Appendix D: Glossary
10Base-T
An adaptation of the Ethernet standard for Local Area Networks (LANs). 10Base-T uses a twisted pair cable with maximum lengths of 100 meters.
Adapter
A device that makes the connection to a network segment, such as Ethernet and modem cards and adapters.
ADSL
Asymmetric Digital Subscriber Line (ADSL), as it’s name indicates, is an asymmetrical data trasmission technology with higher traffic rate downstream and lower traffic rate
upstream. ADSL technology satifies the bandwidth requirements of applications which demand “asymmetric” traffic, such as web surfing, file downloads and telecommuting.
ATM
(Asynchronous Transfer Mode) A network technology supports real time voice, video, and data transmission. The topology uses switches that establish a logical circuit from
end to end, which guarantees quality of service (QoS). ATM works by transmitting all traffic as fixed-length, 53-byte cells. This fixed unit allows very fast switches to be
built ATM is widely used as a backbone technology in carrier networks and large enterprises. ATM is highly scalable and supports transmission speeds of 1.5, 25, 100, 155,
622, 2488 and 9953 Mbps. ATM is also running as slow as 9.6 Kbps between ships at sea.
Bandwidth
The amount of data that can be transmitted in a fixed amount of time.
Browser
A software application used to locate and display web pages. Examples include Netscape Navigator and Microsoft Internet Explorer.
Communications Protocols
Communications between devices requires they agree on the format in which thedata is to be transmitted, sent and received. The communications protocols are a set of
rules that define the data format.
DHCP
DHCP, short for Dynamic Host Configuration Protocol, is a protocol for assigning dynamic IP Addresses to devices on a network. Dynamic Addressing means that a device
can have a different IP Address each time it connects to the network.
Domain Name
A name that identifies one or more IP Addresses. For example, the domain name microsoft.com represents about a dozen IP Addresses. Domain names are used in URLs to
identify particular web pages. For example, in the URL http://www.pcwebopedia.com/index.html, the domain name is pcwebopedia.com.
DNS
Short for Domain Name Server, translates domain names into IP Addresses. To help us recognize and remember domain names they are alphabetic in form, however, the
Internet actually runs on numbered IP Addresses. DNS servers translate domain names into their respective IP Addresses.
Encapsulation
A method for transmitting multiple protocols within the same network. The frames of one type of protocol are carried within the frames of another.
Ethernet
One of the most common Local Area Network (LAN) protocols. Ether uses a bus topology which supports a data transfer rate of 10 Mbps.
Firewall
A security system used to enforce an access control policy between an organisation’s networks and the internet.
IEEE
Short for Institute of Electrical and Electronics Engineers, an organization best known for developing standards for the computer and electronics industry.
Internet
A global network connecting millions of computers for the exchange of data, news and opinions.
Intranet
A network based on TCP/IP Protocol (an internet) belonging to an organization, and accessible only by that organization's members, employees, or others with authoriza-
tion.
IP Address
An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP Protocol route messages based on the IP Address of the destination. The format of
an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be from zero to 255.
IPSec
Internet Protocol Security is a security standard for network transmission. It provides authentication and packet encryption over the internet.
ISP
Short for Internet Service Provider, a company that provides access to the internet for a monthly fee. The ISP provides a software package, username, password and access
phone number allowing users to log on to the internet, browse the World Wide Web and send and receive e-mail.
LLC
Logical Link Control is the sublayer of data link layer defined in IEEE 802.2. The LLC provides a common interface point to the MAC layers, which specify the access
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