Chapter 1 Flashcards
Most devices encountered when working with a network involve what
a computer
what are the operating systems that most workstations and network servers run?
Windows, Linux, UNIX, Mac OS X
What are the three basic functions of a computer
- Input
- example: a user types an “A” on the keyboard which sends a code representing a into the computer
- Processing
- The computer’s CPU processes the input, be it from the keyboard or somewhere else
- Output
- The CPU acts upon the processed input and sends back information such as telling the graphics card to display the letter a on the monitor
What are some common user controlled input devices
keyboards, microphones, webcams, scanners
What is a computer’s main processing component
the Central Processing Unit (CPU)
What are current CPUs composed of
two or more processors called cores
Having two cores is like a person having two brains that are able to think and act simultaneously
what are some common computer outputs
Monitors, Printers, storage devices, network cards, speakers
The processes of writing files to a connected disk drive would be considered an output
What does having more storage mean for a computer?
Most storage components are both ___ and ___ devices
What are the two main categories of storage
better performance
input and output
Short-term storage and Long-term storage
What does RAM stand for and for what is it used
What does a computer do if not enough RAM is avaiable for a particular program
RAM is Random Access Memory which is also known as “working storage”
The amount of RAM avaiable to a computer is crucial to it’s ability to run a program.
If not enough RAM is available the computer’s disk drive will supplement
What happens to RAM when the computers power is turned off
It is erased. RAM requires an electrical charge to retain information
What are examples of Long Term storage and how does long term differ from short term
Long term includes Hard disks, CDs/DVDs, USB flash drives
Long term is slower to access but doesn’t require an electrical charge meaning that it won’t be lost in the event of power failure
what represents a 1 bit and what represents a 0 bit using electricity
With fiber optic how are 1 and 0 represented
5 volts is a 1, 0 volts or the absence of volate is a 0
The presense or absence of light
what is a byte
this is a storage unit that is comprosed of 8 bits
What are the four major PC components
Motherboard
Hard drive
RAM
BIOS/CMOS
Describe the following key component of a motherboard: PCI bus expansion slots
Peripheral Component Interconnect (PCI)
these are used to add functionality to a PC by adding expansion cards that have a Peripheral Component Interconnect (PCI) connector
Describe the following key component of a motherboard: PCI-Express expansion slots
Peripheral Component Interconnect PCI-Express supersedes PCI and supports faster data transfer speeds.
The larger slots are suitable for high-performance expansion cards, such as graphics cards and disk controllers.
The smaller slots are best suited to sound cards and network interface cards
Describe the following key component of a motherboard: Chipset with heat sinks
The chipset consists of two chips - Northbridge and Southbridge. (In modern machines there is only one chip)
These chips control data transfer between memory, expansion slots, I/O devices, and the CPU.
The heat sink sits on top of the chipset to prevent it from overheating
Describe the following key component of a motherboard: SATA connectors
Used for connecting hard drives and CD/DVD drives that use the Serial AT Attachment (SATA) specification
Describe the following key component of a motherboard: IDE connector
Used for connecting integrated Drive Electronics (IDE) hard drives and CD/DVD-ROM drives. Most systems now use SATA for hard drives and IDE for CD/DVD-ROM drives
What is a BUS
Where are they found
A BUS is a collection of wires carrying data from one place to another in the computer. All data that goes into or comes out of the computer must travel through the motherboard.
There are buses between:
CPU and RAM
CPU and disk drives
CPU and expansion slots
What is the Primary long-term storage component on a computer
Hard Drive
How does a Hard drive consist of and what is typicall stored on it
A hard drive is made up of magnetic disks called “platters” that are able to store information in the form of magnetic pulses
The hard drive stores the documents you use as well as the applications that open those documents.
The hard drive also stores the operating system that is loaded when the computer boots up
What are Solid State Drives
why are they used
These are a replacement for hard drives that have increased speed and reliability
They use Flash memory which means there are no moving parts resulting in faster access times
They are more expensive then hard drives and are most often found in mobel devices as well as high-performance desktops and servers
What is the primary short-term storage component
Are there moving parts?
RAM is the primary short term and has no moving parts meaning that data is accessed much faster than accessing data on hard drive would be
What is BIOS
a basic input/output system
Its a set of instructions located in a chip on the motherboard.
It tells the CPU to perform certain tasks when power is first applied to the computer
One of those instructions is to perform a power-on self test (POST)
What does BIOS do on startup and what is CMOS
when a computer boots the BIOS program offers a chance to run the setup utility in order to configure hardware components
This confguration is stored in a type of memory called complementary metal oxide semiconductor (CMOS)
What is the computer boot procedure? (6 steps)
- Power is applied to the motherboard
- The CPU starts
- The CPU carries ot the BIOS startup routines, including the POST
- Boot devices, as specified in the BIOS configuration, are searched for an OS
- The OS is loaded into RAM
- OS services are started
What does a computer network consist of
two or more computers connected by some kind of transmission medium
(such as a cable or air waves)
What are the Hardware components needed for a Network
- Network interface card
- an add-on card plugged into a motherboard expansion slot that provides a connection between the computer and the network
- Network medium
- A cable that plugs into the NIC and makes the connection between a computer and the rest of the network
- Network media can also be the air waves, as in a wireless network
- A cable that plugs into the NIC and makes the connection between a computer and the rest of the network
- Interconnecting device
- allow two or more computers to communicate on the network without havng to be connected directely to one another (switches, hubs, routers, wireless access points)
What are the Software Components for a Network
- Network clients and servers
- Network client software requests information stored on another network computer or device
- Network server software allows a computer to share its resources
- Protocols
- define the rules and formats a computer must use when sending information across the network
- NIC driver
- receives data from protocols and forwards this data to the physical NIC
What kind of operating system is android
What kind of operating system is mac
What kind of operating system is linux
androids are open source
Macs are close source
This results in androids have reduced security
Linux is close source
What is responsible for corrupted files
This is a hard drive problem. If part of the disk becomes unreadable the file is corrupted and can’t be recovered.
What kind of memory system do solid state drives use
What potential problem does this cause
They use flash memory meaning transistors and capacitors rather than moving parts.
This can result in residue which damages the drive
What is the CMOS
The Complementary metal oxide semiconducter (CMOS) holds the configuration data the user enters such as devices the CPU should check for an OS to boot, the status of hardware devices, and even a system password if needed.
It’s a type of low-power memory that requires only a small battery to maintain its data
It’s refered to as “non-volatile” memory because it doesn’t require power from the computer’s main power supply
What does the POST do?
The power-on self test (POST) checks to see if all of the computers primary systems are working properly
What are OS services
these are programs that are part of the operating system and can be viewed in the task manager
What is an “onboard processor”?
This is an ancillary processor associated with input/output (I/O) devices, such as graphics cards
Why is running out of RAM when attempting to operate a program bad?
RAM is thousands of times faster than a disk drive.
How many bytes does it take to play 1 second of an MP3 song
over 17,000 bytes
What is a NIC
a Network Interface Card
What is the term for a computer that lacks both the hardware and software to connect to a network
a “stand-alone computer”
What does MAC in MAC address stand for and where is it stored
This is the Media Access Control address
The MAC address is stored as part of the physical NIC which is how it got the name “physical address”
What are the steps of Network Communication
- Application tries to access a network resource by sending a message
- Client software formats the message and passes the message on to the network protocol
- Protocol packages the message in a format suitable for the network and sends it to the NIC driver
- NIC driver sends data in the request to the NIC card to be converted into necessary signals to be transmitted on the network
What is each step required for a client to access network resources referred to as?
a layer
Each layer has a task and all layers work together
Starting with the sending machine what are all the layers that must occur before the communication completion with the receiving machine
user application (sending machine) > network software > network protocol > network interface >
Network Medium
network interface > network protocol > network software > user application (receiving machine)
Describe what happens in each of the four layers of the network communication process:
- User Application
- Network Client or Server Software
- Network Protocol
- Network Interface
- User Application
- An application tries to access a network resource
- Network Client or Server Software
- Client software detects the attempt to access the network and passes the message on to the network protocol
- Network protocol
- The protocol packages the message in a format suitable for the network and sends it to the NIC driver
- Network Interface
- The NIC driver sends the data in the request to the NIC, which converts it into the necessary signals to be transmitted across the network medium
What is the most common protocol (language) used on networks
TCP/IP
What are the two addresses TCP/IP uses to identify devices
- Logical address (IP address)
- Think of a zip code
- Physical address (MAC address)
- Think of a street address
How do two computers communicate on a LAN (5 steps)
- A user at comp A types ping 10.1.1.2 (the IP address of computer b) as a command prompt
- Network software creates a ping message
- The network protocol packages the message by adding IP address of sending and destination computers and acquires the destination computer’s MAC address
- The network interface software adds MAC addresses of sending and destination computers
- Comb B receives message, verifies that the addresses are correct and then sends a reply to Comp A using steps 2-4
What is the network communication process for saving a file? (7 steps) include the layer where each happens
What is a driver
a set of instructions for how to operate a device
Client for Microsoft Networks is able to run in the background and does what
it is installed automatically in windows and allows a word-processing program to open a file that’s shared on another windows computer or print to a printer attached to another windows computer
What is a name server
This is an address book of sorts that computers use to get a computer’s IP address, given its name
What is a network security feature that is performed by the modem
It hides the users IP address
Describe the following type of network: LAN
Local Area Network (LAN) - This is a small network, limited to a single collection of machines and connected by one or more interconnecting devices in a small geographical area
Can a LAN be wireless?
Yes, there could be a situation where a user has a wireless pc, wireless laptop, and wireless tablet or some other configuration of wireless items all operating off a single wireless access point.
Describe the following type of network: Internetwork
Why might an internetwork be needed? (3 reasons)
- This is a networked collection of LANs tied together by devices such as routers
- Two or more groups of users and their computers need to be logically separated but still need to communicate
- Number of computers in a single LAN has grown and is no longer efficient
- The distance between two groups of computers exceeds the capabilities of most LAN devices
Describe the following type of network: WAN
Wide Area Network (WAN) - uses the services of third-party communication providers to carry network traffic from one location to another
GEOGRAPHIC DISPERSION OF YOUR NETWORK
Describe the following type of network: MAN
Metropolitan Area Network (MANS) - use WAN technologies to interconnect LANs in a specific geographic region, such as a county (or?) a city
What does the term Internet refer to?
what is the most common protocol used?
a worldwide public internetwork
Uses protocols such as TCP/IP and HTTP to transfer and view information
What does the term Intranet refer to?
a private internetwork in which devices and servers are only available to those users connected to the internal network
What does the following term refer to: Extranet
allows unlimited and controlled access to internal resources by outside users
How do computers transfer information across networks?
Why is data transferred in this way?
In short bursts of about 1500 bytes of data
- pauses between bursts allows other computers to transfer data during pauses
- Allows the receiving computer to process received data
- Allows the receiving computer to receive data from other computers at the same time
- Give sthe sending computer an opportunity to receive data from other computers and perform other processing tasks
- If an error occurs during transmission of a large file, only the chunks of data involved in the error have to be sent again
What is a packet
- a chunk of data with a source and destination IP address added to it
- In the mail analogy this would be like an envolope that has a zip code but no street address
What is a frame
why is it called a “frame”
This is a packet with the source and destination MAC addresses added to it
The packet is “framed” by the MAC addresses on one end and an error-checking code on the other
Information added to the front of the data is called a header and information added to th end is called a trailer
What is the process of adding IP addresses and MAC addresses to chunks of data?
encapsulation
What is a client?
What are the three contexts in which the word is typically used?
A workstation running a client OS or it can refer to the network software on a computer that requests network resources from a server
Client operating system - the OS installed on a computer
Client computer - primary role is to run user applications and access network resources
Client software - software that requests network resources from server software on another computer
Under what conditions does a computer become a server
What are the three contexts in which the term server is used
when software is installed on it that provides a network service to client computers
- Server operating system - OS installed on a computer designed to share network resources and provide other network services
- Server computer – a computer’s primary role in the network is to give client computers access to network resources and services
- Server software – responds to requests for network resources from client software
What does a network model do?
A network model defines how and where resources are shared and how access to these resources is regulated
What are the two major types of network models
- Peer-to-peer network – most computers function as clients or servers (no centralized control over who has access to network resources)
- Server-based network – certain computers take on specialized roles and function mainly as servers, and ordinary users’ machines tend to function mainly as clients
What is the Peer-to-Peer/worgroup Model
- Computers on a peer-to-peer network can take both a client and a server role
- Any user can share resources on his/her computer with any other user’s computer
- Every user must act as the administrator of his/her computer
- Can give everyone else unlimited access to their resources or grant restricted access to other users
- Usernames and passwords (credentials) are used to control that access
Which Network Model does this describe:
Well suited for small organizations that have small networks and small operating budgets
Peer-to-Peer/Workgroup Model
What are the potential problems with peer-to-peer networks?
- Must remember multiple sets of credentials to access resources spread out over several computers
- Desktop PCs and the OS installed on them aren’t made to provide network services as efficiently as dedicated network servers
- Data organization – If every machine can be a server, how can users keep track of what information is stored on which machine?
What is a Server/Domain Based Network Model
- A domain is a collection of users and computers whose accounts are managed by Windows servers called domain controllers
- Users and computers in a domain are subject to network access and security policies defined by a network administrator
- The software that manages this security is referred to as a directory service.
- On Windows servers, the directory service software is Active Directory
Describe the following network services found on network servers:
- Naming services
- E-mail services
- Application services
- Communication services
- Web services
- translate computer names to their address
- manage incoming and outgoing email
- grant client computers access to complex applications that run on the server
- give remote users access to a network
- provide comprehensive Web-based application services
Which kind of networks are easier to expand?
How many users can peer-to-peer networks handle
How many users can Server-based networks handle
Server-based networks are easier to expand
peer-to-peer should be limited to 10 or fewer users
Server-based networks can handle up to thousnads of users
what is the advantage of having multiple servers configured to work together
efficiency and fault tolerance
How does the following network attribute work on Peer-to-Peer network and on Server-based networks:
Resource access
Security
Performance
Cost
A ___ network model has no centralized authority over resources
A ___ network model usually is used as a directory service to provide centralized resource management
A peer-to-peer network model has no centralized authority over resources.
A server-based network model usually is used as a directory service to provide centralized resource management
___ have the source and destination IP address added and are processed by the network protocol
___ have the MAC addresses and an error code added and are processed by the network interface
Packets have the source and destination IP address added and are processed by the network protocol
Frames have the MAC addresses and an error code added and are processed by the network interface
What does a lightning bolt symbol refer to
A WAN connection
What is the final state of data before it’s placed on the network medium
frames
At which layer are frames delt with?
Link layer
At which layer are packets dealt with?
Network Layer
What is a legacy hub
What can be done with intelligent hubs and switching hubs
- Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports and when a packet arrives in one port it is copied and sent to all other ports of the Hub.
- Hubs don’t distinguish which port something should go to so network traffic can get very heavy when packets are being sent.
- Intelligent hubs include additional features that allow an administrator to monitor the traffic
- Switching hubs are able to read the destination for a packet and send it to the correct location
What is a router
What is a gateway
A router is a device that connects to at least two networks (commonly a home network such as a LAN, and its Internet Service Providers network) and uses these connections to transfer packets.
Routers use headers and forwarding tables to determine the best path for forwarding packets and routers use protocols such as ICMP
Routers are located at “gateways” which just means a place where two or more networks connect.
What is ICMP?
what does it contain?
what uses it?
ICMP or Internet Control Message Protocol is a protocol used by routers for packet delivery
ICMP supports packets containing error, control, and information messages
It is an error reporting protocol and is used by routers, hosts, and home network devices to generate error messages when there are problems delivering IT packets
What is a switch
in a network, a device that filters and forwards packets between LAN segments is known as a switch.
Switches support all packet protocol
How are hubs and switches similar and in what way are they different
- Hubs and Switches both amplify and then transfer frames on a network
- The difference lies in the destination. Hubs are unable to distinguish which port a frame should be sent to so the frame is sent to all ports on the Hub.
- A switch keeps of a record of the MAC addresses of all connected devices and can therefor recognize where a frame should go upon arrival and only send it to the correct port.
- Finally Hubs share bandwith between all attached devices. A switch allows each device to have the full bandwith it is capable of providing at all times
