Network

Network

1. Types of Topology

   • Mesh
     • Generally used for WANs and their are no wires connecting computers together and they are connected randomly and send relays to each other.
   • Star
     • A hub/switch in which sends information down a wire which has a computer connected to it
   • Bus
     • A long wire connecting all the computers with terminators at either end of the wire
   • Ring
     • Series of computers connected in a ring with seperate wires between the computers

2. LAN

   • Local Area Network
     • Advantages
       • 1. Can easily exchange data across computers on that LAN. 2.Every user can share messages. 3. Users can log on to every computer and can access the same data.
     • Disadvantages
       • 1. If the server is set up wrong, unauthorised users can access the clients data. 2. The distance is limited within a building or nearby building. 3. Catastrophic failure if server crashes.

3. Switching

   • Circuit Switching
     • The route is locked down until the data has been sent to the other computer which means it can be blocked for a long amount of time
     • Advantages and disadvantages
       • Data's speed is consistent and arrives in the order it was sent meaning no sorting is needed. Data can be read as soon as it has arrived, as it is in the right order. The network is clogged due to the line being shut down
   • Packet switching
     • Advantages and disadvantages
       • Multiple transmissions can happen simultaneously and large transmissions can happen without clogging the network. Their is lag due to the packets arriving in a different order and cant read until all packets have arrived.
     • The data is split into packets and is then sent along different routes meaning it arrives in a different order which means the packets have to be numbered so they can be reorder

4. Pathfinding

   • Each node on a network tests its connection speed and depending on the speed depends on the weight it is assigned. An algorithm then finds the route with the lowest weight in which will be the quickest.

5. WAN

   • Wide Area Network is a series of LAN networks connected together
     • Advantages
       • 1. Allow for much larger and more intricate network. 2. Can cover near infinite geographical distance.
     • Disadvantages
       • 1. It is expensive to maintain and set up. 2.It is slower due to the amount of computers. 3. Ease of use.

6. Protocols

   • A protocol is a set of agreed rules that both sides of a communication channel follow.
   • Standard Protocol
     • Standard protocols are well known protocols that are used by a wide variety of applications.
     • HTTP and HTTPS
       • HTTP is Hyper Text Transfer Protocol
       • HTTPS is Hyper Text Transfer Protocol Secure
       • This is standard protocol for requesing a HTML (Hyper Text markup language) link from a website
     • FTP (File Transfer Protocol)
       • Transfers files in between computers
     • POP3 (Post Office Protocol 3)
       • Downloading emails from mail server
     • SMTP (Simple Mail Transfer protocol)
       • Uploading emails to the computer
     • IMAP (Internet Message Transfer Protocol)
       • Allows you to read the same email from different computers.