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Glossary

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exterior routing protocol

Routing protocol that connects and advertises

autonomous systems.

failure domain

The region in which a failure has occurred in a Token

Ring. When a station gains information that a serious problem, such as a
cable break, has occurred with the network, it sends a beacon frame that
includes the station reporting the failure, its NAUN, and everything
between. This defines the failure domain. Beaconing then initiates the pro-
cedure known as autoreconfiguration. See also: autoreconfiguration and
beacon.

fallback

In ATM networks, this mechanism is used for scouting a path if

it isn't possible to locate one using customary methods. The device relaxes
requirements for certain characteristics, such as delay, in an attempt to find
a path that meets a certain set of the most important requirements.

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.

Fast Ethernet

Any Ethernet specification with a speed of 100Mbps. Fast

Ethernet is 10 times faster than 10BaseT, while retaining qualities like MAC
mechanisms, MTU, and frame format. These similarities make it possible for
existing 10BaseT applications and management tools to be used on Fast
Ethernet networks. Fast Ethernet 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.

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