1.3.3 Flashcards
What is a network?
2 or more computers connected with the ability to transmit data between each other
What is a WAN?
A network which covers a large geographical area
What is a LAN?
A network which spans a small geographical location
What is a physical topology?
The physical layout of the wires/components which form the network
What is a logical topology?
The layout of how data flows in the network
What are the advantages of a bus topology?
- cheap
- doesn’t require additional hardware
What are the disadvantages of a bud topology?
- if backbone fails the network fails
- high traffic reduces performance
- all computers see data transmission
What are the advantages of a star topology?
- performance is consistent
- if a cable fails only that terminal is affected
- transmits data faster
- easy to add new stations
- no collisions
What are the disadvantages of star topology?
- if the server fails the network fails
- expensive
What are the advantages of mesh topology?
- No cables needed if wireless
- high traffic results in high reliability
- high speed
What are the disadvantages of mesh topology?
- Expensive if wired
- difficult to maintain
What is a protocol?
A set of rules defining how computers are to interact with each other
What are the 4 components of the TCP/IP stack?
- application layer
- transport layer
- network layer
- link layer
What does the application layer do?
Specifies which protocol is needed depending on the application
What does the transport layer do?
- Uses TCP to establish an end-to-end connection
- splits data up into packets and labels these with the packet number, total number of packets and a port number
- if any packets are lost the transport layer requests retransmission of these
What does the network layer do?
- adds the source/destination IP addresses
What does the link later do?
- adds the MAC and NIC addresses
What is the DNS?
Used to name and organise internet resources
What is pocket switching?
Data is transmitted across a network using packets
What are the advantages of using packet switching?
- data can be sent across multiple routes
- multiple methods to ensure data arrives intact
- data can be send across very large networks
What are the disadvantages of using packet switching?
- time is spent constructing and deconstructing the packets
- must wait for all packets to arrive
What is circuit switching?
An end to end connection is made between the source and destination computer and is maintained throughout the conversation
What are the advantages of circuit switching?
- data arrives in logical order which results in faster reconstruction
- enables two users to hold a call without a speech delay
What are the disadvantages of using circuit switching?
- bandwidth is wasted while data isn’t being sent
- devices must send/ receive data at the same rate
What is a firewall?
A device designed to monitor and filter access to a network
What is a proxy?
Acts as an intermediary sending and receiving data on behalf of the user
What are the advantages of using a proxy?
- user remains anonymous
- can reduce traffic
- caches frequently used websites
- can be used by administrators to limit access
What is a network interface card?
A NIC assigns a unique MAC address to a device and is required to connect a device to a network
What is a switch?
As with is a devise used to control the flow of data across a network
What is a wireless access point?
A WAP allows a device to connect to a network and is often paired with a Router to enable internet access
What is a router?
A device which connects two or more networks together
What is a gateway?
A device which translates protocols when the are not the dame
What is a client server network?
- consists of clients connected to a central server
- sever holds all info and resources
- clients request use of server
What are the advantages of a client server system?
- more secure
- no need for individual backups
- data/ resources can be shared easily
What are the disadvantages of a client server network?
- expensive
- requires specialist staff to maintain server
- if server fails, network fails
What is a peer to peer network?
The computers are connected to each other without a server
What are the advantages of a peer-to-peer network?
- cheap
- easy to maintain
- not dependent on server
- no specialist staff required
What are the disadvantages of a peer-to-peer network?
- impossible to race origin of files
- backups performed locally
- poor security
