Echelon 42150 User Manual
LONWORKS® Router
User’s Guide
078-0018-01E
Echelon, LonMaker, LONMARK, LonTalk, LONWORKS, Neuron,
NodeBuilder, 3120, 3150, and the Echelon logo are
trademarks of Echelon Corporation registered in the United
States and other countries. LonScanner and 3170 are
trademarks of the Echelon Corporation.
Other brand and product names are trademarks or
registered trademarks of their respective holders.
Smart Transceivers, Neuron Chips, and other OEM Products
were not designed for use in equipment or systems, which
involve danger to human health or safety, or a risk of
property damage and Echelon assumes no responsibility or
liability for use of the Smart Transceivers or Neuron Chips in
such applications.
Parts manufactured by vendors other than Echelon and
referenced in this document have been described for
illustrative purposes only, and may not have been tested
by Echelon. It is the responsibility of the customer to
determine the suitability of these parts for each
application.
ECHELON MAKES AND YOU RECEIVE NO WARRANTIES OR
CONDITIONS, EXPRESS, IMPLIED, STATUTORY OR IN ANY
COMMUNICATION WITH YOU, AND ECHELON SPECIFICALLY
DISCLAIMS ANY IMPLIED WARRANTY OF MERCHANTABILITY
OR FITNESS FOR A PARTICULAR PURPOSE.
No part of this publication may be reproduced, stored in a
retrieval system, or transmitted, in any form or by any means,
electronic, mechanical, photocopying, recording, or
otherwise, without the prior written permission of Echelon
Corporation.
Printed in the United States of America.
Copyright © 1992, 2012 Echelon Corporation.
Echelon Corporation
www.echelon.com
Welcome
A LONWORKS® router connects two communications channels within a
ONWORKS network, and routes LonTalk
L
ONWORKS router supports the installation of small or large networks, with
L
dozens to thousands of nodes.
This document describes how to design and develop a L
either the Echelon Router 5000 chip or the Echelon RTR-10 Router Core Module.
This document does not describe any of the following Echelon prepackaged router
products: MPR-50 Multi-Port Router, i.LON 600 L
3000 Power Line/RF Bridge, or LonPoint Router.
Audience
This guide provides user instructions for users of LONWORKS routers. It also
provides information for developers who plan to develop a L
based on the Router 5000 chip or who plan to integrate the RTR-10 router into
embedded or standalone routers.
Related Documentation
The following manuals are available from the Echelon Web site
(www.echelon.com
applications for Neuron® Chip or Smart Transceiver devices:
) and provide additional information that can help you develop
®
messages between them. Using a
ONWORKS router based on
ONWORKS/IP Server, CRD
ONWORKS router
• Connecting a Neuron 5000 Processor to an External Transceiver
Engineering Bulletin (005-0202-01D). This bulletin describes how to
connect a Neuron 5000 Processor’s communications port to external
transceivers for TP/XF-1250 channels or for EIA-485 networks, using an
external transceiver circuit. It also describes how to connect a Neuron
5000 Processor to a link-power TP/FT-10 channel using a L
ONWORKS
LPT-11 Link Power Transceiver.
• FT 3120 / FT 3150 Smart Transceiver Data Book (005-0139-01D). This
manual provides detailed technical specifications on the electrical
interfaces, mechanical interfaces, and operating environment
®
characteristics for the FT 3120
and FT 3150® Smart Transceivers.
• Introduction to the LONWORKS Platform (078-0391-01B). This manual
provides an introduction to the ISO/IEC 14908 (ANSI/CEA-709.1 and
EN14908) Control Network Protocol, and provides a high-level
introduction to L
ONWORKS networks and the tools and components that
are used for developing, installing, operating, and maintaining them.
• Junction Box and Wiring Guidelines for Twisted Pair LonWorks Networks
(005-0023-01P). This bulletin identifies the different types of junction
boxes and interconnections that can be used in twisted pair L
ONWORKS
networks in building and industrial control applications.
• LonMaker User's Guide (078-0333-01A). This manual describes how to
®
use the LonMaker
control, maintain, and manage a L
Integration Tool to design, commission, monitor and
ONWORKS network.
• LonMark
®
Application Layer Interoperability Guidelines. This manual
describes design guidelines for developing applications for open
interoperable L
Web site, www.lonmark.org
ONWORKS devices, and is available from the LonMark
.
• LonWorks FTT-10A Free Topology Transceiver User's Guide (078-0156-
01G). This manual provides specifications and user instructions for the
FTT-10A Free Topology Transceiver.
• LonWorks LPT-11 Link Power Transceiver User's Guide (078-0198-01A).
This manual provides technical specifications on the electrical and
mechanical interfaces and operating characteristics for the LPT-11 Link
Power Transceiver.
• LonWorks TPT Twisted Pair Transceiver Module User's Guide (078-002501C). This manual provides detailed specifications on the electrical and
mechanical interfaces and operating environment characteristics for the
TPT/XF-78 and TPT/XF-1250 transceiver modules.
®
• NodeBuilder
how to develop a L
FX User’s Guide (078-0405-01A). This manual describes
ONWORKS device using the NodeBuilder tool.
• PL 3120 / PL 3150 / PL 3170 Power Line Smart Transceiver Data Book
(005-0193-01C). This manual provides detailed technical specifications
on the electrical interfaces, mechanical interfaces, and operating
environment characteristics for the PL 3120, PL 3150, and PL 3170™
Smart Transceivers.
• Series 5000 Chip Data Book (005-0199-01B). This manual provides
detailed specifications on the electrical interfaces, mechanical interfaces,
and operating environment characteristics for the FT 5000 Smart
Transceiver and Neuron 5000 Processor.
All of the Echelon documentation is available in Adobe
PDF files, you must have a current version of the Adobe Reader
download from Adobe at: get.adobe.com/reader
For information about previous generation Neuron Chips, see one of the Neuron
Chip Data Books: Motorola
Neuron Chip TMPN3150/3120, or Cypress™ Neuron Chip Technical Reference
Manual.
Getting Support
You can get technical support for any of Echelon’s current product offerings by
contacting Echelon Support: www.echelon.com/support
You can also search the Echelon Knowledge Base for known product issues:
www.echelon.com/support/kb/search.asp
of information about Echelon products and technologies, including technical
articles that range from “How to” articles that describe how to complete a specific
task to “Bug” articles that document known issues with Echelon products.
PDF format. To view the
, which you can
.
®
LONWORKS Technology Device Data, Toshiba
.
. The Knowledge Base contains a wealth
iv
FCC Notice
The RTR-10 Router Core Module is designed to comply with the limits for a Class
B digital device, pursuant to Part 15 of the FCC Rules. The Router 5000 chip is
designed to comply with FCC Part 15 Subpart B and EN 55022 Level B.
These limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a commercial environment. This
equipment generates, uses, and can radiate radio frequency energy and, if not
installed and used in accordance with the instruction manual, may cause harmful
interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation.
Caution: Changes or modifications not covered in this manual must be
approved in writing by the manufacturer’s Regulatory Engineering
department. Changes or modifications made without written approval
may void the user’s authority to operate this equipment.
VDE Notice
The RTR-10 Router Core Module product is designed to comply with VDE 0871
Level B as a peripheral device. To ensure continued compliance, this product
should only be used in conjunction with other compliant devices.
Canadian DoC Notice
The RTR-10 Router Core Module digital apparatus does not exceed the Class A
limits for radio noise emissions from digital apparatus set out in the Radio
Interference Regulations of the Canadian Department of Communications.
L’ appareil RTR-10 Router Core Module numérique n’émet pas de bruits
radioélectriques dépassant les limites applicables aux appareils numériques de la
classe A prescrites dans le règlement sur la brouillage radioélectrique édicté par
le Ministère des Communications du Canada.
Table of Contents
Welcome ......................................................................................................... iii
Audience ........................................................................................................ iii
Related Documentation ................................................................................ iii
Getting Support ............................................................................................. iv
FCC Notice ..................................................................................................... v
VDE Notice ..................................................................................................... v
Canadian DoC Notice ..................................................................................... v
Chapter 1. Introduction to LonWorks Routers.......................................... 1
Introduction .................................................................................................... 2
LonWorks Router Products ........................................................................... 3
RTR-10 Overview ..................................................................................... 4
Router 5000 Overview ............................................................................. 6
Router Types .................................................................................................. 8
Repeater ................................................................................................... 8
Bridge ....................................................................................................... 8
Configured Router ................................................................................... 8
Learning Router....................................................................................... 9
Loop Topology ............................................................................................... 11
Power Line Routers ...................................................................................... 12
LonTalk Protocol Support for Routers ........................................................ 13
Message Buffers ........................................................................................... 13
RTR-10 Message Buffers ....................................................................... 14
Router 5000 Message Buffers ............................................................... 15
Router Performance ..................................................................................... 16
Chapter 2. LonWorks Router Electrical Interfaces ................................ 17
Overview ....................................................................................................... 18
Electrical Interface ....................................................................................... 18
RTR-10 Electrical Interface .................................................................. 18
ACLK2, BCLK1, and BCLK2 ......................................................... 20
ACP[4..0] and BCP[4..0] ................................................................. 20
ASVC~ and BSVC~ ......................................................................... 20
AXID[4..0] and BXID[4..0] .............................................................. 20
PKT .................................................................................................. 22
RESET~ ........................................................................................... 22
SERVICE~ ....................................................................................... 23
Router 5000 Electrical Interface ........................................................... 23
Clock Pins ........................................................................................ 25
CP[4..0] ............................................................................................ 27
IO[11..0] ........................................................................................... 28
JTAG Interface ................................................................................ 29
Memory Interface ............................................................................ 30
Power and Ground .......................................................................... 30
RST~ ................................................................................................ 30
SVC~ ................................................................................................ 32
Network Activity Indicator ............................................................. 34
Power Requirements .................................................................................... 35
RTR-10 Power Requirements ............................................................... 35
Router 5000 Power Requirements ........................................................ 35
Power Supply Decoupling and Filtering ..................................................... 36
Low Voltage Protection ................................................................................ 37
Chapter 3. LonWorks Router Mechanical Interfaces............................. 39
RTR-10 Mechanical Description ................................................................. 40
Router 5000 Mechanical Description .......................................................... 42
Chapter 4. Developing a LonWorks Router .............................................. 45
Developing a Router with the RTR-10 ........................................................ 46
Using Predefined Transceivers ............................................................. 48
Using Custom Transceivers .................................................................. 48
Developing a Router with the Router 5000 ................................................ 49
Configuring a Router 5000 Half-Router ............................................... 53
NodeBuilder Hardware Template .................................................. 53
NodeBuilder Device Template ....................................................... 54
Buffer Configurations ..................................................................... 55
Creating a Pre-Configured NME File ............................................ 55
Example Neuron C Source ............................................................. 56
Chapter 5. LonWorks Router Design Issues ............................................. 59
PCB Layout Guidelines ............................................................................... 60
EMI Design Issues ....................................................................................... 62
Designing Systems for EMC (Electromagnetic Compatibility) ................. 62
EMC Design Tips ................................................................................... 62
ESD Design Issues ................................................................................ 63
Designing Systems for ESD Immunity ................................................ 63
Chapter 6. Installing a LonWorks Router ................................................. 65
Introduction .................................................................................................. 66
Defining a Network Topology ...................................................................... 66
Attaching the Router to a Network ............................................................. 66
Connecting Power ........................................................................................ 67
Installing the Router on a Network ............................................................ 68
Router Installation with the LonMaker Integration Tool .................. 68
Router Installation with Network Management Messages ................ 68
Testing Router Installation ......................................................................... 69
Chapter 7. Network Management Messages ............................................ 71
Introduction .................................................................................................. 72
Standard Messages ...................................................................................... 72
Router-Specific Messages ............................................................................ 73
Router-Specific Network Management Messages ............................... 74
Set Router Mode .............................................................................. 74
Group or Subnet Table Clear ......................................................... 75
Group or Subnet Table Download .................................................. 75
Group Forward ................................................................................ 75
Subnet Forward............................................................................... 76
Group No Forward .......................................................................... 76
Subnet No Forward ......................................................................... 76
Group or Subnet Table Report ....................................................... 77
Router Status .................................................................................. 77
Far Side Escape Code ..................................................................... 78
Router Options Set with Write Memory .............................................. 78
Set Routing Algorithm .................................................................... 78
Set Buffer Size ................................................................................. 78
Set Priority Output Buffer Queue Count ...................................... 79
Set Input and Non-Priority Buffer Queue Count ......................... 80
viii
Appendix A. Communications Parameters for LonWorks Routers .... 81
Communications Parameters ...................................................................... 82
1
Introduction to LonWorks Routers
This chapter describes the router theory of operation, including router
types, LonTalk protocol support for routers, and router use of message
buffers.
LonWorks Router User’s Guide 1
Introduction
In general terms, a router is a device that forwards data packets between
communications networks. The router connects to the data lines from each
network, and reads address information in each data packet to determine the
packet’s destination.
ONWORKS router connects two communications channels within a LONWORKS
A L
network, and routes LonTalk messages between them. Using a L
router supports the installation of small or large networks, with dozens to
thousands of nodes.
Figure 1 shows a typical router installation, with a free topology channel and a
78 kbps bus topology channel connected to a 1.25 Mbps backbone twisted pair
channel. Because the network includes the routers, applications on each of the
ONWORKS devices can communicate with each other transparently, as if they
L
were installed on a common channel.
ONWORKS
Figure 1. Sample Router Installation
A single router can connect two channels, or multiple routers, called redundant
routers, can connect the same pair of channels. Redundant routers provide fault
tolerance by providing more than one routing path from one channel to another.
They are also required when not all devices on a given channel are able to hear
one another (referred to as an “ear shot problem”), for example on a radio
frequency channel. For a router to function as a redundant router, the router
must be configured to be a Configured router.
ONWORKS routers are used to:
L
• Extend the limits of a single channel. You can use a router to add a
channel to a L
ONWORKS network to support additional devices or to
extend the maximum channel length. You can add multiple routers,
depending on the capacity or distance needed.
• Interface different communications media, or bit rates, in a L
ONWORKS
network. For example, you might want to trade data rate for distance on
portions of the network, or to use a 1.25 Mbps backbone twisted pair
channel to connect several 78 kbps free topology and link power channels.
Alternatively, you might want to use power line for a portion of the
2 Introduction to LonWorks Routers
network where the devices are subject to frequent physical relocation, or
if cable installation is difficult. For each of these cases, you use a router
to connect the dissimilar L
ONWORKS channels.
• Enhance the reliability of the L
connect to a router are logically isolated, so a failure on one channel does
not affect the other channel. For example, in an industrial control
network, isolation among connected cells might be desirable to prevent a
failure in a single cell from bringing down multiple cells. You can achieve
this goal by dedicating channels to individual cells and isolating them
from one another with routers.
• Improve overall network performance. You can use routers to isolate
traffic within subsystems. For example, in a cluster of industrial cells,
most of the communications might be between devices within cells rather
than across cells. Using intelligent routers across cells avoids forwarding
messages addressed to devices within a cell, thus increasing the capacity
and decreasing the response time of the overall network.
The use of routers across channels is transparent to the application programs
within devices. Thus, you can develop applications without needing to know the
workings of the routers or even if the device’s channel will use a router. You only
need to consider routers when determining the network image of a device. When
you move a device from one channel to another, you need only change the
network image. Use a network management tool, such as the LonMaker
Integration Tool, to manage network images.
LonWorks Router Products
ONWORKS network. The two channels that
Echelon provides the following router products:
• MPR-50 Multi-Port Router (Model: 42150)
Five-channel (one TP/XF-1250 channel and four TP/FT-10 channels)
ONWORKS router. The MPR-50 can be used to connect two, three, or
L
four TP/FT-10 channels together, or it can be used to connect these
TP/FT-10 channels to a high-speed TP/XF-1250 backbone.
• i.LON 600 L
ONWORKS/IP Server (Model: 7260x)
An EIA-852 compliant LonTalk-to-IP router. The i.LON 600 provides
secure Internet access to L
ONWORKS devices and transforms the Internet
(or other IP-based network) into a pathway for L
information.
• CRD 3000 Power Line/RF Bridge (Model: 76520R)
A Power Line (PL) to RF communications device, designed primarily for
intelligent L
ONWORKS street lighting networks.
• LonPoint Router (Model: 4210x)
A two-channel router for TP/FT-10, TP/XF-78, or TP/XF-1250 L
channels. Six models are available for various network connection
combinations.
ONWORKS control
ONWORKS
LonWorks Router User’s Guide 3
• RTR-10 Router Core Module (Model: 61000R)
A compact module used by OEMs to build L
10 consists of the core electronics and firmware needed to implement a
router.
• Router 5000 (Model: 14315R)
A semiconductor product used by OEMs to build half-routers or full
routers for L
required to implement a half-router.
Packaged routers eliminate the need to build hardware and obtain the necessary
electrical interference and safety certifications. Thus, they allow direct, off-theshelf integration into the user’s L
Web page (www.echelon.com/products/routers
packaged Echelon router products.
This manual describes those Echelon router products that allow OEMs to design
and build their own custom routers for L
Core Module and the Router 5000 chips.
RTR-10 Overview
The RTR-10 Router Core Module is a compact module used by OEMs to design
and build L
channels and route LonTalk messages between them. They support installation
of networks with dozens to thousands of devices.
ONWORKS routers. A LONWORKS router connects two communications
ONWORKS routers. The RTR-
ONWORKS channels. The Router 5000 includes the firmware
ONWORKS network. See the Echelon router
) for information about the pre-
ONWORKS channels: the RTR-10 Router
The RTR-10 Module consists of the core electronics and firmware required to
implement a router. Its compact single inline module (SIM) form factor
minimizes the board space required to implement a router. Vertical SIM sockets
are available to minimize board space; right-angle SIM sockets are also available
to minimize component height.
A complete router, using an RTR-10 module, consists of the module, two
transceivers, and a motherboard to connect the RTR-10 router to the two
transceivers, as shown in Figure 2 on page 5.
4 Introduction to LonWorks Routers
Figure 2. Block Diagram of a LonWorks Router Based on the RTR-10
As the figure shows, an RTR-10 router and two transceiver modules (one to
handle each of two channels connected by the router) can be mounted on a
motherboard, along with a single power supply and two network connectors.
This sub-assembly constitutes a L
ONWORKS router. It can be packaged in an
enclosure to meet unique form factor and environmental requirements.
Depending on the application, the package could contain a single router subassembly, or could include other application-specific hardware. Multiple routers
can be packaged together for some applications, such as a backbone connecting
multiple channels.
The RTR-10 router comes preconfigured with many common L
transceiver parameters. Two sets of five transceiver identification (XID) pins on
the RTR-10 router select the appropriate transceiver type for each side. The
transceiver ID inputs eliminate a manufacturing step by automatically
configuring the RTR-10 router for most transceivers. A special transceiver ID is
reserved for programming any custom type.
One side of the RTR-10 router has a fixed input clock rate of 10 MHz. This side
can be used with transceivers running at interface bit rates from 9.8 kbps to 1.25
Mbps. The second side of the RTR-10 router can be tied to the 10 MHz output of
the first side, requiring no external components for interface bit rates from 9.8
kbps to 1.25 Mbps. Alternatively, the 10 MHz output can be divided to a lower
frequency with external hardware and used as the input clock for the second side
to support transceivers running at bit rates as low as 610 bps.
LonWorks Router User’s Guide 5
ONWORKS
Any pair of channel types can be connected by a router by selecting the
appropriate pair of transceivers. The RTR-10 router is compatible with all
ONWORKS transceivers, including standard transceivers for free topology, link
L
power, twisted pair, and power line. Using multiple communications media can
minimize installation costs and increase system performance by allowing easily
installed media, such as power line or link power, to be combined with media
such as TP/XF-1250 twisted pair.
Router 5000 Overview
The Router 5000 chip is an Echelon semiconductor product, based on the Echelon
Neuron 5000 Core, that is used to build half-routers and full routers for
ONWORKS channels. A LONWORKS router connects two communications
L
channels and route LonTalk messages between them. They support installation
of networks with dozens to thousands of devices.
The Router 5000 includes the Router firmware required to implement a halfrouter. The chip’s compact form factor minimizes the space required to develop a
half-router. You can implement two half-routers to develop a full router for the
same, or different, external transceiver types. Table 1 lists commonly used
channel and transceiver types for Router 5000-based router halves. Echelon
provides special licensing for other transceiver types, such as a Power Line Smart
Transceiver. Contact Echelon Support for additional information.
Table 1. Common Channel and Transceiver Types
Channel Type Transceiver for Half Router Notes
TP/FT-10 Echelon FTT-10A Free Topology
Transceiver (Model 50051)
TP-RS485 Any EIA-485 transceiver Can use any standard 3.3V or 5V
TP/XF-78 Echelon TPT Twisted Pair
Transceiver Module (Model
50010)
TP/XF-1250 Echelon TPT Twisted Pair
Transceiver Module (Model
50020)
Link-power Echelon LPT-11 Link Power
Transceiver (Model 50040)
Connection to the Router 5000 is
similar to the connection to a Neuron
Chip (see LonWorks FTT-10A Free
Topology Transceiver User's Guide)
EIA-485 transceiver (see the
Connecting a Neuron 5000 Processor
to an External Transceiver
Engineering Bulletin)
Add differential driver and
differential comparator circuits
(contact Echelon Support)
Add differential driver and
differential comparator circuits (see
the Connecting a Neuron 5000
Processor to an External Transceiver
Engineering Bulletin)
Add linear regulator and TX buffer
circuit (see the Connecting a Neuron
5000 Processor to an External
Transceiver Engineering Bulletin)
6 Introduction to LonWorks Routers
These external transceivers can run at interface bit rates from 9.8 kbps to 1.25
Mbps.
A complete router, using the Router 5000, consists of two Router 5000 half
routers, two transceivers, and a motherboard to connect the two half routers, as
shown in Figure 3.
Figure 3. Block Diagram of a LonWorks Router Based on the Router 5000
As the figure shows, two Router 5000 half routers and two transceiver modules,
one to handle each of two channels connected by the router, can be mounted on a
motherboard, along with a single power supply and two network connectors.
This sub-assembly constitutes a L
enclosure to meet unique form factor and environmental requirements.
Depending on the application, the package could contain a single router subassembly, or could include other application-specific hardware. Multiple routers
can be packaged together for some applications, such as a backbone connecting
multiple channels.
Unlike an RTR-10 router, you store the L
each Router 5000 half router in external EEPROM, thus allowing you to define
the appropriate transceiver type for each side.
LonWorks Router User’s Guide 7
ONWORKS router. It can be packaged in an
ONWORKS transceiver parameters for
Router Types
A LONWORKS router can use one of four routing algorithms: configured router,
learning router, bridge, and repeater. This selection allows you to trade system
performance for ease of installation. The configured router and learning router
algorithms create intelligent routers that selectively forward messages based on
network topology. Both sides of a router must use the same routing algorithm.
The following general rules apply to all four routing algorithms:
• For a message to be forwarded, it must fit into the router’s input and
output message buffers. A free input message buffer must be available.
• For a message to be forwarded, it must have a valid cyclic redundancy
check (CRC) code.
• Priority messages are forwarded as priority messages, but with the
priority level of the transmitting side rather than the priority level of the
originator of the message. If the transmitting side has not been installed
with a priority value, then priority messages are not forwarded in a
priority slot. The priority message is still flagged as a priority message,
so that if it passes through a second router that is installed with a
priority level, the second router transmits the message in a priority slot.
Repeater
A Repeater is a router that forwards all messages in both directions, regardless of
the message’s destination or domain. That is, a repeater forwards all valid
messages (that is, messages with a valid CRC code) to the other channel.
A Permanent Repeater behaves similarly, but its type cannot be changed after
creation.
Bridge
A Bridge is a router that forwards all messages received on either of the router’s
domains, regardless of the message’s destination. That is, a bridge forwards
packets received on one channel to the other channel, if the packet is sent on a
domain to which the bridge belongs. Use a bridge to span domains. In a single
domain network, a bridge functions essentially the same as a repeater.
A Permanent Bridge behaves similarly, but its type cannot be changed after
creation.
Configured Router
A Configured Router determines which packets to forward based on internal
routing tables. A configured router forwards only those messages which are
received on either of the router’s domains and which meet the forwarding rules
shown in Figure 4 on page 10 and Figure 5 on page 11. Configured routers
maintain their routing tables in non-volatile memory, and thus retain them after
a reset. These tables control forwarding of subnet and group-addressed
messages, and are managed by a network management tool.
8 Introduction to LonWorks Routers
A forwarding table is used for each domain on each side of the router. Each
forwarding table contains a forwarding flag for each of the 255 subnets and 255
groups in a domain. As shown in Figure 4 and Figure 5, these flags determine
whether or not a message should be forwarded or dropped based on the
destination subnet or group address of the message.
A network management tool initializes the forwarding tables using the network
management messages described in Chapter 7, Network Management Messages,
on page 71. By configuring the routing tables based on network topology, a
network management tool can optimize network performance and make the most
efficient use of available bandwidth. Configured routers should be used for
looping topologies; see Loop Topology on page 11.
For a L
volatile memory (typically EEPROM) and one in RAM. The non-volatile table is
copied to the RAM table when the router is initially powered-up, after a reset,
and when the router receives the Set Router Mode command with the Initialize
Routing Table option. The RAM table is used for all forwarding decisions.
Several of the operations in shown in Figure 4 and Figure 5 help prevent
message loops for service-pin messages. Service-pin messages require special
handling because they are broadcast to all nodes on the zero-length domain, and
have a source subnet ID of zero. When a router receives a service-pin message
with a source subnet ID of zero, the router modifies the source subnet field of the
message to be the router’s subnet on the receiving side. If the receiving side is
installed in two domains, two service-pin messages are forwarded, one for each
domain. Thus, the router can drop the service-pin message if a loop causes the
message to be received again on the same side.
ONWORKS router, there are two sets of forwarding tables, one in non-
Learning Router
A Learning Router, like a configured router, determines which packets to forward
based on internal routing tables. A learning router forwards only those messages
which are received on either of the router’s domains and which meet the
forwarding rules shown in Figure 4 on page 10 and Figure 5 on page 11. A
learning router always forwards all group-addressed messages. Learning routers
maintain their routing tables in non-volatile memory, and thus retain them after
a reset. These tables control forwarding of subnet and group-addressed
messages, and are updated automatically by the router firmware, rather than
their being configured by a network management tool. The group forwarding
tables are configured to always forward (flood) all messages with group
destination addresses.
When a router receives a packet with a destination address using a subnet ID, it
uses the subnet ID to determine whether to forward the packet. Learning
routers learn network topology by examining the source subnet of all messages
received by the router. Whenever a learning router receives a packet from one of
its channels, it uses the source subnet ID to learn the network topology. It sets
the corresponding routing table entries to indicate that the subnet in question is
to be found in the direction from which the packet was received. Because subnets
cannot span two channels connected to an intelligent router, the router can learn
which side a subnet is on whenever that subnet ID appears in the source address.
The subnet forwarding tables are initially configured to forward all messages
with subnet destination addresses. Each time a new subnet ID is observed in the
source address field of a message, its corresponding flag is cleared (that is,
LonWorks Router User’s Guide 9
forwarding is disabled) in the subnet forwarding table. The forwarding flag for
the destination address is then checked to determine whether the message
should be forwarded or dropped. The forwarding flags are all cleared whenever
the router is reset, so the learning process restarts after a reset.
The forwarding flag for a given subnet should never be cleared on both sides of a
router. However, the flag can be cleared on both sides if a device is moved from
one side of a router to the other side. For example, if subnet 1 is located on side
A of a router, the router will learn subnet 1’s location as soon as it receives a
message generated by any device in subnet 1. If any subnet 1 device is moved to
side B without reinstalling it, the router will learn that subnet 1 is also on side B,
and will stop forwarding subnet 1 messages to side A. The router detects this
error and logs it, as described in Chapter 7, Network Management Messages, on
page 71.
Figure 4. Configured and Learning Router Forwarding Rules, Part 1
10 Introduction to LonWorks Routers
Figure 5. Configured and Learning Router Forwarding Rules, Part 2
As with configured routers, learning routers sometimes modify source addresses
for service-pin messages to help prevent message loops.
Learning routers, in general, are less efficient in using channel bandwidth
because they always forward all messages with group destination addresses.
Their advantage is simplified installation because the installation tool does not
need to know the network topology to configure the router.
Loop Topology
A looping topology is a network topology that has the potential for message loops.
A loop is a path through two or more routers that forwards a message from a
channel to itself. For example, Figure 6 on page 12 shows a looping topology
with two channels and two routers. A message on channel A could be forwarded
LonWorks Router User’s Guide 11
by router 1 to channel B, then the same message could be forwarded by router 2
back to channel A, starting an endless loop of forwarded messages.
Figure 6. Looping Topology
The LonTalk protocol does not support topologies where loops can occur.
However, looping topologies can be desirable for the following reasons:
• Increased Reliability. Redundant routers can increase system reliability
by providing multiple paths between two channels.
• Support for Open Media. Open media (such as radio frequency [RF]
communications) might require redundant routers with overlapping
coverage to ensure complete coverage of an area.
You can use configured routers (see Configured Router on page 8) to support
looping topologies by configuring the routers to prevent message loops. For
example, the topology in Figure 6 can be supported if both routers are
configured to forward all messages addressed to subnets on channel B from
channel A; and all messages addressed to subnets on channel A from channel B.
Any groups with members on both channels can only be forwarded by one of the
two routers.
Network management tools, such as the LonMaker Integration Tool, can
automatically set up the forwarding tables for configured redundant routers.
Power Line Routers
A looping topology can be inadvertently created when using power line (PL)
media. Passive coupling between different phases of a power line system can
cause packets transmitted on one phase to be received by devices installed on
another phase. A loop can be formed when active coupling provided by a router is
combined with passive coupling. Figure 7 on page 13 shows an example looping
topology with a power line router.
12 Introduction to LonWorks Routers
Figure 7. A Looping Topology with One Router
Routers can be used between power line channels only if the two channels are
fully isolated. Such isolation is generally not the case between two phases on the
same circuit, but can be the case between phases on different distribution
transformers. Use Echelon’s PLCA-10, PLCA-20, or PLCA-30 Power Line
Communication Analyzers to confirm isolation between power line channels
before installing power-line-to-power-line routers.
LonTalk Protocol Support for Routers
The LonTalk protocol1 is designed to provide transparent routing of messages
between devices that communicate through routers. To increase the efficiency of
routers, the LonTalk protocol defines a hierarchical form of addressing using
domain, subnet, and device (node) addresses. An intelligent router operates at
the subnet level. The router determines which subnets lie on each of its two
sides, and forwards packets accordingly.
Subnets do not span intelligent routers, which allows intelligent routers to make
routing decisions based on the subnet component of a device’s logical address. To
further facilitate the addressing of multiple dispersed devices, the LonTalk
protocol defines another class of addresses using domain and group addresses.
Intelligent routers also can be configured to make routing decisions based on the
group addressing component of a message.
In general, a network management tool, such as the LonMaker Integration Tool,
is responsible for domain, subnet, node, and group address assignments.
See the ISO/IEC 14908 Control Network Protocol specification for detailed
information about the LonTalk protocol.
Message Buffers
As messages are received by a router, they are placed in an input buffer queue.
By default, this queue is limited to two message buffers to ensure that priority
messages are never enqueued behind more than one non-priority message. When
1
Echelon’s implementation of the ISO/IEC 14908 Control Network Protocol is called the
LonTalk protocol. Echelon has implementations of the LonTalk protocol in several product
offerings, including the Neuron firmware, LNS Server, SmartServers, and various network
interfaces. This document refers to the ISO/IEC 14908-1 Control Network Protocol as the
“LonTalk protocol”, although other interoperable implementations exist.
LonWorks Router User’s Guide 13
forwarded to the transmitting side of the router, priority messages have their
own outgoing buffer queue. Thus, priority processing of these outgoing messages
is assured because the transmitting side will send messages from the priority
output buffer queue before sending messages from the non-priority output buffer
queue. Figure 8 shows the message flow through the input and output buffer
queues. This message flow is duplicated for messages moving in the opposite
direction, that is, another set of input and output buffer queues exist for
messages flowing in the opposite direction.
Figure 8. Buffering Scheme for a LonWorks Router
The size and count of the message buffers is limited by the amount of RAM on
the router.
RTR-10 Message Buffers
Each router side has 1254 bytes of buffer space available. By default, this space
is allocated as two input buffers, two priority output buffers, and 15 non-priority
buffers. The default buffers are all 66 bytes in size. Table 2 shows the default
buffer configuration.
Table 2. Default RTR-10 Buffer Configuration
Queue Count
Input Buffer Queue 2 66 132
Priority Output Buffer Queue 2 66 132
Non-Priority Output Buffer Queue 15 66 990
Total 1254
The default buffer size of 66 bytes allows the router to handle packets with
maximum address overhead and data size for any network variable message and
explicit messages with up to 40 bytes of data; this size is large enough for any
network management or network diagnostic message. In applications that must
route large explicit messages with more than 40 bytes of data, the buffer size
Size
(Bytes) Total Bytes
14 Introduction to LonWorks Routers
must be increased, and the count of nonpriority buffers decreased. See Chapter 8
of the Neuron C Programmer’s Guide to understand how the network buffer sizes
are calculated. See Chapter 7, Network Management Messages, on page 71, for a
description of how to change the size and count of buffers. You can also use the
NodeUtil Node Utility, which you can download from the Echelon Web site.
However you allocate the buffer sizes and counts, the total memory required by
the three buffer queues must not exceed 1254 bytes.
The default buffer configuration places the bulk of the buffers on the output
queues of the router. For example, the standard configuration places two
network buffers on the input queue and 17 buffers on the output queue (2 priority
and 15 non-priority) of each router side. The reasoning behind this configuration
is to keep buffered packets on the output queues, after they have been processed
for forwarding. This processing includes checking for priority packets. Priority
packets are sensed and forwarded through the router’s priority output buffers, so
that priority packets are processed as quickly as possible, rather than allowing
them to be delayed behind non-priority packages in a large input queue.
There are applications, however, where the network traffic can be “bursty”,
where many packets appear on the network almost at the same time. In these
cases, the traffic bursts could cause the input queue to become full and lose
excess packets.
In this case, it might be preferable to move more of the packet buffering from the
output queue to the input queue by increasing the size of the input queue and
decreasing the size of the output queue. A router with a larger input queue can
handle larger bursts of traffic, at the risk of priority messages’ being queued
behind a number of non-priority messages.
Router 5000 Message Buffers
Each router side has maximum 26 623 bytes of buffer space available. Because
the Router 5000 has sufficient RAM available for any router configuration, you
can allocate this space with any combination of buffers, for example, seven input
buffers, two priority output buffers, and seven non-priority buffers. You can
specify any valid buffer size (see Chapter 8 of the Neuron C Programmer’s Guide
for information about valid buffer sizes), but, in general, there is no reason not to
specify the maximum size of 255 bytes. Table 3 shows a general buffer
configuration.
Table 3. General Router 5000 Buffer Configuration
Queue Count
Input Buffer Queue 7 255 1785
Priority Output Buffer Queue 2 255 510
Non-Priority Output Buffer Queue 7 255 1785
Total 4080
The buffer size of 255 bytes allows the router to handle packets with maximum
address overhead and data size for any network variable message or explicit
Size
(Bytes) Total Bytes
LonWorks Router User’s Guide 15
message. See Configuring a Router 5000 Half-Router on page 53 and the
example Neuron C code in Example Neuron C Source on page 56, for a
description of how to change the size and count of buffers. You can also use the
NodeUtil Node Utility, which you can download from the Echelon Web site.
However you allocate the buffer sizes and counts, the total memory required by
the three buffer queues must not exceed 25 K bytes.
The general buffer configuration shown in Table 3 balances the buffers between
the input and output queues of the router. For systems with large bursts of
traffic, you could specify additional non-priority output buffers. Priority packets
are sensed and forwarded through the router’s priority output buffers, so that
priority packets are processed as quickly as possible, rather than allowing them
to be delayed behind non-priority packages in a large input queue.
Router Performance
A major criterion of router performance is network throughput. An optimal
router would be able to forward traffic at the wire-rate, with zero packet loss and
minimal delay. Thus, an optimal router would forward traffic from 9.8 kbps to
1.25 Mbps, depending on the router’s transceiver type.
A real router typically does not perform at the wire-rate because of latency within
the router, including the time to receive and buffer the incoming packet at the
near side, the time to forward the packet between the halves, and the time to
buffer and transmit the packet at the far side. You should measure your router
device’s latency to determine if its design meets your system’s needs.
Example: For a 20 MHz Router 5000 device (where both halves use the Router
5000 chip), a measured data transfer rate for sending a service-pin message
between the router halves was approximately 1.2 μs per byte (or 830 kbytes/sec).
Some additional latency was also seen for the time between the beginning of the
original packet transmission and the beginning of the forwarded packet
transmission.
For slower channel types, this router latency is not significant, but could become
significant for faster channel types.
The latency between router halves is relatively invariant, with respect to router
configuration, whereas overall router latency depends on the router type and
configuration. For an RTR-10 device, the maximum data transfer rate between
router halves is approximately 2.4 μs per byte (or 416 kbytes/sec). For a Router
5000 device (where both halves use the Router 5000 chip), the maximum data
transfer rate between router halves is approximately 300 ns per byte (or 3.3
Mbytes/sec, assuming an 80 MHz system clock for both halves; this rate scales
with the system clock setting).
16 Introduction to LonWorks Routers
2
LonWorks Router Electrical
Interfaces
This chapter provides an overview of the electrical interfaces for the
RTR-10 Router Core Module and the Router 5000 chip.
LonWorks Router User’s Guide 17
Overview
This chapter describes the electrical interface and power requirements for a
ONWORKS router.
L
Electrical Interface
The following sections describe the electrical interface for a LONWORKS router,
including detailed descriptions of each of the RTR-10 and Router 5000 pins.
RTR-10 Electrical Interface
Figure 9 shows a schematic view of a connector for the RTR-10 Router Core
Module, and Table 4 shows the pinout of the RTR-10 Router Core Module. See
the Neuron Chip Data Book for more information about the use of the Neuron
Chip communications port pins.
Figure 9. RTR-10 Header Pinout
Table 4. RTR-10 Pinout
Pin Name Pin Description Pin Number
ACLK2 A-side output clock 27
ACP0 A-side network communication port 0 8
ACP1 A-side network communication port 1 7
ACP2 A-side network communication port 2 6
ACP3 A-side network communication port 3 9
ACP4 A-side network communication port 4 5
18 LonWorks Router Electrical Interfaces
Pin Name Pin Description Pin Number
ASVC~ A-side Service output 12
AXID0 A-side transceiver ID 0 (LSB) 20
AXID1 A-side transceiver ID 1 18
AXID2 A-side transceiver ID 2 17
AXID3 A-side transceiver ID 3 16
AXID4 A-side transceiver ID 4 (MSB) 15
BCLK1 B-side input clock 29
BCLK2 B-side output clock 33
BCP0 B-side network communication port 0 37
BCP1 B-side network communication port 1 38
BCP2 B-side network communication port 2 39
BCP3 B-side network communication port 3 36
BCP4 B-side network communication port 4 40
BXID0 B-side transceiver ID 0 (LSB) 22
BXID1 B-side transceiver ID 1 24
BXID2 B-side transceiver ID 2 23
BXID3 B-side transceiver ID 3 21
BXID4 B-side transceiver ID 4 (MSB) 19
BSVC~ B-side Service output 28
GND Ground 1, 2, 3, 11, 26, 30, 32, 34
PKT Packet forward output 14
RESET~ Reset input and output) 25
SERVICE~ Combined Service input 13
VCC +5 VDC input 10, 31
NC No Connect 4, 35
LonWorks Router User’s Guide 19
ACLK2, BCLK1, and BCLK2
A 10 MHz crystal is provided for Side A of the RTR-10 router, which can run at
only 10 MHz. This clock rate allows Side A to be used with transceivers running
at interface bit rates from 9.8 kbps to 1.25 Mbps. The 10 MHz clock is output on
the ACLK2 pin, which allows Side B to be tied directly to the same clock through
pin BCLK1. Thus, no external components are required to support the same
range of bit rates on Side B.
The 10 MHz output can be divided to a lower frequency with external hardware,
and used as the input clock for Side B to support transceivers running at
interface bit rates as low as 610 bps.
ACLK2 can drive five LS-TTL loads.
ACP[4..0] and BCP[4..0]
The ACP[4..0] and BCP[4..0] signals are connected to the CP[4..0] pins of the
core module Neuron Chips. The function of these pins is described in the Neuron
Chip Data Book.
ASVC~ and BSVC~
Each side of the RTR-10 router has an independent service-pin output: ASVC~
for the A Side and BSVC~ for the B Side. You can connect these output pins to
service LEDs, as shown in Figure 23 on page 47 (in chapter 4). The function of
the service pin is described in the Neuron Chip Data Book. The internal pullup
resistor for the service pin on each side is enabled.
The service LEDs reflect the firmware status:
• Blinking means that the router side is unconfigured
• Off means that the side is configured
• On means that the side has failed
AXID[4..0] and BXID[4..0]
The RTR-10 router comes preconfigured with many common LONWORKS
transceiver parameters. Two sets of five transceiver identification (ID) pins on
the RTR-10 router select the appropriate transceiver type for each side. The
transceiver ID inputs eliminate a manufacturing step by automatically
configuring the RTR-10 router for most transceivers. A special transceiver ID is
reserved for programming any custom transceiver type; this value causes the
communication port pins to be configured as inputs so that no line will be driven
by both the transceiver and RTR-10 Neuron before the RTR-10 Neuron Chips can
be properly configured.
The RTR-10 firmware reads the transceiver ID inputs on power up and reset. If
the router is being powered-up for the first time, or if the transceiver ID is
different from the last time it was powered-up, the parameters specified in Table
5 on page 21 are loaded. If the router is being re-powered-up, and the transceiver
ID is not 30 (0x1E), the RTR-10 firmware compares the network bit rate and
input clock for the specified transceiver to the current transceiver parameters. If
these parameters do not match, all transceiver parameters are reinitialized. This
20 LonWorks Router Electrical Interfaces
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