towards distributed protocol stacks for wireless sensor networks

Towards Distributed Protocol Stacksfor Wireless Sensor Networks

IEEE International Conference on Cyber, Physical and Social ComputingNovember 20-23, 2012, Besançon, France

Peter Rothenpieler, Dennis PfistererInstitute of Telematics, University of Lübeck

Dipl.-Inf. Peter [email protected]

http://www.itm.uni-luebeck.de/users/rothenpieler

mailto:[email protected]


2

Content Motivation

Idea: Distributed Protocol Stacks

(Short) Protocol Overview

Design considerations & Limitations

Evaluation

Code size

Round Trip Time

Goodput

Summary and Conclusion




Motivation: From WSNs to the Internet of ThingsWSN: problem specific, custom tailored solutions standardized protocol

stacks

Advantages:

Layered Protocols: Divide and Conquer

Interoperability & Heterogeneity

Disadvantages:

Additional protocols/layers increase code size

(+ adaptation layer?)



Application

6LoWPAN

IPv6

UDP ICMP

IEEE 802.15.4 MAC & PHY

Application

6LoWPAN

IPv6

UDP ICMP


3



Motivation: Code Size of 6LoWPAN & IPv6



OSPlatformFlash

ContikiMSP430

48 KB

ContikiJN5139

96 KB

iSenseJN5139

96 KB

ContikiJN5148128 KB

iSenseJN5148128 KB

6LoWPAN 4.6 8.0 7.8 5.9 5.1

IPv6 7.4 12.3 31.6 8.7 18.3

ND 6.8 13.3 7.6 9.3 5.0

ICMP 0.8 1.3 2.1 1.0 1.2

UDP 0.7 0.3 2.1 0.2 1.1

Routing (RPL)

9.0 12.9 N/A 8.4 N/A

Σ 29.3 48.1 51.2 33.5 30.6

% of Flash 61 % 50 % 53 % 26 % 24 %

Source: Instant Contiki 2.6, Jennisense (07/2012), iSense SVN (04/2012)

Cheap /

Small

Expensive / Big

4



Idea: Distributed Protocol Stack Cooperation between layers cooperation between nodes

Share implementations of layers with neighboring nodes

asynchronous RPC calls (“message passing”)



Application

6LoWPAN

IPv6

UDP ICMP


Application

6LoWPAN

IPv6

UDP ICMP


IPv6 stub

UDP ICMP

Application


DPS


IPv6 skeleton

UDP ICMP

Application

DPS

6LoWPAN

RPC

Serve

r

Client

5



Protocol Overview

Three phases

Discovery & Advertise



ServerServer

Client

2. Advertise2. Advertise

1.Discovery

6



Protocol Overview

Three phases


Three-way-Handshake



ServerServer

Client

Handshake

7

Protocol Overview

Three phases


Three-way-Handshake

Exchange of RPC messages

Optionally supports the use of

Acknowledgements



ServerServer

Client

RPC messages

8

Design considerations & Limitations DPS Covers only single-hop communication

Clients need at least one Server within radio range

Placement of nodes during deployment

Certain fraction of nodes need to be Servers

(topology/deployment)

Clients can not communicate directly (need Server in-between)



9



Evaluation: Code Size Code size of native IPv6 implementation on JN5139 > 96 KB Flash

Use of IPv6 on JN5139 now possible (26.5 KB reduction)



Native IPv6JN5139

DPS ClientJN5139

Native IPv6JN5148

DPS ServerJN5148

Application

5.5 KB 3.8 KB

Os 43.9 KB 36.4 KB

IPv6 Stack 50.2 KB 10.1 KB 27.6 KB 27.6 KB

DPS - 13.6 KB - 8.0 KB

Σ 99.6 KB 73.1 KB 67.8 KB 75.8 KB

Relative100 % -27 %

-26.5 KB100 % + 12 %

+8.0 KB

ServerClient

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Evaluation: Single-Hop Round Trip Time Data based upon 100 ICMP echo request/reply packets for each payload

size



(Un-)compressed IPv6 header determines payload in first fragment

Increase for additional fragments6LoWPAN: 07 msDPS: 07 msDPS (ACK): 23 ms

Increase for additional payload6LoWPAN: 0.068 ms/byteDPS: 0.075 ms/byte (+10%)DPS (ACK): 0.075 ms/byte (+10%)

x ms

1 byte

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Evaluation: Single-Hop Goodput Data based upon 1000 UDP packets for each payload size and output

speed



DPSNative 6LoWPAN

Decrease1st Fragment: 32 %Following Fragments: 4.2 % - 5.7 %

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Summary & Conclusion Motivation and Introduction: Distributed Protocol Stacks

Code size reduced by 27.5 KB for the DPS Client

Increase of 8.0 KB for the DPS Server

RTT increases by only 10 % (+ Offset of 6 ms)

Goodput decreases only by 4.2 - 6.7 % (32% first fragment)

Acknowledgements

Increase RTT by additional 16ms / fragment

Should be used

for DPS calls that change the state of the Server or Client

require reliability that is not offered by the protocol itself



13



Thank you for your attention!





Example Exchange of IP Address & Sending of IP Packet



Instead of receiving A, the Serverwill forward it using IPv6/6LoWPAN,if it is not the destination of the packet



towards distributed protocol stacks for wireless sensor networks

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