E

E-1 European designation for T-1.

E-3 European designation for T-3.

EBCDIC (Extended Binary Coded Decimal Interchange Code) An 8-bit data-exchange code used in IBM* mainframes, other computer systems, and associated communications equipment. EBCDIC and ASCII are the two most widely used data codes.

EDI (Electronic Data Interchange) Method for passing database information and other transactions in standard form electronically between locations or organizations.

EDL Ethernet Data Link

EEPROM Electronically Erasable Programmable Read-Only Memory

EGP (Exterior Gateway Protocol)(TCP/IP) The service by which gateways exchange information about what systems they can reach; generally, an exterior gateway protocol is any internetworking prototcol for passing routing information between autonomous systems.

EISA (Extended Industry Standard Architecture) PC bus systems that is an alternative to IBM's Micro Channel Architecture (MCA). The EISA architecture, backed by an industry consortium headed by Compaq*, is compatible with the IBM AT bus; MCA is not.

E-mail Attachment A binary file attached to an e-mail message carrying more complex information, for example, a document with formatting codes, images or sound.

Encapsulation Wrapping a data set in a protocol header. For example, Ethernet data is wrapped in a specific Ethernet header before network transit. Also, a method of bridging dissimilar networks where the entire frame from one network is simply enclosed in the header used by the link-layer protocol of the other network.

Encryption Applying a specific algorithm to data so as to alter the data's appearance and prevent other devices from reading the information. Decryption applies the algorithm in reverse to restore the data to its original form.

End system End-user device on a network. Also, a nonrouting host or node in an OSI network.

Enterprise network Larger network connecting most major points in a company. Differs from a WAN in that it is typically private and contained within a single organization.

Entity Individual, manageable device in a network. Also, OSI terminology for a layer protocol machine. An entity within a layer performs the functions of the layer within a single computer system, accessing the layer entity below and providing services to the layer entity above at local service access points.

EPROM Erasable Programmable Read-Only Memory

ES-ES End System To End System Protocol

ESF Extended Super Frame

ES-IS (end system to intermediate system protocol) The OSI protocol by which end systems such as networks personal computers announce themselves to intermediate systems such as hubs.

ESMTP Extended Simple Mail Transfer Protocol - proposed extensions to SMTP for things like maximum message length and allowing content wider than 7 bits. Related to the MIME specifications. The core of the specification is in RFC 1425 and more is in RFC1426 and RFC1427.

Ethernet IEEE-standard data link protocol that specifies how data is placed on and retrieved from a common transmission medium. Forms the underlying transport vehicle used by several upper-level protocols, including TCP/IP and XNS. See CSMA/CD for a description of Ethernet's media-access method. Contrast TR (token ring).

Explorer super frame Frame sent out by a networked device in a source route bridging environment to determine the optimal route to another networked device.

E.164 Specifies the ISDN numbers, including telephone numbers up to 15 digits long.

Edge Device A device, such as a router or Ethernet-to- ATM switch, that is directly connected to an ATM network. The UNI defines the connection between the edge device and the ATM network switch. It is the first device a user sees when sending traffic to the ATM network. Also called an end device.

EGPE Extended Generalized Programming Environment

EIA/TIA Electronic Industries Assn/Telecommunications Industries Assn

EISA Extended Industry Standard Architecture

ELM Ethernet LAN module

ESM Ethernet switching module

ESMTP Extended Simple Mail Transfer Protocol. Proposed extensions to SMTP (see SMTP) to achieve such things as increased maximum message length and allowing content wider than 7-bits. Related to the MIME spec. Defined in RFCs 1425, 1426 and 1427.

ETSI ETSI is the European Telecommunications Standards Institute.