Zusammenfassung der Ressource
OSI Model
- Open System Interconnection
- Defines how messages should
be transmitted from one device
to another
- Application (layer 7)
- Supports application and
end user processes
- Partners identified, quality
identified, user authentication and
privacy considered
- Constraints on
data syntax
identified
- Application specific
- Presentation (Layer 6) -
sometimes known as
syntax layer
- Provides independence
from differences in data
representation
(encryption)
- Translate from application to network format
- Works to transform data
into form that application
layer can accept it
- Encrypts data to be sent across a network
- Session (Layer 5)
- Establishes, manages and
terminates connections
between applications
- Sets up, coordinates, and
terminates exchanges
between applications at
each end.
- Deals with session and connection coordination
- Transport (Layer 4)
- Provides transparent transfer
of data between end systems,
or hosts and is responsible for
end to end error recovery and
flow control
- Ensures
complete
data
transfer
- Network (Layer 3)
- Provides switching and
routing technologies,
creating logical paths
known as virtual circuits
for transmitting data from
node to node
- Addressing,
inter-networking, error
handling, congestion
control and packet
sequencing
- Data Link (Layer 2)
- Data packets
encoded and
decoded into bits.
- Handles errors in
physical layer, flow
control and frame
sync
- 2 sub-layers
- Media Access Control (MAC)
- Controls how network
gains access to data and
permission to transmit it
- Logical Link Control (LLC)
- Controls frame sync, flow control and error checking
- Physical (Layer 1)
- Coveys bit stream
- Electrical impulse, light or radio signal
- Provides hardware means of
sending and receiving data on a
carrier
- Benefits
- Independent of country
- Any hardware/ software that
meets OSI standard can
communicate
- Consumers have a wider range of choice
- Not dependant on operating system