CCNA Cisco Certified Network Associate Study Guide - FTP Server

Glossary 677
firewall A barrier purposefully erected between any connected public networks
and a private network, made up of a router or access server or several
routers or access servers, that uses access lists and other methods to ensure
the security of the private network.
Flash Electronically Erasable Programmable Read-Only Memory
(EEPROM). Used to hold the Cisco IOS in a router by default.
flash memory Developed by Intel and licensed to other semiconductor
manufacturers, it is nonvolatile storage that can be erased electronically and
reprogrammed, physically located on an EEPROM chip. Flash memory permits
software images to be stored, booted, and rewritten as needed. Cisco
routers and switches use flash memory to hold the IOS by default. See also:
EPROM, EEPROM.
flat network Network that is one large collision domain and one large
broadcast domain.
flooding When traffic is received on an interface, it is then transmitted to
every interface connected to that device with exception of the interface from
which the traffic originated. This technique can be used for traffic transfer by
bridges and switches throughout the network.
flow control A methodology used to ensure that receiving units are not
overwhelmed with data from sending devices. Pacing, as it is called in IBM
networks, means that when buffers at a receiving unit are full, a message is
transmitted to the sending unit to temporarily halt transmissions until all the
data in the receiving buffer has been processed and the buffer is again ready
for action.
FRAD Frame Relay Access Device: Any device affording a connection
between a LAN and a Frame Relay WAN. See also: Cisco FRAD, FRAS.
fragment Any portion of a larger packet that has been intentionally segmented
into smaller pieces. A packet fragment does not necessarily indicate
an error and can be intentional. See also: fragmentation.
fragmentation The process of intentionally segmenting a packet into
smaller pieces when sending data over an intermediate network medium that
cannot support the larger packet size.