Network & Security

10Base2

10Mbps over coaxial cable up to 185 m

Frame check sequence

A 4-byte CRC value used for error detection. The CRC is performed on the bits from the destination MAC address through the Pad fields. If an error is detected, the frame is discarded.

Start frame delimiter

A binary 8-bit sequence of 1 0 1 0 1 0 1 1 that indicates the start of the frame.

ipconfig /all

A command that enables the MAC address information to be displayed from the command prompt

switch

A device that forwards a frame it receives directly out of the port associated with its destination address

range extender

A device that relays the wireless signals from an access point or wireless router into areas with a weak signal or no signal at all

wireless router

A device used to interconnect wireless networking devices and to give access to wired devices and establish the broadband Internet connection to the ISP

Pad

A field used to bring the total number of bytes up to the minimum of 46 if the data field is less than 46 bytes.

frame

A format that provides grouping of information for transmission

Token Ring hub

A hub that manages the passing of the token in a Token Ring network

hotspots

A limited geographic area that provides wireless access for the public

service set identifier (SSID)

A name that is used to identify your wireless network and is used by your access point or wireless router to establish an association

IP internetwork

A network that uses IP addressing for identifying devices connected to the network

wired network

A network that uses radio signals to establish the network connection

wireless network

A network that uses radio signals to establish the network connection

Token Ring topology

A network topology configured in a logical ring that complements the token passing protocol

overloading

A process in which NAT translates a home network's private IP addresses to a single public IP address

virtual private network (VPN)

A secure network connection that helps protect your LAN's data from being observed by outsiders

OSI model

A seven-layer model that describes network functions

bus topology

A system in which the computers share the media (coaxial cable) for data transmission

token passing

A technique in which an electrical token circulates around a network, and control of the token enables the user to gain access to the network

port address translation (PAT)

A technique that involves tracking a port number with the client computer's private address when translating to a public address

network address translation (NAT)

A technique that involves translating a private IP address to a public address for routing over the Internet

Mesh Topology

A topology in which all networking devices are directly connected to each other

stateful packet inspection (SPI)

A type of firewall that inspects incoming data packets to make sure they correspond to an outgoing request

deterministic

A type of network in which access to the network is provided at fixed time intervals

firewall protection

A type of protection used to prevent unauthorized access to your network

IP address

A unique 32-bit address that identifies on which network a computer is located and differentiates the computer from all other devices on the same network

MAC address

A unique 6-byte address assigned by the vendor of a network interface card

Access point

An access point is used to interconnect wireless devices and provide a connection to the wired LAN. The data transfer speeds for access points are dictated by the choice of wireless technology for the clients, but these devices can support up to Wireless-ac.

Preamble

An alternating pattern of 1s and 0s used for synchronization.

port forwarding

An application of NAT in which packets from one IP address/port number are redirected to another

Length/type

An indication of the number of bytes in the data field if this value is less than 1500. (If this number is greater than 1500, it indicates the type of data format—for example, IP and IPX.)

intranets

An internal network that provides file and resource sharing but is not accessed from the Internet

multiport repeater

Another name for a hub

FTP

Application

HTTP

Application

topology

Architecture of a network

CSMA/CD

Carrier sense multiple access with collision detection, the Ethernet LAN media access method

Mesh

Connects all networking devices directly to each other which provides full redundancy in the network paths

Router

Connects two or more networks using a single connection to the ISP (Internet service provider)

Which of the following issues should be considered when planning for a home network?

Data Speed Public Access Cost

hub

Device that broadcasts the data it receives to all devices connected to its ports

Switch

Establishes a direct connection from the sender to the destination without passing the data traffic to other networking devices

VPN

Establishes a secure network connection and helps protect the LAN's data from being observed by outsiders

A protocol defines the network architecture used to interconnect the networking equipment.

False

Class A

Governments, very large networks 0.0.0.0 to 127.255.255.255

private addresses

IP addresses set aside for use in private intranets

Bus

Includes coaxial cable which is looped through each networking device to facilitate data transfer

Star

Includes twisted-pair cables with modular plugs which are used to connect the computers and other networking devices

IEEE

Institute of Electrical and Electronics Engineers, one of the major standards-setting bodies for technological development

access point

Interconnects wireless devices and provides a connection to the wired LAN

IANA

Internet Assigned Numbers Authority, the agency that assigns IP addresses to computer networks

Wireless network

Involves simple installations Slower data transfer speed within the LAN Inexpensive to set up

The NIC operates at which layer of the OSI model?

Layer 1

Physical layer

Layer 1 of the OSI model, which provides the electrical and mechanical connection to the network

Data link layer

Layer 2 of the OSI model, which handles error recovery, flow control (synchronization), and sequencing

Network layer

Layer 3 of the OSI model, which accepts outgoing messages and combines messages or segments into packets, adding a header that includes routing information

TCP functions at which layer of the OSI model?

Layer 4

Transport layer

Layer 4 of the OSI model, which is concerned with message integrity between source and destination

Session layer

Layer 5 of the OSI model, which provides the control functions necessary to establish, manage, and terminate the connections

Presentation layer

Layer 6 of the OSI model, which accepts and structures the messages for the application

HTTP functions at which layer of the OSI model?

Layer 7

Application layer

Layer 7 of the OSI model, which interacts with application programs that incorporate a communication component such as your Internet browser and email

Which of the following network topology is the most expensive to implement?

Mesh

Class B

Midsize companies, universities, and so on 128.0.0.0 to 191.255.255.255

IP

Network

IPX

Network

IP is an example of a protocol that operates in which layer of the OSI model?

None of these.

Ethernet, Physical, Hardware, or Adapter

Other names for the MAC address

Gateway

Provides high-speed data access via a cable or a telephone company's DSL connection

Wired network

Requires the use of specialized tools Faster network data transfer speed

Class D

Reserved for multicast groups 224.0.0.0 to 239.255.255.255

protocol

Set of rules established for users to exchange information

Class C

Small networks 192.0.0.0 to 223.255.255.255

Which of the following network topology requires every host to be connected to the central switch/hub?

Star

How do the IP address and MAC address differ?

The MAC address provides the physical address of the network interface card while the IP address provides the network location.

MAC address

The associated MAC address, which is 6 bytes (12 hex characters) in length.

network interface card

The electronic hardware used to interface a computer to a network

organizationally unique identifier (OUI)

The first 3 bytes of the MAC address that identifies the manufacturer of the network hardware

star topology

The most common networking topology in today's LANs, where all networking devices connect to a central switch or hub

ports

The physical input/output interfaces to networking hardware

host number

The portion of an IP address that defines the location of a networking device connected to the network; also called the host address

network number

The portion of an IP address that defines which network an IP packet is originating from or being delivered to

Destination MAC address and source

The unique media access control address associated with each computer's Ethernet network interface card (NIC) or network adapter.

Data

The variable length of data being transferred from the source to the destination.

DSL modem

This device is used to make a broadband network connection from your home network to the ISP using the telephone line. Broadband access to the Internet is provided via the phone company or a separate ISP. The DSL connection requires the placement of filters on all telephone lines except the one going into the modem to prevent interference.

Cable modem

This device is used to make a broadband network connection from your home network to the ISP, using your cable connection. This setup requires a splitter to separate the cable TV from the home network. Access to the Internet is typically provided by the cable TV service provider.

802.11ac (Wireless-AC)

This is the latest wireless standard. It provides single-station data transfer rates of 1.3Gbps and operates in the 5GHz frequency band.

802.11n (Wireless-N)

This is the next generation of high-speed wireless connectivity promising data transfer rates over 200+ Mbps. It operates at 2.4 Ghz and also 5 GHz. (Modulation - DSSS or OFDM)

802.11b (Wireless-B)

This standard can provide data transfer rates up to 11Mbps, with ranges of 100-150 feet. It operates at 2.4GHz.

802.11a (Wireless-A)

This standard can provide data transfer rates up to 54Mbps and an operating range up to 75 feet. It operates at 5GHz.

802.11g (Wireless-G)

This standard can provide data transfer rates up to 54Mbps up to 150 feet. It operates at 2.4GHz.

Broadband modem/gateway

This type of device is used to provide high-speed data access via your cable connection or via a telephone company's DSL connection. A gateway combines a modem and a router into one network box.

TCP/IP

Transmission Control Protocol/Internet Protocol, the protocol suite used for internetworks such as the Internet

broadcast

Transmission of data by a hub to all devices connected to its ports

TCP

Transport

The MAC address on a Windows computer can be accessed by typing ipconfig /all at the command prompt.

True

Wi-Fi

Wi-Fi close Wi-Fi Alliance—an organization that tests and certifies wireless equipment for compliance with the 802.11x standards

local area network (LAN)

a network of users that share computer resources in a limited area.