E-1 Describes the multiplexing of 30 separate 64 kbps voice channels, plus one 64 kbps control channel, into a single, wideband digital signal rated at 2.048 Mbps. E-1 is the basic telecommunications service used in Europe. E-2 A multiplexed circuit that combines four E-1 circuits and has an aggregate bandwidth of 8.448 Mbps. E-3 A multiplexed circuit that combines 16 E-1 circuits and has an aggregate bandwidth of 34.368 Mbps. E-4 A multiplexed circuit that combines 64 E-1 circuits and has an aggregate bandwidth of 139.264 Mbps. E-5 A multiplexed circuit that combines 256 E-1 circuits and has an aggregate bandwidth of 565.148 Mbps. E-commerce Short for electronic commerce , which involves using the Internet for credit card purchases of items such as automobiles, airline tickets, computer hardware and software, and books. EGP An acronym for exterior gateway protocol , which refers to any Internet interdomain routing protocol used to exchange routing information with other autonomous systems. Also refers to Exterior Gateway Protocol, which is a specific EGP defined in RFC 904. Another EGP is the Border Gateway Protocol (BGP), defined in RFC 1105 and RFC 1771. Both EGP and BGP are part of the TCP/IP protocol suite. Of the two, however, BGP has evolved into a robust Internet routing protocol and the term “Border Gateway Protocol” is used in favor of the term “Exterior Gateway Protocol.”
283 283 EIGRP An acronym for enhanced IGRP , which is routing protocol designed by Cisco that combines the best features of distance-vector and link-state routing protocols. Encapsulation A process in which a packet or frame is enclosed or “wrapped” in a specific protocol header. For example, routers typically perform protocol encapsulation in which packets from one network protocol are wrapped into the header of another network protocol so the packet can be transmitted to a different network. Also called tunneling . Encryption The process of coding a message so that it is incomprehensible to unauthorized users. When retrieved by authorized users, encrypted messages are then reconverted (i.e., decoded) into meaningful text. Encrypted output is called ciphertext . Error Control The process of guaranteeing reliable delivery of data. Error control can be provided through error detection or error correction . Error Correction The process in which a destination node, upon detecting a data transmission error, has sufficient information to correct the error autonomously. Error correction implies error detection . Error Detection The process in which a destination node detects a data transmission error and requests a retransmission from the sending node. Error detection is also called error correction through retransmission . Ethernet A local area network protocol developed jointly by Xerox, Intel, and Digital Equipment Corporation (DEC) at the Xerox Palo Alto Research Center (PARC) in the mid-1970s. The name “Ethernet” was derived from the old electromagnetic theoretical substance called luminiferous ether , which was formerly
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