Glossary A

In mathematics, in a number with multiple digits or numerals, this is the digit on the far-right end of the multidigit number. This digit represents the value of the digit times 1.

A reference to the fact that a leased line typically uses two pairs of wires.

An abbreviation of the term 10 Gigabit Ethernet.

An Ethernet standard that transmits data at 10 billion bits per second, or 10 Gigabits per second.

An Ethernet NIC that can run at either 10 Mbps or 100 Mbps, including autonegotiation of the speed and duplex setting.

A name for 10 Mbps Ethernet when using twisted-pair cabling.

In mathematics, in a decimal number with multiple digits or numerals, this is the digit second from the right end of the multidigit number. This digit represents the value of the digit times 10.

In mathematics, in a decimal number with multiple digits or numerals, this is the digit third from the right end of the multidigit number. This digit represents the value of the digit times 100.

A name for 100 Mbps Ethernet when using twisted-pair cabling.

The IEEE committee that defined common features for several types of LANs, including Ethernet. Also known as Logical Link Control (LLC).

The IEEE committee that defined Ethernet-specific details of Ethernet. Also known as Media Access Control (MAC).

The process of authentication, authorization, and accounting. Pronounced "triple A."

An authentication, authorization, and accounting server. This term is typically used when the AAA functions are being performed as users access an ISP.

The speed at which the access link is clocked. This choice affects the price of the Frame Relay connection.

In the context of network security, the process of recording and reporting events that occur as part of the authorization and authentication processes.

A field in the TCP header that identifies the number of the next byte of data that the computer sending the TCP segment expects to receive next. It is used as part of the error recovery process.

The process of putting a number in a header, with that number defining where to send the data in the packet.

The distance in a graph between the X-axis and the highest point on the graphed curve.

An electrical signal whose voltage level changes continuously. When graphed over time, the curve gently changes between the maximum and minimum voltage levels, creating a continuous curve, which works well for transmitting voice traffic.

Software that typically resides on the end user computer; it examines all files that are copied to the computer, typically by e-mail or web browsers, and removes files that contain computer viruses.

The protocol by which any IP host can, given an IP address on the same LAN subnet, discover the LAN address used by that other IP host.

A LAN broadcast frame that holds an ARP request. The request has an IP address listed; if the host who uses that IP address gets the request, it should reply, stating its LAN MAC address in an ARP reply message.

A table on each IP host, including routers, which holds the IP address and MAC address mappings learned using the ARP protocol. (Note that "cache" is pronounced just like the word "cash.")

A LAN unicast frame that holds an ARP reply. The reply has an IP address listed and the MAC address used on the same LAN interface. It is sent in reply to an ARP broadcast.

The use of different transmission speeds depending on the direction that traffic is sent.

The process of verifying the identity of a user, typically by exchanging usernames and passwords.

A server that holds a list of usernames and passwords for the purpose of allowing other servers to query the authentication server as to whether a particular username/password combination is valid.

The DNS server that knows the names and IP addresses that are related to a particular domain.

The process of deciding what resources a particular user can access.

A process by which a NIC and a switch port can choose the Ethernet speed to use, as well as whether to use full duplex.