Openldv application architecture – Echelon OpenLDV User Manual
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OpenLDV Programmer’s Guide
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the seven layers of the OSI Model and which OSI layers a Layer 2 or Layer 5
network interface handles.
Physical Layer
Data Link Layer
Network Layer
Transport Layer
Session Layer
Presentation Layer
Application Layer
Layer 5
Network
Interface
Layer 2
Network
Interface
Figure 3. Network Interfaces and the Seven Layers of the OSI Model
A Layer 2 network interface handles only the first two layers of the OSI Model,
and thus only sends and receives network packets; an application must
implement the rest of the ISO/IEC 14908-1 protocol to communicate with the
network.
A LonScanner Protocol Analyzer uses a Layer 2 network interface. The
LonScanner Protocol Analyzer implements the rest of the ISO/IEC 14908-1
protocol to communicate with and analyze the network.
A Layer 5 network interface handles the first five layers of the OSI Model, and
thus not only sends and receives network packets, but also implements layers 1
through 5 of the ISO/IEC 14908-1 protocol to communicate with the network.
Most OpenLDV applications use Layer 5 network interfaces so that they need not
implement Layers 3 to 5 of the ISO/IEC 14908-1 protocol.
OpenLDV Application Architecture
The OpenLDV application architecture also uses the OSI Model, and provides a
programming framework for communicating with the network, as shown in