Echelon LonTal Stack - Manual (Page 14)

2 Introduction to the LonTalk Stack
Overview
Automation solutions for buildings, homes, utility, transportation, and industrial
applications include sensors, actuators, and control systems. A L
ON W ORKS
network is a peer-to-peer network that uses an international-standard control
network protocol for monitoring sensors, controlling actuators, communicating
with devices, and managing network operation. In short, a L ON W ORKS network
provides communications and complete access to control network data from any
device in the network.
The communications protocol used for L
ON W ORKS networks is the ISO/IEC
14908-1 Control Network Protocol. This protocol is an international standard
seven-layer protocol that has been optimized for control applications and is based
on the Open Systems Interconnection (OSI) Basic Reference Model (the OSI
Model, ISO standard 7498-1). The OSI Model describes computer network
communications through seven abstraction layers. The implementation of these
seven layers in a L ON W ORKS device provides standardized interconnectivity for
devices within a L ON W ORKS network. The following table summarizes the CNP
layers.
OSI Layer Purpose Services Provided
7 Application Application compatibility Network configuration, self-installation,
network diagnostics, file transfer,
application configuration, application
specification, alarms, data logging,
scheduling
6 Presentation Data interpretation Network variables, application messages,
foreign frame transmission
5 Session Control Request/response, authentication
4 Transport End-to-end
communication reliability
Acknowledged and unacknowledged
message delivery, common ordering,
duplicate detection
3 Network Destination addressing Unicast and multicast addressing,
routers
2 Data Link Media access and framing Framing, data encoding, CRC error
checking, predictive carrier sense
multiple access (CSMA), collision
avoidance, priority, collision detection
1 Physical Electrical interconnect Media-specific interfaces and modulation
schemes
Echelon’s implementation of the ISO/IEC 14908-1 Control Network Protocol is
called the LonTalk protocol. Echelon has implementations of the LonTalk
protocol in several product offerings, including the Neuron firmware (which is
included in a ShortStack
® Micro Server), OpenLNS Server, SmartServers, i.LON