B-20
Appendix B: Glossary
FECN Forward Explicit Congestion Notification. The DTE sending data can set this
bit to indicate that the network is experiencing congestion and the destination
DTE should stop sending so many requests for data. See also Frame Relay
and BECN.
Fiber Optics An optical transmission medium consisting of thin, plastic or glass strands
that reflect light pulses within their interior core all along their length. Fiber
optics can provide a great deal of bandwidth.
Fiber Optic
Carrier Network
A network that supports fiber optic voice and data transmission.
Field A space allocated in a protocol header or packet for a particular item of
information.
FIFO First In First Out. A queuing method that sends packets over a line strictly
according to the order in which they were received. FIFO does not require the
receiver to reassemble out-of-order packets because packets always arrive in
order.
Firewall A security device that establishes a barrier between a trusted and an untrusted
network. The firewall contains designated network traffic within a specified
area and protects the interior network from unauthorized traffic. Depending
on its type, the firewall may screen packets at the Network, Session, or
Application Layer, or some combination of these layers. For example, a
firewall can be programmed to drop certain kinds of external traffic destined
to the private network or to monitor TCP sessions and ensure that they are
legitimate.
Flash A solid-state electronic memory device that does not lose information when
no longer connected to a power source.
FQDN Fully-Qualified Domain Name. An FQDN is a domain name that includes both
a hostname and domain name. For example, www.ProCurve.com is a fully-
qualified domain name. The hostname is www, and ProCurve is the domain
name within the top-level domain, com.
FRAD Frame Relay Assembler/Disassembler. A generic name for a device that
encapsulates packets in Frame Relay headers to prepare them for transmis-
sion across a Frame Relay network. (The device also decapsulates incoming
packets.) The router or other DTE that connects to the Frame Relay network
usually includes the FRAD.
To Next Page
Loading...
Need help?
General
