous
The lack of an imposed time ordering on a bit stream. Practically, both sides agree to the same speed, but there is no check or adjustment of the rates if they are slightly different. However, because only 1 byte per transfer is sent, slight differences in clock speed are not an issue.
ATM
Asynchronous Transfer Mode. The international standard for cell relay in which multiple service types (such as voice, video and data) are conveyed in fixed length (53-byte cells). Fixed-length cells allow cell processing to occur in hardware, thereby reducing transit delays.
Autonegotiation
An IEEE standard mechanism (802.3u) with which two nodes can exchange messages for the purpose of choosing to use the same Ethernet standards on both ends of the link, ensuring that the link functions and functions well.
Autonomous System
An internetwork in the administrative control of one organization, company, or governmental agency, inside which that organization typically runs an interior gateway protocol.
Auxiliary Port
A physical connector on a router that is designed to be used to allow a remote terminal, or PC with a terminal emulator, to access a router using an analog modem.
Back to Back Link
A serial link between two routers, created without CSU/DSUs, by connecting a DTE cable to one router and DCE cable to the other. Typically used in labs to build serial links without the expense of an actual leased line from the telco.
Balanced Hybrid
A term that, over the years, has been used to refer to the logic behind the EIGRP routing protocol. More commonly today, this logic is referred to as advanced distance vector logic.
Bandwidth
A reference to the speed of a networking link.
Basic Services Set (BSS)
In wireless LANs, a WLAN with a single access point.
bitwise Boolean AND
A Boolean AND between two numbers of the same length in which the first bit in each number is ANDed, and then the second bit in each number, and then the third, and so on.
Boolean AND
A math operation performced on a pair of one-digit binary numbers. The result is another one-digit binary number. 1 AND 1 yields 1; all other combinations yield a 0.
Boot Field
The low-order 4 bits of the configuraiton register in a Cisco router. The value in the boot field in part tells the router where to look for a Cisco IOS image to load.
Broadcast Address
Generally, any address that represents all devices, and can be used to send one message to all devices. In Ethernet, the MAC address of all binary 1s, or FFFF.FFFF.FFFF in hex. For IPv4, see subnet broadcast address.
Broadcast Domain
A set of all devices that receive broadcast frames originating from any device within the set. Devices in the same VLAN are in the same broadcast domain.
Broadcast Frame
An Ethernet frame sent to destination address FFFF.FFFF.FFFF, meaning that the frame should be delivered to all hosts on that LAN.
Broadcast Subnet
When subnetting a Class A, B, or C network, the one subnet in each classful network for which all subnet bits have a value of binary 1. The subnet broadcast address in this subnet has the same numeric value as the classful network’s network-wide broadcast address.
Bus
A common physical signal path composed of wires or other media across which signals can be sent from one part of a computer to another.
Cable Internet
An Internet access technology that uses a cable TV (CATV) cable, normally used for video, to send and receive data.
CDP
Cisco Discovery Protocol. A media- and protocol-independent device-discovery protocol that runs on most Cisco-manufactured equipment, including routers, access servers, and switches. Using CDP, a device can advertise its existence to other devices and receive information about other devices on the same LAN or on the remote side of a WAN.
CDP Neighbor
A device con the other end of some communications cable is advertising CDP updates.
CIDR
Classless interdomain routing. An RFC-standard tool for global IP address range assignment. CIDR reduces the size of Internet routers’ IP routing tables, helping deal with the rapid growth of the Internet. The term classless refers to the fac tthat the summarized groups of networks represent a group of addresses that do not conform to IPv4 classful (Class A, B, and C) grouping rules.
Circuit Switching
A generic reference to network servies, typically WAN services, in which the provider sets up a (Layer 1) circuit between two devices.