Networks and the internet Flashcards Preview

A-Level Computer Science OCR > Networks and the internet > Flashcards

Flashcards in Networks and the internet Deck (126)
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1

Network

an interconnected set of devices

2

Physical network topology

The actual architecture of a network i.e. how its laid out

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Positives of Networks

- allows sharing of data
- allows collaberative working
- good for communication
- allows sharing of resources e.g. printers, storage and scanners
- easy to backup to a central point

4

Drawbacks of networks

- The user can become dependent on the network (If the network stops operating then it may not be possible to access various resources)
- Efficiency of a network can be very dependent on a network manager
- It is difficult to make a network of computer secure for hackers and outside threats
- As traffic increases on a network the performance can degrade

5

Protocol

A protocol is a set of rules relating to the communication between devices.

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TCP

Transmission Control Protocol – used with IP to ensure error free transmission and package switching

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IP

Internet Protocol – used to transfer all packets across the internet between routers

8

NIC

receive and send electrical signals in a network.

9

Router

devices which are used to connect networks. they receive data packets from one network and based on the address on the packet forward them of

10

Switches

devices used to connect devices on a network, they use the physical hardware MAC address to send data on to the required destination node.

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MAC Address

identifier that is permanently added to a device by the manufacturer

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Hubs

connects nodes together by broadcasting a signal to all possible destinations. The correct destination will accept the signal

13

WAP (wireless access point)

use wireless to connect a node to a WiFi network avoiding the need for lots of physical caballing

14

Transmission media

the wires that connect a network

15

Coacial Copper Cables

older, slower and cheaper

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Fibre Optic Cables

newer, faster and high-capacity

17

Bus Topology

an arrangement where nodes are connected to a central communication channel. Each end of the backbone is connected to a terminator. Each node is passive and data is sent in one direction at a time only

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Bus topology advantages

Inexpensive to set up
Devices can easily be added
Good for small networks

19

Bus Topology Disadvantages

Main cable is a single point of failure
Limited cable length
Performance degrades with heavy use
Poor security

20

Star Topology

an arrangement where a central node or hub provides a common connection point for all other nodes.

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Star Topology advantages

Easy to isolate problems
Good performance
More secure is a switch is used a data is sent only to the recipient

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Star topology disadvantages

Can be expensive to set up because of the length of cable required
Central device is a point of failure

23

Ring topology

an arrangement where on node is connect to two others to form and ring.

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Mesh Topology

an arrangement where ever node is connected to every other node.

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Client-Server Model:

one device (the client) requests services from another device (the server).

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Peer-to-Peer Model:

all terminals have equal status and there is no powerful central server, each computer acts as both a client and a server.

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advantages of Client-Server

-User IDs, passwords and access levels centrally controlled
-Backup is centralised and usually automated
-No access to other users’ files

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disadvantages of Client-Server

-Can be expensive to set up and to manage
-Server is single point of failure

29

advantages of peer-to-peer

-cheap to set up and maintain
- easy sharing

30

disadvantages of peer-to-peer

- no central backing up
-slower performance
-bad security