OSI layer services
Briefly, the services provided at each layer of the stack are:
Provision of network services TO the user’s application programs
Note: the user’s actual application programs do NOT reside here
Maps the data representations into an external data format that will enable
correct interpretation of the information on receipt. The mapping can also
possibly include encryption and/or compression of data
Control of the communications between the users. This includes the
grouping together of messages and the coordination of data transfer between
grouped layers. It also affects checkpoints for (transparent) recovery of
aborted sessions
The management of the communications between the two end systems
Responsible for the control of the communications network. Functions
include routing of data, network addressing, fragmentation of large packets,
congestion and flow control.
Responsible for sending a frame of data from one system to another.
Attempts to ensure that errors in the received bit stream are not passed up
into the rest of the protocol stack. Error correction and detection techniques
are used here
Defines the electrical and mechanical connections at the physical level, or
the communication channel itself. Functional responsibilities include
modulation, multiplexing and signal generation.
from : Practical TCP/IP and
Ethernet Networking
- Deon Reynders Pr Eng, BSc BEng, BSc Eng (Elec)(Hons), MBA
- Edwin Wright MIPENZ, BSc(Hons), BSc(Elec Eng), IDC Technologies, Perth,
Australia
Understanding TCP/IP
A clear and comprehensive guide to TCP/IP protocols
- Libor Dostálek
- Alena Kabelová
