IPv6 for the Masses (Of sensors)

Transcription

1 IPv6 for the Masses (Of sensors) Presentation By: Colin O'Flynn Atmel Corporation Eric Gnoske Blake Leverette Michael Vidales NewAE Colin O'Flynn Cisco Systems Julien Abeillé Mathilde Durvy Patrick Wetterwald Proto6 LLC Geoff Mulligan Swedish Institute of Computer Science Adam Dunkels Niclas Finne Nicolas Tsiftes

2 Presentation Plan Smart Objects Download this presentation at: Overview of IPv6 Overview of Overview of 6lowpan Overview of Contiki Contiki uipv6 Project Demonstration of Contiki Demonstration of Spitfire/Rum Questions

3 Smart Objects - Background

4 Smart Objects Why Smart Objects?? Let's look at a few examples...

5 Wireless Smart Objects Cost-Savings Power-Savings Convenience Lamp: Only need to run power wires to light fixture Easy to retro-fit adding switch anywhere Easy to chain many lights to one switch afterwards Central Heating/Cooling: Trivial to install temp sensors and thermostat around house Inventory Management: Tag items to quickly find them Smart sensors can react to their environment tag a pallet of meat, and it will tell you it's being stored improperly

6 Wireless Smart Objects Cost-Savings Power-Savings Convenience Lamp: Have lights turn off automatically when no one is in room, at night, etc Central Heating/Cooling: Avoid rolling blackouts by allowing central power companies to turn down blocks of AC's Inventory Management: Items can communicate storage requirements to their environment. Aka: Freezer truck that sets it's temperature based on what it's transporting

7 Wireless Smart Objects Cost-Savings Power-Savings Convenience Lamp: Play a DVD, lights dim automatically Have one 'master switch' that shuts all lights off when you go to bed Alarm clock interfaces to lights to turn on gradually Central Heating/Cooling: Put temperature sensors where you want them (bedrooms), not where it's easy to run wire to Inventory Management: Centralize management, access inventory lists from anywhere without specialized hardware/software

8 Smart Objects Just a few examples many many more: Wireless power meters, allows utility companies to instantly see power usage across a city Wireless parking meters, communicates to drivers where a free space is, and allows them to pay wirelessly Networks of cars that could form maps of traffic congestion

9 Why IP? IP is Open IP is Lightweight Almost every OS has it, IP connectivity everywhere DNS, SNMP, etc all exist and well-used already IP is Stable ie: The Internet IP is Manageable ie: VoIP, FTP, HTTP, SSH, all very different but all use IP Runs on many physical layers! IP is Ubiquitous IP is Scalable Stacks with <10 KB ROM, <1.5KB RAM required IP is Versatile IETF defines IP standards through RFCs IP has existed for 30 years, most techs familiar with it already IP is End-to-End No protocol translation needed anywhere

10 The IPSO Alliance Promoting the use of IP for Smart Objects Brings the Internet of Things to life Launched Sept 2008 IPSO's goals include: Promoting IP Developing white papers Find industries that could use IP Organize interoperability tests Support development of relevant standards

11 The IPSO Alliance Promoting the use of IP for Smart Objects _ _ ,00.html

12 IEEE Background

13 Background Low Speed, Low Cost, Low Power! Specifically, as defined in : Over-the-air data rates of 250 kbits/s, 100 kbits/s, 40 kbits/s, and 20 kbits/s Star or peer-to-peer operation Allocated 16-bit short or 64-bit extended addresses Optional allocation of guaranteed time slots (GTSs) Carrier sense multiple access with collision avoidance (CSMA -CA) channel access Fully acknowledged protocol for transfer reliability Low power consumption Energy detection (ED) Link quality indication (LQI) 16 channels in the 2450 MHz band, 10 channels in the 915 MHz band, and 1 channel in the 868 MHz band

14 Background Supports Multiple Topologies Star for more managed networks Peer-to-Peer for ad-hoc networks

15 MAC Frames PAN identifier (PANID) is 16-bits, all nodes on one network have same PANID Each full MAC address is 64-bits, but nodes can use a 16-bit short address Not all addresses are present (aka: beacon packet has no dest address)

16 MAC Frames

17 Atmel's Radios Device AES Freq Link Budget Data Rate Current Current Antenna (Max) (Tx /Rx) (Sleep) Diversity AT86RF230 No 2.4 GHz 104 db 250 Kbit/s 16.5 ma 20nA 15.5 ma No AT86RF231 Yes 2.4 GHz 104 db* 2 Mbit/s 14.3 ma 20nA 13.2 ma Yes AT86RF212 Yes 800 / 120 db 900 MHz 1 Mbit/s 9 ma 19 ma Yes * at 250 Kbit/s All feature: Auto CSMA-CA CCA RSSI Calculation at 20Kbit/s 200nA At maximum possible Tx power FCS calculation on Tx/Rx Address filtering Energy Detection

18 Atmel's Radios 104 db at 2.4 GHz: ~300 meter range in free space 120 db at 900 MHz: ~4 km range in free space Raven Boards / RCB have max of 5 db gain on loop antenna 700 meter range in free space with proper orientation Raven USB Stick has max of 0 db gain on folded-dipole antenna Range drops without proper orientation!

19 AT86RF231 Reference Design RF Section Antenna Diversity, two antennas mounted perpendicular External components limited to crystal, capacitors, and antenna with matching circuitry (and switch for antenna diversity in this example)

20 IPv6 - Background

21 Background - IPv6 Massive address space Uses 128-bit addresses compared to 32-bit IPv4 addresses 2128 addresses could give every grain of sand multiple IP addresses! Better Quality of Service (QoS) guarantees Aka: VoIP packets transmitted with reduced latency Stateless autoconfiguration No need for DHCP, nodes can configure their own addresses

22 IPv6 Addressing Defined in RFC4291, IP Version 6 Addressing Architecture Address written in hexadecimal notation, with ':' between groups of 16 bits: 2001:0DB8:0000:0000:0008:0800:200C:417A Can replace groups of zero, and drop leading zeros: 2001:DB8:0:0:8:800:200C:417A If have a number of zeros in the middle of the address, can replace them all with '::' 2001:DB8::8:800:200C:417A Length of prefix specified with a '/' at end, for example if our network is using the 2001:0DB8:0000:0000 prefix (64-bits): 2001:DB8::8:800:200C:417A/64

23 IPv6 Addressing Defined in RFC4291, IP Version 6 Addressing Architecture IPv6 defines certain prefixes and addresses to make management easier. For example: ::1/128 FF00::/8 FE80::/ :0DB8::/32 loopback address (note 128-bit prefix) multicast link-local unicast Reserved for documentation/examples Due to IPv6's huge address space, it's possible to set aside easy to remember prefixes yet not 'waste' any appreciable address space. This is reasoning behind huge address space. ie: The documentation prefix reserves 296 IP addresses, that's 264 times more addresses than the entire IPv4 address space!

24 IPv6 Addressing Defined in RFC4291, IP Version 6 Addressing Architecture Link-Local Addresses Used for addressing a single link for address configuration, neighbor discovery, etc Routers will not forward packets with link-local source or destination addresses! Multicast addresses Send a packet to a group of nodes, mostly for neighbor discovery Predefined multicast addresses include: FF01::1 FF01::2 FF02::1:FFXX:XXXX All-nodes address All-routers address Solicited-node address

25 IPv6 Stateless Auto-Configuration Defined in RFC4862, IPv6 Stateless Address Autoconfiguration A number of ICMPv6 message types defined, which are: Neighbor Solicitation A neighbor solicitation is sent attempting to discover who owns a certain IP address Neighbor Advertisement Neighbor advertisement is sent on receipt of a neighbor solicitation, includes information such as physical address Router Solicitation Used by an end-node to discover the address of any routers on this network Router Advertisement Sent periodically by routers, and in response to a router solicitation. Includes router IP address, physical address, and network information

26 IPv6 Stateless Auto-Configuration Defined in RFC4862, IPv6 Stateless Address Autoconfiguration Example: Node Powers up, who am I, who is around me?? 1) Gets MAC address programmed into it 2) Creates an IPv6 address with link-local scope from above 01-1C-23-2B-BD-6C generates FE80::21C:23FF:FE2B:BD6C 3) Checks if anyone else is using that address using neighbor solicitation packets (duplicate address detection, or DAD) 4) Performs router solicitation to get default route, prefix information 5) From router it finds this network has a prefix of 2001:BD8::/64 for example, so it then generates address 2001:DB8::21C:23FF:FE2B:BD6C

27 IPv6 Stateless Auto-Configuration Defined in RFC4862, IPv6 Stateless Address Autoconfiguration Example cont'd 6) Performs DAD on that address 7) Now has joined the network! All without any intervention.

28 6LoWPAN - Background

29 6LoWPAN IPv6 over Low power Wireless Personal Area Networks Internet Engineering Task Force (IETF) Working Group Released RFC's: RFC4919: Overview, Assumption, Problem Statement, Goals RFC4944: Transmission of Ipv6 Packets over IEEE Networks

30 6LoWPAN Problems Running IPv6 Over has 127 byte maximum frame size, with available for data depending on header options Devices may spend most of their time asleep Ad-hoc network creation, with possibly huge networks Nodes may be totally inaccessible (HVAC, etc) Low bandwidth of radio link Low-cost nodes with limited ROM and RAM 6LoWPAN helps work around these problems!

31 6LoWPAN Header Compression IP header is very large! That is a problem... so compress it!

32 IPv4 Header Unsuitable for Compression Bits 0-3 Bits 4-7 Bits 8-15 Bits Version Header Length Type of Service Total Length Identification TTL Flags Protocol Bits Fragment Offset Checksum Source Address Destination Address Options Variable header lengths allowed! Minimum length = 20 octets

33 IPv6 Header Suitable for compression Bits 0-3 Version Bits 4-7 Bits 8-11 Bits Bits Traffic Class Bits Flow Label Payload Length Next Header Source Address Source Address Source Address Source Address Destination Address Destination Address Destination Address Destination Address Fixed header length of 40 octets Hop Limit (TTL)

34 6LoWPAN Header Compression We already have destination and source addresses from packet We know that autoconfigured addresses will be created from addresses... Hence it's possible to remove IP addresses completely in some cases! Other bytes are known such as version, traffic class, and flow - in this case entire 40-byte header is represented in two bytes: 1 byte for Header Compression 1 (HC1) 1 bytes for hop limit (which is never compressed)

35 6LoWPAN Header Compression Header Compression can be applied variably, so some fields carried uncompressed if needed. Header compression defined for UDP as well, allowing compression of UDP packets Currently more advanced header compression defined in draft-ietf-6lowpan-hc* *As of Nov 2008 check 6lowpan status pages at

36 6LoWPAN Fragmentation Second main problem: IPv6 has minimum transmission unit (MTU) as 1280 bytes, has maximum frame size of 127 bytes! Fragmentation will be needed split large packets up. 6LoWPAN adds support for fragmentation, including out of order delivery, which is very likely in a mesh network.

37 6LoWPAN Routing Mesh Under Mesh is formed at layer Routing done at 6LoWPAN layer IP unaware of intermediate nodes Requires all nodes to use same mesh header Route Over Routing is done at IP layer IP aware of intermediate nodes Allows use of standard IP routing protocols Can route across multiple physical layers

38 6LoWPAN Mesh Under Requires all nodes to use same mesh header Wouldn't this kill interoperability?? NO Interoperability still present at IP layer Vendor-Specific Mesh Edge Router Edge Router IPv6 Link

39 6LoWPAN Sleeping Nodes Always-on receiver wastes precious power! Will kill a coin-cell battery in hours to days With proper power management same battery source could last a year or more Possible solutions Synchronized wake of nodes Requires good synchronization, but has best power savings Low-power listening Node sleeps briefly, wakes up quickly to see if any activity it should listen to Works well with ad-hoc networks Router buffers sleeping node's traffic Routers assumed to be always awake

40 6LoWPAN Network Security Infiltration Snoop network traffic Control other nodes outside user turns off your lights! Denial of Service Overloading node with requests Drain a nodes battery by faking network traffic it thinks it needs to listen to RF Jamming (harder to defend against)

41 6LoWPAN Network Security IPsec Suite of security protocols for authenticating and encrypting IP packets Too heavy for low-cost embedded systems! Encryption has security measures in protocol Can secure 6lowpan with encryption Key management and distribution becomes important

42 6LoWPAN See Archrock 6lowpan overview for more detail:

43 The Project

44 Contiki OS Open-source multitasking OS Designed for constrained embedded systems Has 'uip' for network support, a stack with IPv4, TCP, and UDP Number of features such as loadable module support, event system Created by Adam Dunkels at the Swedish Institute of Computer Science (SICS)

45 Contiki OS Selected as base for this project due to: Existing IP code in Contiki Existing higher level protocols / apps in Contiki Already used in a number of wireless sensor apps Open source

46 Results Network Stack Atmel, Cisco, Proto6, SICS added an IPv6 stack, 6lowpan layer, and MAC to Contiki: OSI Layer Number uipv6 Layer 3 sicslowpan sicslowmac Layer Radio Layer 1

47 Results - uipv6 Complete IPv6 Stack added to Contiki Passed all tests required to be called 'IPv6 Ready' this is a complete stack, not a crippled version only for embedded systems Size bench-marks of stack: Item ROM (bytes) RAM (bytes) ND Input/Output ND Structures Network interface management Stateless address autoconf IPv6 (header processing, etc) Packet Buffer ICMPv6

48 Results - sicslowpan 6LoWPAN Layer added to Contiki Implements initialization, header compression, and packet fragmentation Item ROM (bytes) RAM (bytes) Sicslowpan - base HC1 processing HC01 processing Packet fragmentation processing

49 Results - sicslowmac MAC Layer that interfaces to Atmel radio Provides a limited MAC: Set/Get device address Set/Get device PAN ID Set/Get operating channel Data request Data indication Item ROM (bytes) RAM (bytes) Sicslowmac Radio driver Frame Parsing

50 Results new-ipv6 example Simple example that provides an IPv6 stack sitting on a device with UDP support. Node will acquire IPv6 address, can then ping node Node can send/receive data using UDP Item new-ipv6 example ROM (bytes) RAM (bytes) If IP stack is so small, where does all that ROM and RAM come from?? Current implementation respects OSI model separate buffers for each layer, hence two 1292 byte buffers present in system! Also duplication of 127-byte 6lowpan buffers. About 300 bytes of string constants stored in SRAM

51 Results new-ipv6 example minimum size Disable fragmentation processing to minimize buffer duplication Item new-ipv6 example ROM (bytes) RAM (bytes) Still multiple buffers present Has ability to process full 1280 byte IP packet Tiny nodes will never need such a large packet Could have node ignore packets over a certain size to limit buffer needed

52 Results webserver-ipv6-raven example Complete webserver example, can access node from any browser. Item webserver-ipv6-raven example ROM (bytes) RAM (bytes) Code is very wasteful of SRAM stores a number of constants in there, simply because it was easier and we have 16K SRAM in the device. FLASH memory is 128K in this device, under half-used. IP queuing is enabled in this example so you can send a packet while receiving another. This adds another 1292 byte buffer!

53 Hardware Raven AT86RF230 Radio ATMega1284p micro for radio ATMega3290p micro for LCD 128 Kbyte ROM, 16 Kbyte RAM

54 Results Jackdaw Jackdaw is name given to combination of hardware and software that allows you to access 6LoWPAN network: Computer's IPv6 Stack Layer 3 Host Computer sicslowpan sicslowmac Layer Radio Layer 1 Jackdaw

55 Results - Jackdaw Mounts as Ethernet interface in Windows and Linux

56 Results - Jackdaw Allows you to use computer as router / gateway Provides translation between 8-byte link-layer addresses and 6-byte link-layer addresses Sniffs raw frames for debugging at the same time as passing IPv6 frames:

57 Results - Jackdaw Additional Features: Mounts as USB mass storage device to store it's own drivers Mounts USB serial port to change parameters and for debugging information

58 Jackdaw Limitations Jackdaw is doing 6lowpan to IPv6 translation Requires Jackdaw to buffer up to 1280 bytes before passing entire IPv6 frame to computer Jackdown has 8K SRAM total, so can only afford a single buffer due to SRAM needed for USB, RNDIS protocol, serial port, etc etc Means Jackdaw can only process fragmentation from a single node at a time! While waiting on part of a fragmented packet, it drops any other incoming packets Solution More powerful 6lowpan bridge (ARM, AVR32, etc) Move 6lowpan implementation into PC

59 Sensys 2008 Poster to right was presented at Sensys and won Best Poster award!

60 Demonstration - Contiki

61 Demonstration - Local

62 Demonstration - Local Jackdaw Bridge to PC Raven Boards embedded webserver with IPv6 Radio Control Boards (RCBs) - IPv6 stack, will respond to ping

63 Demonstration - Local Note: My hosts file contains the following for ease of access: aaaa::11:22ff:fe33:4455 aaaa::11:22ff:fe33:4456 aaaa::11:22ff:fe33:4457 aaaa::11:22ff:fe33:4458 aaaa::11:22ff:fe33:4459 aaaa::11:22ff:fe33:445a aaaa::11:22ff:fe33:445b spongebob patrick squidworth krabs sandy plankton gary Spongebob & Patrick are Ravens (aka: webservers) Rest are RCB's

64 Demonstration - Local

65 Demonstration - Local

66 Demonstration - Local Note: flood control on Jackdaw limits outgoing packets to one per 200 ms! Hence when running multiple pings you see long latency

67 Next Steps High-performance Router Gateway between 6LoWPAN and 'The Internet' Use higher performance processor (ARM) Embedded Linux? Allows for true embedded router, not just interface to computer Supports larger networks

68 Next Steps Autoconfiguration IPv6 Autoconfiguration works at IP layer What about at MAC layer? Need to select RF channel, PANID, etc

69 Next Steps Very Constrained Devices 128K flash and 16K SRAM is HUGE in embedded systems Core IPv6 stack, 6lowpan, and MAC can be tiny Majority of SRAM and FLASH usage comes from desire of our system to be sane to understand and modify: Separate buffers for each layer Some string literals stored in SRAM Full-featured OS Target is AtMega32: 32K FLASH, 2K SRAM Smaller targets possible for very dumb devices Only have ability to process certain IP messages such as neighbor discovery packets, and send a simple hardcoded UDP message

70 Demonstration - Spitfire

71 Spitfire with RUM Overview Tiny end nodes Route Under MAC (RUM) for mesh-under 6LoWPAN routing Forms self-healing mesh network MAC demo is 6.8K FLASH, 479 Bytes SRAM Will have minimal IPv6 implementation ARM Network Bridge coordinator Running 'Ethernut' OS Embedded webserver to display network status, node status

72 Spitfire with RUM Overview

73 More Information Download this presentation at: Contiki 6lowpan IPv