6LoWPAN

Advisor: Quincy WuSpeaker: Kuan-Ta LuDate: Aug. 19, 2010

Outline

Wireless Technologies802.15.4IPv66LoWPANReference

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Wireless Technologies

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Wireless Technologies

Cellular (2.5G & 3G - > 10,000m) EDGE/HSDPA (Cingular) EV-DO (Verizon,Sprint/Nextel)

MAN (Municipal Area Network - 10,000m) 802.16 WiMax - Worldwide Interoperability for Microwave

Access

LAN (Local Area Network – 30 to 100m) 802.11 a,b,g,n WiFi

PAN (Personal Area Network > 30m) 802.15.4 / Zigbee / 6LoWPAN RFID & Bluetooth

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Wireless Issues & Concerns

Batteries Replacement labor Environmental Issues New battery and power technologies

Loss of Service We deal with it every day Must be considered Self healing networks and smart routing

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What is 802.15.4?

IEEE standard for low cost, low speed, low power wireless communication

Targeted at device to device communication Supports multiple frequencies, including the

worldwide unlicensed 2.4 GHz band Sixteen 802.15.4 channels Shares spectrum with 802.11 (WiFi) and Bluetooth

250 kbit/s data rate @ 2.4 GHz 127 bytes max packet length Each device has a unique 8 byte identifier (MAC

address)

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802.15.4 Networks

802.15.4 specification defines methods by which devices can form networks Networks are known as Personal Area Networks (PANs) Each network has a unique PAN ID Three type of nodes – coordinator, routers, end device

Network is managed by the “coordinator” When end devices start up, they broadcast a request to associate with a

network Coordinator will respond to association request and assigns address to

device, updates routing tables throughout the network

Multiple network topologies supported, but not specified by standard. types include star, tree, linear and mesh Each topology requires a different routing algorithm

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Mesh Network

Each node dynamically determines best path to other nodes, changing its routing as paths fail or degrade

Most complicated routing algorithm, requires largest code and memory footprint

All devices that perform mesh routing must be powered

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Wireless Appliance Architecture

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IPv6

Next generation of Internet Protocol (IP) addressing scheme

Expands address space from 4 bytes to 16 bytes 2128 bits worth of address space ~3.4 x 1038 addresses

Lots of address space = well suited for addressing devices and M2M applications Every switch, lamp, appliance, etc. in your home can now have

its own IP address

Uses different notation for specifying addresses IPv4 - 192.168.0.1 IPv6 - 2001:0db8:0000:0000:a526:2962:3960:c0e1

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What is 6LoWPAN?

6LoWPAN = IPv6 over Low power Wireless Personal Area Networks

Internet standard defined by IETF RFC4944 – Transmission of IPv6 packets over IEEE802.15.4 http://www.ietf.org/rfc/rfc4944.txt Large open community concerned with evolution of the Internet

architecture – network designers, operators, vendors, researchers

Enables 802.15.4 wireless devices to interoperate with other IP-enabled devices using standard protocols

An extension of wired IP into the wireless domain….. Benefits: global addressing / routing – it’s a Standard.. Devices have globally unique addresses

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6LoWPAN - Purpose

To extend IP services down to low power, embedded wireless devices – sensors, controls, actuators

Enabling IP and wireless to work together Small packet sizes, low power consumption, a protocol stack suitable

for embedded devices – small footprint, efficient

6LoWPAN defines IPv6 packets over IEEE802.15.4 Packet fragmentation, header compression, multi-hopping Compact and efficient implementation for low power wireless

Clusters of wireless nodes connected to the wired infrastructure Nodes within a cluster talk wirelessly Nodes on different clusters talk through the wired domain

Benefits from reuse of existing IP infrastructure Simple integration and deployment

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Why use 6LoWPAN?

Leverages existing standards IP is the field-proven protocol winner

Generic solution regardless of device or application type Permits integrating 802.15.4 devices without requiring gateway

cognizant of the application• A programming tool can communicate directly to a device without special

application software and mapping, communications are simply routed through the network!

Works with wired and wireless devices, just like the computer world, just like the telecom world.

A smart 6LoWPAN router can present an IPv4 address. In this case the router will have a configuration table to handle mapping the extended address to IPv4 addresses.

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6LoWPAN Overview

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6LoWPAN Stack Architecture

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6LoWPAN : Adaptation Layer

The adaptation layer is the main component of 6LoWPAN. The first major function of this layer is the TCP/IP header

compression. TCP/IP headers are too large for 802.15.4, which has a maximum packet size of 127 bytes; instead IPv6 header size is 40 bytes, UDP and ICMP header sizes are both 4 bytes, TCP header size is 20. Without compression, 802.15.4 is not possible to transmit any payload effectively.

A second major function of the adaptation layer is to handle packet fragmentation and reassembling. IEEE 802.15.4 has a maximum frame size of 127 bytes, while IPv6 requires a minimum MTU of 1280 bytes. This mismatch has to be handled in the adaptation layer.

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6LoWPAN : Adaptation Layer continued...

The third major function of the adaptation layer is routing. The border nodes of the WSN should be able to route IPv6 packets into the WSN nodes from outside and route inside packets to outside IP network. Different routing protocols of adaptation layer are

shown in table. There are other functions of the adaptation layer

on networking related things like neighbor discovery and multicast support.

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6LoWPAN : Adaptation Layer continued...

Routing per se is a two phased problem that is being considered for 6LoWPAN. 1)Mesh Routing in the PAN Space 2)Routability of packets to/from the IPv6 domain

from/to the PAN domain Some of the routing protocols currently being

developed by 6LoWPAN Community, those are LOAD, DYMO-LOW, Hi-Low.

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6LoWPAN Communications

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Reference

http://ms11.voip.edu.tw/~jryan/ref/6LoWPAN Technical Overview.pdf

http://ms11.voip.edu.tw/~jryan/ref/A Review of 6LoWPAN Routing Protocols.pdf

http://ms11.voip.edu.tw/~jryan/ref/IPv6 over Low Power Wireless Personal Area Network (6LoWPAN).pdf

http://ms11.voip.edu.tw/~jryan/ref/SedonaFrameworkand6loWPAN.pdf

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Q&A

The End

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