1.3 network set ups Flashcards
What is a network
Group or system of connected devices
What is a LAN
Local Access Network - network that is geographically confined to a building or site
What is a WAN
Wider Access Network - network spread over a wider geographical area
Advantages of networks
- file sharing
- hardware sharing - such as a printer
- communication
- roaming access - sign into any computer to access information from network
- centralised updates, maintenance and security
- user monitoring
- levels of access - different users can be given different levels of access
Disadvantages of networks
Cost
Management
Spread of malware
Hacking
Factors that effect the performance of networks
- amount of devices
- bandwidth and transmission medium - how much data is being transmitted and how
- type of network traffic
- network latency
- number of transmission errors
What is bandwidth
Amount of data that can be transmitted in a certain time. Each connected devices requires it to be able to communicate
What is latency
Measure of how long it takes to send a messages from one device to another across a network. Low latency has few transmission delays whereas high latency has lots of transmission delays
Do hub based networks or switch based networks experience higher latency
Hub based as they broadcast messages to all devices
How do client server networks work
Separate computers into servers and clients. The clients rely on the servers to provide and manage data. They don’t usually store data
What is a server
Store files or provides services to other computers on the network control network and allow other computers to communicate
How does a peer to peer network work
All computers have equal status. Store their own files which can be accessed by other peers on the network
What is an NIC
Network Interface Card - method of connecting to a network. Offers an interface port for a wired connection or a radio transceiver for connecting wirelessly. Most modern PCs come with a NIC built in
What is a hub
Small device that allows wired devices to connect to a network. No knowledge of the computers connected so any data it receives is sent to all computers making it slower
What is a switch
Connects devices using wires like a hub but it also records which devices are connected to which port so only intended recipient gets data. Uses IP and MAC addresses
What is a WAP
Wireless Access Point - allows wireless devices to connect to a network. It creates its own wireless network, which devices connect to. The WAP then sends wireless traffic it receives onto the main wired network.
Can also be used to extend range of wireless network
What is a router
They are used to send data signals across the
internet. Routers work by collecting knowledge of available routes to transmit data. They then determine the most suitable route for sending data.
What is the internet
A worldwide collection of networks. Enables communication on an international level
What is DNS
Domain Name Servers - every website has a network address consisting of four sets of three digits. This is hard to remember so domain names are given. When a user enters the domain name as a URL, a DNS looks it up and converts it to a network address then sends the request to the server under that address
What is the cloud
The cloud is a generic term for remotely accessed storage. This storage is accessed through the internet. Users do not actually know where their data is stored - the geographical location is unimportant. Users only need to know that their data is stored on a server connected to the internet.
Advantages of cloud
ability to 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
reduced need to make
backups - cloud storage services back up the data for you
Disadvantages of the cloud
there is no guarantee that someone else is not accessing your data
there is no guarantee that your data is being backed-up
access to data is only possible with an internet connection - no connection means no access to data
What is a star network
all nodes indirectly connect to each other through one or more switches. The switch acts as a central point through which all communications are passed.
Large networks using star topology
usually controlled by one or more servers. Hence, the client-server model usually uses a star topology
Advantages of star topology
each node is separately connected, therefore a failure of one node or its link, does not affect any other nodes
new nodes can be added to the network simply by connecting them to the switch
star networks tend to have higher performance as a message is passed on to its intended recipient only
Disadvantages of 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
Star topology in use
tend to be found in large organisations, such as educational establishments and businesses, where high performance is a must.
They are also found in home networks, especially those that are wireless. In this case, a
router with a wireless access point (WAP) provides the central connection for all nodes.
What is a topology
the arrangement, or pattern, in which all nodes on a network are connected together.
What is mesh topology
No central connection point. Instead, each node is connected to at least one other node and usually to more than one. Each node is capable of sending messages to and receiving messages from other nodes. The nodes act as relays, passing on a message towards its final destination.
Two types of mesh topology
Full mesh - all nodes connected to all other nodes
Partial mesh - nodes only connected to some other nodes
Advantages of mesh topology
- messages can be received more quickly if the route to the intended recipient is short
- messages should always get through as they have many possible routes on which to travel
- multiple connections mean (in theory) that no node should be isolated
- 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 or interfering with other nodes
Disadvantages of 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
