CIP over 6LoWPAN
Prepared by Dayin Xu, Paul Brooks, Yi Yu, David Brandt
Presented by Paul Brooks

Technical Trackwww.odva.org

ContentMotivation
Industrial IP Network Architecture
Common Network Stack for FWN
Requirements, Challenges and Proposals
CIP over 6LoWPAN Stack Prototype
CIP over 6LoWPAN Proof of Concept
Future Work

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 2www.odva.org

A Platform for Innovation
Internet of Things creates huge opportunities
But often with devices that can’t support the cost of an Ethernetand Power ConnectionSome problems that sound familiar being solved inhomes

Remotely turning something on and off and monitoring thepower?
Managing the temperature in a vessel?

Marketing must identify the problemsWe need to give thema platform

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 3www.odva.org

6LoWPAN
Promising standard for Field WirelessSensor Actuator Network

Good technical alignment with EtherNet/IP

802.15.4
Technical Track© 2014 ODVA, Inc.

UDP/IPv6

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 4www.odva.org

CIP over IP Network Expansion
IPv6 transition
Enterprisenetwork
convergence
Field wirelessnetwork
integration
Expanded CIPTM
networkarchitecture
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 5www.odva.org

Common Network Stack
CIP over 6LoWPAN?
CIP Application Objects and Device
ProfilesExplicit Message

Implicit Message

ODVA

Encapsulation

EtherNet/IP

UDP
IPv6

IETF

6LoWPAN802.15.4 MAC

IEEE

802.15.4 PHY
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 6www.odva.org

Requirements and Challenges
6LoWPAN Requirements

EtherNet/IP and CIP’s Challenges

IPv6

Not IPv6 readyUDP-only

TCP for explicit messages

Small packet size (127 bytes PHYpayload)

EtherNet/IP assumes larger packet size
(1,500 bytes PHY payload)

Limited resources (e.g., secondto-minute level update rate, 128
Kbytes Flash and 32 Kbytes RAM)CIP and EtherNet/IP assumes there areenough resources (e.g., millisecond level
update rate, 256 Kbytes Flash and 128
Kbytes RAM)

Sleep and battery-power

Doesn’t consider sleep mode, always
mains-poweredTechnical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 7www.odva.org

Requirements and Challenges(Cont’d)
6LoWPAN Requirements

EtherNet/IP and CIP’s Challenges

Peer-to-peer communication
among field devices

Difficult to support peer-to-peer
communication for field devices due to theirlimited resources

Security

EtherNet/IP and CIP rely on external
security services but do not integrate them

Backward compatibility

How to operate with old CIP devices

Wireless network management(large scale, dynamic topology)

Doesn’t consider 6LoWPAN wirelessnetwork managementTechnical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 8www.odva.org

Assumptions
IPv6 Migration of EtherNet/IPcompletedWork ongoing in EtherNet/IP System Architecture
SIG
See Rockwell Automation and Cisco papers

Security
Work ongoing in EtherNet/IP System Architecture
SIG

Both projects will consider the needs ofField Wireless Networks
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 9www.odva.org

UDP and TCP in EtherNet/IPToday, Explicit Messages use TCP andImplicit Messages use UDP

TCP not generally available in 6LoWPAN
CIP has its own reliable data transmission checks• Transaction ID• Typically only 1 outstanding transaction• Client Server model for Explicit MessagesOptions
Implement TCP in 6LoWPAN
Move to all UDP communications

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 10www.odva.org

Small Packet Size
Ethernet supports a 1500 byte packet;
6LoWPAN supports a 127 byte packet

102 byte MAC payload (IP packet + overhead)
CIP Max packet size 511 bytes + encapsulation
Typical packet size for target devices 5 – 64bytesOptions:
Compress CIP header (Encapsulation Protocol)• Increases complexity in end devices

Optimize CIP header and limit packet size
• Remove unnecessary fields and functions

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 11www.odva.org

Limited End Device Resources
Target 128Kb Flash and 32Kb RAM


Based on available siliconRemove and optimize backbone centricfunctionality

Removal of TCP reduces device loadRemove session management• Relocate revision checkRemove connected explicit messaging• Typically more used at host level today

Remove bi-directional produce-consume• Need marketing analysis

Remove CIP Routing• Need marketing analysis too

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 12www.odva.org

Sleep and Battery PowerManagement
EtherNet/IP assumes permanently
powered devices


No native mechanisms available for adaptation

Considerations:Reduce packet size (discussed earlier)
Make Change of State default communications
methodDevelop aggregation method• Minimize headersEliminate all polling activities

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 13www.odva.org

Backward Compatibility with
EtherNet/IP
User experience should be seamless
Network Architecture should be unchanged
Requirements for 6LoWPAN OriginatorsNone – 6LoWPAN target packets will flow through IP Centric
Ethernet

Requirements for EtherNet/IP Originators:
Need to be able to distinguish between packets destined for
Ethernet and 6LoWPAN targets• Either IANA Port or Protocol Type field in headerProxy function needed in gateway to change TCP
encapsulation to UDP encapsulation
Proxy function needed to map EtherNet/IP
Produce/Consume (non-trivial)

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 14www.odva.org

CIP over 6LoWPAN Stack
Features
Application
Objects

Assembly

EtherNet/IP

CIP over 6LoWPAN

IPv4

IPv6

TCP and UDP

UDP only

Session-based
encapsulation protocol

Simplified session-lessencapsulation protocol

Class 3 and UCMM

UCMM only

Bidirectional Class 0/1
Produce/Consumeconnection

Simplified unidirectional
Produce/Consumeconnection

Technical Track© 2014 ODVA, Inc.

Identity
Message
RouterConnection
ManagerIO

UCMM

Session-less Encapsulation andUDP Sockets

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 15www.odva.org

CIP over 6LoWPAN Stack
Memory Consumption
Subsystem

Flash (Byte)

RAM (Byte)

CIP

12,153

9.27%

1,444

4.41%

6LoWPAN20,08315.32%

358

1.09%

JNET1

29,54922.54%

1,216

3.71%

Others (Debug,Storage, etc.)

11,400

8.70%

166

0.51%

Heap

N/A

N/A

10,35231.59%

Stack

N/A

N/A

4,096

12.5%

Total73,185(71.45K2)

55.83%

17,632(17.22K)

53.81%

Available

131,072(128K)

100%

32,768(32K)

100%

Left forApplication

57,877(56.55K)

44.17%

15.136(14.78K)

46.19%

1 JNET is a commercial personal area wireless networking and management protocol
2 1 Kbytes is 1024 bytes
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 16www.odva.org

CIP over 6LoWPAN Proof ofConcept Platform
CIP over 6LoWPAN in one IPv6 subnet
CIP over Ethernet/Wi-Fi in another IPv6 subnet

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 17www.odva.org

CIP over 6LoWPAN
Demonstration
6LoWPAN NodeUCMM
Dimmable lights

Output connection

Application Object: Bulb
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 18
www.odva.org

Future Work
Active report
Network management
Peer-to-peer communication
Backward compatibility

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 19
www.odva.org

Q&A

Technical Trackwww.odva.org