Network Plus 2005 In Depth

752 Appendix E ANSWERS TO CHAPTER REVIEW QUESTIONS

ANSWERS TO CHAPTER REVIEW QUESTIONS Appendix E 753

754 Appendix E ANSWERS TO CHAPTER REVIEW QUESTIONS

ANSWERS TO CHAPTER REVIEW QUESTIONS Appendix E 755

Chapter 14

1.c

2.a

3.d

4.b

5.a

6.True

7.False

8.False

9.True

10.True

11.denial-of-service attack

12.security policy

13.packet-filtering firewall

14.private key, symmetric

15.IPSec, Internet Protocol Security

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Glossary

1 gigabit per second (Gbps)—1,000,000,000 bits per second.

1 kilobit per second (Kbps)—1000 bits per second.

1 megabit per second (Mbps)—1,000,000 bits per second.

1 terabit per second (Tbps)—1,000,000,000,000 bits per second.

1000BASE-CX—A Physical layer standard for achieving 1-Gbps throughput over twinaxial copper wire. 1000BASE-CX segments are limited to 25 meters, and are useful mainly to connect devices such as servers or switches.

1000BASE-LX—A Physical layer standard for networks that specifies 1-Gbps transmission over fiberoptic cable using baseband transmission. 1000BASE-LX can run on either single-mode or multimode fiber. The “LX” represents its reliance on “long wavelengths” of 1300 nanometers. 1000BASE-LX can extend to 5000-meter segment lengths using single-mode, fiber-optic cable. 1000BASE-LX networks can use one repeater between segments.

1000BASE-SX—A Physical layer standard for networks that specifies 1-Gbps transmission over fiberoptic cable using baseband transmission. 1000BASE-SX runs on multimode fiber. Its maximum segment length is 550 meters. The “SX” represents its reliance on “short wavelengths” of 850 nanometers. 1000BASE-SX can use one repeater.

1000BASE-T—A Physical layer standard for achieving 1 Gbps over UTP. 1000BASE-T achieves its higher throughput by using all four pairs of wires in a CAT 5 or higher twisted-pair cable to both transmit and receive signals. 1000BASE-T also uses a different data encoding scheme than that used by other UTP Physical layer specifications.

100BASE-FX—A Physical layer standard for networks that specifies baseband transmission, multimode fiber cabling, and 100-Mbps throughput. 100BASE-FX networks have a maximum segment length of 2000 meters. 100BASE-FX may also be called Fast Ethernet.

100BASE-T—A Physical layer standard for networks that specifies baseband transmission, twisted-pair cabling, and 100-Mbps throughput. 100BASE-T networks have a maximum segment length of 100 meters and use the star topology. 100BASE-T is also known as Fast Ethernet.

100BASE-TX—A type of 100BASE-T network that uses two wire pairs in a twisted-pair cable, but uses faster signaling to achieve 100-Mbps throughput. It is capable of full-duplex transmission and requires CAT 5 or higher twisted-pair media.

10BASE-2—See Thinnet.

10BASE-5—See Thicknet.

10BASE-F—A Physical layer standard for achieving 10-Mbps throughput over multimode fiber-optic cable. Three different kinds of 10BASE-F exist. All require two strands of multimode fiber, in which one strand is used for data transmission and one strand is used for reception, making 10BASE-F a full-duplex technology.

758 Glossary

10BASE-FL—The most popular version of the 10BASE-F standard. 10BASE-FL is designed to connect workstations to a LAN or two repeaters and can take advantage of fiber-optic repeating technology to reach its maximum segment length of 2000 meters. 10BASE-FL makes use of the star topology, with its repeaters connected through a bus.

10BASE-T—A Physical layer standard for networks that specifies baseband transmission, twisted-pair media, and 10-Mbps throughput. 10BASE-T networks have a maximum segment length of 100 meters and rely on a star topology.

10GBASE-ER—A Physical layer standard for achieving 10-Gbps data transmission over _single-mode, fiber-optic cable. In 10GBASE-ER the “ER” stands for “extended reach.” This standard specifies a star topology and segment lengths up to 40 kilometers.

10GBASE-LR—A Physical layer standard for achieving 10-Gbps data transmission over _single-mode, fiber-optic cable using wavelengths of 1310 nanometers. In 10GBASE-LR, the “LR” stands for “long reach.” This standard specifies a star topology and segment lengths up to 10 kilometers.

10GBASE-SR—A Physical layer standard for achieving 10-Gbps data transmission over multimode fiber using wavelengths of 850 nanometers. The maximum segment length for 10GBASE-SR can reach up to 300 meters, depending on the fiber core diameter and modal bandwidth used.

2.4-GHz band—The range of radiofrequencies from 2.4- to 2.4835-GHz. The 2.4-GHz band is often used for wireless network transmissions.

3DES—See Triple DES.

3-tier architecture—A client/server environment that uses middleware to translate requests between the client and server.

5-4-3 rule—A guideline for 10-Mbps Ethernet networks stating that between two communicating nodes, the network cannot contain more than five network segments connected by four repeating devices, and no more than three of the segments may be populated.

802.11a—The IEEE standard for a wireless networking technique that uses multiple frequency bands in the 5-GHz frequency range and provides a theoretical maximum throughput of 54 Mbps. 802.11a’s high throughput, compared with 802.11b, is attributable to its use of higher frequencies, its unique method of encoding data, and more available bandwidth.

802.11b—The IEEE standard for a wireless networking technique that uses DSSS (direct sequence spread spectrum) signaling in the 2.4–2.4835-GHz frequency range (also called the 2.4-GHz band). 802.11b separates the 2.4-GHz band into 14 overlapping 22-MHz channels and provides a theoretical maximum of 11-Mbps throughput. 802.11b is also known as Wi-Fi.

802.11g—The IEEE standard for a wireless networking technique designed to be compatible with 802.11b while using different encoding techniques that allow it to reach a theoretical maximum capacity of 54 Mbps. 802.11g, like 802.11b, uses the 2.4-GHz frequency band.

802.11i—The IEEE standard for wireless network encryption and authentication that uses the EAP authentication method, strong encryption, and dynamically assigned keys, which are different for every transmission. 802.11i specifies AES encryption and weaves a key into each packet.

802.11—The IEEE standard for wireless networking.

802.15.1—The IEEE standard for wireless personal area network (WPAN) technology, including Bluetooth.

Glossary 759

802.16a—An IEEE standard for wireless MANs that specifies the use of the frequency ranges between 2 and 11 GHz. In IEEE 802.16a, antennas do not require a line-of-sight path between them and can exchange signals with multiple stations at once. 802.16a is capable of achieving up to 70-Mbps throughput and its range is 50 kilometers (or approximately 30 miles).

802.16—An IEEE standard for wireless MANs that specifies the use of frequency ranges between 10 and 66 GHz and requires line-of-sight paths between antennas. 802.16 antennas can cover 50 kilometers (or approximately 30 miles) and connections can achieve a maximum throughput of 70 Mbps.

802.2—The IEEE standard for error and flow control in data frames.

802.3ab—The IEEE standard that describes 1000BASE-T, a 1-Gigabit Ethernet technology that runs over four pairs of CAT 5 or better cable.

802.3ae—The IEEE standard that describes 10-Gigabit Ethernet technologies, including 10GBASESR, 10GBASE-ER, and 10GBASE-LR.

802.3af—The IEEE standard that specifies a way of supplying electrical power over Ethernet (PoE). 802.3af requires CAT 5 or better UTP or STP cabling and uses power sourcing equipment to supply current over a wire pair to powered devices. PoE is compatible with existing 10BASE-T, 100BASE-TX, and 1000BASE-T implementations.

802.3—The IEEE standard for Ethernet networking devices and data handling.

802.3u—The IEEE standard that describes Fast Ethernet technologies, including 100BASE-TX, 100BASE-T4, and 100BASE-FX.

802.3z—The IEEE standard that describes 1000Base (or 1-Gigabit) Ethernet technologies, including 1000BASE-LX, 1000BASE-SX, and 1000BASE-CX.

802.5—The IEEE standard for Token Ring networking devices and data handling.

A+—The professional certification established by CompTIA that verifies knowledge about PC operation, repair, and management.

access method—A network’s method of controlling how nodes access the communications channel. CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is the access method specified in the IEEE 802.3 (Ethernet) standard. CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) is the access method specified by IEEE 802.11 (wireless LAN) standards.

access point—See AP.

access server—See remote access server.

account—A record of a user that contains all of her properties, including rights to resources, password, user name, and so on.

ACK (acknowledgment)—A response generated at the Transport layer of the OSI Model that confirms to a sender that its frame was received. The ACK packet is the third of three in the three-step process of establishing a connection.

acknowledgment—See ACK.

Active Directory—The Windows Server 2003 method for organizing and managing objects associated with the network.

760 Glossary

active monitor—On a Token Ring network, the workstation that maintains timing for token passing, monitors token and frame transmission, detects lost tokens, and corrects problems when a timing error or other disruption occurs. Only one workstation on the ring can act as the active monitor at any given time.

active scanning—A method used by wireless stations to detect the presence of an access point. In active scanning, the station issues a probe to each channel in its frequency range and waits for the access point to respond.

active topology—A topology in which each workstation participates in transmitting data over the network.

ad hoc—A type of wireless LAN in which stations communicate directly with each other (rather than using an access point).

address—A number that uniquely identifies each workstation and device on a network. Without unique addresses, computers on the network could not reliably communicate.

address management—The process of centrally administering a finite number of network addresses for an entire LAN. Usually this task can be accomplished without touching the client workstations.

Address Resolution Protocol—See ARP.

address resource record—A type of DNS data record that maps the IP address of an Internet-connected device to its domain name.

addressing—The scheme for assigning a unique identifying number to every workstation and device on the network. The type of addressing used on a network depends on its protocols and network operating system.

Administrator—A user account that has unlimited privileges to resources and objects managed by a server or domain. The Administrator account is created during NOS installation.

Advanced Encryption Standard—See AES.

AES (Advanced Encryption Standard)—A private key encryption algorithm that weaves keys of 128, 160, 192, or 256 bits through data multiple times. The algorithm used in the most popular form of AES is known as Rijndael. AES has replaced DES in situations such as military communications, which require the highest level of security.

AFP (AppleTalk Filing Protocol or Apple File Protocol)—The native file access protocol used by Macintosh computers.

agent—A software routine that collects data about a managed device’s operation and provides it to the network management application running on the console.

AH (authentication header)—In the context of IPSec, a type of encryption that provides authentication of the IP packet’s data payload through public key techniques.

AIX—A proprietary implementation of the UNIX system distributed by IBM.

alias—A nickname for a node’s host name. Aliases can be specified in a local host file.

AM (amplitude modulation)—A modulation technique in which the amplitude of the carrier signal is modified by the application of a data signal.

American National Standards Institute—See ANSI.

Glossary 761

amplifier—A device that boosts, or strengthens, an analog signal.

amplitude—A measure of a signal’s strength.

amplitude modulation—See AM.

analog—A signal that uses variable voltage to create continuous waves, resulting in an inexact transmission.

ANDing—A logical process of combining bits. In ANDing, a bit with a value of 1 plus another bit with a value of 1 results in a 1. A bit with a value of 0 plus any other bit results in a 0.

ANSI (American National Standards Institute)—An organization composed of more than 1000 representatives from industry and government who together determine standards for the electronics industry in addition to other fields, such as chemical and nuclear engineering, health and safety, and construction.

anycast address—A type of address specified in IPv6 that represents a group of interfaces, any one of which (and usually the first available of which) can accept a transmission. At this time, anycast addresses are not designed to be assigned to hosts, such as servers or workstations, but rather to routers.

AP (access point)—A device used on wireless LANs that transmits and receives wireless signals to and from multiple nodes and retransmits them to the rest of the network segment. Access points can connect a group of nodes with a network or two networks with each other. They may use directional or omnidirectional antennas.

API (application program interface)—A set of routines that make up part of a software _application.

Apple File Protocol—See AFP.

AppleShare IP—A proprietary network operating system from Apple Computer that offers file, print, Web, DNS, and mail services. AppleShare IP was the predecessor to Mac OS X Server.

AppleTalk—The protocol suite used to interconnect Macintosh computers. Although AppleTalk was originally designed to support peer-to-peer networking among Macintoshes, it can now be routed between network segments and integrated with NetWareor Microsoft-based networks.

AppleTalk Filing Protocol—See AFP.

AppleTalk network number—A unique 16-bit number that identifies the network to which an AppleTalk node is connected.

AppleTalk node ID—A unique 8-bit or 16-bit number that identifies a computer on an AppleTalk network.

AppleTalk zone—A logically defined group of computers on an AppleTalk network. application gateway—See proxy server.

Application layer—The seventh layer of the OSI Model. Application layer protocols enable software programs to negotiate formatting, procedural, security, synchronization, and other requirements with the network.

Application layer gateway—See proxy server.

application program interface—See API.

application switch—Another term for a Layer 3 or Layer 4 switch.