Wireless embedded systems 0120442x ipv6 over low power wireless personal area networks 6lowpan
This presentation is the property of its rightful owner.
Sponsored Links
1 / 37

Chaiporn Jaikaeo [email protected] Department of Computer Engineering Kasetsart University PowerPoint PPT Presentation


  • 112 Views
  • Uploaded on
  • Presentation posted in: General

Wireless Embedded Systems (0120442x) IPv6 over Low-Power Wireless Personal Area Networks (6LoWPAN). Chaiporn Jaikaeo [email protected] Department of Computer Engineering Kasetsart University. Outline. 6LoWPAN IPv6 overview Header compression tecniques Routing JenNet -IP

Download Presentation

Chaiporn Jaikaeo [email protected] Department of Computer Engineering Kasetsart University

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Wireless embedded systems 0120442x ipv6 over low power wireless personal area networks 6lowpan

Wireless Embedded Systems(0120442x) IPv6 over Low-Power Wireless Personal Area Networks(6LoWPAN)

Chaiporn Jaikaeo

[email protected]

Department of Computer EngineeringKasetsart University


Outline

Outline

  • 6LoWPAN

  • IPv6 overview

  • Header compression tecniques

  • Routing

  • JenNet-IP

  • The 6lo Working Group


6lowpan

6LoWPAN

  • IPv6 over Low-power Wireless Personal Area Networks

  • Nodes communicate using IPv6 packets

  • An IPv6 packet is carried in the payload of IEEE 802.15.4 data frames


Example 6lowpan systems

Example 6LoWPAN Systems


Ipv6 overview

IPv6 Overview

  • Larger address space compared to IPv6

    • 232 vs. 2128

  • Autoconfiguration

    • Supporting both stateful (DHCPv6) and stateless operations

  • Simplified headers

    • Fixed header with optional daisy-chained headers

  • Mandatory security


Ipv6 header

IPv6 Header

  • Minimum header size = 40 bytes

    • Header compression mechanism is needed

Bit

0

4

8

12

16

20

24

28

0

Ver

Traffic Class

Flow Label

32

Payload Length

Next Header

Hop Limit

64

Source Address

96

128

160

192

Destination Address

224

256

288


Ipv6 extended headers

IPv6 Extended Headers

  • More flexible than IPv4’s option fields

  • Example 1: no extended header

  • Example 2: with a routing header

Next header = 6 (TCP)

TCP hdr + payload

Next header = 43 (routing)

Next header = 6 (TCP)

TCP hdr + payload


Ipv6 addressing

IPv6 Addressing

  • Global unicast addresses

    • Start with 001

    • Host ID usually incorporates MAC address

001

Prefix provided byservice provider

Subnet ID

Host ID

48

16

64


Ipv6 address scopes

IPv6 Address Scopes

  • Global addresses

    • Globally routable

  • Link-local addresses

    • Only used within directly attached network

    • Belonging to FE80::/10 subnet

0

Interface ID

1111 1110 10

96

db

c9

FF

FE

00

16

fe

10 bits

xxxxxxUx

U = 0: not uniqueU = 1: unique

94

db

c9

00

16

fe


Ieee 802 15 4 revisited

IEEE 802.15.4 Revisited

  • Allows 127 bytes MTU

    • Good for buffering cost and low packet error rate

  • Supports both 16-bit and 64-bit addresses

  • Supports both star and mesh topologies

  • Usually operates in an ad hoc fashion with unreliable links

  • IEEE 802.15.4 networks are considered Low-power and Lossy Networks (LLN)


6lowpan adaptation layer

6LoWPAN Adaptation Layer

  • Needs to make IEEE 802.15.4 comply with IPv6’s MTU size of 1280 bytes

    • IEEE 802.15.4’s MTU is 127 bytes

    • MAC header: ≤ 25 bytes

    • Optional security header: ≤ 21 bytes

  • Provides three main services

    • Packet fragmentation and reassembly

    • Header compression

    • Link-layer forwarding


6lowpan header stack

6LowPAN Header Stack


Header dispatch byte

Header Dispatch Byte


Mesh address header 1

Mesh Address Header (1)

  • Used with mesh-under routing approach

    • Only performed by FFDs


Mesh address header 2

Mesh Address Header (2)

  • Hop left field is decremented by one every hop

    • Frame is discarded when hop left is 0

  • Address fields are unchanged

802.15.4Header

MeshHeader

802.15.4Header

MeshHeader

B

A

A

D

Data

D

C

A

D

Data

Dst

Src

Orig

Final

Dst

Src

Orig

Final

Originator

Final

A

B

C

D


Mesh under vs route over routing

Mesh-under vs. Route-over Routing

Application

Application

Transport

Transport

Network (IPv6)

Network (IPv6)

Routing

6LoWPAN Adaptation

6LoWPAN Adaptation

802.15.4 MAC

802.15.4 MAC

802.15.4 PHY

802.15.4 PHY

Mesh-under routing

Route-over routing


Fragment header

Fragment Header

  • Fragmentation is required when IPv6 payload size exceeds that of IEEE 802.15.4 payload limit

  • All fragments are in units of 8 bytes

(in 8-byte units)


Ipv6 header compression

IPv6 Header Compression

  • Can be either stateless or stateful

  • Independent of flows


Hc1 compression 1

HC1 Compression (1)

  • Optimized for link-local addresses

  • Based on the following observations

    • Version is always 6

    • IPv6 address’s interface ID can be inferred from MAC address

    • Packet length can be inferred from frame length

    • TC and flow label are commonly 0

    • Next header is TCP, UDP, or ICMP

Ver

Traffic Class

Flow Label

Payload Length

Next Header

Hop Limit

Source Address

Destination Address


Hc1 compression 2

HC1 Compression (2)


Hc2 compression

HC2 Compression

  • Compress UDP header

  • Length field can be inferred from frame length

  • Source and destination ports are shortened into 4 bits each

    • Given that ports fall in the well-known range of 61616 – 61631


Hc1 hc2 compression

HC1 + HC2 Compression


Iphc compression 1

IPHC Compression (1)

  • HC1 and HC2 are only optimized for link-local addresses

    • Globally routable addresses must be carried non-compressed

  • IPHC will be the main compression technique for 6LoWPAN

    • HC1 and HC2 will likely be deprecated


Iphc compression 2

IPHC Compression (2)

  • TF: Traffic class and flow label

  • NH: Next header

  • HLIM: Hop limit (0NC, 11,264,3255)

  • CID: Context Identifier

  • SAC/DAC: Src/Dst address (stateful or stateless)

  • SAM/DAM: Src/Dst mode


Iphc s context identifier

IPHC’s Context Identifier

  • Can be used to derive source and destination addresses

  • Not specified how contexts are stored or maintained


Rpl routing protocol for low power and lossy networks

RPL – Routing Protocol for Low-power and Lossy Networks


Low power and lossy networks

Low-power and Lossy Networks

  • Abbr. LLN

  • Packet drops and link failures are frequent

  • Routing protocol should not over-react to failures

  • Not only applied to wireless networks

    • E.g., power-line communication

Packet delivery ratio


Routing requirements

Routing Requirements

  • IETF formed a working group in 2008, called ROLL (Routing over Low-power and Lossy Networks) to make routing requirements

  • Major requirements include

    • Unicast/multicast/anycast

    • Adaptive routing

    • Contraint-based routing

    • Traffic characteristics

    • Scalability

    • Auto-configuration and management

    • Security


Lln example

LLN Example


Different objective functions

Different Objective Functions

- Minimize low and fair quality links

- Avoid non-encrypted links

- Minimize latency

- Avoid poor quality links and battery-powered node


Rpl protocol

RPL Protocol

  • IPv6 Routing Protocol for Low-power and Lossy Networks

  • Designed to be highly modular for flexibility

  • Employing distance vector mechanism


Rpl operations

RPL Operations

  • DODAG (Destination Oriented Directed Acyclilc Graph) is created

    • Based on the objective function

LBR

LBR

1

1

11

12

13

11

12

13

21

22

23

24

21

22

23

24

31

32

33

34

35

31

32

33

34

35

41

42

43

44

45

46

41

42

43

44

45

46


Multiple dodags 1

Multiple DODAGs (1)

  • Provide alternate routes for different requirements


Multiple dodags 2

Multiple DODAGs (2)

- High reliability (no battery-powered node)

- Low latency


Jennet ip

JenNet IP

  • Jennic’simplementation of 6LoWPAN

  • Supports tree topology

  • Routing is performed over a tree


The 6lo working group

The 6lo Working Group

  • Works on IPv6 over networks of constrained nodes, such as

    • IEEE 802.15.4

    • ITU-T G.9959

    • Bluetooth LE

      https://datatracker.ietf.org/wg/6lo/charter/


References

References

  • G. Montenegro, N. Kushalnagar, J. Hui, and D. Culler. Transmission of IPv6 Packets over IEEE 802.15.4 Networks, RFC 4494, September 2007.

  • NXP Laboratories. JenNet-IP WPAN Stack User Guide (JN-UG-3080 v1.3). 2013.

  • Jean-Philippe Vasseur and Adam Dunkels. Interconnecting Smart Objects with IP: The Next Internet. Morgan Kaufmann. 2010.


  • Login