Chapter 20 - Types Of Network

Chapter 20 - Types Of Network

1. Main features of a client network server and P2P

   • A contolling network/server which handles processing requests from other computers on the network and then retrives the required data files for them. It aslo provides comunication links/ controls access
     • There is a central node. The client is a dumb terminal. The server makes a request for resources and the serevr meets the request
   • All computers on the network are equal with no controlling server. Each node has resources which the others can request. Each node is in charge of its own security

2. Centrailised Database

   • A single copy of a database is held in a central location. Information such as prices will be updated immediately. All database maintainence takes place there and users can access databse remotely
   • Decentrailised Database
     • Multiple copies held at different places where it is most elevent Must be synchronised to keep updated
   • Advantages over decentralised
     • Single copy so maintainence is more effective. At a single location so data acess can be better managed

3. Benefit and drawback for P2P

   • Low installation costs as there is no need to resource a dedicated server. No need for sophisticated OS
   • Low level of security as security cannot be controlled centrally

4. 3 advantages of network over standalone

   • Software/ Hardware shared. Possible communication between users. User are not rescrited to certain computer. Security can be controlled centrally

5. Data encryption

   • Data is encoded before transmission using a special key or algrorithim. One recieved it is transmitted back to normal. If intercepted it is meaningless woth the key

6. Distributed Database

   • Portions of the database are stored at different locations within the network. Each location holds the portion they access regularly. The DBMS synchronises it at regular intervels
   • Disadvantages
     • Each location is responsible for own security / IT specialists
   • Specific Shop one
     • Each shop will store data that is specifc to the store where it is most used at. Data such as stock levels will be accessed directly at each shop. head office wil store data required for overall management of shop. Eachshop will download data from head office

7. 3 advantages of network over standalone

   • Software/hardware can be shared, there electronic communication between users, a user can log on at any terminal