Prof.  Carsten  Bormann,    cabo@tzi.org

2013-­‐11-­‐14

Prof.  Dr.-­‐Ing.  Carsten  BormannTZI  –  Universität  Bremen

Scaling  the  Webto  billions  of  nodes:Towards  the  “Internet  of  Things”

1

Source: Ericsson

Connecting:Places ➔ People ➔ Things

Scale up:Number of nodes(50 billion by 2020)

3

Scale down:node

4

Scale down:costcomplexity

6

centkilobyte

megahertz7

http://6lowapp.net core@IETF80, 2011-03-28

10/100 vs. 50/250� There is not just a single class of “constrained node”

� Class 0: too small to securely run on the Internet§ “too constrained”

� Class 1: ~10 KiB data, ~100 KiB code § “quite constrained”, “10/100”

� Class 2: ~50 KiB data, ~250 KiB code§ “not so constrained”, “50/250”

� These classes are not clear-cut, but may structure the discussion and help avoid talking at cross-purposes

8

Constrained nodes: orders of magnitude

9http://www.flickr.com/photos/blahflowers/3878202215/sizes/l/

10http://www.flickr.com/photos/blahflowers/3878202215/sizes/l/

Constrained networks

} Node: ... must sleep a lot (µW!)� vs. “always on”

} Network: ~100 kbit/s, high loss, high link variability

} May be used in an unstable radio environment} Physical layer packet size may be limited

(~100 bytes)

} “LLN low power, lossy network”

11

802.15.4 „ZigBee“Bluetooth SmartZ-Wave DECT ULE

Constrained Node Networks

Internet of Things IoTWireless Embedded Internet WEILow-Power/Lossy Networks LLNIP Smart Objects IPSO

12

“IP is important”IP = Integration Protocol

13

We make the net work14

Constrained Node/Networks in the IETF} WGs:

} Documenting techniques: LWIG (INT area,Light-Weight Implementation Guidance)

} IETF has many supporting WGs (and RFCs), e.g. security, management

15

6Lo(WPAN) ROLL CoRE DICEINT area(Internet) L2/L3 interface

RTG area(Routing)L3 routing

APP area(Applications)L7 application

SEC area (Security)L7 security

(1) The Network

6LoWPAN & RPL

16

Exhaustion of IANA IPv4 Unicast Address Free Pool

3 February 2011 17

APN

IC: a

lrea

dy g

one

2011

-04-

19

RIP

E (E

urop

e): 2

012-

09-1

4

America

s: ~20

14

Source: http://www.potaroo.net/tools/ipv4/

18

IPv4 = gone

IPv6 = 340282366920938463463374607431768211456 addresses

} There are only ~ 1025 grains of sand on the earth

} Let’s settle for a billion (109) objects on the net

} Danfoss (EU): 0.4×109 thermostats so far} Walmart (US): 0.1×109 CFL light bulbs per year

3.4×1038

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Constrained network example:IEEE 802.15.4} popular low-power (~ 1 mW) radio

} 0.9 and 2.4 GHz bands� 868 MHz: Europe (1 % duty cycle, 20 kbit/s)� 900 MHz: US (40 kbit/s)� 2.4 GHz: World (256 kbit/s)

} up to 127-byte packets} multicast works radio-range only

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“ZigBee”

RFC 4944: make 802.15.4 look like an IPv6 link} Basic Encapsulation

� Efficient representation of packets < ~100 bytes� First approach to stateless Header Compression

} Fragmentation (map 1280 byte MTU to < 128 bytes)� Datagram tag/Datagram offset

} Mesh forwarding� Identify Originator/Final Destination

} Minimal use of complex MAC layer concepts� cf. RFC 3819 “Advice for Internet Subnetwork Designers”

21

2007

RFC 6282: 6LoWPAN Header Compression (6LoWPAN-HC)} RFC 4944 header compression is stateless} Traditional header compression (ROHC, RFC 3095 etc.) is

flow-based stateful

} Is there a middle ground?

} Context-based HC*): maintain a single area context state for an entire 6LoWPAN

        Infrastructure Cloud                 |                 |              +-----+                 +-----+              |     | Gateway         |     | Host              |     |                 |     |              +-----+                 +-----+                 |                       |                 |     Backbone link     |           +--------------------+------------------+           |                    |                  |        +-----+             +-----+             +-----+        |     | Edge        |     | Edge        |     | Edge        |     | router      |     | router      |     | router        +-----+             +-----+             +-----+           o         o       o   o  o      o        o o       o o   o  o  o  o  o o   o  o  o  o  o   o  o  o  o      o  o o  o o   o    o   o  o  o  o     o   o  o  o o      o   o  o  o     o    o    o  o     o      o  o   o        o   o o     o          o  o      o    o       o

22

2011

*) draft-bormann-6lowpan-cbhc (2008-07)

RFC 6775 (6LoWPAN-ND):elements beyond RFC 4861} ARO (address registration option):

� hosts register their addresses to routers (6LRs): NS/NA� 6LRs can check the address with edge router (6LBR):

new ICMP messages DAR/DAC� replaces NS/NA use for address resolution (off-link model),

but keeps NS/NA intact for NUD (neighbor unreachability detection)} ABRO (authoritative border router option)

� distribute information about available 6LBRs (edge routers)

} 6CO (6LoWPAN Context Option)� distribute header compression context in entire LoWPAN

23

2012

6LoWPAN =

RFC4944 – HC1/HC2 + RFC6282 (6LoWPAN-HC) + RFC6775 (6LoWPAN-ND)

24

✔

6LoWPAN:  2013  ETSI  plugtest

} Before  IETF87  (Berlin):} Free  of  charge  6LoWPAN  plugtest  event

25

http://www.etsi.org/news-events/events/663-2013-6lowpan-plugtests

6LoWPAN beyond IEEE 802.15.4:

} Bluetooth Low Energy (“Bluetooth Smart” in 4.0)� global 2.4 GHz, very low power, already in many phones� popular in e-health applications� 6LoWPAN for BTLE: draft-ietf-6lowpan-btle

} Z-Wave (G.9959)� Regional 900 MHz variants� draft-brandt-6man-lowpanz

} DECT ULE (“Ultra Low Energy”)� can use European cordless phone spectrum� draft-mariager-6lowpan-v6over-dect-ule

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✔Pretty much cooked

Back-Burner

waiting for BT-SIGchannel assignment

6Lo: Bundle Internet Area standardization in Constrained Node Networks

} 6Lo@ietf.org} has just had its first WG meeting} replacing 6LoWPAN WG

} work closely with 6man (IPv6 maintenance), homenet (IPv6 home networking), dnssd

27

RPL: Routing for CN/N} RFC 6550: Specialized routing protocol RPL

– Rooted DAGs (directed acyclic graphs)

28

Root

33 2

5 35 4

7

4

6

7

1 Root

33 2

5 35 4

7

4

6

7

1

} redundancies in the tree help cope with churn

} “rank”: loop avoidance

} Storing Mode: Every router has map of subtree

} Non-Storing Mode: Only root has map of tree

Metrics: e.g., ETX

2012

RPL Route-over: Routing at Layer 3

} As we are used to in the Internet� Alternative: L2 routing, mesh

networks, “mesh-under”} Advantage: can bring together

multiple subnets� one or more constrained radio

technologies� use Ethernet, WiFi as backbones

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LBR

Router

Local Server

LBR

H

H H H H

RR

R

R

R R

Backbone link

Internet

Low-Power and Lossy Network (LLN)

LLN Border Router (LBR)

Router

Host

Downstream Upstream

(2) The Application

CoAP

30

For which applications did the Internet first scale massively?

} Remote Login} E-Mail} NetNews

} The Web

31

The elements of success of the Web} HTML

� uniform representation of documents� (now moving forward to HTML5 with CSS, JavaScript)

} URIs� uniform referents to data and services on the Web

} HTTP� universal transfer protocol� enables a distribution system of proxies and reverse proxies

32

✔

Translating this to M2M

} HTML� uniform representation of documents� (now moving forward to HTML5 with CSS, JavaScript)

} URIs� uniform referents to data and services on the Web

} HTTP� universal transfer protocol� enables a distribution system of proxies and reverse proxies

New data formats:

M2M semantics instead of

presentation semantics

33

UDP [RFC0768], TCP [RFC0793],DCCP [RFC4340], SCTP [RFC4960],

and NORM [RFC5740]

tunneling technologies such as the Tunnel mode of IPsec, IP-in-IP, and Generic Route Encapsulation (GRE) [RFC2784]; circuit networks such as MPLS [RFC4364], GMPLS, and ATM; local wireless (IEEE 802.11, 802.15.4,

or 802.16) networks and switched Ethernet (IEEE 802.3) networks.

IPv4, IPv6

IEEE, ITU

Many.If in doubt, use HTTP :-)

34

UDP [RFC0768], TCP [RFC0793],DCCP [RFC4340], SCTP [RFC4960],

and NORM [RFC5740]

tunneling technologies such as the Tunnel mode of IPsec, IP-in-IP, and Generic Route Encapsulation (GRE) [RFC2784]; circuit networks such as MPLS [RFC4364], GMPLS, and ATM; local wireless (IEEE 802.11, 802.15.4,

or 802.16) networks and switched Ethernet (IEEE 802.3) networks.

IPv4, IPv6

IEEE, ITU

If in doubt, use HTTP

35

HTTPUDP [RFC0768], TCP [RFC0793],DCCP [RFC4340], SCTP [RFC4960],

and NORM [RFC5740]

tunneling technologies such as the Tunnel mode of IPsec, IP-in-IP, and Generic Route Encapsulation (GRE) [RFC2784]; circuit networks such as MPLS [RFC4364], GMPLS, and ATM; local wireless (IEEE 802.11, 802.15.4,

or 802.16) networks and switched Ethernet (IEEE 802.3) networks.

IPv4, IPv6

IEEE, ITU

If in doubt, use REST

36

Constrained Node/Networks➔ Compressed HTTP?} Saves some bytes} Retains all the complexity

� lots of historical baggage� still needs TCP below

} Adds the CPU requirements for compression} Limited gain

� compression only takes you so far✗37

„Make things as simple as possible, but not simpler.

38

Attributed to Albert Einstein

The Constrained Application Protocol

} implements HTTP’s REST model� GET, PUT, DELETE, POST; media type model

} while avoiding most of the complexities of HTTP

} Simple protocol, datagram only (UDP, DTLS)} 4-byte header, compact yet simple options encoding

} adds “observe”, a lean notification architecture

CoAP

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CoAP Examples

} GET coap://temp1.25b006.floor1.example.com/temperature� ASCII string: 22.5� could use JSON, e.g. as in draft-jennings-senml

} PUT coap://blue-lights.bu036.floor1.example.com/intensity� ASCII string: 70 %

} GET coap://25b006.floor1.example.com/.well-known/core� </temp>;n="TemperatureC",</light>;ct=41;n="LightLux"� see RFC 6690 (CoRE link format)

40

More in draft-vanderstok-core-bc-05see also draft-ietf-core-interfaces

Payload Marker

Example Interchange

C: CON + GET coap://server/resource

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+-+-+-+-+-+-+-+-+-+-+-,-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| 1 | 0 | 0 | GET = 0.01 | MID=1234 |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| +3 =3 | 6 | "server" (6 Bytes) ...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| +8=11 | 8 | "resource" (8 Bytes) ...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

S: ACK, ct=application/cbor, payload: {“hlo”:“World”}

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+-+-+-+-+-+-+-+-+-+-+-,-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| 1 | 2 | 0 |Content = 2.05 | MID=1234 |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|+12=12 | 1 | 60 | Content-Format = 60 (application/cbor)+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|1|1|1|1|1|1|1|1| A1 63 h l o 65 W o r l d (11 Bytes) ...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Option

Payload

41

Combining CoAP and HTTP

} CoAP is usedin constrainedenvironment

} CoAP and HTTPshare proxy modelbased on REST

} Enables standard,application-independent proxy

42

Proxying and caching

43Source: 6lowpan.net

Constrained!RESTful!Environments (CoRE) Working Group

Drafts:

• Constrained Application Protocol draft-ietf-core-coap

• Observing Resources in CoAP draft-ietf-core-observe

• Blockwise Transfers in CoAP draft-ietf-core-block

• CoRE Link Format draft-ietf-core-link-format44

RFC 6690 ✔

✔

Prof.  Carsten  Bormann,    cabo@tzi.org

Character-­‐based

Concise  Binary

Document-­‐Oriented

Data-­‐Oriented

XML EXI

JSON ???

Data  Formats

45

46

Data Formats: CBOR(Concise Binary Object Representation)} JSON: Highly successful data model

� true/false/null; numbers, strings; arrays, maps (“objects”)� Add binary data (byte strings)� Provide tags for specific types (e.g., date/time)

} Add concise binary format� Inspired by CoAP Option Coding, MessagePack� Internet standards document: RFC 7049

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Concise (Counted) Streaming (Indefinite)

Prof.  Carsten  Bormann,    cabo@tzi.org

Character-­‐based

Concise  Binary

Document-­‐Oriented

Data-­‐Oriented

XML EXI

JSON CBOR

Data  Formats

48

Security is not optional!

} HTTP can use TLS (“SSL”)} CoAP: Use DTLS 1.2

� Add 6LoWPAN-GHC for efficiency} Crypto: Move to ECC

� P-256 curve� SHA-256� AES-128

} To do:� Commissioning models (Mother/Duckling, Mothership, …)� Authorization format and workflow� Performance fixes (DICE)

49

128-bit security

(~ RSA 3072-bit)

Prof.  Carsten  Bormann,    cabo@tzi.org

The next billions of nodes • Carsten Bormann • 2013-11-14

50Disclaimer: Nobody speaks for the IETF