Networking Essentials - Chapter 1 Test

OSI Layer 7

*Application Layer* Interacts with *network aware* application programs that incorporate a communication component such as Internet browsers and email servers. *Technology:* Transfer Protocol (HTTP) for web browsing, File Transfer Protocol (FTP) for transferring files, and Simple Mail Transfer Protocol (SMTP) for email transmission.

Securing the Home Network

*Change the default factory passwords* *Change the default Service Set Identifier* (name used to identify the wireless network) *Turn encryption on* -Wired Equivalent Privacy (WEP) -Wi-Fi Protected Access (WPA) -WPA2: *stronger encryption than WPA and is also backward compatible with adapters using WPA* *Turn Off the SSID Broadcast* *Enable MAC Address Filtering* - Network device will not allow devices to connect unless the MAC address is registered and recognized. *FirewaLLProtection* - Used to prevent unauthorized access to your network. *Stateful Packet Inspection (SPI)* - Type of firewall that inspects incoming data packets to make sure they correspond to an outgoing request. *Virtual Private Network (VPN)* - Establishes a secure network connection and is a way to protect your LAN'sdata from being observed by outsiders.

OSI Layer 2

*Data Link Layer* Handles error recovery, Flow control (i.e. synchronization) and sequencing. *Protocol(s):* Media Access Control (MAC) address is defined, 802.3 standardization. *Device(s):* Bridges and Layer 2 Switches.

IANA

*Internet Assigned Numbers Authority* The agency that assigns IP addresses to computer networks and makes sure no two different networks are assigned the same IP network address.

ICMP

*Internet Control Message Protocol* Echo requests and replies to test that a device on the network is reachable. The ICMP protocol verifies that messages are being delivered.

IPv4

*Internet Protocol version 4* The current TCP/IP addressing technique being used on the Internet. *Address space for IPv4 is quickly running out due to the rapid growth of the Internet and the development of new Internet-compatible technologies*.

NAT

*Network Address Translation* Translate the private IP address to a public address for routing over the internet.

NIC

*Network Interface Card* An OSI Layer 1 device that allows network connection between devices or computers. The NIC contains a unique network address called the MAC address.

OSI Layer 3

*Network Layer* Accepts outgoing messages and combines messages or segments into packets, adding a header that includes routing information. *Device(s):* Router (think routing data packets) *Protocol(s):* Internet Protocol (IP) and Internetwork Packet Exchange (IPX).

OSI

*Open Systems Interconnect* Developed by the International Organization of Standardization. A standard that was developed to ensure that all software and hardware components within a network will communicate regardless of country, make, or model.

OSI Layer 1

*Physical Layer* Provides electrical and mechanical connections to a network. *Device(s)*: EIA/TIA related technologies, UTP, Coaxial, fiber, Layer 1 Switches, Hubs, and NICs.

PAT

*Port Address Translation* A port number is tracked with the client computer's private address when translating to a public address.

OSI Layer 6

*Presentation Layer* Accepts and structures the messages for the application. It *translates* the message from one code to another if necessary. This layer is responsible for data compression and encryption. *Technology:* American Standard Code for Information Interchange (ASCII) and Joint Photographic Experts Group (JPEG).

OSI Layer 5

*Session Layer* Provides the control functions necessary to establish, manage, and terminate the connections *Technology:* Network File System (NFS) and Structured Query Language (SQL).

TCP/IP

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

OSI Layer 4

*Transport layer* Concerned with message integrity between source and destination. It also segments/reassembles (the packets) and handles flow control. *Device(s):* Firewalls *Protocol(s):* Transmission Control Protocol (TCP) - Connection Oriented; and User Datagram Protocol (UDP) - Connectionless Oriented

Wi-Fi

*Wireless Fidelity* Wifi Alliance is an organization whose function is to test and certify wireless equpment for compliance with 802.11x standards.

802.11a

*Wireless-A* Transfer Rate: 54 Mbps Range: 75 Feet Frequency: 5 GHz

802.11b

*Wireless-B* Transfer Rate: 11 Mbps Range: 100-150 Feet Frequency: 2.4 GHz

802.11g

*Wireless-G* Transfer Rate: 54 Mbps Range: 150 Feet Frequency: 2.4 GHz

802.11ac

*Wireless-N* Transfer Rate: 200+ Mbps Range: 150 Feet Frequency: 2.4 GHz

802.11n

*Wireless-N* Transfer Rate: 200+ Mbps Range: 150 Feet Frequency: 2.4 GHz

1000BaseFX

1000Mbps over fiber

1000BaseT

1000Mbps over twisted-pair

100BaseFX

100Mbps over fiber

100BaseT

100Mbps over twisted-pair (also called Fast Ethernet)

lOGE

10GB Ethernet

10BaseFL

10Mbps over 850 nm multi mode fiber-optic cable

10Base2

10Mbps over coaxial cable up to 185 m, also called ThinNet (seldom used anymore)

10Base5

10Mbps over coaxial cable up to 500 m, also called ThickNet (seldom used anymore)

10BaseF

10Mbps over multimode fiber-optic cable

10BaseT

10Mbps over twisted-pair

Packet Trailer

A *4-byte* cyclic redundancy check (eRC) value used for error checking.

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.

IP Internetwork

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

Token Ring Topology

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

Ethernet

A protocol (not a cable) that is commonly used in modern networks. It is a carrier sense multiple access with collision detection (*CSMA/CD*) protocol for local area networks.

Uplink-port

A straight-through port that allows the connection of a hub or switch to another hub or switch without having to use a crossover cable.

Token Passing

A technique where an electrical token circulates around a network-control of the token enables the user to gain access to the network

ThinNet

A type of coaxial cable used to connect LANsconfigured with a bus topology

IPv4 Classes

A.B.C.D where the A.B.C.D values are written as the decimal equivalent of the 8-bit binary value. The range for each of the decimal values is 0-255.

Deterministic

Access to the network is provided at fixed time intervals

Packet Data

Actual data being transmitted, followed by the pad used to bring the total number of bytes up to the minimum of 46 if the data field is less than 46 bytes

Intranet

An internal network that provides file and resource sharing but is not accessed from the Internet. However, these addresses can be used within a private LAN (intranet) to create an IP internetwork.

The ping -t ip address command (select all that apply) A.) Pings the host at the specified IP address until it is stopped. B.) Pings the MAC address of the host at the specified IP address. C.) Allows the ping to pass through routers. D.) Allows the ping command to be executed from the command prompt.

Answer: *A.)* Pings the host at the specified IP address until it is stopped. *C.)* Allows the ping to pass through routers. *D.)* Allows the ping command to be executed from the command prompt.

The network administrator needs to verify a network connection. Which of the following steps should be taken? (select two) A.) Verify the link lights. B.) Use the ping command to verify network connectivity. C.) Perform an ARP request. D.) Ping the MAC address.

Answer: *A.)* Verify the link lights. *B.)* Use the ping command to verify

TCP functions at which layer of the OSI Model? A.) Layer 4 B.) Layer 2 C.) Layer 3 D.) Layer 5 E.) Layer 7

Answer: *A.)*

The MAC address on a Windows computer can be accessed by typing ipconfig /all from the command prompt. A.) True B.) False

Answer: *A.)*

The NIC operates at which layer of the OSI model? A.) Layer 1 B.) Layer 3 C.) Layer 5 D.) Layer 7 E.) All answers are correct

Answer: *A.)*

The OUI for the MAC address OO-lO-A4-13-99-2E is 13992E. A.) True B.) False

Answer: *B.)*

What is NAT? A.) Network Asynchronous Transfer B.) Network Address Translation C.) Network Address Transfer D.) None of these answers are correct

Answer: *B.)* Network Address Translation

HTTP functions at which layer of the OSI Model? A.) Layer 6 B.) Layer 5 C.) Layer 4 D.) Layer 7 E.) All answers are correct

Answer: *D.)*

How do the IP address and MAC address differ? (select one) A.) They are the same B.) the MAC address is only used in LANs C.) the IP address is only used on the Internet D.) The MAC address provides the physical address of the network interface card.

Answer: *D.)*

Which of the following are examples of wireless technologies? A.) 802.lla B.) 802.11g C.) 802.1ln D.) All of these answers are correct

Answer: *D.)* All of these answers are correct

Which of the following issues should be considered when planning for a home network? A.) Data speed B.) Public access C.) Cost D.) All of these answers are correct

Answer: *D.)* All of these answers are correct

How does MAC address filtering help to secure a wireless network? A.) This is used to help prevent the theft of network interface cards. B.) This requires an additional login step requiring the user to enter his MAC address. C.) MAC address filtering is seldom used anymore because of NIC restrictions. D.) This can be used to select which networking devices can be allowed access to the network.

Answer: *D.)* This can be used to select which networking devices can be allowed access to the network.

IP is an example of a protocol that operates at which layer of the OSI Model? A.) Layer 7 B.) Layer 6 C.) Layer 5 D.) Layer 2 E.) All answers are correct

Answer: *E.)* - Layer 3 would be the correct layer

Topology

Architecture of a network

ipconfig /all Command

Command used to display the computer's address including the MAC address.

ipconfig Command

Command used to display the computer's address.

Ping Command

Command used to test that a device on the network is reachable.

OSI Model

Consists of *7 layers* with each layer describes a network function. 1.) Physical 2.) Data Link 3.) Network 4.) Transport 5.) Session 6.) Presentation 7.) Application

Network Setup Considerations

Data Speed Cost Ease of Implementation Appearance Home Access Public Access

Wireless Router

Device used to interconnect wireless networking devices and give access to wired devices and establish the broadband Internet connection to the ISP using radio frequency **combination of three or more devices: Wireless access point, switch, and router (sometimes even the modem)

Range Extender

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

Network Adapter

Establish connection to a network via a wireless adapter or by a physical adapter called a NIC *OSI Layer 1 Device*

Private Addresses

IP addresses set aside for use in private intranets. Three address blocks for the private IP addresses are as follows: 10.0.0.0-10.255.255.255 172.16.0.0-172.31.255.255 192.168.0.0-192.168.255.255

Link light

Indicates that the transmit and receive pairs are properly aligned.

Mbps

Mega*bits* per second

Broadband Modem/Gate

Networking device that allows high speed data access via cable connection or telephone's company DSL connection.

link Integrity Test

Protocol used to verify that a communication link between two Ethernet devices has been established.

Packet

Provides grouping of information for transmission Includes a header, data, and trailer The minimum length of the Ethernet frame is 64 bytes from the destination MAC address through the frame check sequence. The *maximum Ethernet frame length is 1,518 bytes*; 6 bytes for the destination MAC address; 6 bytes for the source MAC address; 2 bytes for length/type; and 1,500 bytes for the data.

MAC Address

Provides the physical address for the network interface card but provides no information as to its network location. A unique *6-byte*, or *48 bits*, address assigned by the vendor of the network interface card. The address is displayed in 12 hexadecimal digits with the first 6 digits identifying the manufacture. *Example:* OO-lO-A4-13-99-2

Link Pulses

Sent by each of the connected devices via the twisted-pair cables when data is not being transmitted to indicate that the link is still up.

Protocol

Set of rules established for users to exchange information.

RJ-45

The 8-pin modular connector used with CAT6/5e/5 cable

CSMA/CD

The Ethernet LAN media-access method, carrier sense multiple access with collision detection

Bus Topology

The computers share the media (coaxial cable) for data transmission.

Packet Header

The header consists of the preamble, start frame delimiter, destination and source addresses, and length/type field.

Ports

The interface for the networking devices switch inputs marked with an "x" or uplink port indicate that these devices are cross-connected, meaning the transmit and receive pairs on the twisted-pair cable are crossed to properly align each for data communication.

Star Topolog

The most common networking topology in tcday's LANswhere all networking devices connect to a central switch or hub.

Star Topology

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

Host Number

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

Network Number

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

Straight-through

Transmit and receive signal pairs are aligned end-to-end.

Crossover

Transmit and receive signal pairs are crossed to properly align the transmit signal on one device with the receive signal on the other device.

CAT6 Cable

Twisted-pair cables capable of carrying up to 10000Mbps (10 gigabits) of data at 250 Mhz up to a length of 100 meters (Max data transfer rate at 55 meters)

CAT5E Cable

Twisted-pair cables capable of carrying up to 1000Mbps (1 gigabit) of data at 350 Mhz up to a length of 100 meters (Max data transfer rate at 50 meters)

CAT5 Cable

Twisted-pair cables capable of carrying up to 100Mbps of data at 100 MHz up to a length of 100 meters

CAT3 Cable

Twisted-pair cables capable of carrying up to 10Mbps of data at 16 MHz up to a length of 100 meters

IP Addressing

Unique *32-bit* address that identifies on which network the computer is located as well as differentiates the computer from all other devices on the same network. Divided into four *8-bit* parts. IP addresses are classified as either IPv4 or IPv6.

Access Point

Used to interconnect *wireless* devices and provide a connection to the wired LAN

Hub

Used to interconnect networking devices. Broadcasts information to ALL devices connected to the device. *OSI Layer 1 Device*

Switch

Used to interconnect networking devices. Establishes a direct connection from he sender to the destination without passing the data traffic to other networking devices. *OSI Layer 1 and Layer 2 device*

Overloading

Where NAT translates the home network's private IP address to a single public IP address.

802.11x Standard

Wireless standards developed by the Institute of electrical and Electronics Engineers.