1.3.1 Networks and Topologies Flashcards
LAN (Local Area Network)
A network of connected computers in a limited geographical area where the equipment used is typically owned by the organization
WAN (Wide Area Network)
A network of connected networks in a large geographical area where the equipment used is typically rented by the organization
Factors the affect the performance of the networks
Bandwidth - the amount of data that can be transferred through a specific connection in a given amount of time, measure in bits per second
Amount of traffic (number of devices attached) - as the amount of network traffic increases, the share of the available bandwidth decreases
WAP (Wireless Access Point)
Allows a device to connect wirelessly to a LAN (by cable)
NIC (Network Interface Card)
Stores the MAC address (wired and wireless)
Switch
A networking device to connect computers (nodes) to a LAN - breaks up collision domains by ensuring that frames of data get send to the specifies destination (specified by the MAC address)
Transmission Media
- Copper Wire (Ethernet Cable)
- Fibre Optic Cable
- WiFi (does not use media - it uses radio waves that pass through the air)
ALL THE ABOVE ARE USED IN LAN
Router
Interconnection device that routes packets and can:
- Resolve private IP addresses to public IP addresses (vice versa)
- Decide which is the best path to send a packet along
- Connect together networks of different types
*Routers are used BETWEEN (or on the boundary) of networks
Peer to Peer
In a peer to peer network all computers have EQUAL status
Client Server
In a client server network, there are some computers that are designated as servers that provide a service to the other computers known as clients
Examples of servers
- Web server
- Games server
- DNS server
- Apps server
- Print server
- File server
- Mail server
- Proxy server
- DHCP server (gives IP address)
- VPN server
DNS (Domain Name System)
- Translates URLs (Uniform Resource Locator) into IP addresses, by looking up the URL in a DNS server database
- If the URL is NOT found in the database, a request is sent to the top level domain name system server, which will return the IP address or a “destination unreachable” message
Hosting
The storing of files and data on a web server - referred to as the host
e.g. cheltladiescollege.sharepoint.com
“.com” is the top level of the host name
“.sharepoint” is the second level
“cheltladiescollege.” is the third level and the name of the organisation
The Cloud
The term given for services that run over the Internet
Typical cloud services include storage, computation, AI, software as a service
Advantages of The Cloud
- Accessible anywhere (that has an Internet connection)
- Reduce the need for backups - the service will backup for you
- You can grant access to others
Disadvantages of The Cloud
- You need an Internet connection - no Internet, no access
- No guarantee that the data is being backed up
- No guarantee that someone else is not using the data
Star Topologies
- Networked together
- Has a central device that directs all the data in the network
- Able to send messages directly to any other device in the network
- Has ONE failure point (aka the switch)
- Easier to connect and troubleshoot than the Mesh
- Most commonly found in classrooms and home networks
Mesh Topologies
- Networked together
- Able to send messages directly to any other device in the network
- Ideal for a network where reliability is important (because there is no one, single device that can stop the whole network from working)
- Requires more cabling
Client Server vs Star Topologies
Client server networks are about the ROLES of the computer in the network
Star topologies are about the ARRANGEMENT of the cables and computers
