F
fast
convergence
In
EAPS, Fast Convergence allows convergence in the range of 50
milliseconds. This parameter is configured for the entire switch, not by EAPS
domain.
fast path
This term refers to the data path for a packet that traverses the switch and does not
require processing by the CPU. Fast path packets are handled entirely by ASICs and are
forwarded at wire speed rate.
FDB
Forwarding database. The switch maintains a database of all MAC address received on
all of its ports and uses this information to decide whether a frame should be forwarded or
filtered. Each FDB entry consists of the MAC address of the sending device, an identifier for
the port on which the frame was received, and an identifier for the VLAN to which the device
belongs. Frames destined for devices that are not currently in the FDB are flooded to all
members of the VLAN. For some types of entries, you configure the time it takes for the
specific entry to age out of the FDB.
FHSS
Frequency-Hopping
Spread Spectrum. A transmission technology used in Local Area Wireless Network (LAWN)
transmissions where the data signal is modulated with a narrowband carrier signal that 'hops'
in a random but predictable sequence from frequency to frequency as a function of time over a
wide band of frequencies. This technique reduces interference. If synchronized properly, a
single logical channel is maintained. (Compare with
DSSS.)
FIB
Forwarding Information Base. On BlackDiamond 8800 series switches and Summit family
switches, the Layer 3 routing table is referred to as the FIB.
fit, thin, and fat
APs
A thin AP architecture uses two components: an access
point that is essentially a stripped-down radio and a centralized management controller that
handles the other WLAN system functions. Wired network switches are also required.
A fit AP, a variation of the thin AP,
handles the RF and encryption, while the central management controller, aware of the
wireless users' identities and locations, handles secure roaming, quality of service, and
user authentication. The central management controller also handles AP configuration and
management.
A fat (or thick) AP architecture concentrates all the WLAN
intelligence in the access point. The AP handles the radio frequency (RF) communication, as
well as authenticating users, encrypting communications, secure roaming, WLAN management,
and in some cases, network routing.
frame
This is the unit of transmission at the data link layer. The frame contains the header
and trailer information required by the physical medium of transmission.
FQDN
Fully Qualified Domain
Name. A 'friendly' designation of a computer, of the general form
computer.[subnetwork.].organization.domain. The FQDN names must be translated into an IP
address in order for the resource to be found on a network, usually performed by a
DNS.
full-duplex
This is the communication mode in which a device simultaneously sends and receives
over the same link, doubling the bandwidth. Thus, a full-duplex 100 Mbps connection has a
bandwidth of 200 Mbps, and so forth. A device either automatically adjusts its duplex mode to
match that of a connecting device or you can configure the duplex mode; all devices at 1 Gbps
or higher run only in full-duplex mode.
FTM
Forwarding Table
Manager.
FTP
File Transfer
Protocol.