Computer Science Easter Homework

Computer Science Easter Homework

1. LANS and WANS

   • A LAN is a network over a small geographical location
   • Advantages of connecting to a LAN: 1. Sharing files is easier in a LAN (work at the same time). 2. Share peripherals 3. Share internet connection 4. update software at the same tune 5. communicate cheaply.
   • A WAN is a network over a large geographical area.
   • A WAN is used to communicate with othr servers and connects to the internet. Data can be backed up in a server not in the school so if something goes wrong, it can still be accessed.
     • Internet access may be faster as people are not logging into one server.
   • 3 things that can affect internet speed connection
     • Types of connection. A wored connection (etherent) is much faster than a wireless connection (WiFi)
     • Types of topology. A mesh topolgy is quicker than a star topology as data packets will find the quickest routes
     • Bandwidth. If there is not enough bandwidth for the people on the network, the amount of data transferred will take a longer amount of time.

2. Topologies

   • Advantages of a star topology.
     • If a device fails, then the rest of the network is not effected. It is easy to add other devices to the network. The performance is better because the data travels straight to the central point.
     • Disadvantages of using a star network
       • Every device needs to connect to the central point- this can be expensive if it is with wires. If the switch fails, then the network will fail.
   • Advantage and disadvantage of using a mesh topology over a star topology.
     • ADV: There is no point in the topology where the network can fail.
     • DISAD: More expensive to set up compared to star topologies because of the hardware needed.

3. Protocols

   • A MAC address is a unique binary code assigned to an address that cannot be changed.
   • TCP- splitting data packets
     • IP- packet switching
       • HTTP- access websites and communicate with servers. HTTPS- More secure version of HTTP
         • FTP- move, edit and access files between devices, from client to server.
           • POP3- receive emails. Deletes once seen the email
             • IMAP- receive emails. Hold until manually deleted
               • SMTP- used to send emails
   • One layer and function
     • layer 4 turns data into websites (HTTP)
   • 3 advantages of using layers
     • Breaks down communication into smaller pieces. It is easier to manage.
     • A layer is self- contained, they can change without other layers being effected.
     • The rules that are set makes sure that companies are performing at a good standard.

4. Client Server + Peer to Peer

   • A client server network is when all devices are centrally managed and connects to a server. The server processes and responds to the client's requests.
   • A peer to peer network is when all devices are equal and connected to each other.
   • ADV of client server networks
     • Easier to perform back- ups. Easier to keep track to files. Easier to install and update software. Easier to manage network security. Servers are reliable and always turned on.
     • DISAD of client server networks
       • Expensive to set up and require a specialist. If the server breaks, everything is lost. Server may overload if there are too many people on it at once.
   • ADV of peer to peer networks
     • It is easy to maintain (no special hardware). It is not dependant on a server.
     • DISAD of peer to peer networks
       • No centralised management. Copying files creates duplicates and it is easy to lose track of where they are. The devices are less reliable and files will be lost if one fails. Machines will slow down when others access them.

5. Network Hardware

   • NIC connects to a network and is built into the motherboard. They all have a MAC address
   • Switches connect to a LAN and forward the data packets to parts of the network. MAC addresses are used for this.
   • A router connects to a LAN and forwards data packets between networks. IP addresses are used for this.
   • WAP allows wireless connection within a wired network. Networks usually have ethernet connection to them, so a WAP allows wireless connection to the devices.
     • This can be on its own or connected to the router in a house.