1.3 Networks , Connection And Protocols Flashcards
What is the internet ?
A collection of inter-connected networks
What is the World Wide Web?
A service that makes use of the Internet.
What is a Wide Area Network ?
Any network in which computers communicate using resources supplied by a “third party carrier”.
What are features of a WAN ?
- Uses cables, telephone lines , satellites or radio waves to connect two remote locations
- Have an admin team.
What is an IP address ?
Internet Protocol Address
What is IPv4 ?
- 4 8-bit numbers separated by dots (0 -255)
- eg. 72.129.214.16
What is IPv6 ?
- 128 bit numbers represented in hex.
- eg. 1023:Oefl:0000:0000:34dd
What is a packet ?
A smaller part of a larger piece of data.
What is packet switching ?
messages are broken up into very small pieces and packets are sent individually across the network and put back together to reform the message at the other end.
What does each packet contain ?
A header containing Dest IP address, Origin IP address, sequence in packets and number of packets
What is a Local Area Network ?
- a network that is geographically confined to one building or site.
- LANs are owned and maintained by the organisation.
What affects performance of networks ?
- number of devices on the network
- bandwidth of the transmission medium
- type of network traffic
- network latency
- number of transmission errors
What is Bandwidth ?
measure of the amount of
data that the medium can transfer over a given period of time.
What is Network Latency ?
how long it takes a message to travel from one device to another across a network
What types of transmission medium are there ?
- Ethernet
- Wifi
- Satellite
- Bluetooth
- Fiber Optic
- Copper Cable
How is latency affected ?
number of devices on the network and the type of connection device.
How does a transmission error happen ?
A collision occurs when two devices on a network try to communicate simultaneously along the same communication channel.
What is a client - server network ?
computer networking where the data is hosted on a server and accessed by client computers.
What is a peer-to-peer network ?
- all computers on the network share responsibility
- there is no one central server.
What is a server ?
- A computer that holds data to be shared with other computers
- require server software.
What are typical servers ?
- File servers
- Application servers
- Web servers
- Print servers
- Mail servers
What is client ?
a computer that relies on other computers (servers) to provide and manage
data
What are characteristics of a client?
- do not usually store data
- no control over the network as a whole or over individual computers.
What are characteristics of a peer-to peer network ?
- Peers store their own files, which can be accessed by other peers on the network.
- peer is both a client and a server.
- best suited to smaller organisations
What is a NIC ?
A card that is installed in a computer so it can be connected to a network .
What are the characteristics of a NIC and a wireless NIC ?
- offers an interface port
- provides a radio transceiver
What are characteristics of a fibre-optic cable ?
- Expensive
- Over 40 terabits per s
- maximum distance over 2 km
What are characteristics of a twisted copper cable ?
- Cheap
- Up to 1 gigabit per s
- maximum distance up to 100m
What are characteristics of a wireless connection ?
- use radio waves to carry signals.
- signals are limited in range (usually up to 50 metres)
- ideal for mobile devices
What is a router ?
- Transfer data packets between computer networks
- used to gain a broadband internet connection
What is a hub ?
- A multiport repeater having several input/ output ports that allows wired devices to connect to a network ?
What is a switch ?
- Receives data from a port
- uses packet switching to resolve the destination
- forwards the data rather then broadcasting it as a hub
What is a WAP ?
- uses a radio transceiver to allow wireless connections to a network
- used to extend the range of a wireless network
What model does the internet mainly work on ?
Client- server
What is Hosting ?
storing of files and
data on a web server
What is a Host ?
The web server
What is the URL ?
- Uniform resource locator
- Each web page address on a network is written as a URL. It contains the IP address and the DNS and web page details.
What does the host name consist of ?
three hierarchical levels in reverse
What is the DNS ?
- The Domain Name System made up of domain names
What is the DNS used for ?
- Used to refer to an IP address .
-Translates a web address into an IP address
Can your IP address change ?
YES
What is a MAC ?
A media access control address that is assigned to each NIC card by the manufacturer.
Is every single MAC address unique ?
YES there are 2^48 possibilities.
What is Bluetooth ?
A wireless method of connecting devices together over a short distance.
- Uses radio waves at 2.4 GHz
- Devices typically within 10 m
What are the advantages/disadvantages of 2.4 GHz ?
- Greater range and coverage
- More interference due to crowded frequency.
What are the advantages/disadvantages of 5 GHz ?
- Less crowded with 23 non-overlapping channels and higher data transmission rates
- Less able to penetrate through walls.
What is the cloud ?
remotely accessed storage via the internet
What are advantages of cloud storage ?
- access files from any location or any device, so long as an internet connection exists
- access can be granted to another user so they can remotely access your data
- cloud storage services back up the data for you
What are disadvantages of cloud storage ?
- no guarantee that someone else is not accessing your data
- no guarantee that your data is being backed-up
- no connection means no access to data
What is a node ?
Any device connected to a network either by wire or wirelessly.
What is a network topology ?
A network’s topology is the arrangement, or pattern, in which all nodes on a network are connected together.
What is a star topology ?
-all nodes indirectly connect to each other through one or more switches
-The switch acts as a central point
How are large networks using a star topology ?
Controlled by one or more server
What are advantages of using star topology ?
- each node is separately connected, failure of one node or its link does not affect any other nodes
-new nodes can be added by connecting to switch
-have higher performance as a message is passed on to its intended recipient only
What are disadvantages of using star topology ?
- the whole network fails if the switch fails as no node can communicate
-a wired star topology requires plenty of cable - in a large network this can be expensive
Where can star topologies be found ?
-found in large organisations, such as educational establishments and businesses
-also home networks
What is a mesh topology ?
- no central connection point
- each node is connected to at least one other node and usually to more than one
-nodes act as relays
What are the two types of mesh topology ?
- full mesh topology
- partial mesh topology
How does a full mesh network work ?
-each node is directly connected to every other node.
- enables a message to be sent along many individual routes.
How does a partial mesh network work ?
- not all nodes are connected directly to each other.
- A partial mesh therefore has fewer routes for a message to travel along
-simpler to implement.
What are the advantages of using a mesh topology ?
- messages can be received more quickly
- messages should always get through
- multiple connections mean each node can transmit to and receive from more than one node at the same time
- new nodes can be added without interruption
What are the disadvantages of using a mesh topology ?
- full mesh networks can be impractical to set up because of the high number of connections needed
- many connections require a lot of maintenance
What are the main protocols ?
- TCP/IP
- HTTP/S
- FTP
- SMTP
- POP + IMAP
What is layering ?
breaking up communication into separate components or activities.
What are the four layers of the TCP/IP model ?
- Application Layer
- Transport Layer
- Network Layer
- Link Layer
What is the purpose of the application layer ?
encodes/decodes the message in a form that is understood by the sender and the recipient.
What is the purpose of the Transport layer ?
- breaks down the message into packets
- packets are given a number and total packets
What is the purpose of the Network layer ?
- Adds the sender’s and recipients IP address
- Network knows where to send and where it came from
What is the purpose of the Link Layer ?
- enables the transfer of packets between
nodes on a network, and between one network and another.
What does layering allow for the development of ?
Standards
