Network Topology & Protocols

Network Topology & Protocols

1. Topologies: How computers are connected to a network. There are 3 main types of network topology

   • Bus network
     • All workstations, servers and printers are joined to one cable( the bus). At each end of the cable a terminator is fitted to stop signals reflecting back down the bus
       • Advantages
         • Easy to and cheap to install. Doesn't require much cable
       • Disadvantages
         • If the main cable fails or gets damaged the whole network fails
         • As more workstations are connected the performance of the network become slower because of data collisions
         • every workstation on the network "sees" all of the data on the network- this is a security risk
   • Star network
     • Each device on the network has its own cable that connects to a switch or hub. A hub sends every packet of data to every device whereas a switch only sends a packet of data to the destination device.
       • Advantages
         • Very reliable - if one cable or device fails then all the others will continue to work
         • High performing as no data collisions occur
       • Disadvantages
         • Expensive to install as this type of network uses the most cable
         • extra hardware required which adds cost
   • Ring network
     • In a ring network each device is connected to two other devices, this forms a ring for the signals to travel around. Each packet of data on the network travels in one direction and each device recivees each packet in turn until the destination device recieves it
       • Advantage
         • Can transfer data quickly even if there a large number of devices connected becuase the data only flows in one direction, so there wont be any data collisions
       • Disadvantage
         • If the main cable fails or any device is faulty the the whole network will fail

2. Protocols establish how two computers send and receive a message. Data packets travel between source and destination from one router to the next. This is called packet switching

   • TCP/IP
     • Set of protocols used over the internet. It organises how data packets are communicated and makes sure packets have a source, destination, packet sequence, data and an error check.
   • FTP
     • Used to transfer large files. Often used for organising files on a web server for a website.
   • HTTP
     • Transfers web pages from web servers to the client. All web pages start with http. a https address is a secure web address which nhas been encrypted. It is used for sites holding bank details and secure information
   • SMTP & POP
     • Email uses these protocols to communicate with mail serveers. SMTP is used to send the email, POP is used to receive the email
   • VOIP
     • Set of protocols the enables people to have voice conversations over the internet.