Chapter 17

port

(1) As applied to services running on a computer, a number assigned to a process on a computer so that the process can be found by TCP/IP. Also called a port address or port number. (2) Another name for an I/O address. See also I/O address. (3) A physical connector, usually at the back of a computer, that allows a cable from a peripheral device, such as a printer, mouse, or modem, to be attached.

IP address

A 32-bit address consisting of four numbers separated by periods, used to uniquely identify a device on a network that uses TCP/IP protocols. The first numbers identify the network; the last numbers identify a host. An example of an IP address is 206.96.103.114ISDN (Integrated Services Digital Network).

virtual private network (VPN)

A VPN works by using encrypted data packets between a private network and a computer somewhere on the Internet.

Ping (Packet Internet Groper)

A Windows and Unix command used to troubleshoot network connections. It verifies that the host can communicate with another host on the network.

unshielded twisted pair (UTP) cable

A cable that is made of one or more twisted pairs of wires and is not surrounded by shielding.

Internet service provider (ISP)

A commercial group that provides Internet access for a monthly fee. AOL, Earthlink, and CompuServe are large ISPs.

LAN (local area network)

A computer network that covers only a small area, usually within one building.

UDP (User Datagram Protocol)

A connectionless protocol that does not require a connection to send a packet and does not guarantee that the packet arrives at its destination. UDP is faster than TCP because TCP takes the time to make a connection and guarantee delivery.

RJ-45

A connector used with twisted-pair cable that connects the cable to the NIC.

WPA (WiFi Protected Access)

A data encryption method for wireless networks that use the TKIP (Temporal Key Integrity Protocol) encryption method and the encryption keys are changed at set intervals while the wireless LAN is in use.

WEP (Wired Equivalent Privacy)

A data encryption method used on wireless networks that uses either 64-bit or 128-bit encryption keys that are static keys, meaning the key does not change while the wireless network is in use.

WPA2 (WiFi Protected Access 2)

A data encryption standard compliant with the IEEE802.11i standard that uses the AES (Advanced Encryption Standard) protocol. WPA2 is currently the strongest wireless encryption standard.

router

A device that connects one network to another.

network adapter

A device that interfaces a computer with a network.

switch

A device used to segment a network. It can decide which network segment is to receive a packet, on the basis of the packet's destination MAC address.

patch cable

A network cable that is used to connect a PC to a hub, switch, or router.

PAN (personal area network)

A network consisting of personal devices at close range such as a cell phone, PDA, and notebook computer in communication.

hub

A network device or box that provides a central location to connect cables.

WAN (wide area network)

A network or group of networks that span a large geographical area.

MAN (metropolitan area network)

A network the covers a large campus or city.

Institute of Electrical and Electronics Engineers (IEEE)

A nonprofit organization that develops standards for the computer and electronics industries.

RJ-11

A phone jack on a modem card.

intranet

A private network that uses the TCP/IP protocols.

multicasting

A process in which a message is sent by one host to multiple hosts, such as when a video conference is broadcast to several hosts on the Internet.

NAT (Network Address Translation)

A process that converts private IP addresses on a LAN to the proxy server's IP address before a data packet is sent over the Internet.

TDMA (Time Division Multiple Access)

A protocol standard used by cellular WANs and cell phones.

PPP (Point-to-Point Protocol)

A protocol that governs the methods for communicating via modems and dial-up telephone lines. The Windows Dial-up Networking utility uses PPP.

SMTP AUTH (SMTP Authentication)

A protocol that is used to authenticate or prove that a client who attempts to use an email server to send email is authorized to use the server. The protocol is based on the Simple Authentication and Security Layer (SASL) protocol.

subnet mask

A subnet mask is a group of four numbers (dotted decimal numbers) that tell TCP/IP if a remote computer is on the same or a different network.

multiple input/multiple output (MIMO)

A technology used to increase speed and range on a wireless network.

wireless LAN (WLAN)

A type of LAN that does not use wires or cables to create connections, but instead transmits data over radio or infrared waves.

HTTPS (HTTP secure)

A version of the HTTP protocol that includes data encryption for security.

shielded twisted pair (STP) cable

A version of twisted-pair cable popular for cabling local networks. STP uses a covering around the pairs of wires inside the cable that protects it from electromagnetic interference caused by electrical motors, transmitters, or high-tension lines. It costs more than unshielded cable, so it's used only when the situation demands it.

NetBIOS (Network Basic Input/Output System)

An API protocol used by some applications to communicate over a NetBEUI network. NetBIOS has largely been replaced by Windows Sockets over a TCP/IP network.

public IP address

An IP address available to the Internet.

private IP address

An IP address that is used on a private TCP/IP network that is isolated from the Internet.

network interface card (NIC)

An expansion card that plugs into a computer's motherboard and provides a port on the back of the card to connect a PC to a network. Also called a network adapter.

internet card

Another name for an air card. It works like a cell phone to connect to a cellular WAN to give your computer Internet access. The device can be a USB device or can be a card that inserts into a PC Card slot or ExpressCard slot on a laptop.

ThinNet

Another term for 10Base2 Ethernet.

ThickNet

Another term for 10Base5 Ethernet.

port address

Another term for I/O address.

MAC (Media Access Control) address

Another term for an adapter address.

physical address

Another term for an adapter address.

port number

Another term for port.

Wi-Fi (Wireless Fidelity)

Another term for the IEEE 802.11b standard.

latency

Delays in network transmissions.

status light indicators

Most network cards also provide status light indicators near the RJ-45 port. Depending on the card, the lights might indicate the speed of transmission being used among those the card supports, connectivity, and activity.

TCP (Transmission Control Protocol)

Part of the TCP/IP protocol suite. TCP guarantees delivery of data for application protocols and establishes a session before it begins transmitting data.

packet

Segment of network data that also includes header, destination address, and trailer information that is sent as a unit. Also called data packet or datagram.

octet

Term for each of the four 8-bit numbers that make up an IP address. For example, the IP address 206.96.103.114 has four octets.

Telnet

The Telnet protocol is used by the Telnet client/server applications to allow an administrator or other user to control a computer remotely.

HTTP (Hypertext Transfer Protocol)

The communications protocol used by the World Wide Web.

Service Set Identifier (SSID)

The name of the wireless access point.

name resolution

The process of associating a NetBIOS name or host name to an IP address.

SMTP (Simple Mail Transfer Protocol)

The protocol used by e-mail clients and servers to send e-mail messages over the Internet. See POP and IMAP.

TCP/IP (Transmission Control Protocol/Internet Protocol)

The suite of protocols that supports communication on the Internet. TCP is responsible for error checking, and IP is responsible for routing.

POP3 (Post Office Protocol, version 3)

Used by a client to receive e-mail.

NetBIOS name

Used with the NetBIOS protocol. Can be up to 15 characters long.

IMAP4 (Internet Message Access Protocol, version 4)

Version 4 of the IMAP protocol, which is an e-mail protocol that has more functionality than its predecessor, POP. IMAP can archive messages in folders on the e-mail server and can allow the user to choose not to download attachments to messages.