Networking -Client/Server and Peer to Peer

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Client Server Model

This type of model (setup) separates the network into clients and servers. There are more clients than servers

What is a server?

A server is a computer that manages/stores data centrally. They process client requests

They are more powerful than clients and often have more CPU processing power, more RAM and larger capacity.

There are different types of servers that can be found in a local area network

  • File server – a computer with large capacity that holds all users files.
  • Email server – handles email within and outside the local area network
  • Web server – Stores web pages and often images/audio that form the web content
  • Printer server – manages all the printers within a local area network. Remember in school there is more than one printer

What is a client?

  • A client is a computer that is less powerful than a server. Think of the computers you use at school. These will be clients.
  • The clients will often request data/services from the server
  • Clients will not store your data, or handle the printers or emails they will communicate to the servers to do this.
  • Clients have no control over the network.

Task 1

A) What are the advantages of using a client / server model ?

Everything is stored centrally. This means it is easier to manage the security of the files. Easier to backup (all in one place). Easy to install new software. Imagine a technician having to install a new piece of software 500 times going to each client individually.

B) What could be a disadvantage of having a server?

Servers are powerful computers – they are much more expensive than clients. The more servers, the more costly it is and requires technical staff to maintain it. As all data is stored centrally if the server fails then the clients would be unable to access this data unless the server was fixed / or data recovered.

The more clients that access the server the more difficult it is for the server to process all the requests (depends on power of the server and network connectivity) but a server can only process a certain number of requests at once.

C) What servers might you find in a school?

Your school has multiple printers – there could be a server managing the printers. All of your data is stored centrally this is why you can access your data from any computer room your school will have a file server. If you have your own school email address then it will also have an email server.

Peer to Peer Model

What does peer to peer mean?

Peer to peer is where all computers have the same status. This means there isn’t one powerful computer (server) where everything is stored centrally.

Each peer will store its own files and data.

Each peer will be able to share the data with other peers.

  • Each peer will store its own data and files
  • Each peer will be able to share the data with other peers
  • Each peer is responsible for its own backup and security

Task 2

A) What are the advantages of using Peer to Peer compared to Client Server

It is cheaper, there is no need to buy an expensive server to hold data centrally. Clients such as the computers you use at school could be used to achieve the same outcome. It is easy to maintain and no dependency on a single computer. If one peer fails you may lose a feature of your network perhaps access to one printer but you would not lose access to all of them.

B) What are the disadvantages of using a Peer to Peer network.

The network is less secure – A server is often in a separate building protected and has limited access, people will be using the peers often – security is not guaranteed. It is much more difficult to backup and maintain – each peer would have to be backed up and maintained individually.

C) Can you think of an example of a peer to peer like models?

Content delivery systems (while some may not exactly be peer to peer) they mimic the same qualities. Imagine 1000 people watching a film all connected to the same server, the server may not be able to respond fast enough. Using peer to peer we would be able to use each others connections.

Microsoft windows uses peer to peer to send updates to everyone in the world. Rather than the world downloading off of one server, there is the ability to download the updates (securely) off of each other

File sharing networks – such as bit torrent – allow files to be shared across the internet and people download parts of the file off of each other.

Extended learning

Use the internet to find how much file servers cost. Some of the cheaper servers will be designed for home use or small businesses – think how much it would cost for larger businesses.

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