Transcript 投影片 1 - PEARL

6LoWPAN
Advisor: Quincy Wu
Speaker: Kuan-Ta Lu
Date: Aug. 19, 2010
Outline
Wireless Technologies
802.15.4
IPv6
6LoWPAN
Reference
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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/SedonaFrameworkand
6loWPAN.pdf
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The End
Q&A
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