Zusammenfassung der Ressource
Networks
- LAN
- A LAN is a local
area network
and is used for
local devices
- Advantages
- Much cheaper to
set up than a WAN
- Disadvantages
- Cannot provide network
for as many devices.
- WAN
- A WAN is a wide area
network that spans a
relatively large
geographical area
- Disadvantages
- They are very
expensive too
set up
- Advantages
- They can spread
long distances and
provide networks
in a large area
- Topologies
- Bus
- A single cable connects all
the computers. All the
clients and servers
connect to this cable
- Ring
- Each computer is
connected to two other
computers in a ring
formation
- Mesh
- Each computer is
connected to one
or more other
computers
- Packet Switching
- So for this one. Whatever kind
of data you are trying to send
through the network is
chopped into smaller parts and
sent down different paths. This
means that some parts of the
information get there later
than others creating LAG
- Pathfinding
- When either the packet switch or
circuit switch is active it needs to
find a suitable path to its device
or server. The way it does this is
by using path finding algorithms.
Some paths are cheaper than
others so these algorithms try
and find the cheapest one
- Circuit Switching
- Circuit switching finds a
path in the network and
blocks any other devices
from using it, an
example of where this is
used is a telephone call.
It eliminates LAG
- Star
- All computers
are connected to
a central hub or
switch
- Ethernet and Wi-Fi
- Ethernet
- Ethernet is a wired
connection / protocol
used for wired
connection
- Wi-Fi
- Wi-Fi is the
protocol for
wireless
connection
- 801.11
- wifi
- Bluetooth
- small range
wireless
connection
- HTTP and HTTPS
- HTTP(Hyper Text Transfer Protocol)
- Standard protocol
used for
requesting a HTML
file from a
webserver
- HTTPS
- Secure version of
HTTP that encrypts
your data
beforehand in order
to stop interception
- POP3 and SMTP
- POP3(Post office protocol 3)
- protocol used for
downloading email from a
server. Its old and can only
be accessed from one
device
- SMTP(Simple Mail
Transfer Protocol)
- Uploads mail to a
server for it to then be
received and
downloaded by POP3
- IMAP
- IMAP(Internet Message
Access Protocol)
- replaced POP3 as does not
need to be downloaded from
the server and can be kept on
there. As well as this it can be
read and accessed on many
different devices unlike POP3
- FTP
- FTP(File Transfer Protocol)
- Protocol used for
transferring files between
2 computers and normally
used by web developers to
upload their HTML files to
their websites
- TCP/IP Layers
- Application Layer: Provides application services
- Transport Layer: Handles data consistency (error checking)
- Network Layer: Provides network addressing and routing
- Data Link Layer: Prepares and corrects data for physical
- Physical Layer: Transmits and receives bits
- Each layer performs its own
protocol action, then passes on
the data to the next layer.
- IP Adresses
- Internet Protocol addresses
are the unique identifiers
assigned to computers on a
TCP/IP network (including
the internet)
- IPV4: Between 0.0.0.0 and
255.255.255.255, there are 2 to
the power of 32 different
values. This version of the IP
address system is called IPV4
- IPV6: uses a 128 bit address.
This is 2 to the power of 128
different possible addresses.
- DNS
- Every computer
on the internet is
identified by its IP
address
- When you type a web address into a
browser, your ISP (Internet service
provider) sends the domain name to
its DNS server, wich returns the IP
address
- DNS is essentially a large address book