IEB IT theory LU3 networking summary grade 12

Centralized vs Distributed processing in LAN

 Centralized network
- A single server is responsible for some or all the processing.
- Less powerful workstations that connect to the server.
- The server is used for apps, data storage and utilities.
 Decentralized network
- Distributes workloads amongst several machines instead on relying on a single
server.
- Some powerful devices are designed for distributed processing.
 Distributed network
- Computer systems that use more than one computer to run a single application.
- Detect idle CPUs on the network and allocate programs to use them.
- Includes parallel processing. (Using more than one CPU to execute programs)

Thin clients
 What is a thin client?
- A desktop terminal that has no hard drive
 Notes
- All applications are stored on the server that the thin client is connected to.
 Benefits
- Cost, Security, Manageability, Scalability

Fat Clients
 What is a fat client?
- A networked computer where storage is done locally with limited dependence
on network resources.
 Notes
- Fat clients allow you to customise and customise and configure computers.
- Processing occurs locally, applications that require intensive resources such as
the GUI, can efficiently be processed. Reduces the load on the central server
and network traffic.

Smart Clients
 What is a smart client?
- Stores most data remotely but uses processing power and resources from the
local device.
 Examples of smart clients
- Many google applications are Smart Client applications. (Google Earth, YouTube,
Google Drive)
 Notes
- These applications have features that are not found on a web browser such as
drag and drop, undo-redo, and context-sensitive help.
- They can handle heavy data entry requirements with navigation across multiple
screens. While they use network data, they are not dependent on having
continual network connections.

, Sharing across a WAN

What is a WAN?
- A Wide Area Network is a network, used to connect computers that span a wide
geographical area

Peer-to-Peer File Sharing (P2P)
 What is P2P?
- Every computer becomes a server (peer) instead of only the server delivering
files, each computer acts as a server making communication a two-way street.
 Seeding
- Each computer can share data to other users
 Leeching
- if a computer only downloads, not giving anything back,
 Advantages
- Easy file sharing (file sharing is quick)
- Reduced costs (no need to buy a separate computer for a server)
- Adaptability (extends to new clients easily)
- Reliability (remains functionable even if the central server crashes)
- High performance (performance improves when more clients join)
 Disadvantages
- Easy to make files sharable
- Security risks
- Malware
BitTorrent
 What is a BitTorrent?
- Peer-to-peer protocol where multiple peers swarm (a group of computers upload
and download the same torrent) without the need of a server.
 Notes
- Large files are split into smaller parts to increase upload and download speeds.
- Once a peer has a complete file, it becomes a seed.
- The more seeds, the quicker the files can be shared.
 BitTorrent tracker
- A BitTorrent tracker is a type of server that assists in the communication
between peers using the BitTorrent protocol.
- The tracker server records which peer machines have file copies so that
accessible peers can help to coordinate efficient transmission and reassembly of
the copied file.
 BitTorrent is not illegal
- It does however have a bad reputation for having copyrighted material on sites
 What is WebDAV?
- WebDAV protocol provides a framework for users to create, change and move
documents on a server.
 How P2P differs from FTP
- FTP is a client-server which allows the exchange o the files to and from a remote
computer. FTP is a standard Internet Protocol used to transfer files between
computers.