Wireless LAN Network Topologies (ENG)

1/27Wireless LAN

Network Topologies

Geert BrackeAcc. Manager BeLux

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Markets

Automation – Production, Service

Energy – Data Transfer, Management

Transportation – Data Transfer, Traffic Monitoring

Industrial Wireless LAN

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Applications

Interconnection to Mobile Devices

Enlighting of Halls and Production Environments

Adding WLAN as Redundant Connection to Cable Installations

Replacement of Cabling

BAT54-Rail - Industrial Wireless LAN

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Focussed on Security

There are three Types of Security :

> Safety of Operation using Redundancy

> Transmission Stability by optimzed WLAN Quality

> Network Security by Authentication, Encryption and Firewall

Industrial Wireless LAN

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Possible topologies of networks

Advantages of the available possibilities

Disadvantages

Goals for improvement of WLAN availability

Threats to solve

possible solutions

Today’s possibilities with WLAN in industrial environments

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Extension of existing LAN

Clients can be: Notebooks, PCs or BAT54-Rail in Client Mode

Frequency ranges: 5GHz or 2,4 GHz

Clients move in between Access-Points

Local Area Network

WLAN Infrastructures

Client

Access-Point

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BAT54-Rail at Client or „Client Bridge“ Mode

LAN-LAN coupling via WLAN

LAN 1LAN 2

SNR signalization by LED for Clients and Point-to-Point-Connections

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Enhanced Stability for WLAN

Two Radio Interfaces in access point and client

Redundant connection using Rapid Spanning Tree

Transparent to Industrial Ethernet Protocols (Layer 4)

Two Frequency Ranges simultaneously

Network

2,4GHz

Redundant Wireless LAN

5GHz

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5 GHz Backbone

2,4 GHzwith Client

interconnection

WLAN Distribution

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Relay functionality to interconnect

between radio cells

Illumination of areas (campus, hot spots)

Wireless Distribution

11/27Possible WLAN Topologies

LAN connectionMax. 6x P2P/Interface

AP1

AP 1

Local NetworkPoint-to-Point-Connection

AP 2 AP 3 AP 4

AC1/AP2 AC2/AP3AP n

12/27Map of customer site

Laboratory

Hall 9

Hall 6

13/27WLAN Topology at Customer

Laboratory Hall 9

Hall 6

Hall 9-1

Hall 6-1Hall 9-3

Hall 9-4

Hall 9-5

Lab 1 Hall 9-2

Local NetworkPoint-to-Point-Connection

4th floor

2nd floor

Ground

floor

14/27Threats for industrial WLAN networks

There are still some threats for WLAN in industrial environment:

- the connections are not stable enough

- rough environmental conditions

- Industrial Ethernet Protocols are very sensitive to packet latency and interruptions (Profinet, Ethernet/IP)

- Safety applications need very high availability (failover < 99,999%)

- Usability should be as easy as plugging cables

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Field level

Control level

TRANSMITTER

PLC

VALVESENSOR

HMI / IPC

TRANSMITTER PENDENTBUTTONS

DRIVES &MOTORS

Enterprise Resource Planning

WLAN

Bluetooth/Zigbee/Wise/UWB/Varan etc.

Industrial network layer

16/27Utilizing Rapid Spanning tree for fixed network redundancy

17/27Utilizing Rapid Spanning tree for fixed network redundancy

Advantages:- Available today- standardized protocol (802.1w)- also used for ethernet networks

Missing:- No automatic configuration of the topology- fixed installation needed- still high handover times

18/27Goals for improvement of industrial WLAN networks

Goals:- rise the availability

- no more single points of failure

- easy-to-setup and to use

- reduce packet latency and handover times

Achieve by:- create redundancy (which is basically controversial to 802.11 MAC functionality)

using other topology: meshed networks

19/27Meshed network topology

History:

- Mid 1990ies created by DARPA for military applications on battlefields- Improved by R&D companies like SRT International- Wikipedia offers today more than 50 possible routing protocols for meshing

Features:

- Better scalability: network power increases by each hop added to it- Automatic configuration and scalability- very fast or even no handover times- increase of availability of WLAN network- quick and easy setup - reduction of cables needed

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Gateway to Sensor networks

search for the best itinerary self healing network no cabling

WAN/LAN-Gateway

Meshed networks

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fast handover allways more than one connection avilable Increase of availability

WAN/LAN-Gateway

Meshed networks

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search for the best itinerary Addition of bandwidth Increase of availability

WAN/LAN-Gateway

Meshed networks

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Gateway to Sensor networks

more CPU power needed routing capabilities are not part of basic access points at least two WLAN interfaces needed

WAN/LAN-Gateway

Meshed networksAccess Points need to

-Route-Negotiate-encrypt

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The way to keep the overview - Management System

A meshed network is basically self-configuring

How to keep the overview?

Over the current topology

Over possible vulnerabilities

Over possible attacs

Management Systems today base on SNMP protocol (polling)

Mesh APs need to declare themselves LLDP

Meshed networks have higher demands to management than current WLAN!

Wireless management

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Network Security is still a must!

A meshed network is very flexible

Authentication mechanisms are very static today

802.1x needs external servers

How to know which device may connect?

How about Rogue APs?

802.1x can be part of the AP already (BAT54-Rail Version 7.10)

Meshed networks have higher demands to security functionality WLAN!

Wireless security

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Hirschmann BAT54-Rail

The operating system offers many capabilities today

IP routing is already implemented

802.1x internal server and supplicant is available

Equipped with two WLAN interfaces

Equipped with powerful Intel CPU and sufficient memory

It’s more than just a basic access point

Meshing will be available by software update. No new hardware needed.

Roadmap:

Find out which protocol is best (IEEE 802.11s is in discussion but maybe not suitable for industrial applications): Q1/2008

Implement and test: Q3/2008

The roadmap to Meshing

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Thank you for your attention!