AntHocNet is an adaptive routing algorithm for mobile ad hoc networks (MANETs) inspired by ideas from Ant Colony Optimization (ACO).

1. ANTHOCNET
HYBRID ROUTING ALGORITHM
FOR MANET
Guided By
Shalini L
Asst. Prof. CSE Dept.
Presented By
Dhanith Krishna B
S7 CSE

2. 1
Presentation Structure
INTRODUCTION
MANETS
CHALLENGES IN MANETS
ROUTING ALGORITHMS
ANTHOCNET
REACTIVE ROUTE SETUP
PROACTIVE ROUTE MAINTENANCE
STOCHASTIC DATA FORWARDING
LINK FAILURES
ADVANTAGES

3. 2
History
First network – ARPANET

4. 3
History
First Wireless network – ALOHANET

5. 4
Traditional Networks
Fixed infrastructure
Dedicated Communication Devices
AP
BA

6. 5
MANET
MOBILE AD HOC NETWORK
Continuously self-configuring
Infrastructure-less network
Connected without wires.
A B C D

7. 6
MANET
Each device is router.

8. 7
Properties
Host movement frequent
Topology change frequent
Decentralized and scalable

9. 8
Examples
VANET

10. 9
Examples
TACTICAL NETWORKS

11. 10
Routing ???
selecting best paths in a network.

12. 11
Challenges
Dynamic topology
Unidirectional Links
Power Constraints

13. 12
Where to find
an answer ?

14. 13
Ants Ants Everywhere

15. 14
Ants
Can explore vast areas without global view of
the ground.
Can find the food and bring it back to the
nest.
Will converge to the shortest path.

16. 15
Ants
Communication using pheromones.
Explored area is marked with pheromone
Other ants find explored path by sensing
pheromones

17. 16
Double Bridge Experiment

18. 17
Back to
Reality

19. 18
Routing Protocols
Proactive Routing Protocols
Table Driven
Each Node Knows Network Topology
Reactive Routing Protocols
On Demand Routing

20. 19
AntHocNet
Hybrid Routing Protocol
Has both Reactive and Proactive components
Developed by Di Caro et al

21. 20
Overview
Reactive path setup
Stochastic data routing
Proactive path maintenance and exploration
Handling of link failures

22. 21
Data Structures
Pheromone Table
Neighbour Table
Each node has two tables

23. 22
Pheromone Table
Regular Pheromone rij
d
Virtual Pheromone wij
d
Average Hop Count hij
d
Helps in making routing decisions

24. 23
Neighbour Table
Helps in identifying neighbours of a node

25. 24
Reactive path setup
Occurs when path from source to destination is
unknown.
S
F
A
H
G
B C
I
J
DSource Destination

26. 25
Reactive path setup
A reactive forward ant is broadcasted from
source to destination.
S
F
A
H
G
B C
I
J
DSource Destination
[s]
[s]

27. 26
Reactive path setup
Intermediate node unicasts or broadcasts ant
packet to neighbours depending on whether it
knows the route to destination or not.
S
F
A
H
G
B C
I
J
DSource Destination
[S,A]
[S,F]

28. 27
Reactive path setup
A node that receives two copies of an ant
forwards only one ant.
S
F
A
H
G
B C
I
J
DSource Destination
[S,A,B]
[S,F,H]
[S,F,G]

29. 28
Reactive path setup
This method of working is called flooding.
S
F
A
H
G
B C
I
J
DSource Destination
[S,A,B,C]
[S,F,H,I]
[S,A,B,G]

30. 29
Reactive path setup
S
F
A
H
G
B C
I
J
DSource Destination
[S,A,B,C]
[S,F,H,I]

31. 30
Reactive path setup
First ant reaching destination finds the best
path
S
F
A
H
G
B C
I
J
DSource Destination
[S,A,B,C,D]
[S,F,H,I,J]

32. 31
Reactive path setup
Other ants are rejected.
S
F
A
H
G
B C
I
J
DSource Destination
[S,F,H,I,J,D]

33. 32
Reactive Backward Ant
First ant to reach destination is made a
backward ant.
It traverses the best path in reverse.
On the way the pheromone table is updated
at all visiting nodes.

34. 33
Reactive Backward Ant
Hop count is updated as
Regular pheromone is updated as

35. 34
Data Routing
Once path is setup data is stochastically routed.

36. 35
Data Routing
I
D
A
B
C
Source Destination

37. 36
Proactive Path Maintenance
Pheromone Dissolution
End to End path sampling

38. 37
Pheromone Dissolution
Every node broadcasts a hello message to all
neighbours.
The pheromone table is piggybacked to the
hello packet.

39. 38
End to End Path Sampling
While the session is active proactive ant
agents explore to find additional paths.
Proactive ants like forward ants update
pheromone table when it becomes a backward
ant.

40. 39
Link Failures
Hello messages help to find link failures.
The link failure is notified to all nodes by
flooding.
Repair ants try to find alternate path to
destination if failure is in the midst of a
transmission.

41. 40
Advantages
Automatic load Balancing.
Higher Delivery ratio.
Robust , Adaptive and scalable.

42. 41
References
[1] The internet engineering task force mobile ad-hoc networking
page(MANET). Available from: http://www.ietf.org/html.charters/
manet-charter.html.
[2] Microsoft Mesh Networks. Available from: http://research.
microsoft.com/mesh/.
[3] ANTHOCNET, Available from http://www.idsia.ch/~frederick
/anthocnet/anthocnet.html
[4] B. Baran and R. Sosa. A new approach for AntNet routing. In
Proceedings of the 9th International Conference on Computer
Communications Networks, Las Vegas, USA, 2000.

43. Thank You

44. Queries