slide rpl standart

Routing Algorithms

for

Wireless Sensor

Networks

Artemis Paradisi

Jacques Tiberghien

- RPL: IPv6 Routing protocol for low power

and lossy networks.

IPv6 on Low Power and Lossy

Networks?

3

Applications

TCP/UDP

MAC&PHY

IPv6

Applications

TCP/UDP

IEEE 802.15.4

RPL

6LowPan

A

G F E

I J K

B C

D

H

L M

The Internet

The LowPower network is just one subnet

The sink node plays the role of a router

6LowPan Why ?

4

TCP/UDP

IEEE 802.15.4

RPL

6LowPan

Frame length : IPv6:

6LowPan Why ?

5

A

G F E

I J K

B C D

H

L M

The Internet

IPv6 : One subnet = one broadcast domain

This is not true in LowPans!

Solutions :

- Link level routing

- Routing in the subnet !

Route over uses simplified versions

of IPv6 ND protocols.

Routing Protocol for

Low Power and Lossy Networks

RPL origin: The Internet of things.

IETF working group for IPv6 routing.

None of the existing protocols is adequate!

New design combining interesting ideas of all.

RPL Basic Mechanisms

Routing based upon one or more Destination Oriented Directed Acyclic Graphs (DODAGs)

Optimal routes between sink and all other nodes for both the collect and distribute data traffics.

Redundant equivalent routes are kept for reliability in case of link or node failure.

Multiple DODAGs if different optimisation criteria.

6

RPL:

the DODAG

7

A

H F

C

G

E D B

I

N M L K

Grounded

DODAG

Flo

ating D

AG

J

For node I,

E is a parent

G & H are siblings

1 1 1

1 1 1

For node G,

D,H,L are neighbors

D is preferred parent

Each link has a

cost. (distance,

latency, ETX, ) This cost can be

augmented with

node related data

(battery state, ) 1

The ETX cost function

8

ETX = Estimated number of transmissions from x to y.

= Number of times a frame needs to be transmitted

over a link before being acknowledged.

= (dxy x dyx) -1 dxy = success rate from x to y.

Each node broadcasts precisely once per second a

short message, each receiver counts during 10

seconds the number of broadcasts it receives from

each neighbor.

dxy = (number of frames received from x by y) / 10

What about RDC ?

RPL:

the RANK of nodes in a DODAG

9

A

H F

C

G

E D B

I

N M L K

Grounded

DODAG

Flo

ating D

AG

J

Rank =

1.0

Rank =

2.0

For node I,

E is a parent

G & H are siblings

1 1 1

1 1 1

For node G,

D,H,L are neighbors

D is preferred parent

RPL:

the RANK of nodes in a DODAG

10

A

H

2

C

1

G

3

E

1

D

1

I

2

N M L

Grounded

DODAG

For node I,

E is a parent

G & H are siblings

1 1 1

5 1 1

For node G,

If route via a sibling (H)

is better , then it should increase its

rank.

1

RPL:

Messages for routing

11

A

H F

C

G

E D B

I

N M L K

Grounded

DODAG

Flo

ating D

AG

J

DA

O

1 1 1

1 1 1

DIO

DIS

RPL:

Collect, Distribute and P2P routing

12

A

H

C

G

E D

I

N M L

1 1 1

1 1 1

A

H

C

G

E D

I

N M L

1 1 1

1 1 1

A

H

C

G

E D

I

N M L

1 1 1

1 1 1

Collect Distribute P2P

13

Routing in sensor networks(1).

1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

A

0/0

G F E

I J K

B C

1

1

1

1

D

H

L M 4 1

The Internet

For this example,

links have a distance

as in DV and AODV.

The Rank

calculations are

made so that

Rank = hop count

14


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G F E

1/1

I J K

B

1/4 C

1

1

1

1

D

H

L M 4 1

The Internet

A sends DIO to B and E.

A becomes their preferred

parent.

A

0/0

15


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G

2/7

F

2/5

E

1/1

I J K

2/8

B

1/4

C

2/5

1

1

1

1

D

H

L M 4 1

The Internet

B sends DIO to A,C,F,G

and K.

A ignores (rank).

B becomes the parent of

all others. A 0/0

16


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G

2/7

F

2/2

E

1/1

I

2/2

J

2/2

K

2/8

B

1/4

C

2/5

1

1

1

1

D

H

L M 4 1

The Internet

E sends DIO to A,F,I and J.

A ignores (rank).

E becomes the parent of F,I

and J.

A

0/0

17


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

3/6

F

2/2

E

1/1

I

2/2

J

2/2

K

2/8

B

1/4

C

2/5

1

1

1

1

D

3/8

H

L M 4 1

The Internet

C sends DIO to B,D and G.

B ignores (rank).

C becomes the parent of

D and G.

A

0/0

18


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

3/6

F

2/2

E

1/1

I

2/2

J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

L M 4 1

The Internet F sends DIO to B,E and K.

B and E ignore (rank),

F becomes parent of K.

A

0/0

19


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

3/6

F

2/2

E

1/1

I

2/2

J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

L M 4 1

The Internet

A

0/0

I sends DIO to E and J.

E ignores (rank),

J ignores (distance)

20


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

3/6

F

2/2

E

1/1

I

2/2 J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

L M 4 1

The Internet

A

0/0

J sends DIO to E,I and K.

E ignores (rank),

I and K ignore (distance)

21


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

3/6

F

2/2

E

1/1

I

2/2 J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

4/9

L M 4 1

The Internet

A

0/0

D sends DIO to C and H.

C ignores (rank),

D becomes parent of H

22


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

3/6

F

2/2

E

1/1

I

2/2 J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

4/7

L M 4 1

The Internet

A

0/0

G sends DIO to B,C,H and K.

B and C ignore (rank),

K ignores (distance)

G becomes parent of H.

23


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

4/4

F

2/2

E

1/1

I

2/2 J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

4/7

L

4/6 M

4 1

The Internet

A

0/0

K sends DIO to B,F,G,J and L.

B,F and J ignore (rank),

K becomes parent of G and L.

24


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

4/4

F

2/2

E

1/1

I

2/2 J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

5/5

L

4/6 M

4 1

The Internet

A

0/0


B,C and K ignore (rank),

H adapts its rank and distance

and keeps G as a parent

25


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

4/4

F

2/2

E

1/1

I

2/2 J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

5/5

L

4/6

M

5/7

4 1

The Internet

A

0/0

L sends DIO to K,H and M.

K ignores (rank),

H ignores (distance)

L becomes parent of M

26


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

4/4

F

2/2

E

1/1

I

2/2 J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

5/5

L

4/6

M

6/6

4 1

The Internet

A

0/0

H sends DIO to D,G,L and M.

D,G and L ignore (rank),

H becomes parent of M

27


1

3

3 3 1

1 4

1

4

1

1

1 1 1

1

G

4/4

F

2/2

E

1/1

I

2/2 J

2/2

K

3/3

B

1/4

C

2/5

1

1

1

1

D

3/8

H

5/5

L

4/6

M

6/6

4 1

The Internet

A

0/0

Finally, the entire DODAG

has been constructed.

28


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G F E

I J K

B C

1

1

1

1

D

H

L M 4 1

The Internet

For this example, links

have a distance as in

DV and AODV.

The Rank calculations

are made so that

Rank = Distance to sink A 0

29


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G F E

1

I J K

B

4 C

1

1

1

1

D

H

L M 4 1

The Internet

A sends DIO to B and E.

A becomes their

preferred parent.

A

0

30


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G F

2

E

1

I

2

J

2 K

B

4 C

1

1

1

1

D

H

L M 4 1

The Internet

E sends DIO to A,F,I and J.

A ignores (rank).

E becomes parent

F,I and J.

A

0

31


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G F

2

E

1

I

2

J

2

K

3

B

3 C

1

1

1

1

D

H

L M 4 1

The Internet

F sends DIO to B,E and K.

E ignores (rank).

F becomes parent of B

and K.

A

0

32


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G

6

F

2

E

1

I

2

J

2

K

3

B

3

C

4

1

1

1

1

D

H

L M 4 1

The Internet B sends DIO to A,C,F,G and K.

A and F ignore (rank).

B becomes parent of C and G.

K keeps its previous parent

(distance). A

0

33


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G

4

F

2

E

1

I

2

J

2

K

3

B

3

C

4

1

1

1

1

D

H

L

6 M

4 1

The Internet

K sends DIO to B,F,G,J and L.

J ignores (rank),

B ignores (distance),

K becomes parent of G and L.

A

0

34


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G

4

F

2

E

1

I

2

J

2

K

3

B

3

C

4

1

1

1

1

D

7

H

L

6 M

4 1

The Internet

C sends DIO to B,D and G.

B ignores (rank),

G ignores (distance),

C becomes parent of D.

A

0

35


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G

4

F

2

E

1

I

2

J

2

K

3

B

3

C

4

1

1

1

1

D

7

H

5

L

6 M

4 1

The Internet


B and K ignore (rank),

C ignores (distance),

G becomes parent of H.

A

0

36


1

3

3 3

1

1 4

1

4

1

1

1 1 1

1

G

4

F

2

E

1

I

2

J

2

K

3

B

3

C

4

1

1

1

1

D

6

H

5

L

6

M

6

4 1

The Internet

H sends DIO to D,G,L and M.

G ignores (rank),

L ignores (distance),

H becomes parent of D and M.

A

0

RPL

Conclusions

When the network is started up, the DODAG is build.

The DODAG supports optimal routing, both for collect and distribute protocols.

Protocols for detecting network changes and subsequent DODAG repairs (local and global) are

part of the RPL proposal (not explained here)

An Objective Function, giving the rank of the nodes in function of the properties of the links and the

nodes, can freely be chosen to influence the DODAG

topology and prevent loops.

37

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