3.1.13 Networking Flashcards
what is a computer network?
2 or more computers connected together through a communication medium to form a network
what is the purpose of a network (connecting computers together) ? {2}
- to exchange information and data
- use the resources of other computers on the network
Advantages of computer networks {9}
- allows users to share software stored in a main system
- site (network) software licenses are less expensive than buying several standalone licenses
- files can be easily shared between users over a network
- network users can communicate via email, instant messenger and VoIP
- security over networks is of high standard
- much more straightforward to back up data as it is stored on a file server
- allows data to be transmitted to remote areas that are connected within local areas
- allows users to share common peripheral resources (saves money)
- cost of computing is reduced per user
Disadvantages of computer networks {5}
- cabling to construct a network and file servers van be costly
- management of a large network is complicated (requires training and a specialist network manager needed)
- files on the server can become inaccessible if the file server breaks down
- a virus an easily spread throughout the network to other computers if it gets into the system
- risk of hacking (security measures e.g. firewalls required to prevent this)
exam tip
you need to be able to discuss the advantages and disadvantages of using a computer network (press 5 to move on)
NEW TOPIC: Basic components of a computer network
press 5 to move on
what are servers?
powerful computers that provide services to other computers on the network
what are clients?
computers that use the services that the server provides
is a server or client LESS powerful?
clients are less powerful than the server
what does a communication media consist of?
the physical connections between the devices on a network (e.g. wireless signal/ internet)
what is a network adapter also referred to?
a netwrok interface card (NIC)
what is a network adapter / NIC?
a circuit board equipped with the necessary components for sending and receiving data
usually plugged into one of the available slots on a computer and a transmission cable is attached to the connector on the NIC
what is meant by resources?
{2}
any peripheral device that is available to a client on the network
also refers to data and information
who is the user?
any person that uses a client to access resources on the network
what are the protocols of a network?
rules used for the network communications
NEW TOPIC: Network topologies
press 5 to continue
what is a bus topology?
draw a sketch
acts as a shared communication medium that connects to devices via an interface connecter
https://nooradelima.files.wordpress.com/2014/11/bus.gif
^click this link to check answer for your sketch
adv of bus topology {5}
- Easy and cheap to install
- Suitable for small networks
- Easy to add extra workstations
- Uses less cable than a Star network
- Best choice for temporary networks
disadv of bus topology {4}
- Cable length is limited (restricts number of devices that can be connected to the network)
- As more devices are connected, the performance of the network slows down (due to data collisions)
- If there is a problem with the central cable, the entire network stops working
- Low security - every workstation can see all of the data in the network
what is a ring topology?
draw a sketch
data passes from one computer to the next one all the way around the ring until it reaches the destination computer.
http://www.teach-ict.com/images/network_ring.jpg
^click this link to check answer for your sketch
adv of ring topology {5}
- central server not required
- messages sent between 2 workstations pass through all the intermediate devices
- Transmission of data is fairly simple as it only travels in one direction
- No data collisions
- Extra computers can be added easily with little effect on performance - although you have to shut down the network to do this.
disadv of ring topology {2}
- failure of any cable within the network can cause network to crash
- alterations to any device within the network can affect performance of the whole network
what is a star topology?
draw a sketch
each workstation is connected by its own cable directly to the server.
http://www.teach-ict.com/gcse_new/networks/topologies/miniweb/pg4.htm
^click this link to check answer for your sketch
adv of star topology {5}
- Star networks are very reliable. If one connection fails, it does not affect other users
- Very few data collisions as each workstation has its own cable to the server
- Good security - no workstation can interact with another without going through the server first
disadv of star topology {4}
- The most expensive network layout to install because of the amount of cables needed
- Installing the network usually needs experts to set it up
- Extra hardware such as hubs and switches may be needed
- If the server crashes then nobody will be able to use the network.
the number of bits that can be transmitted over a network I’m a certain period of time is:
bandwidth
a technique in which stem resources are shared among multiple users is:
multiplexing
3.1.13.1 Client-server
press 5 to continue
what is the client-server model?
a structure that splits tasks between servers and clients
what is a server?
they provide a service to the clients
what is a client?
they use the services provided by the server
what is a protocol?
a set of rules that control the transfer of data between computers
why are protocols essential? {3}
they determine the:
- speed of transmission
- size of bytes
- error checking methods
what is Handshaking?
don’t describe the process just yet
two computers exchange signals in order to set up a communication link.
explain what happens during Handshaking?
when 2 computers connect
- establishes what protocols to use and controls the flow of data between the computers
- protocol parameters are negotiated
- handshaking protocols must be completed before finishing the action requested by the user
how would a typical Handshaking process go?
- a request to connect is sent
- a connection is granted
- protocol parameters agreed
what is client-side programming?
writing code that will run on the client, done in languages that can be executed by the browser
what is server-side programming?
writing code that runs on the server e.g. PHP
check your understanding:
what are the 5 basic needs of a networked communication system?
- data source
- transmitter
- transmission medium
- receiver
- destination (where data will be placed)
Advantages of client server applications over web-based applications.
- You are in control of upgrades.
- You have to manage your own systems and pay for technical support.
- Applications tend to run faster when they are local to the user’s computer.
