6LoWPAN IPv6 for Wireless Sensor Network

Transcription

1 6LoWPAN IPv6 for Wireless Sensor Network SASE 2012 Carlos Taffernaberry UTN - Mendoza - Argentina [email protected] This work is licensed under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. To view a copy of this license, visit or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA

2 References N. Kushalnagar, G. Montenegro, C. Schumacher IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs):Overview, Assumptions, Problem Statement, and Goals, RFC 4919, August 2007, IETF G. Montenegro,N. Kushalnagar,J. Hui, D. Culler Transmission of IPv6 Packets over IEEE Networks, RFC 4944, September 2007, IETF Shelby & Bormann, The Wireless Embedded Internet ISBN: , (c) 2009 John Wiley & Sons Ltd David E. Culler & Jonathan Hui 6LoWPAN Tutorial: IP on IEEE Low-Power Wireless Networks, Arch Rock Corporation Compression Format for IPv6 Datagrams in 6LoWPAN Networks draft-ietf-6lowpan-hc-13. RFC Neighbor Discovery Optimization for Low-power and Lossy Networks draft-ietf-6lowpan-nd-15 Design and Application Spaces for 6LoWPANs, draft-ietf-6lowpan-usecases-09. This work is licensed under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. To view a copy of this license, visit or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA

3 Outline Introduction, Motivation Introduction to 6LoWPAN The 6LoWPAN Format Neighbor Discovery Routing Application Layer Implementing 6loWPAN This work is licensed under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. To view a copy of this license, visit or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA

4 Introduction

5 Internet of Things - A global network infrastructure, linking physical and virtual objects through the exploitation of data capture and communications capabilities. - This infrastructure includes existing and evolving Internet and network developments. - It will offer specific object-identification, sensor and connection capability as the basis for the development of independent federated services and applications. - These will be characterised by a high degree of autonomous data capture, event transfer, network connectivity and interoperability. Source CASAGRAS 2

6 Internet of Things

7 Internet of Things Scope

8 Internet of Things Interconnection Challenge Wires are too expensive Electrical wall socket + installation = $50 Cat5 socket + installation = $150 1 Trillon nodes >> 1000 DGP Argentina Wireless? Technolog y Range Speed Power Use Cost Wifi 100 mts Mb/s High $$$ Bluetooth mts mts. 1-3 Mb/s Medium $$ 0,25-Mb/s Low $

9 Evolution of Wireless Sensor Networks Price Scalability Cabling Proprietary radio + network ZigBee 6lowpan Internet Any vendor Z-Wave, prop. ISM etc. ZigBee and WHART 6lowpan ISA100 Cables Vendor lock-in Complex middleware Open development and portability 1980s > Increased Productivity

10 Internet (v4) Regional Registry Exhaustion Addresses Challenge IANA Unallocated Address Pool Exhaustion: 03-Feb-2011 "Exhaustion" when the pool of available addresses in each RIR reaches the last /8 threshold.

11 IP next generation IPv6 Features: Address space: 128 bits (2 128 ) = addr. There are only ~ grains of sand on the earth Let s settle for a trillion objects on the net Fix size Header No fragmentation in the path Extensibility by adding extension header Unicast, Multicast y Anycast (NO Broadcast) Stateless and stateful address autoconfiguration

12 Benefits of 6LoWPAN Technology IPv6 over Low-Power Wireless Personal Area Networks Low-power RF + IPv6 = The Wireless Embedded Internet 6LoWPAN makes this possible The benefits of 6LoWPAN include: Open, long-lived, reliable standards Easy learning-curve Transparent Internet integration Network maintainability Global scalability End-to-end data flows Use of existing Internet infrastructure

13 Introduction to 6LoWPAN

14 What is 6LoWPAN? IPv6 over Low-Power wireless Area Networks Defined by IETF standards RFC 4919, 4944 draft-ietf-6lowpan-hc and -nd draft-ietf-roll-rpl Stateless header compression Enables a standard socket API Minimal use of code and memory Direct end-to-end Internet integration Multiple topology options ( , Bluetooth,etc)

15 Challenge to LoWPAN's Hard to implement in embedded devices: -Power and duty-cycle: Battery-powered wireless devices need to keep low duty cycles. -Frame size: Current Internet protocols require links with sufficient frame length. -Multicast: Wireless embedded radio technologies, do not typically support multicast. -Reliability: Standard Internet protocols are not optimized for low-power wireless and lossy networks. -WebServices: Internet services today rely on webservices, mainly using the transmission control protocol (TCP). -Management: Management with SNMP or web services.

16 6LoWPAN Applications 6LoWPAN has a broad range of applications Facility, Building and Home Automation Personal Sports & Entertainment Healthcare and Wellbeing Asset Management Advanced Metering Infrastructures Environmental Monitoring Security and Safety Industrial Automation SIPIA

17 Protocol Stack

18 6loWPAN Features Useful with low-power link layers such as IEEE , narrowband ISM and power-line comunications (Bluetooth working) Support for e.g. 64-bit and 16-bit addressing Efficient header compression IPv6 base and extension headers, UDP header Network autoconfiguration using neighbor discovery Unicast, multicast and broadcast support Multicast is compressed and mapped to broadcast Fragmentation 1280 byte IPv6 MTU -> 127 byte frames Support for IP routing (e.g. IETF RPL) Support for use of link-layer mesh (e.g )

19 The 6LoWPAN Format

20 Architecture

21 Architecture LoWPANs are stub networks Simple LoWPAN Single Edge Router Extended LoWPAN Multiple Edge Routers with common backbone link Ad-hoc LoWPAN No route outside the LoWPAN Internet Integration issues Maximum transmission unit Application protocols IPv4 interconnectivity (transition) Firewalls and NATs Security IPv6-LoWPAN Router Edge Stack

22 The 6LoWPAN Format 6LoWPAN is an adaptation header format Enables the use of IPv6 over low-power wireless links IPv6 header compression UDP header compression Format initially defined in RFC4944 Updated by draft-ietf-6lowpan-hc (work in progress)

23 The 6LoWPAN Format 6LoWPAN makes use of IPv6 address compression RFC4944 Features: Basic LoWPAN header format HC1 (IPv6 header) and HC2 (UDP header) compression formats Stateless compression mechanism Fragmentation & reassembly Mesh header feature (depreciation planned) Multicast mapping to 16-bit address space draft-ietf-6lowpan-hc Features: New HC (IPv6 header) and NHC (Next-header) compression Support for global address compression (with contexts) Support for IPv6 option header compression Support for compact multicast address compression

24 IPv4 and IPv6 Format

25 IPv6 Addresses Unicast Address Scope Local-link : fe80::/64 Local-Site : fec0::/64 Global : 2000::/3 Global Site-Local Link-Local

26 IPv6 Addressing Stateless Address Autoconfiguration (SAA) Prefix (64 bits) + Subfix (64bits) Prefix: (Scope of an address) Local link (prefix fe80::) Global Link (prefix: Router Advertisement Router Solicitation) Subfix: EUI64 64-bit (Global Identifier - IEEE) example wlan0 Link encap:ethernet HWaddr 00:25:d3:67:79:ad inet6 addr: 2001:1291:200:829e:225:d3ff:fe67:79ad/64 Scope:Global inet6 addr: fe80::225:d3ff:fe67:79ad/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:10732 errors:0 dropped:0 overruns:0 frame:0 TX packets:9573 errors:0 dropped:0 overruns:0 carrier:0 RX bytes: (7.8 MB) TX bytes: (1.1 MB)

27 Dispatch First byte of the Payload ( Bit Pattern Header Type Reference 00 xxxxxx NALP - Not a LoWPAN frame [RFC4944] Reserved as a replacement value for ESC [RFC6282] IPv6 - uncompressed IPv6 Addresses [RFC4944] LOWPAN_HC1 - compressed IPv6 [RFC4944] to reserved for future use LOWPAN_BC0 - broadcast [RFC4944] to reserved for future use 01 1xxxxx LOWPAN_IPHC [RFC6282] 10 xxxxxx MESH - Mesh header [RFC4944] xxx FRAG1 -- Fragmentation Header (first) [RFC4944] to reserved for future use xxx FRAGN -- Fragmentation Header (subseq) [RFC4944] to reserved for future use

28 IPv6/UDP Headers Without compression IPv6 UDP Payload Version Traffic Class Flow Label Flow Label cont Payload Length Next Header Hop Limit Source Address Destination Address Source Port Destination P Dest. P. cont Length Checksum Checksum cont UDP Payload

29 IP Header Compression (HC1 and HC2) No gzip techniques No end to end technique IP addr is needed in every route Stateless compression SAE DAE C NH 0 Non-Compressed fields \ dispatch / \_ HC1 header_/ SAE DAE C NH 1 S D L N.-C. fields \ dispatch / \_ HC1 header_/ \_ HC2 header_/ C = Class and Flow Label SAE/DAE = Source/Destination Address Encoding NH = Next Header S/D = Source/Destination Port Compression ( ) L= whenever the length es compressed Never Compressed Hop Limit and UDP Checksum

30 LoWPAN UDP/IPv6 Headers 6 Bytes! LoWPAN IPv6 UDP Dispatch with LOWPAN_IPHC LOWPAN_NHC Src Dst UDP Checksum UDP Payload Payload draft-ietf-6lowpan-hc

31 IP Header Compression (IPHC) Most of the time is used Global Routeable Ipv6 Addresses. Base Header Dispatch + LOWPAN_IPHC (2-3 octets) Compressed IPv6 Header LOWPAN_IPHC Encoding TF NH HLIM CID SAC SAM M DAC DAM TF = Traffic Class, Flow Label NH = Next Header Flag HLIM = Hop Limit CID = Context Identifier Extension SAC = Source Address Compression SAM = Source Address Mode M = Multicast Compression DAC = Destination Address Compression DAM = Destination Address Mode draft-ietf-6lowpan-hc

32 IP Header Compression (IPHC) Cont. S/SAM Inlline inline (address fully inline, no compression) FE80:0:0:0:inline (link-local + 64-bit Interface ID) FE80:0:0:0:0:0:0:inline (link-local + 16-bit short address) FE80:0:0:0:link-layer (link-local + link-layer source address) 1 00 reserved context[0..63]:inline (context + 64-bit Interface ID) context[0..111]:inline (context + 16-bit short address) context[0..127] (context)

33 Next-header Compression (NHC) NHC Format var-len NHC ID compressed next header UDP NHC Encoding C P C = Checksum Compression P = UDP Port Compression draft-ietf-6lowpan-hc

34 6LoWPAN Headers Orthogonal header format for efficiency Stateless header compression

35 Fragmentation IPv6 requires underlying links to support Minimum Transmission Units (MTUs) of at least 1280 bytes IEEE leaves approximately bytes of payload! RFC4944 defines fragmentation and reassembly of IPv6 The performance of large IPv6 packets fragmented over lowpower wireless mesh networks is poor! Lost fragments cause whole packet to be retransmitted Low-bandwidth and delay of the wireless channel 6LoWPAN application protocols should avoid fragmentation Compression should be used on existing IP application protocols when used over 6LoWPAN if possible Fragment recovery is currently under IETF consideration

36 Fragmentation Initial Fragment datagram_size datagram_tag Following Fragments datagram_size datagram_tag datagram_offset

37 Neighbor Discovery

38 ICMPv6 ICMP ARP IPv4 IGMP Multicast ND Neighbor Discovery ICMPv6 IPv6 MLD Multicast Listener Discovery Multicast Broadcast Ethernet Ethernet

39 IPv6 Neighbor Discovery IPv6 is the format - ND is the brains One-hop routing protocol defined in RFC4861 Finding Neighbors Neighbor Solicitation / Neighbor Advertisement Finding Routers Router Solicitation / Router Advertisement Stateless Address Autoconfiguration using NS/NA Detecting Addresses Duplication (DAD) using NS/NA Neighbor Unreachability Detection (NUD) using NS/NA DHCPv6 may be used in conjunction with ND Requirements: Link-layer Multicast Transitive relation between Neighbor

40 IPv6 Neighbor Discovery Multicast Address: All nodes All routers : ff02::1/128 : ff02::2/128

41 LoWPAN Information Option Simplification: Removed a second lifetime Removed a Reserved field Added a CID field for context-based compression Type Length Info Length L A C V CID Valid Lifetime Prefix or Address Information

42 Prefix Dissemination In normal IPv6 networks RAs are sent to a link based on the information (prefix etc.) configured for that router interface In ND for 6LoWPAN RAs are also used to automatically disseminate router information across multiple hops

43 Addressing Example

44 Duplicated Address Detection in 6loWPAN The Router Edge mantains a table (whiteboard) Nodes must register in the whiteboard New ICMP type: Node Registration New ICMP type: Node Confirmation Node registration exchange enables Host/router unreachability detection Address resolution (a priori) Duplicate address detection Registrations are soft bindings Periodically refreshed with a new NR message

45 Typical 6LoWPAN-ND Exchange

46 NR/NC Format Type (NR)/(NC) Code Checksum TID Status P Binding Lifetime Advertising Interval Owner Interface Identifier Owner Nonce Registration option(s)

47 The Whiteboard The whiteboard is used in the LoWPAN for: Duplicate address detection for the LoWPAN (= prefix) Dealing with mobility (Extended LoWPANs) Locating nodes

48 Routing

49 6LoWPAN Routing Multihop Mesh Topology Link Layer Forwarding (Mesh Under) : Link Layer mesh (e.g ) LoWPAN mesh (RFC but not forward algorithm) IP Layer Routing (Route Over): Routing in a LoWPAN Single-interface routing Flat address space (exact-match) Stub network (no transit routing)

50 Types of Routing Protocols Algorithm classes Distance-vector Links are associated with cost, used to find the shortest route. Each router along the path store local next-hop information about its route table. Link-state Each node aquires complete information about the network, typically by flooding. Each node calculated a shortest-path tree calculated to each destination. Types of Signaling Proactive Routing information aquired before it is needed. Reactive Routing information discovered dynamically when needed. Route metrics are an important factor

51 Protocols for 6LoWPAN IP is agnostic to the routing protocol used It forwards based on route table entries Thus 6LoWPAN is routing protocol agnostic Special consideration for routing over LoWPANs Single interface routing, flat topology Low-power and lossy wireless technologies Specific data flows for embedded applications MANET protocols useful in some ad-hoc cases e.g. AODV, DYMO New IETF working group formed Routing over low-power and lossy networks (ROLL) Deloped specifically for embedded applications

52 IETF ROLL Routing Over Low power and Lossy networks (ROLL) Working group at the IETF Standardizing a routing algorithm for embedded apps Application specific requirements Home automation Commercial building automation Industrial automation Urban environments Analyzed all existing protocols Solution must work over IPv6 and 6LoWPAN Protocol in-progress called RPL Ripple Proactive distance-vector approach See draft-ietf-roll-rpl for detailed information

53 Application Formats and Protocols

54 Introduction The processes of applications communicate over IP using an Internet Socket approach 6LoWPAN also uses the Internet Socket paradigm Application protocols used with 6LoWPAN however have special design and performance requirements

55 Socket API The Socket API provides access to data communications for applications Well-known interface for handling data flow and buffer management via socket Supports also control messages to protocols Commands include: socket, bind, send, read, close etc. Examples of Socket APIs Berkeley sockets in *nix systems Mac OSX (Darwin) Contiki uip (Pseudo socket approach)

56 End-to-end Paradigm

57 Application Formats and Protocols

58 Custom Protocols The most common solution today Application data typically binary encoded, application specific Application protocol uses a specific UDP port, application specific As 6LoWPAN is end-to-end IPv6 communications, not a problem Advantage: Compact, efficient, security can be integrated, end-to-end Disadvantage: Custom server app needed, little re-use, learning curve, interoperability Custom Protocol UDP IPv6 / 6lowpan L2/DLL L1/PHY

59 Streaming and RTP The correct streaming solution For audio or continuous sensor streaming Audio over needs good codec Advantages: RTP can be used over 6LoWPAN Provides end-to-end solution No server modifications needed Jitter control Disadvantages: Headers could be more efficient for simple sensor data streaming Stream RTP UDP IPv6 / 6lowpan L2/DLL L1/PHY

60 XML/HTTP De-facto for inter-server communications Well-known XML schema important All Internet servers speak HTTP/XML Useable for RPC, pub/sub and events SOAP or REST paradigm Advantages: Well known XML schema Formal message sequences Internet-wide support Disadvantages: Inefficient, complex Solution: Embedded web-services See the IETF 6lowapp effort XML Messages SOAP HTTP TCP IP L2/DLL L1/PHY

61 Implementation

62 Chips Solutions Single-Chip (App + 6LowPAN + Transceiver) Minimizing cost and size is critical. All soft on the same micro increases complexity and development time. Complexity of the embedded application is low. Examples TI CC2530, ATMEGA 128RF and the Jennic JN5139. Two-Chip (App + 6LowPAN <UART/SPI> Transceiver) Great application complexity and performance requirements. Leaves the developer freedom in the choice of application microcontroller. 6LoWPAN and application need to be integrated in the same microcontroller and may require extensive engineering and testing. Examples of radio transceivers are TI CC2520, Atmel AT86RF231. Network Processor (App <UART/SPI> 6LowPAN + Transceiver) Projects in which a design or application software already exists. Programming is often realized as an extended socket-like protocol. Not be possible for devices with extreme cost limitations. Example of network processor is TI CC1180.

63 Protocols Stacks Contiki Low-Power uipv6/rpl Network Tiny OS BLIP, the Berkeley Low-power IP stack IPv6 Ready Nano Stack (Sensinode) Nano Stack, Nano Router, Nano Service Nano Sensor Jennic 6LoWPAN (Jennic) JN5139 Wireless Microcontroller Jenie API, SNAP, JenNet

64 SIPIA Net Wireless Sensor Network for Agronomical Research SIPIA Net Propietary STACK (gridtics) SIPIA6 Net 6loWPAN STACK

65 PREGUNTAS Gracias por su asistencia Carlos Taffernaberry UTN - Mendoza - Argentina [email protected]

66 SPARE SLIDES

67 Mobility & Routing

68 Types of Mobility Mobility involves two processes Roaming - moving from one network to another Handover - changing point of attachment (and data flows) Mobility can be categorized as Micro-mobility - within a network domain Macro-mobility - between network domains (IP address change) Consider also Node vs. Network mobility What causes mobility? Physical movement Radio channel Network performance Sleep schedules Node failure

69 Node Mobility

70 Network Mobility

71 Dealing with Mobility Micro-mobility Do nothing (restart) Link-layer techniques (e.g. GPRS, WiFi) 6LoWPAN-ND extended LoWPANs Routing also plays a role Macro-mobility Do nothing (restart) Application layer (SIP, UUID, DNS) Mobile IPv6 [RFC3775] Proxy Home Agent Network mobility Do nothing (restart all nodes) NEMO [RFC3963]

72 IPv4 Interconnectivity

73 IPv4 IPv6 Transition Redes separadas Protocolos no compatibles entre si.disruptivo Working group at the IETF Transition Mechanisms [RFC 4213] Dual Stack Tunnel Manual Automatic 6to4 Tunnel Broker Traslation Application Layer Gateway NAT64/DNS64

74 IP Protocol Stack

75 Internet Architecture Image source: (Wikipeida) GFDL