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Glossary

EEPROM

Electronically Erasable Programmable Read-Only Memory:

Programmed after their manufacture, these nonvolatile memory chips can be
erased if necessary using electric power and reprogrammed. See also: EPRO
and PROM.

EFCI

Explicit Forward Congestion Indication: A congestion feedback

mode permitted by ABR service in an ATM network. The EFCI may be set
by any network element that is in a state of immediate or certain congestion.
The destination end system is able to carry out a protocol that adjusts and
lowers the cell rate of the connection based on the value of the EFCI.
See also: ABR.

80/20 rule

The 80/20 rule means that 80 percent of the users' traffic

should remain on the local network segment and only 20 percent or less
should cross the routers or bridges to the other network segments

EIGRP

See: Enhanced IGRP.

EIP

Ethernet Interface Processor: A Cisco 7000 series router interface pro-

cessor card, supplying 10Mbps AUI ports to support Ethernet Version 1 and
Ethernet Version 2 or IEEE 802.3 interfaces with a high-speed data path to
other interface processors.

ELAN

Emulated LAN: An ATM network configured using a client/server

model in order to emulate either an Ethernet or Token Ring LAN. Multiple
ELANs can exist at the same time on a single ATM network and are made
up of a LAN Emulation Client (LEC), a LAN Emulation Server (LES), a
Broadcast and Unknown Server (BUS), and a LAN Emulation Configuration
Server (LECS). ELANs are defined by the LANE specification. See also:
LANE, LEC, LECS, and LES.

ELAP

EtherTalk Link Access Protocol: In an EtherTalk network, the link-

access protocol constructed above the standard Ethernet Data Link layer.

enable packets

Packets that complete the flow cache. Once the MLS-SE

determines that the packet meets enable criteria, such as source MAC
(SMAC) address and destination IP, the flow cache is established and subse-
quent packets are Layer 3 switched. See also: MLS-SE and MLS-RP.

encapsulation

The technique used by layered protocols in which a layer

adds header information to the protocol data unit (PDU) from the layer
above. As an example, in Internet terminology, a packet would contain a
header from the Physical layer, followed by a header from the Network layer
(IP), followed by a header from the Transport layer (TCP), followed by the
application protocol data.

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