3Com 510, 520, 530 manual Chapter C Glossary

C-4 CHAPTER C: GLOSSARY

Datagram A message that is sent from one computer or device to another to confirm it location or status on a network.

Data link layer The second layer of the OSI reference model. This layer is responsible for controlling message traffic.

Data packet (packet) A sequence of binary digits, including data and control signals that is transmitted across a LAN or WAN.

DCE Data circuit-terminating equipment.

DTE Data Terminal Equipment. The physical interface and link access procedures between DTE and data circuit-terminating equipment (DCE).

DTMF Dial tone multi-frequency, the signalling system used by PSTN. Refer to PSTN.

Downloading A user initiated transfer of data from a server to the user’s own workstation. Also used to classify the transfer of files from one system to another, usually to upgrade or revise system software.

EPROM Erasable programmable read-only memory. A chip whose memory can be erased and reused.

Ethernet A 10 Mbps baseband local area network protocol, compatible with IEEE 802.3 standards.

FastConnect The OfficeConnect Remote’s proprietary connection protocol that allows fast connection between units either over the ISDN link or over a permanent leased line WAN link.

Fiber optics A technology that uses laser light pulses, sent over thin glass fibres, which is able to deliver data at speed up to several gigabits per second.

File server A computer running a special operating system that allows workstations to access files.

Filter A configuration that removes types of data frames based on user-entered parameters.

Firewall A method of preventing unauthorized access to a network or a host on a network. A firewall is usually implemented within a router’s software.