Components and Architecture - Networking Basics Reference
Revision 5 HC900 Hybrid Controller Installation and User Guide 25
9/03
Table 3 - Open System Interconnection Model
Layer
Number .. Name
Function
Components
reside in:
Protocols
(examples)
Network
components
affected (examples)
7. Application
Identifies communications
partners, quality of service,
authentication and privacy,
and syntax constraints
PC Networking
Software (e.g.,
Windows Client,
Novell Client32)
FTP
SMTP
Modbus
drivers
Networking software
packages in PC hosts
6. Presentation
Translation between
application format and
network format, including
data encryption; also
compression/de-compression
5. Session
Establishes, manages, and
terminates connections
between applications (client to
server or peer to peer.)
4. Transport
Transparent transfer of data
between hosts. Error recovery
and flow control.
PC Software (e.g.,
Windows
NT/2000, Novell
NetWare)
TCP
UDP
Networking
packages in PC hosts
and in controllers
3. Network
Routing and Forwarding,
addressing, inter-networking,
error handling, congestion
control, packet sequencing
Software (e.g.,
Modbus/TCP)
IP Routers
2. Data-Link
(Includes 2 sub-
layers:
1. MAC (Media
Access Control)
2. LLC (Logical
Link Control)
MAC: Frame
assembly/disassembly, error
detection/correction,
addressing
LLC: call setup/termination
NIC drivers
Ethernet
802.3
Network nodes
(devices with MAC
addresses, usually
Network Interface
Cards) and
networking devices
such as Switches.
1 . Physical
Electrical transmission of bits
from one node to another
Cable, NICs
Ethernet
802.3
