1.7 Industrial Redundant Networks - Marc Lee, Belden Automation

Industrial Redundant NetworkIndustrial Redundant Network

Marc Lee Technical Manager Industrial NetworkingTechnical Manager, Industrial NetworkingBelden Automation (Asia Pacific) Pted Ltd

The Green Field Site

The “Green Field Site” Scenario

• Industrial Ethernet network design is complex• Industrial Ethernet network design is complex…..‐ Cabling standards

‐ Industrial Ethernet Protocols

‐ Harsh environment

‐ High resilience / availability

‐ Specific routing requirementsSpecific routing requirements

‐ Traffic shaping

‐ Convergent networking

Wireless‐Wireless

‐ Security

‐ Industrial network management

The “Green Field Site” Scenario

• You must provide a complete solutionou ust p o de a co p ete so ut o

– How do you design the network?

– How does it all fit together?

How do you give your customers more than they expected?– How do you give your customers more than they expected?

The Scenario

• Green field site

• Architects have designed the campus

• You have to design the network

• Mixture of office and manufacturing environmentsMixture of office and manufacturing environments

Initial Consultation

• Consultation– Customer requirements

– Your experience

Symbiosis– Symbiosis

High Level Office Requirements

• 600 employees using PCs– Company Managementp y g– Internal Sales– Administration– Human Resources– Marketing– IT Department– Research and Development

C t T h i l S t– Customer Technical Support– Security

• Remote connections• Remote connections– Partners– Suppliers– Internet AccessInternet Access– Teleworkers

High Level Factory Requirements

• 99.999% network availability

• Network modifications during live operation

• High temperature

• High electromagnetic interferenceHigh electromagnetic interference

• Manufacturing information available in the offices

• Industrial Ethernet protocol

Site Plan

1. Manufacturing F ilitiFacilities

2. Goods In/Out3

57

3. Stores4. Admin / Human

1

2

36

Resources5. R&D / Tech

1

11

Support6. IT Department

4

87. Sales / Marketing8. Security

8 9

OSI 7 Layer Model

Application

Session

Presentation

Network

Transport

IP

TCP / UDP

Physical

Data Link

Cabling

Ethernet

Redundancy Design looking at …

Causes of network faults…..

3 %Application programs

Application

8 %

7 %

Network operating system

Session

Presentation

10 %

12 %

system

NetworkNetwork

Transport

35 %

25 % Network components

Physical

Data Link

Source: Datacom, Network Management Special

MRP (Media Redundancy Protocol)

• Switched Ethernet networksin ring topology

• Guaranteed failover time of < 200ms / < 500ms (10 i f t l )(10ms in future release)

• Developed by Hirschmann in 1998 (“HiperRing”TM)

• International standard (IEC 62439) since March 2008

IEC 62439

IEC 62439 defines four different redundancy protocols:

MRP, PRP, CRP, BRP

62439 © IEC:2008(E)

CONTENTS

, , ,

CONTENTS

FOREWORD.........................................................8INTRODUCTION....................................................101 Scope 111 Scope.........................................................112 Normative references .........................................113 Terms, definitions, abbreviated terms, acronyms, conventions..124 Concepts for high availability automation networks............225 MRP – Media Redundancy Protocol based on a ring topology .....376 PRP – Parallel Redundancy Protocol............................817 CRP – Cross-network Redundancy Protocol .................... 1038 BRP – Beacon redundancy protocol ........................... 133Annex A (informative) Classification of networks.............. 163A B (i f ti ) A il bilit l l ti 165Annex B (informative) Availability calculations .............. 165Annex C (normative) Network management information base ...... 174

MRP Products

• Many products from different vendors already on the market

Hi h h i l t d MRP i ll f it d it h• Hirschmann has implemented MRP in all of its managed switches

• Portable code for MRP Media Redundancy Protocol is available from IP suppliers

Types of Network Redundancy

• Media redundancy

– STP, RSTP (mesh)

– MRP BRP (ring)MRP, BRP (ring)

in case of failure switchover to alternative path

• Parallel Networks

– PRP (duplicated networks)

– HSR (ring)

sending data in parallel over two different paths Zero failover timedifferent paths, Zero failover time

….end node

endnode

end node

LAN A

LAN B

Failover time of Redundancy Protocols

Protocol StandardTypical re-config time Remark

Available since

any topology / mesh, STP Spanning Tree IEEE802.1 30s diameter limited 1990

RSTP Rapid Spanning Tree IEEE802.1 2sany topology / mesh, diameter limited

2001 / 2004

MRP Media Redundancy Protocol IEC 62439200ms, 500ms (50 switches) ring

1998 (1) / 2007

CRP Cross Network Protocol IEC 624391 s worst casefor 512 end nodes

any topology / duplicated networks

PRP Parallel Redundancy Protocol IEC 62439 0msany topology / duplicated networks -

4 8 ms worst case Two top switches withBRP Beacon Redundancy Protocol IEC 62439

4,8 ms worst casefor 500 end nodes

Two top switches with star, line or ring -

Optimized RSTP Rapid Spanning Tree Future release of IEC 62439 5..20ms per hoplimited to special config set 2008

Fast MRP Media Redundancy Protocol Future release of IEC 624395..20ms (up to 50 switches) ring 2007Fast MRP Media Redundancy Protocol Future release of IEC 62439 (up to 50 switches) ring 2007

HSR High Available Seamless Ring Future release of IEC 62439 0ms ring -

DRP Distributed Redundancy Protocol Future release of IEC 62439100 ms worst casefor 50 switches ring, double ring -

(1) pre standard Hiper Ring since 1998 MRP since 2007(1) pre-standard Hiper Ring since 1998, MRP since 2007

MRP Overview

• MRP is a Data Link Layer protocol on top of Eth t MAC

MRPMana-gement

MRP

Ethernet MAC

• It uses similar mechanisms as RSTP, e.g.

gement(Service) (Protocol) DATA

LINKLAYER

802.3 MEDIUM

802.3 MEDIUM

802.1 Bridge

, g– Delete forwarding data

base after re-configurationSet ports into

PHYSICALLAYER

MEDIUM ACCES S

802.3 P HY

MEDIUM A CCESS

802.3 PHY

– Set ports into blocking or forwarding mode

• MRP defines a Redundancy Manager (MRM) and Redundancy Clients (MRC)

MRP Features

MRP Features:• Works with 10/100/1000/10 000 Mbit/s Ethernet• Works with 10/100/1000/10.000 Mbit/s Ethernet • More than 50 Switches • Deterministic fail-over time <10ms or <200ms

(depending on implemented parameter set)• Simple layer 2 redundancy• Plug and Play without any configuration• Ring topology• Works on total network distances of• Works on total network distances of

more than 3.000 kmup to 120 km between 2 switches

MRP – How it Works

High Availability Network with MRP



Failure of a link can be bypassed by switching to redundant link

Close the ring


Communication Control by Watchdog-Packets

Redundancy Manager sendsRedundancy Manager sends continuously Watchdog-Packets into the network to check communication

RedundancyManager



RedundancyManager



RedundancyManagerNormally no data packets are

transmitted over the redundant link. Only watchdog packet are forwarded



RedundancyManager



As soon as the redundancyRedundancy

Manager

As soon as the redundancy manager receives no more Watchdog-Packets, the redundant path will be activated immediately.

ACTIVE


„Self-healing“

RedundancyManager ACTIVE


„Self-healing“

When the failed link goes active RedundancyManager

When the failed link goes active again, the redundancy managerswitches back to normal operation



RedundancyManager

RSTP versus MRP: RSTP Operation Principles

RSTP switchPort Port

RSTP SwitchPort

RSTP Switch Port

RSTP

MAC

RSTP

MACMAC MACRSTP

Phy PhyPhy Phy

Switching F nction

Forwarding of topology / control informationFunction

RSTP BPDU• Point to point propagation =>

Communictaion from switch to switch, • latency depends on implementation in devices

E d i dd dditi l l t• Every devices adds additional latency

RSTP versus MRP: MRP Operation Principles

MRP switchPort Port

MRP Switch Port

MRP SwitchPort

MRP

MAC

MRP

MACMAC MACMRP

Phy PhyPhy Phy

Switching F nction

Forwarding of topology / control informationFunction

MRP DU• Immediate forwarding by switch• Latency nearly independant from number of

cascaded switchL t tl d d i l t ti i• Latency mostly depends on implementation in redundancy manager

RSTP versus MRP

Summary: Comparison MRP versus RSTPSummary: Comparison MRP versus RSTPMRP RSTP

Loops No + Possible ‐

Duplicated packets No + Possible ‐

Deterministic failover time Yes + No ‐

Failover time vs. number of switches in ring Nearly independent

+ Increases with every

‐

add. switch

Failover control based on physical link Yes + Yes +

Failover control based on data link layer Yes + Yes, but slow ‐

Implementation effort and resources needed

Low + Medium ‐

1.7 Industrial Redundant Networks - Marc Lee, Belden Automation

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