Cisco Computer Networking

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zip code Stands for zone improvement plan. It's a five-or nine-digit decimal number that the U.S. Postal Service uses for fast, easy, high-speed sorting of mail. [full story]

wall plate A rectangular plastic mold that is used to cover a hole in a wall. The wall plate has a plug in it, into which a networking cable can be connected. The hidden side of the wall plate also has ... [full story]

VC (virtual circuit) A logical concept that represents the path that frames travel between Frame Relay DTEs. VCs are particularly useful when comparing Frame Relay to leased physical circuits. vendor consortium An organization of vendors who have similar goals and who ... [full story]

UDP (User Datagram Protocol) A TCP/IP transport layer protocol that provides basic transport services but does not provide error recovery. unicast address An Ethernet MAC address that represents a single NIC. uniform resource locator (URL) See [URL]unshielded twisted-pair (UTP) See ... [full story]

T1 circuit See [T/1 line]T1 line A 4-wire circuit that runs at 1.544 Mbps and is composed of 24 channels at 64 Kbps each, plus 8 Kbps of management overhead. TACACS+ ... [full story]

sales engineer (SE) See [SE]SE (sales engineer) A person who sells a company's products or services, with focus on the engineering or technical aspects of the sale. segment See [TCP segment]segmentation The process by which an application gives TCP some data, ... [full story]

RADIUS A TCP/IP standard protocol that routers and AAA servers use to exchange AAA information. remainder In an algorithm in Appendix B, "Converting IP Addresses Between Decimal and Binary," this term represents the result of subtracting one number from another. ... [full story]

packet A group of bits that are combined for transmission in a network. This term specifically refers to the header and data defined by OSI layer 3 (network) layer protocols. PAP (Password Authentication Protocol) A component protocol of PPP, used to ... [full story]

object In the context of WWW, an object is a single file that can be transferred using HTTP. Web pages consist of one or more objects, with more complex single web pages containing hundreds of objects. octet A different generic term ... [full story]

name resolution The process of finding an IP address that corresponds to a known name. Netscape The name of a popular web browser software product, more fully named Netscape Navigator. The product was originally written by a company called Netscape and ... [full story]

MAC (Media Access Control) Another name for 802.3. MAC address Another name for Ethernet Address. MAC address table A table containing a list of MAC addresses and the physical switch ports out which a switch should forward frames that are destined ... [full story]

LAN (local-area network) A network that by definition includes components that are relatively near to each other, typically in the same building. LAN legal A term created just for this book to make an analogy to having a car be "street ... [full story]

Kbps (kilobits per second) Units that describe the speed at which data is sent over some communication media. Kbps represents 1000 bits in 1 second; for example, 2 kbps is 2000 bits per second. Kerberos A TCP/IP standard protocol used to ... [full story]

jamming signal An electrical signal specified by Ethernet standards that is sent when a collision occurs to ensure that all devices realize a collision took place. [full story]

IDS(intrusion detection system) A device or software that examines packets that are allowed by a firewall, looking for things that a cracker might use to deny service or to place a virus on a computer. IDS signature A set of characterizations ... [full story]

hacker A person who attempts to access networks and computer systems, but without malicious intent. half duplex Logic used by a device on a LAN, for which it chooses to either send or receive a frame at a point in time, ... [full story]

gateway A term for a myriad of networking devices that generally convert from one standard to another. Gbps Acronym for gigabit per second. GE (Gigabit Ethernet) Defined by IEEE 802.3z and IEEE 802.3ab, it specifies Ethernet with a transmission speed of ... [full story]

Fast Ethernet (FE) See [FE]FCS (frame check sequence) A field in an data link protocol trailer that allows the receiver of a frame to determine whether the frame had errors during transmission. FE (Fast Ethernet) Defined by IEEE 802.3u, FE specifies ... [full story]

EIGRP (Enhanced Interior Gateway Routing Protocol) An IP routing protocol, defined by Cisco, making it proprietary. It is an enhanced version of IGRP. electrical cabling Cabling that includes copper wires inside the cable so that electricity can be sent over the ... [full story]

data-link connection identifier (DLCI) See [DLCI]decimal digit In mathematics, a digit or numeral that is part of a number based on the decimal numbering systemnamely 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. decimal numbering system In mathematics, ... [full story]

cable A long, somewhat cylindrical piece of plastic, often used to enclose some wires. canonical A shortened version of the term canonical format. canonical format A term referring to the format of TCP/IP addresses when written in decimal. carrier sense ... [full story]

bandwidth Jargon that generally refers to the speed at which bits can be sent across a physical link. BGP (Border Gateway Protocol) An IP routing protocol, defined in RFCs, making it a public protocol. BGP is used mainly to exchange routing ... [full story]

Glossary A 1s digit In mathematics, in a number with multiple digits or numerals, this is the digit on the far-right end of the multidigit number. This digit represents the value of the digit times 1. 4-wire circuit A reference to ... [full story]

Binary/Decimal Conversion Chart Decimal Value Binary Value Decimal Value Binary Value 0 0000 0000 23 0001 0111 1 0000 0001 24 0001 1000 2 0000 0010 25 0001 1001 3 0000 0011 26 0001 1010 4 0000 0100 27 0001 1011 5 0000 0101 28 0001 1100 6 0000 0110 29 0001 1101 7 0000 0111 30 0001 1110 8 0000 1000 31 0001 1111 9 0000 1001 32 0010 0000 10 0000 1010 33 0010 0001 11 0000 1011 34 0010 0010 12 0000 1100 35 0010 0011 13 0000 1101 36 0010 0100 14 0000 1110 37 0010 0101 15 0000 1111 38 0010 0110 16 0001 0000 39 0010 ... [full story]

Using a Conversion Chart Now you understand the basics of how decimal and binary work and how to convert between the two. You also know a few rules you must follow when converting IP addresses between the two formats. You can always ... [full story]

Conversion of Binary IP Address to Decimal   First Octet Second Octet Third Octet Fourth Octet Binary value, separated into 4 octets (Step 1) 01100100 11101011 00000001 00000001 Each octet converted to decimal (Step 2) 100 235 1 1 Decimal IP address in dotted decimal format (Step 3) 100.235.1.1 The resulting IP address, with the periods added, ... [full story]

Converting Binary IP Addresses to Decimal IP Addresses To convert from a binary IP address to its decimal equivalent, you already know the 32-bit IP address. The process is rather simple compared to converting from decimal to binary: Step 1. Separate the 32 ... [full story]

Conversion of Decimal IP Address 100.235.2.2 to Binary   First Octet Second Octet Third Octet Fourth Octet Decimal octet 100 235 2 2 Each octet converted to binary (Step 1) 1100100 11101011 10 10 Binary octets, after putting 0s in front (Step 2) 01100100 11101011 00000010 00000010 Resulting 32-bit number (Step 3) 01100100111010110000001000000010 Table B-15 begins with the decimal IP address in ... [full story]

Converting Decimal IP Addresses to Binary IP Addresses You have already read about the math behind the conversion process between decimal and binary. To convert IP addresses, you simply need to follow a few additional rules: 1. When converting from a decimal ... [full story]

Converting IP Addresses IP addresses are 32-bit binary numbers, but because humans would find it inconvenient to write down 32-bit numbers, the addresses are written in decimal. The format of decimal IP addresses is often called canonical format, and sometimes called ... [full story]