Glossary
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Fast EtherChannel
Fast EtherChannel uses load distribution to share the
links called a bundle, which is a group of links managed by the Fast Ether-
Channel process. Should one link in the bundle fail, the Ethernet Bundle
Controller (EBC) informs the Enhanced Address Recognition Logic (EARL)
ASIC of the failure, and the EARL in turn ages out all addresses learned on
that link. The EBC and the EARL use hardware to recalculate the source and
destination address pair on a different link.
FastEthernet
Any Ethernet specification with a speed of 100Mbps.
FastEthernet is 10 times faster than 10BaseT, while retaining qualities like
MAC mechanisms, MTU, and frame format. These similarities make it pos-
sible for existing 10BaseT applications and management tools to be used on
FastEthernet networks. FastEthernet is based on an extension of IEEE 802.3
specification (IEEE 802.3u). Compare with: Ethernet. See also: 100BaseT,
100BaseTX, and IEEE.
fast switching
A Cisco feature that uses a route cache to speed packet
switching through a router. Contrast with: process switching.
FDM
Frequency-Division Multiplexing: A technique that permits informa-
tion from several channels to be assigned bandwidth on one wire based on
frequency. See also: TDM, ATDM, and statistical multiplexing.
FDDI
Fiber Distributed Data Interface: A LAN standard, defined by ANSI
X3T9.5 that can run at speeds up to 200Mbps and uses token-passing media
access on fiber-optic cable. For redundancy, FDDI can use a dual-ring
architecture.
FECN
Forward Explicit Congestion Notification: A bit set by a Frame
Relay network that informs the DTE receptor that congestion was encoun-
tered along the path from source to destination. A device receiving frames
with the FECN bit set can ask higher-priority protocols to take flow-control
action as needed. See also: BECN.
FEIP
FastEthernet Interface Processor: An interface processor employed on
Cisco 7000 series routers, supporting up to two 100Mbps 100BaseT ports.
firewall
A barrier purposefully erected between any connected public net-
works 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.
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