6lowpan

6LoWPAN6LoWPAN(IPv6 over Low power Wireless Personal Area

Networks)

Introduction Introduction

• IP based devices• web services• security• management• frame size

• issues• power & duty cycle• multi cast• topology• bandwidth• reliability

Internet of things

Related TechnologiesRelated TechnologiesRFC 4944 ISA 100 IPSO

ApplicationsApplications

Home building automationHealth care Industry Automation & LogisticsVehicular AutomationEnvironmental monitoring and many more

Architecture Architecture

Protocol stackProtocol stack

• UDP is preferred

Link layersLink layers

Compatibility with existing technologies like 802.15.4, Sub-GHz Radio and Power- line communications.

Adaptation for IP Addressing of nodes (Locally & Globally)

AddressingAddressingExtended Unique identifier(EUI-64) -- like

ZigbeeConfigurable short addressing(8-16 bits)Similar like IPv6 64 bits IID is used---

generally called Stateless Address Auto configuration (SAA)

Forwarding and RoutingForwarding and Routing

1. IP Routing Model

2. LoWPAN Routing(L3 , Route over)

Forwarding and Routing Forwarding and Routing (contd..)(contd..)

3(a). DLL mesh forwarding (L2, Mesh Under)

3(b). LoWPAN adaptation (L2, Mesh Under)

Header CompressionHeader Compression Headers of IP is compressed(IPv6 headers occupy more

space) Router decompresses the header and transmits over

different link

MTU is not sufficient Need to achieve flow control Must be used when needed The throughput of network reduces

Fragmentation and ReassemblyFragmentation and Reassembly

Data Packet of 802.15.4

802.15.4 IPv6 header Payload

802.15.4 Mesh Addr Frag IPv6 header Payload

802.15.4 Fragmentation IPv6 header Payload

128 bytes

Payload

decreases

Fragmentation Header

Mesh Header

IP Header format (HC)

For IP , HC1 is used HC2 bit indicates further transport protocols UDP, TCP, ICMPv6

IPv6 Header

UDP

RFC4944’s HC TF,FL into 2 bits Version, Payload Length,

Link Local Prefix UDP ports (61616-61631)

Uni Cast

Multi Cast

Global

Improved HC (IPHC) TF,FL are

individually compressed

Hop limit compression

Removes prefixes for IPv6 addresses

Supports Multicast for ND, SLAAC

4 bit index represents 16 contexts (if CID is set)

U

M

G

Networking IssuesNetworking Issues

Establishing a network (Commissioning)◦ new node joining◦ Network re-organizing

Uses ◦ Service Set ID (WLAN)◦ Security (Wireless Protected Access)

Prefix match -- Home network Neighbor Discovery

◦ DHCPv6 (Stateless Address Auto configuration)◦ Registration◦ Reg. collision◦ Multi-hop registration◦ Various operations (node, router, edge router)

Bootstrapping

Networking Issues Networking Issues (contd..)(contd..)

Objectives◦ Confidentiality◦ Integrity◦ Availability

Layer2 mechanisms◦ As 802.15.4 implements AES(CCM, RFC 3610)◦ 13 byte key based on 8 byte MAC Id◦ 2^22= 7 weeks of key repetition

Layer3 mechanisms (Internet Key Exchange [RFC 2409])◦ Doesn’t suit for LoWPANs

Key Management (Enhanced L3)◦ Username & Password◦ Long, Short, Group, Pair wise keys

Security

Other AspectsOther Aspects

Mobility◦ Roaming (macro)◦ Handover (micro)

Causes◦ Physical movement◦ Radio channel◦ Network performance◦ Sleep schedules◦ Node failure

Node & Network controlled (Wi-Fi, cellular systems)

Solutions for Mobility◦ Commissioning◦ Bootstrapping◦ Security◦ Updating DNS◦ Notifying upper layers

So far nodes are considered stationary

Other Aspects Other Aspects (contd..)(contd..)

MIPv6 Proxy Home Agent

Other Aspects Other Aspects (contd..)(contd..)

Proxy MIPv6 NEMO (NEtwork MObility)

Application protocolsApplication protocols General IPv6

◦ HTTP, FTP, SIP, SNMP, RTP, SLP Need modifications SOAP, REST (Simple Object Access Protocol,

REpresenational State Transfer) Need Port Address

Application protocols Application protocols (contd..)(contd..)

NetworkingHost IssuesCompressionSecurity

Application protocols Application protocols (contd..)(contd..) Protocol paradigms

◦ End to End◦ Real Time Streaming / Session◦ Pub/ Sub

Common Protocols◦ Web service protocols◦ MQTT (MQTT-S)◦ ZIGBEE Compact Application Protocol◦ Service Discovery

SLP, UPnP, DPWS◦ Industry Specific (BACnet, oBIX, ANSI c12.19)

ZCAP, MQTT has own discovery features

Implementing 6lowpanImplementing 6lowpan

Single Chip Two Chip

Implementing 6lowpanImplementing 6lowpan (contd..)(contd..) Protocol Stacks

◦ ContikiOS & uIPv6◦ TinyOS & BLIP◦ Sensinode NanoStack◦ Jennic 6LoWPAN◦ Nivis ISA100 (Industrial Standard)

Implementing 6lowpanImplementing 6lowpan (contd..)(contd..) ContikiOS

◦ C◦ MSP430, AVR, HC12,

Z60, etc..◦ 2kB RAM, 40kB ROM◦ LoWPAN Support◦ Multitasking◦ Event driven kernel◦ uIP stack◦ Thread based◦ COOJA Simulator◦ TMote

TinyOS◦ nesC◦ MSP430, AVR◦ 0.4kB RAM◦ LoWPAN Support◦ BLIP◦ TOS Simulator◦ FIFO◦ OS merges with

Program◦ TelosB, IMote etc..

Implementing 6lowpanImplementing 6lowpan (contd..)(contd..)

Application development

Hardware Interaction layer

Hardware Implementation Layer

nesC

TinyOS

H/W Platform

Contiki OS

TinyOS