Glossary
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Enhanced IGRP
Enhanced Interior Gateway Routing Protocol: An
advanced routing protocol created by Cisco, combining the advantages of
link-state and distance-vector protocols. Enhanced IGRP has superior con-
vergence attributes, including high operating efficiency. See also: IGP,
OSPF, and RIP.
enterprise network
A privately owned and operated network that joins
most major locations in a large company or organization.
enterprise services
Defined as services provided to all users on the inter-
network. Layer 3 switches or routers are required in this scenario because the
services must be close to the core and would probably be based in their own
subnet. Examples of these services include Internet access, e-mail, and pos-
sibly videoconferencing. If the servers that host these enterprise services were
placed close to the backbone, all users would have the same distance to them,
but this also means that all users' data would have to cross the backbone to
get to these services.
EPROM
Erasable Programmable Read-Only Memory: Programmed after
their manufacture, these nonvolatile memory chips can be erased if necessary
using high-power light and reprogrammed. See also: EEPROM, PROM.
error correction
Error correction uses a checksum to detect bit errors in
the data stream.
ESF
Extended Superframe: Made up of 24 frames with 192 bits each, with
the 193rd bit providing other functions including timing. This is an
enhanced version of SF. See also: SF.
Ethernet
A baseband LAN specification created by the Xerox Corpora-
tion and then improved through joint efforts of Xerox, Digital Equipment
Corporation, and Intel. Ethernet is similar to the IEEE 802.3 series standard
and, using CSMA/CD, operates over various types of cables at 10Mbps. Also
called: DIX (Digital/Intel/Xerox) Ethernet. See also: 10BaseT, FastEthernet,
and IEEE.
EtherTalk
A data-link product from Apple Computer that permits Apple-
Talk networks to be connected by Ethernet.
excess rate
In ATM networking, traffic exceeding a connection's insured
rate. The excess rate is the maximum rate less the insured rate. Depending on
the availability of network resources, excess traffic can be discarded during
congestion episodes. Compare with: maximum rate.
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