MDS iNET 900 Series User manual

User’s Guide

MDS 05-2806A01, Rev. A

MARCH 2002

Wireless IP/Ethernet Transceiver

MDS iNET 900™

MDS 05-2806A01, Rev. A MDS

i

NET 900 User’s Guide i

Contents

1

PRODUCT OVERVIEW & APPLICATIONS 1

1.1 PRODUCT DESCRIPTION...................................................................................................3

1.1.1 Model Offerings ..........................................................................................................................4

1.2 APPLICATIONS....................................................................................................................5

1.2.1 Wireless LAN ..............................................................................................................................5

1.2.2 Point-to-Point LAN Extension .....................................................................................................6

1.2.3 Backhaul for Serial Radio Networks ...........................................................................................6

1.2.4 Multiple Protocols and/or Services .............................................................................................7

1.2.5 Wireless LAN with Extended Range ...........................................................................................7

1.2.6 Upgrading Older Wireless Network with Serial Interfaces ..........................................................8

1.3 NETWORK DESIGN CONSIDERATIONS............................................................................9

1.3.1 Extending Network Coverage with Repeaters ............................................................................9

1.3.2 Protected Network Operation through Multiple Access Points .................................................11

1.3.3 Collocating Multiple

i

NET 900 Networks ..................................................................................12

1.4 ACCESSORIES..................................................................................................................13

2

i

NET EMBEDDED MANAGEMENT SYSTEM 15

2.1 INTRODUCTION ................................................................................................................17

2.1.1 Menu Structure .........................................................................................................................18

2.1.2 Differences in the embedded management system’s browser and

text-based user interfaces ...................................................................................................19

2.1.3 Accessing the Embedded Management System ......................................................................20

2.1.4 Navigating the Menus ...............................................................................................................21

2.1.5 Logging In and Out of the Embedded Management System ...................................................22

2.2 BASIC DEVICE INFORMATION.........................................................................................24

2.2.1 Starting Information Screen ......................................................................................................24

2.2.2 Main Menu ................................................................................................................................25

2.2.3 Conﬁguring Basic Device Parameters ......................................................................................26

2.3 CONFIGURING NETWORK PARAMETERS......................................................................28

2.3.1 Network Conﬁguration Menu ....................................................................................................28

2.4 CONFIGURING RADIO PARAMETERS.............................................................................29

2.4.1 Radio Conﬁguration Menu .......................................................................................................29

2.5 CONFIGURING THE SERIAL INTERFACES.....................................................................31

ii MDS

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NET 900 User’s Guide MDS 05-2806A01, Rev. A

2.5.1 Overview ...................................................................................................................................31

2.5.2 Serial Gateway (Port) Conﬁguration Menu ...............................................................................32

2.5.3 IP-to-Serial Operation and Data Flow .......................................................................................36

2.5.4 Point-to-Point Serial-to-Serial Operation and Data Flow ..........................................................37

2.5.5 Point-to-Multipoint Serial-to-Serial Operation and Data Flow ...................................................38

2.5.6 Mixed Modes ............................................................................................................................39

2.6 PERFORMANCE VERIFICATION ......................................................................................41

2.6.1 Performance Information Menu ................................................................................................41

2.6.2 Diagnostic Tools Menu ..............................................................................................................51

2.7 MAINTENANCE..................................................................................................................53

2.7.1 Maintenance Menu....................................................................................................................53

2.8 NETWORK PERFORMANCE NOTES ...............................................................................56

2.8.1 Principals of Network Operation ...............................................................................................56

2.8.2 Tips for Optimizing Network Performance ................................................................................58

2.9 UPGRADING THE FIRMWARE..........................................................................................59

2.9.1 Introduction ...............................................................................................................................59

2.9.2 Installing

i

NET Firmware by TFTP ...........................................................................................60

2.10 USING CONFIGURATION FILES.....................................................................................62

2.10.1 Introduction .............................................................................................................................62

2.10.2 Sample of an Exported Conﬁguration File ..............................................................................62

2.10.3 Editing Conﬁguration Files ......................................................................................................66

2.11 OPERATING PARAMETERS’ DEFAULTS ........................................................................67

2.12 LOGGED OPERATIONAL EVENTS.................................................................................72

3

TABLETOP EVALUATION & TEST SETUP 77

3.1 OVERVIEW.........................................................................................................................79

3.2 STEP 1—INSTALL THE ANTENNA CABLING...................................................................79

3.3 STEP 2—MEASURE & CONNECT THE PRIMARY POWER............................................80

3.4 STEP 3—CONNECT PC TO THE iNET .............................................................................80

3.5 STEP 4—REVIEW THE

i

NET

’S CONFIGURATION ...........................................................81

3.5.1 Getting Started .........................................................................................................................81

3.5.2 Procedure .................................................................................................................................81

3.5.3 Basic Conﬁguration Defaults ....................................................................................................81

MDS 05-2806A01, Rev. A MDS

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NET 900 User’s Guide iii

3.6 STEP 5—CONNECT LAN AND/OR SERIAL EQUIPMENT...............................................82

3.7 STEP 6—CHECK FOR NORMAL OPERATION.................................................................83

4

TROUBLESHOOTING &

RADIO MEASUREMENTS 85

4.1 TROUBLESHOOTING........................................................................................................87

4.1.1 Interpreting the LEDs ...............................................................................................................88

4.1.2 Troubleshooting Using the Embedded Management System ...................................................89

4.2 RADIO MEASUREMENTS.................................................................................................91

4.2.1 Antenna System SWR and Transmitter Power Output .............................................................92

4.2.2 Antenna Direction Optimization ................................................................................................93

5

PLANNING AN

i

NET RADIO NETWORK 95

5.1 PLANNING AN

i

NET

RADIO NETWORK ...........................................................................97

5.1.1 General Requirements .............................................................................................................97

5.1.2 Site Selection ...........................................................................................................................99

5.1.3 Terrain and Signal Strength ......................................................................................................99

5.1.4 Antenna & Feedline Selection ..................................................................................................99

5.1.5 Conducting a Site Survey .......................................................................................................101

5.1.6 A Word About Radio Interference ...........................................................................................102

5.1.7 How Much Output Power Can be Used? ................................................................................103

5.2 dBm-WATTS-VOLTS CONVERSION CHART ..................................................................105

6

TECHNICAL REFERENCE 107

6.1 DATA INTERFACE CONNECTORS..................................................................................109

6.1.1 LAN Port .................................................................................................................................109

6.1.2 COM1 Port ..............................................................................................................................110

6.1.3 COM2 Port ..............................................................................................................................110

6.2 FUSE REPLACEMENT PROCEDURE.............................................................................111

6.3 MDS iNET 900 TECHNICAL SPECIFICATIONS ..............................................................112

7

GLOSSARY OF TERMS & ABBREVIATIONS 115

iv MDS

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NET 900 User’s Guide MDS 05-2806A01, Rev. A

Copyright Notice

ACCURACY OF DOCUMENTATION

Every reasonable effort has been made to ensure the accuracy of this manual, however product

improvements may result in minor differences between the manual and the product shipped to you.

If you have additional questions or need an exact specification for a product, please contact our

Customer Service Team using the information at the back of this guide. Microwave Data Systems

Incorporated reserves its right to correct any errors or omissions. Updated information may also be

available on our Web site at www.microwavedata.com. This manual is for the use of professionals

to guide them in the installation, operation and basic system maintenance of the equipment cov-

ered.

OTHER MDS

i

NET 900 DOCUMENTATION

Installation Guide

—The associated MDS

i

NET 900 Installation Guide, P/N 05-2873A01, is pro-

vided with the

i

NET transceiver and is limited to essential information for installers. The installa-

tion guide assumes some guidance to installers will be provided by the readers of this manual. This

includes such things as antenna selection, radio communication site survey tools and techniques,

and network design.

Related Materials on the Internet

—Data sheets, frequently asked questions, case studies, appli-

cation notes, firmware upgrades and other valuable information are available on the MDS Web site

at site at www.microwavedata.com.

ABOUT MICROWAVE DATA SYSTEMS

Almost two decades ago, MDS began building radios for business-critical applications. Since then,

we’ve installed more than 500,000 radios in over 110 countries. To succeed, we overcame impass-

able terrain, brutal operating conditions and disparate, complex network configurations. We also

became experts in wireless communication standards and system applications worldwide. The

result of our efforts is that today, thousands of utilities around the world rely on MDS-based wire-

less networks to manage their most critical assets.

The majority of MDS radios deployed since 1985 are still installed and performing within our cus-

tomers' wireless networks. That’s because we design and manufacture our products in-house,

according to ISO 9001 which allows us to control and meet stringent global quality standards.

Thanks to our durable products and comprehensive solutions, MDS is the wireless leader in indus-

trial automation—including oil and gas production and transportation, water /wastewater treat-

ment, supply and transportation, electric transmission and distribution and many other utility

applications. MDS is also at the forefront of wireless communications for private and public infra-

structure and online transaction processing. Now is an exciting time for MDS and our customers

as we look forward to further demonstrating our abilities in new and emerging markets.

As your wireless needs change you can continue to expect more from MDS. We'll always put the

performance of your network above all. Visit us at www.microwavedata.com for more informa-

tion.

MDS 05-2806A01, Rev. A MDS

i

NET 900 User’s Guide v

OPERATIONAL & SAFETY NOTICES

Professional installation required. The radio equipment described in this guide emits radio

frequency energy. Although the power level is low, the concentrated energy from a direc-

tional antenna may pose a health hazard. Do not allow people to come closer than two

meters (6.5 feet) to the antenna when the transmitter is operating. More information on RF

exposure is available at www.fcc.gov/oet/info/documents/bulletins.

Pending Approval: FM/UL/CSA Notice

This product is available for use in Class 1, Division 2, Groups A, B, C & D Hazardous Locations. Such locations are defined in

Article 500 of the National Fire Protection Association (NFPA) publication NFPA 70, otherwise known as the National Electrical

Code.

The MDS

i

NET 900 has been recognized for use in these hazardous locations by three independent agencies —Underwriters Lab-

oratories (UL), Factory Mutual Research Corporation (FMRC) and the Canadian Standards Association (CSA). The UL certifica-

tion for the transceiver is as a Recognized Component for use in these hazardous locations, in accordance with UL Standard 1604.

The FMRC Approval is in accordance with FMRC Standard 3611. The CSA Certification is in accordance with CSA STD C22.2

No. 213-M1987.

Pending Approval: FM/UL/CSA Conditions of Approval

The MDS

i

NET 900 is not acceptable as a stand-alone unit for use in the hazardous locations described above. It must either be

mounted within another piece of equipment, which is certified for hazardous locations, or installed within guidelines, or conditions

of approval, as set forth by the approving agencies. These conditions of approval are as follows:

1. The MDS

i

NET 900 unit must be mounted within a separate enclosure that is suitable for the intended application.

2. The antenna feedline, DC power cable and interface cable must be routed through conduit in accordance with the National

Electrical Code.

3. Installation, operation and maintenance of the MDS

i

NET 900 unit should be in accordance with the transceiver's installation

manual, and the National Electrical Code.

4. Tampering or replacement with non-factory components may adversely affect the safe use of the MDS

i

NET 900 unit in haz-

ardous locations, and may void the approval.

Do not disconnect equipment unless power has been switched off or the area is known to

be non-hazardous.

Refer to Articles 500 through 502 of the National Electrical Code (NFPA 70) for further

information on hazardous locations and approved Division 2 wiring methods.

FCC Notice, U.S.A.

The device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not

cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undes-

ired operation.

This device is specifically designed to be used under Section 15.247 of the FCC Rules and Regulations. Any unauthorized modifi-

cation or changes to this device without the express approval of Microwave Data Systems may void the user’s authority to operate

this device.

Furthermore, this device must be installed by a professional in accordance with the instructions outlined in this manual. Failure to

comply with these instructions may also void the user’s authority to operate this device.

RF Exposure

EXPLOSION

HAZARD!

vi MDS

i

NET 900 User’s Guide MDS 05-2806A01, Rev. A

MDS 05-2806A01, Rev. A MDS

i

NET 900 User’s Guide 1

1

PRODUCT OVERVIEW

AND APPLICATIONS

1 Chapter Counter Reset Paragraph

Contents

1.1 PRODUCT DESCRIPTION .........................................................3

1.1.1 Model Offerings .............................................................................4

1.2 APPLICATIONS...........................................................................5

1.2.1 Wireless LAN ................................................................................5

1.2.2 Point-to-Point LAN Extension ........................................................6

1.2.3 Backhaul for Serial Radio Networks ..............................................6

1.2.4 Multiple Protocols and/or Services ................................................7

1.2.5 Wireless LAN with Extended Range .............................................7

1.2.6 Upgrading Older Wireless Network with Serial Interfaces .............8

Replacing Legacy Wireless Products.................................................8

Supplement legacy wireless network with IP services .......................9

1.3 NETWORK DESIGN CONSIDERATIONS...................................9

1.3.1 Extending Network Coverage with Repeaters ..............................9

What is a Repeater System?..............................................................9

Option 1—Using two

i

NET units to form a repeater station..............10

Option 2—Using the AP as a Store-and-Forward Repeater.............11

1.3.2 Protected Network Operation through Multiple Access Points ....11

1.3.3 Collocating Multiple

i

NET 900 Networks .....................................12

The Network Name and the association process.............................12

Can radio-frequency interference (RFI) disrupt my

MDS

i

NET 900 Network?............................................................12

1.4 ACCESSORIES.........................................................................13

2 MDS

i

NET 900 User’s Guide MDS 05-2806A01, Rev. A

MDS 05-2806A01, Rev. A MDS

i

NET 900 User’s Guide 3

1.1 PRODUCT DESCRIPTION

The MDS

i

NET 900 unit is designed to provide an easy-to-install wire-

less local area network (LAN) service with plug-and-play hardware,

with Ethernet, and serial data interface options supporting up to

512 kbps.

Invisible place holder

Figure 1-1. The MDS

i

NET 900 Transceiver

Rugged Packaging

The

i

NET 900 is housed in a compact and rugged cast-aluminum case

that needs only to be protected from direct exposure to the weather. It

contains a single printed circuit board with all necessary components for

radio operation and data communications. The only user-serviceable

component within the case is the fuse on the DC power input.

Simple Installation

The basic installation typically utilizes an omni-directional antenna at

the Access Point location and a directional antenna at each Remote unit.

The antenna is a vital link in the system and must be chosen and installed

correctly. Consult the

PLANNING AN iNET RADIO NETWORK

on

Page 97 about choosing a site and antenna selection.

For basic services, just hook up an antenna, connect your Ethernet LAN

to the

i

NET 900’s

LAN

port, apply primary power, check and set a few

operating parameters as necessary and you are done. No license is

required for operation in the U.S.A., Canada, and many other countries.

Robust Radio

Operation

The

i

NET 900’s radio transceiver is designed for frequency-hopping

spread-spectrum operation in the license-free 900 MHz band. The

MDS

i

NET 900 can provide reliable communications up to distances of

30 miles (50 km) under favorable conditions, even in the presence of

weak signals or interference.

Flexible Services

Users with a mixture of equipment having Ethernet and serial data inter-

faces can choose to use one or two of the user-configurable serial ports

through the use of a Remote Dual Gateway. This flexibility allows the

i

NET unit to provide services in data networks that are on a path from

legacy serial/EIA-232-based hardware to the faster and more easily

interfaced Ethernet world.

Transceiver

Features

The MDS

i

NET 900’s design makes the installation and configuration

easy, while allowing for changes in the future.

4 MDS

i

NET 900 User’s Guide MDS 05-2806A01, Rev. A

• Long Range—30 miles (50 km) over average terrain, with suf-

ficient antenna height in a point-to-multipoint configuration

• Industrial-Grade Product—Extended temperature range for

trouble-free operation in extreme environments

• Robust Radio Communications—Designed to operate in

high-interference environments

• High Speed—512 kbps is 50-times faster than 9.6 kbps radios

• Plug-and-Play Connectivity—Ethernet bridge configuration

option requires very little setup

• Serial Ports—Gateway for serial interface based equipment to

IP/Ethernet networks with embedded terminal server

• Single hardware package provides configuration as Access

Point or Remote

1.1.1 Model Offerings

The MDS

i

NET 900 comes in two primary models—Access Point and

Remotes. Three types of Remote Gateways are available—the Ethernet

Bridge, the Serial Gateway, and the Dual Gateway supporting

IP/Ethernet and serial services. Table 1-1 summaries the different inter-

face abilities for each type. A unit can be configured by the owner to

operate as an Access Point or as a Remote with some restrictions. Only

the Dual Gateway Remote units can be reconfigured as an Access Point.

Ethernet Bridge and a Serial Gateway Remotes cannot be reconfigured

as Access Point unless they are first upgraded to Dual Gateway type.

This is accomplished with an “Authorization Key” purchased from

MDS. Each one of these individual software keys is associated with the

serial number of the corresponding unit.

Table 1-1. MDS iNET 900 Models and Data Interface Services

Model Type LAN1COM11COM2

Access Point N/A Yes Yes Yes

Remote… Ethernet

Bridge2Yes No No

Serial

Gateway2No Yes Yes

Dual

Gateway3Yes Yes Yes

NOTES

1.Provides access to the embedded Management Sys-

tem on all units.

2.Can be upgraded to Dual Gateway with an Authoriza-

tion Key.

3.Can be conﬁgured as an Access Point through the

embedded Management System.

MDS 05-2806A01, Rev. A MDS iNET 900 User’s Guide 5

1.2 APPLICATIONS

The following sections provide illustrations of typical MDS iNET 900

installations. Most installations will require some planning by a network

manager.

1.2.1 Wireless LAN

The wireless LAN is the most common application of the MDS iNET

900. It consists of a central control station (Access Point) and one or

more associated Remote units, as shown in Figure 1-2. A LAN provides

communications between a central WAN/LAN and remote Ethernet

segments. The operation of the radio system is transparent to the com-

puter equipment connected to the iNET 900 units.

The Access Point is positioned at a location from which it can commu-

nicate with all of the iNET Remote units in the system. Commonly, this

is a relatively high location on top of a building or communications

tower. Messages are exchanged at the Ethernet level. This includes all

types of IP traffic.

An MDS iNET 900 Remote can only talk over-the-air to an Access

Point (AP) unit. Peer-to-peer communications between Remotes can

only take place indirectly through the AP. An AP can only talk

over-the-air to iNET Remote units. Two iNET AP units can communi-

cate with each other through the Ethernet connector over a common

LAN/WAN.

Invisible place holder

Figure 1-2. Typical wireless LAN

iNET 900

Remote

iNET 900

Remote

iNET 900

Acess Point

iNET 900

Remote

iNET 900

Remote LAN

LAN

WAN/LAN

LAN

6 MDS iNET 900 User’s Guide MDS 05-2806A01, Rev. A

1.2.2 Point-to-Point LAN Extension

A point-to-point configuration (Figure 1-3) is a simple arrangement

consisting of an Access Point and a Remote unit. This provides a com-

munications link for the transfer of data between two locations.

Invisible place holder

Figure 1-3. Typical point-to-point link

1.2.3 Backhaul for Serial Radio Networks

One of the primary design features of the iNET design provides a path

for serial devices to migrate to IP/Ethernet. Most radio networks in oper-

ation today rely on serial networks at data rates of 9600 bps or less.

These networks can use an iNET as the means to continue using the

serial service, while allowing the rest of the infrastructure to migrate to

an IP format.

Operational radio networks built with MDS radios, such as

MDS 9790/9710 and MDS 9810, can be supported by an iNET 900

Remote using one serial port for the data stream, and the other for net-

work-wide diagnostics. In the case of older MDS radios, where a single

port is used for data and diagnostics, the capabilities are doubled. The

data streams are delivered to an IP socket in an application, or in serial

format using the Access Point.

Invisible place holder

Figure 1-4. Backhaul Network

LAN/WAN

iNET 900

Access Point iNET 900

Remote

LAN

MDS 4710 Remote

NMS Control

Point SCADA Host

Modbus/IP

HUB

i

NET 900

Access Point

MDS 4710 Remote

MDS 9710 Remote

MDS 9810 Remote

i

NET 900

Remote Serial

i

NET 900

Remote Serial

i

NET 900

Remote Serial

NETWORK

Data

MDS 4790

Master

MDS 9790

Master

MDS 9810

Master

Diagnostics

Data

Diagnostics

ROUTER

ROUTER Serial

Device

Serial

Device

Serial

Device

Serial

Device

Serial

Device

Serial

Device

MDS 05-2806A01, Rev. A MDS iNET 900 User’s Guide 7

1.2.4 Multiple Protocols and/or Services

Prior to the iNET 900, often two radios were used to service two dif-

ferent types of devices (typically connected to different SCADA hosts)

an iNET 900 provides this functionality with a single remote radio. Each

of the two serial ports can be connected via IP to different SCADA

hosts, transporting different (or the same) protocols. Both data streams

are completely independent and the iNET provides seamless simulta-

neous operation as shown in Figure 1-5.

By using a single radio the cost of deployment is cut in half. Beyond

requiring only one radio instead of two, the biggest cost reduction come

from using half of the required infrastructure at the remote site: one

antenna, one feedline, one lightning protector, and ancillary hardware.

Other cost reductions come from the system as a whole, such as reduced

requirements to manage fewer devices. And above all, the potential to

include the availability of Ethernet and IP services for future applica-

tions, such as video for security, make the use of an iNET 900 for serial

or IP applications, such as video, a very intelligent decision.

Invisible place holder

Figure 1-5. Multiple Protocol Network

1.2.5 Wireless LAN with Extended Range

The iNET 900 is an excellent solution for a long-range industrial wire-

less LAN. An iNET 900 system offers several advantages over commer-

cial solutions—primarily improved performance over extended

distances. The rugged construction of iNET 900 and the extended tem-

perature range make it an ideal solution even when outdoor locations are

required in extreme environmental locations. In many extreme environ-

ments, a simple NEMA enclosure is sufficient to house an iNET 900.

NetView SCADA Host

Total Flow

i

NET 900

Access Point

i

NET 900

Remote Serial

i

NET 900

Remote Serial

SCADA Host

Modbus/IP

i

NET 900

Remote Serial

i

NET 900

Access Point

RTU

Flow Meter

EIA-232

ROUTER

HUB Serial

Device

Serial

Device

Serial

Device

Serial

Device

HUB

WAN

8 MDS iNET 900 User’s Guide MDS 05-2806A01, Rev. A

The MDS iNET 900 trades higher speed for longer range. Commercial

802.11b solutions were designed to provide services to relatively small

areas such as offices, warehouses and homes. They provide high data

rates but have limited range. The MDS iNET 900 uses more power, a

different frequency band, higher sensitivity, and a narrower channel to

concentrate the radio energy and reach further distances. This is unlike

commercial spread-spectrum products. The MDS iNET 900 is designed

for industrial operation from the ground up.

IP-based devices include a new breed of more powerful RTU/PLC

devices as well as other services such as Web-based video monitoring,

security applications, and voice over IP. Figure 1-6 shows a typical net-

work.

Invisible place holder

Figure 1-6. Extended-Range LAN with Mixed Applications

1.2.6 Upgrading Older Wireless Network with Serial

Interfaces

Millions of wireless data products have been sold in the last two decades

for licensed and license-free operation, many of them manufactured by

Microwave Data Systems. There are several ways that these systems can

benefit from the more flexible MDS iNET 900 equipment—more flex-

ible serial and Ethernet interfaces, and higher data throughput.

MDS iNET 900 units are well suited to replace leased or dial-up lines,

or existing 900 MHz data transceivers by taking advantage of the

iNET’s serial and Ethernet interfaces.

Replacing Legacy Wireless Products

In most cases, legacy radio transceivers supporting serial-interface

equipment can be replaced with MDS iNET 900 units. This equipment

can be connected to the MDS iNET 900 units through the COM1 or

COM2 port with a DB-25 to DB-9 cable wired for EIA-232 signaling.

The COM2 port supports all standard EIA-232 signaling and acts as a

data-terminal equipment device (DTE).

NMS Control

Point SCADA Host

Modbus/IP

i

NET 900

Access Point

i

NET 900

Remote Bridge

Printer

IP/Ethernet

i

NET 900

Remote Bridge

IP/Ethernet

IP Camera

MDS 05-2806A01, Rev. A MDS iNET 900 User’s Guide 9

Several previous MDS-brand products had non-standard signal lines on

their interface connectors; for example, to control the unit sleep func-

tion. These special functions are not provided nor supported by the MDS

iNET 900 unit at this time.

Supplement legacy wireless network with IP services

The MDS iNET 900 Dual Gateway model can support up to two serial

devices and one Ethernet connection at the same time. The serial inter-

faces (COM1 and COM2) operate in two different modes: Connection-

less Serial-to-Serial and connection-orientated IP-to-serial.

In the Connectionless Serial-to-Serial mode, the iNET 900 supports

point-to-multipoint serial-port to serial-port connectivity. In the connec-

tion-orientated IP-to-serial mode, the iNET 900 supports point-to-point

Ethernet/IP to serial port connectivity.

For further details on the MDS iNET 900 Serial Gateway interface

modes, see “CONFIGURING THE SERIAL INTERFACES” on Page 31.

1.3 NETWORK DESIGN

CONSIDERATIONS

1.3.1 Extending Network Coverage with Repeaters

What is a Repeater System?

A repeater works by re-transmitting data from outlying remote sites to

the Access Point and vice-versa. As with any other store-and-forward

device, it introduces additional end-to-end transmission delay but pro-

vides longer-range connectivity.

In some geographical areas obstacles can make communications diffi-

cult. These obstacles commonly are large buildings, hills or dense

foliage. These obstacles can often be overcome with a repeater station.

See “Extending Network Coverage with Repeaters” on Page 9 for more

details.

The geographic location of a repeater station is especially important. A

site must be chosen that allows good communication from the repeater

to both the Access Point and outlying remote sites. This location is often

on top of a hill, or other elevated terrain from which both sites can be

“seen” by the repeater station antennas. A detailed discussion on the

effects of terrain is given in Section 5.1.2, Site Selection (beginning on

Page 99).

10 MDS iNET 900 User’s Guide MDS 05-2806A01, Rev. A

Option 1—Using two iNET units to form a repeater station

Although the range between iNET 900 units can achieve up to 50 km (30

miles) over favorable terrain, it is possible to extend the range consider-

ably by connecting two units together at one site in a “back-to-back”

fashion to form a repeater, as shown in Figure 1-7. This arrangement

should be used whenever the objective is to utilize the maximum range

between stations. In this case, using high-gain Yagi antennas at each

iNET location will provide more reliable communications than their

counterparts—omnidirectional antennas.

Invisible place holder

Figure 1-7. Typical LAN with an iNET 900 repeater link

Overview Two MDS iNET 900 radios may be connected “back-to-back” through

the LAN Ports to form a repeater station. (The cable must be a

“cross-over” Ethernet cable for this to work). This configuration is

sometimes required in a network that includes a distant Remote that

would otherwise be unable to communicate directly with the Access

Point station due to distance or terrain.

A repeater works by re-transmitting data from the outlying remote site

to the Access Point and vice versa. It introduces a small amount of

end-to-end transmission delay, but this is not a problem in most systems.

The geographic location of a repeater station is especially important. A

site must be chosen that allows good communication with both the

Access Point and the outlying Remote site. This is often on top of a hill,

building, or other elevated terrain from which both sites can be “seen”

by the repeater station antennas. A detailed discussion on the effects of

terrain is given in Section 5.1.2, Site Selection (beginning on Page 99).

The following paragraphs contain specific requirements for repeater

systems.

Antennas Two antennas are required at this type of repeater station—one for each

radio. Measures must be taken to minimize the chance of interference

between these antennas. One effective technique for limiting interfer-

ence is to employ vertical separation. In this arrangement, assuming

both are vertically polarized, one antenna is mounted directly over the

other, separated by at least 10 feet (3 Meters). This takes advantage of

the minimal radiation exhibited by most antennas directly above and

below their driven elements.

iNET 900

Access Point iNET Remote

iNET 900

Remote

iNET 900

Remote

iNET 900

Remote

iNET 900

Access

Point

LAN/WAN

REPEATER

Crossover Cable

LAN

POINT-TO-POINT LINK

MDS 05-2806A01, Rev. A MDS iNET 900 User’s Guide 11

Another interference reduction technique is to cross-polarize the

repeater antennas. If one antenna is mounted in the vertical plane, and

the other in the horizontal plane, an additional 20 dB of attenuation can

be achieved. (Remember that the corresponding stations must use the

same antenna orientation when cross-polarization is used.)

Network Name The two radios that are wired together at the repeater site must have dif-

ferent network names. To set or view the network names, see “STEP 3—

CONNECT PC TO THE iNET” on Page 80 for details.

Option 2—Using the AP as a Store-and-Forward Repeater

A wireless network can be extended through the use of an alternate

arrangement using the Access Point as a repeater to re-transmit the sig-

nals of all stations in the network. The repeater is a standard MDS iNET

900 unit configured as an Access Point. (See Figure 1-8.)

Invisible place holder

Figure 1-8. Typical network with store-and-forward repeater

1.3.2 Protected Network Operation through Multiple

Access Points

Although iNET units have a very robust design and have undergone

intensive testing before being shipped, it is possible for isolated failures

to occur. Down time can be further reduced by using some, or all, of the

following configurations.

In a point-to-multipoint scenario, the Access Point services multiple

remotes. A problem in the Access Point will have an impact on each and

every one of the remotes since none will have access to the network.

When operation of the network does not tolerate any down time, it is

possible to set up a protected configuration for the Access Point to

greatly reduce the possibility of this happening.

Two or more Access Points can be configured with the same Network

Name and kept active simultaneously, each with its own independent

antenna. In this scenario, iNET Remotes will associate with either one

of the available Access Points. In case of a failure of one of the AP’s the

Remotes will quickly associate with another of the remaining Access

Points re-establishing connectivity to the end devices.

iNET 900

Remote

iNET 900

Remote

iNET 900

Remote

iNET 900

Remote

iNET 900

Access Point

LAN/WAN

REPEATER

LAN

POINT-TO-POINT LINK

12 MDS iNET 900 User’s Guide MDS 05-2806A01, Rev. A

The Access Points are unaware of the existence of the other AP’s.

Because the hopping algorithm uses the Network Name and the Wire-

less MAC address of the AP to generate the hopping pattern, multiple

AP’s can coexist. The collocated AP’s will be using different hopping

patterns and frequencies the great majority of the time. Although some

collisions will occur, the wireless-MAC is built to tolerate and recover

from such occurrences with minimal degradation.

1.3.3 Collocating Multiple iNET 900 Networks

Many MDS iNET 900 networks can operate in relatively close physical

proximity to one another providing reasonable measures are taken to

assure the radio signal of one Access Point is not directed at the antenna

of the second Access Point and each network has a unique Network

Name.

The Network Name and the association process

The Network Name is the foundation for building individual MDS

iNET 900 networks. It is part of a beacon signal broadcast by the Access

Point (AP) to any iNET 900 Remote units with the same Network

Name. MDS iNET Remotes that join the network are referred to as

being “associated” with the Access Point unit.

NOTE: All MDS iNET 900’s are shipped with “Not Programmed” as

the Network Name. This puts the unit in a non-operational

mode—the Network Name must be configured in order to pass

data and begin normal operations.

Unless a redundant system is being deployed, multiple APs with the

same Network Name should be avoided. Using the same Network Name

in multiple APs may result in Remotes associating with undesired APs

and preventing data exchange from occurring. If you must use the same

Network Name, use a different Hop Pattern Seed value in each Access

Point. (See “Radio Conﬁguration Menu” on Page 29.)

The use of a different Network Name does not guarantee an interfer-

ence-free system. It does however, assure that only data destined for a

unique network is passed through to that network.

Can radio-frequency interference (RFI) disrupt my MDS iNET

900 Network?

When multiple iNET networks operate in close physical proximity to

other wireless networks, individual units may not operate reliably under

weak signal conditions and may be influenced by strong radio signals in

adjacent bands. This radio frequency interference cannot be predicted

and can only be determined by experimentation. If you need to co-locate

two iNET units, start by using the largest possible vertical antenna sep-

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MDS iNET 900 Series User manual

MDS iNET 900 Series User manual

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