Zusammenfassung der Ressource
4. Networks
- Definition: Collection of
computers and other hardware
connected to allow the
communication and sharing of
resources
- Network
types
- LAN
- Occupy an office or
building
- WAN
- e.g Internet
- Advantages
- Allow software
to be installed
- Communication: email,IM
- Sharing
resources
- Share file access
- Share
printers
- Internet connection
- Network management
- Access to files wherever
you log in(LAN)
- Devices
- Router
- Enables connection between
LAN and internet
- Hub
- Where multiple computers can be
connected by ethernet cables.
- Computers can communicate
with eachother
- Allows internet connection
to be shared
- Switch
- Same as hub, Learns location of
the computers and other devices
plugged in
- More efficient(fewer
unnecessary signals
- Network interface card
(NIC)
- Where ethernet cable
plugged in
- Wireless signals
recieved
- Topology
- Bus
- 2 Terminators
- Backbone
- Advantages
- Cheap/Minimal cabling
- Easy to remove computers
- Disadvantages
- Slowed by by highway
network traffic
- Main cable fails-entire
network fails
- Star
- Single central
device(switch?hub)
- Advantages
- Faults easy to find
- Easy to add extra
devices
- System is secure as data is
only sent to needed device
- If 1 cable fails only that
device at end fails
- Disadvantages
- Lots of cable(expensive)
- Ring
- Connected
in a "circle"
- Advantages
- Very high rates of
transmission possible
- No
collisions
- Disadvantages
- Failure of single device or cable
brings entire network down
- Security not ensured
- Protocols
- Used in communication between computers and their
periphaerals and between computers across a network
- Set of rules that computers mus follow
in order for successful communication
- HTTP(Hyper Text Transfer
Protocol)
- Set of rules governing how hypertext is moved
around the internet from device to device
- FTP(File transfer
Protocol)
- How files are moved from one
computer to the other across the
internet
- Relies upon building websites,moving files
from developer's computer to a server, from
which they can be accessed publicly
- TCP(Transmission
Control Protocol)
- Used by email and web pages to ensure data is
sent securely and in an orderly way.
- IP(Internet
Protocol)
- Provides computer with its
own unique address
- Protocol Stack
- Combination of pieces of
software that allow multiple
protocols to be used on a
single computer in the
correct order
- Networks Security
Measures
- Passwords
- Strong passwords
- Symbols,Numbers,
upper/lower case words
- User access levels
- Different
access and
privileges
levels
according to
user
- Student: Manage
own files
- Trainee network
technician: Install
software + student
level access
- Network manager: Format
drives, delete/create user
accounts + Trainee access
- Encryption
- Turns readable data into apparent nonsense
- Decrypted after sent over internet
- Encryption key
- Samll program that encyptes or decrypts data
- Network Policies
- Acceptable use
- Sets out what users are
allowed to do and not
allowed to do in a
networj
- e.g Whether users can play games
- e.g What personal information
should be entered into a
network
- Without employees signing this they
may break laws by accident and cause
their company legal problems
- Backup
- States what data will be backed up from the network,how often it will be backed
up, where it will be stored and how it would be used to restore any lost data
- Data is less likely to be lost
- Archive
- Long-term storage for data that is not needed on a day-to-day basis
- Archive policy will stipulate what data is to be achieved,where it
will be stored and how old data needs to be before it is archived
- For legal reasons, organisations need to keep data for longer than it is useful to them
- Disaster recovery
- Describes how an organisation's IT
infrastructure will keep it running in the event
of a disaster
- Contains parts of the backup and failover policies
- Important because an organisation without
an IT capability is likely to lose income
- Loose people's trust in their ability to operate