This document summarizes a study on the effect of network dynamics on opportunistic routing. The study evaluated two utility functions - Time-Evolving Contact Duration (TECD) and TECD Importance (TECDi) - that consider the oscillations of social interactions influenced by daily routines. TECD performed better than TECDi, with gains of up to 23.77% over epidemic routing. Both functions reduced message replication compared to other approaches. Future work will explore an information-centric version of the dLife routing framework.

1. Study on the Effect of Network Dynamics on
Opportunistic Routing
Waldir Moreira, Manuel de Souza, Paulo Mendes, and Susana Sargento
waldir.junior@ulusofona.pt
July 9th, 2012
11th International Conference on Ad-Hoc Networks and Wireless (ADHOC-NOW 2012)
Belgrade, Serbia

2. Agenda
• Introduction
• Motivation
• Our Approach
• Evaluation
• Results
• Conclusions and Future Work
2

3. Introduction
• Powerful devices
• Spontaneous networks
• Opportunistic contacts
- Intermittent connectivity
3

4. Motivation
• Many routing solutions
- epidemic, encounter history, social
aspects ...
• Resulting proximity graphs are unstable
• Dynamism of users’ daily life routines
• Study the effect of network dynamics
4

5. Our Approach
• To consider the oscillations of social
interactions (influenced by daily routines)
• Two utility functions
- Time-Evolving Contact Duration (TECD)
- TECD Importance (TECDi)
5

6. Our Approach
6

7. Our Approach: TECD
(1) A
w(B,x)
B
If Mx Buffer(B) and w(B,x) > w(A,x)
(2) Mx
A B
7

8. Our Approach: TECDi
(1) A
I(B)
B
If Mx Buffer(B) and I(B) > I(A)
Mx
(2) A B
8

9. Evaluation
Parameters Values
Simulator Opportunistic Network Environment (ONE)
Contact-based vs Social-based
PRoPHET, Epidemic, TECD Bubble Rap, Rank, TECDi
Heterogeneous Mobility
1036800 sec
150 (people/vehicles)
Working Day, Bus, Shortest Path Map Based
Routing Proposals Bluetooth (250 kbps / 10 m) Wi-Fi (Bus: 11 Mbps / 250 m)
2 MB
24 hours and Unlimited
1 – 100 kB
6000
5 (Bubble Rap)
700 sec (Bubble Rap)
0.8 (Rank) 9

10. Results
- TECD has a gain of: - TECDi has a gain of:
PROPHET: 16.17% (24) and 18.41% (Un) Rank: 6.06% (24) and 4.88% (Un)
Epidemic: 23.77% (24) and 23.26% (Un) Bubble Rap: 12% (24) and -9% (Un)
- PROPHET suffers occasional finite loops - Bubble Rap has more time for communities
=> use transmission opportunities => increased delivery capability
- Epidemic quickly exhausts buffer space - Rank doesn't consider social levels
=> 2 MB per node => important nodes, weak ties
10

11. Results
- TECD with less replicas (57.37 and 121.30): - TECDi with less replicas (266.12 and 363.02):
PROPHET: 272.35 (24) and 247.11 (Un) Rank: 302.05 (24) and 418.21 (Un)
Epidemic: 454.12 (24) and 535.04 (Un) Bubble Rap: 559.69 (24) and 495.69 (Un)
- TECD advantage decreases with unlimited - TECDi reduces the potential next hops
=> messages live longer in the system => important nodes, strong ties
- PROPHET and Epidemic - Bubble Rap has the highest costs
=> buffer limitations => global centrality
11

12. Results
- Latency increases with TTL - TECDi replicates based on importance
=> top-ranked nodes, more time to reach
- Lack of a stale data removal mechanism destination
=> affects all solutions
- Bubble Rap high latency with 24-hour TTL
- Unlimited TTL => formation of communities
=> more messages, increase in delivery => finding higher centrality nodes influences
probability overall latency
12

13. Conclusions and
Future Work
• Dynamism positive affects forwarding decisions
• TECD performs better than TECDi
=> node importance
• "Opportunistic Routing Based on Daily Routines," in Proc. of the
6th IEEE WoWMoM Workshop AOC, SFO, USA, June, 2012
• Internet-Draft (draft-moreira-dlife-00)
DTNRG Meeting, Vancouver, July 2012
• Next steps
Information-Centric
version of dLife
13

14. Acknowledgements
To FCT for financial support via PhD grant
(SFRH/BD/62761/2009) and UCR project
(PTDC/EEA-TEL/103637/2008)
14

15. Study on the Effect of Network Dynamics on
Opportunistic Routing
Waldir Moreira, Manuel de Souza, Paulo Mendes, and Susana Sargento
waldir.junior@ulusofona.pt
July 9th, 2012
11th International Conference on Ad-Hoc Networks and Wireless (ADHOC-NOW 2012)
Belgrade, Serbia