Comptia A+ Chapter 6 - Networking Fundamentals

What ethernet specification would you be running if you needed to make a connection of 10Gbps over a distance of five kilometers?

10GBaseER

BNC coaxial cable connectors are used in _______ ethernet networks

10base2 Ethernet networks

You have been asked to configure a full mesh network with seven computers. How many connections will this require?

21 Formula: (x * (x-1)) divided by 2

Blue-tooth devices can communicate with up to ___ other devices in one piconet

7

If your wireless network supports 802.11 b/g/n, make sure to get an ___ card

802.11n

Name three IEEE 802 standards

802.3 CSMA/CS (Ethernet) LAN 802.5 Token Ring LAN 802.11 Wireless Networks

What is a NOS?

A Network Operating System controls the communication with resources and the flow of data across the network

Fiber-Optic cables come in two varieties:

Single-mode fiber (SMF) & Multi-mode Fiber (MMF)

What is a bridge?

A bridge divides network segments and brings together different topologies into a single network. Only recognizes MAC addresses

What is a switch?

A connectivity device that forwards packets to a specific port based on its MAC address. Disadvantage: Switches forward broadcasts because they are addressed to everyone.

What is a server?

A device that serves up resources to a network Ex: email, web, files

What is a firewall?

A hardware or software security barrier that prevents unauthorized access to or from private networks

In networking, what is media? Provide an example.

A method to interconnect wired or unwired devices Copper cable, fiber optic, WiFi

What is hybrid typology?

A mix of typologies

What is a repeater or extender?

A repeater or extender is a small device that amplifies a signal. Repeaters boost signals, extenders receive signal & pass it on with the same strength

What is a dedicated server?

A server assigned to one specific service for the network and nothing else.

What is a nondedicated server?

A server assigned to provide more than one network service

Which of the following statements are not associated with a star network? (choose all that apply) A. A single cable break can cause complete network disruption B. All devices connect to a central device C. It uses a single backbone computer to connect all network devices D. It uses dual-ring configuration

A, C, D

What is the most commonly installed network topology used today?

Star topology

What is Star Topology?

Star topology uses a network device like a hub or a switch for computers to branch off of.

What type of coaxial cable is recommended for digital television cable signals? A. RG-6 B. RG-8 C. RG-58 D. RG-59

A. RG-6 The two RG standards used for television are RG-6 and RG-59. RG-6 is better and can handle digital signals. RG-59 is for analog signals only. RG-8 is thicknet coax and RG-59 is thinnet coax

Acronym for the OSI Model?

All People Seem To Need Data Processing

What is an EoP adapter? When is it useful?

An Ethernet over Power adapter is an auxiliary device that uses an ethernet cable plugged into an adapter & electrical outlet to power the device. To work, both devices need to be on the same circuit/outlet. Useful when a device only has an RJ-45 port.

What is a peer-to-peer resource model?

An inexpensive network without a server that is generally recommended for small networks with no larger than 10 clients.

What is a router?

An intelligent device that connects multiple network types together & examines each packet of data it receives and then decides which is the best destination to send the packets to based on IP addressing. Stores network addresses in routing tables

What is a resource?

Any item that can be used on a network

What is an access point?

Any point that allows a user on to a network.

Transmitting at 10Gbps, how far can signals on an MMF cable travel? A. 100 meters B. 550 meters C. 1 kilometer D. 40 kilometers

B. 550 meters

What are the five primary topologies?

B.M.R.S.H. Bus, Star, Ring, Mesh, Hybrid

What is a patch panel?

Basically a hub but larger. Can house multiple cable connections but has no intelligence.

PAN is most commonly associated with __ networks

Bluetooth

Which of the following wireless communication standards is often described in terms of wireless personal area network?

Bluetooth

Which of the following devices work at layer 2 of the OSI model? A. Hub B. Router C. Switch D. Bridge

Bridge & switch Note that some switches are called multilayer switches, and they work at layer 3 as well

What is the main disadvantage of using a bridge?

Bridges forward broadcast packets to all computers.

What is bus topology?

Bus topology is simple and consists fo a single cable that's sequentially connected to every workstation.

What is the major advantage and disadvantage of using bus topology?

Bus topology is the cheapest to install but is difficult to maintain or troubleshoot. If a cable breaks, the whole network is disrupted.

Which IEEE 802 standard defines a bus topology using coaxial baseband cable and is able to transmit at 10Mbps? A. 802.1 B. 802.2 C. 802.3 D. 802.5

C - 802.3 802.5 is token ring which is a ring topology 802.11 is wireless networks

_______________ is the type of media access method used by NICs that listen to or sense the cable to check for traffic and send only when they hear that no one else is transmitting. A. Token passing B. CSMA/CD C. CSMA/CA D. Demand priority

CSMA/CD

What does CSMA/CD stand for?

Carrier Sense Multiple Access with Collision Detection Carrier sense = means that computers on the network are always listening to the wire. Multiple access = means that multiple computers have access to the line at the same time. Collision detection = when two senders send information at the same time, a collision happens so collision detection lets each sender know to resend the information. 802.3

Workstations are also known as ____.

Client computers

What are the three main types of wireless network cables?

Coaxial Twisted-pair Fiber-optic

Local Area Network (LAN) connects...

Connects a group of computers in close proximity/ small geographic area, such as in an office building, school, or home. Usually used as a business setting.

What does a modem do?

Connects to a network using plain old phone lines & a dial-up connection. They modulate/demodulate signals from the computer into analog signals that can be used over telephone lines.

Coaxial cable contains a center conductor core made of ____.

Copper.

What level of the OSI model does a switch operate on?

Data Link Layer (2)

Of all network cabling options,_______________ offers the longest possible segment length. A. Unshielded twisted-pair B. Coaxial C. Fiber-optic D. Shielded twisted-pair

Fiber-optic

NIC's send data using which two modes?

Full-duplex mode half-duplex mode

What is the major advantage of mesh topology?

High fault tolerance.

Software firewall is ___ based firewall.

Host based firewall - it only protects the host computer.

A physical star topology consists of several workstations that branch off a central device called a

Hub

The technical specification IEEE ______ describes a WPAN based on _____

IEEE 802.15.1 describes a WPAN (wireless personal area network) based on a Bluetooth version 1.1

What are major advantages of star topology?

If a computer goes down, It doesn't affect the entire network, however, if the central device does down, the entire network goes down with it.

Physical Layer

Layer 1 - Refers to all physical things that connect the computer together. (Ex. network cable being disconnected) Describes how the data gets transmitted over a communication medium. This layer relates electrical, optical, mechanical, and functional interfaces to the cable.

Data Link Layer

Layer 2 - The layer that bridges & switches operate on. Also the layer where MAC addresses reside. This layer arranges the data into chunks called frames. Included in these chunks is control information indicating the beginning and end of the data stream. This layer is very important because it makes transmission easier and more manageable and it allows for error checking within the data frames. The data link layer is actually subdivided into two sections: (MAC) Media access control and (LLC) Logical link control.

On what level of the OSI model does a bridge operate?

Layer 2/ Data Link Layer. Because they work at the data link layer, they are aware only of hardware MAC addresses. They don't recognize IP addresses.

What level of the OSI model does a router operate on?

Layer 3 - Networking bc it recognizes IP addresses

Network Layer

Layer 3 - The layer that routers and IP addresses operate on. Responsible for the routing of messages to their proper final destination. At this layer, the data is organized into chunks called packets. Also manages traffic though packet switching, routing, and controlling congestion of data.

Transport Layer

Layer 4 - Decides how much information should be sent at one time. Controls data flow and troubleshoots problems relating to data. The TCP protocol verifies that the destination host has received all packets at this layer.

Session Layer

Layer 5 - The layer that deals with communication, creating a session between two computers. So when you visit a website, the computer creates a session with the web server that you're trying to access and get data from. For example, all of the procedures needed to transfer a single file make up one session. Once the session is over, a new process beings. This layer enables network procedures, such as identifying passwords, logons, and network monitoring

Presentation Layer

Layer 6 - The layer that the operating system is on. Manages encryption, presentation of data, and translation of character sets.

Application Layer

Layer 7 - The layer that the user is actually interacting with. The layer application operate at. Ex: Firefox.

Each network interface card (NIC) has a unique hardware address called a

MAC address. (Media access control) No two NIC's can have the same MAC address bc they wouldn't be able to communicate.

Wireless hotspots in a city would be considered what type of network?

MAN (Metropolitan Area Network)

A ___ is bigger than LAN but not as big as WAN.

MAN (metropolitan area network)

Ethernet Specifications

MEMORIZE BLUE TABLE FROM BLUE PPT SLIDE!!!

Which of the following connector types is an MFF connector? A. BNC B. ST C. SC D. LC

MFF = mini-form factor LC

What is a mesh topology? Major disadvantage?

Mesh topology is a setup wherein each device is connected directly to every other device on the network. Consequently, it requires a lot of cabling and can be very expensive.

Name the different types of Fiber-optic connectors

Most commonly used - ST (Straight tip) uses a BNC attachment type that makes if easy to connect/disconnect SC - Subscriber connector (AKA Square connector) - uses a latch LC - Local Connector. Mini form factor that looks like a mini, grey SC.

What do Network Devices do? Provide an example of a network device.

Network devices create the network. Switches, routers, access points

What model is used to provide a common way to describe network protocols? A. OSI B. ISO C. IEEE D. CSMA/CD

OSI

What are the two types of hubs? Main difference between the two?

Passive hub - connects all ports but doesn't have a power source Active hub - use electronics to amplify signal before broadcasting to other ports. Main difference between the two: Active hubs extend the length of a network. Passive hubs can't

In which network design do users access resources from other workstations rather than from a central location? A. Client-server B. Star C. Ring D. Peer-to-peer

Peer-to-Peer. Peer-to-peer networks have no servers so all resources are shared from various workstations.

Repeaters and extenders work at which OSI model layer?

Physical layer 1

What does PVC stand for and what does it do?

Polyvinyl chloride. It's plastic that covers common network cables and produces poisonous fumes when burned.

What does a NIC do?

Provides the physical connection to the network by preparing and sending data, as well as controlling the flow of data.

What is Power over Ethernet (PoE)?

Technology that provides power and data transmission through a single network cable.

To avoid poisonous fumes, cables hidden in walls need a ____ coating & are called ___.

Teflon; Plenum-rated.

Coax cables are rated according to the ____ system

RG (radio guide) system

Name the 4 types of coaxial cables

RG-6 RG-8 RG-58A/U RG-59

Unshielded Twister Pair (UTP) uses which type of RJ connector?

RJ-45. RJ-11 isn't even used in networking.

Servers are never shut down unless you have ___.

Redundancy

What devices transfer packets across multiple networks and use tables to store network addresses to determine the best destination?

Routers

What does IEEE stands for? What does this committee do?

The Institute of Electrical and Electronics Engineers creates standards for network types

What is a logical model explaining how network systems are supposed to communicate to each other?

The OSI Model (open systems interconnection)

What was established in 1984 to provide a common way of describing network protocols?

The OSI model (Open Systems Interconnection)

OSI Model Layers

"All People Seem to Need Data Processing" "Please Do Not Throw Sausage Pizza Away" Application, Presentation, Session, Transport, Network, Data Link, Physical

The IEEE 802 standard breaks the Data Link Layer into what two sublayers?

(LLC) Logical Link Control sublayer (MAC) Media access control sublayer

What is another name for NIC?

(Network Interface Card) Network adapter card

Name the two types of Twisted Pair cables and their differences

(STP) Shielded Twisted Pair - Has an extra layer of braided foil shielding around the wires to decrease electrical interference. (UTP) Unshielded Twisted Pair - Has PVC or plenum coating but no outer shield to protect it from interference.

Each station in a peer-to-peer network must be administered ___. For this reason, the network is not very ____.

Separately; secure

Name different types of connectivity devices

-Modem -access point -repeater & extender -patch panel -bridge -hub -switch -router

What is the Client-Server Resource Model?

The client-server resource model is the model recommended for large networks (larger than 10 computers) who emphasize security and constant network access.

What is a Client? Provide examples.

The device the user uses to access the network. PC, smartphone

What is a hub?

The device used to link several computers together. It's an unintelligent device that only repeats any signal and broadcasts it onto other ports. Also called a multiport repeater In a hub, a frame is passed along or "broadcast" to every one of its ports. It doesn't matter that the frame is only destined for one port. The hub has no way of distinguishing which port a frame should be sent to. Passing it along to every port ensures that it will reach its intended destination. This places a lot of traffic on the network and can lead to poor network response times. Works in half-duplex mode only.

Major disadvantage of splitting signals?

The signal weakens and doesn't travel as long

NIC drivers pertain to which OSI model layer?

They operate in the Media Access Control sublayer of the Data Link layer (layer 2)

RG-8 coax table (photo) What is another name for this cable?

Thicknet

RG-58 A/U coax cable (photo) What is another name for this cable?

Thinnet

What is the most important goal of the NIC?

To optimize network performance & minimize the amount of time needed to transfer data packets.

What is the 802.5 standard?

Token ring LAN

A ____ is a way of laying out the network.

Topology

Which OSI layer signals "all clear" by making sure that the data segments are error free?

Transport layer

True or False? Drivers are specific to each NIC and operating system.

True

What is the Twisted-Pair Connector Type?

Twisted-Pair cables use a connector called RJ (registered jack).

What is the most popular type of network cabling to use and why?

Twisted-pair because it's cheap & flexible

How do you configure a firewall?

Use the access control list (ACL). The ACL is the set of rules that determines which traffic gets through and which gets blocked. They usually block traffic by IP address, port number, domain name, or all three.

What does a Single-Mode Fiber (SMF) cable do?

Uses a single mode of light to spread signal through cable This causes it to travel longer distances, but reduces bandwidth

What does a Multimode Fiber (MMF) cable do?

Uses several modes of light that bounces off the walls of the cable. This causes the signal to weaken. It shortens distances, but provides more bandwidth

____ expanded LAN's to include networks outside the local environment and also to distribute resources across great distances.

WAN's (Wide area networks)

What is full-duplex mode?

When data flows in both directions at the same time between sender and receiver.

What is half-duplex mode?

When data flows in one direction at a time. Only one sender or receiver can transmit at one time.

What is ring topology? Major reason why it's not used today?

When each computer connects to two other computers and messages move from workstation to workstation. If one computer is removed, the whole network goes down.

What is the 802.11 standard?

Wireless networks

LAN topologies include:

bus, star, and ring

Every domain is considered a

collision domain

Which tool is used by technicians to connect an RJ-45 connector to the end of a cable?

crimper

Client-server networks are also known as

domains

Worsktations are

everyday computers connected to a network. User perform work activities on them.

Fiber-optic cables are made out of ____ or ____

glass or plastic

Fiber optic cabling uses ___ instead of ____ which makes it immune to EMI (electromagnetic interference)

light instead of electricity, which makes it immune to EMI.

Routers can connect one ___ to another ___

one LAN to another LAN

The PAN is a network centered around

one person (personal area network)

The network established when two Bluetooth devices come within range of each other is called a

piconet

RG-6 coax cables are mainly used for

satellite/cable TV cable modems

Two or more piconet can be linked together using a

scatternet. One or more devices would serve as a bridge between the piconets.

LAN networks require the use of a

server (back end)

The hub or switch is called the

single point of failure

Most firewalls are configured at default deny, which means

that all traffic is blocked unless specifically authorized by the admin.

NIC's need to be connected to the same cable and use the same media access method in order to ____________. What is an example of a media access method?

to send data on the network successfully. Ex: CSMA/CD or token passing

A network links

two or more computers together to communicate and share resources.

Name the 4 types of coax cable connectors and how they work

vampire tap - sinks into a thicknet (RG-8) coax cable by sinking a metal tooth into it BNC connector - Ends up being T-shaped. used for thinnet connectors (RG-58 A/U). Used a terminator to be capped. Splitter -Splits one signal into multiple signals. Used for TV/Internet F-connector - Used for cable TV, the exposed end screws onto another connector. (Looks just like a regular coaxial cable)