1. Delay-Tolerant Mobile Ad-hoc Networks
Network Research Lab
UCLA

2. DTN Background #1: satellite #2: dialup #3: memory stick on motorcycle
Receive data from Ann
Send data to Brandy
#3: memory stick on motorcycle
April 6, 2019
UCLA/CSD

3. DTN Background
DTN: new network architecture for scenarios with intermittent connectivity
Interplanetary communications,
Communications between remote villages (example on previous slide),
Communications with mobile users, etc.
Common DTN characteristics:
Data is aggregated into bundles at intermediate node where connection breaks up.
Bundles await the re-establishment of connectivity
Bundles are sent in steps from one disconnect point to the next until they reach destination (rather than using a single end-to-end file transfer).
April 6, 2019
UCLA/CSD

4. Ad-hoc Storage Overlay System (ASOS)
In MANETs (Mobile AdHoc Networks), connectivity is often disrupted due to mobility, interference, failures, etc.
ASOS: Ad-hoc Storage Overlay System
Proposed DTN approach for MANETs
Peer-to-peer model
Data are transmitted end-to-end directly, if a path exists.
Otherwise, data are stored in the overlay in a redundant and distributed fashion.
April 6, 2019
UCLA/CSD

5. ASOS Example D S 4: ASOS data delivery 2: Network partitioning
ASOS overlay
3: Undeliverable data replicated to reachable ASOS peers
1: Conventional end-to-end connection S
ASOS storage node
Regular node
April 6, 2019
UCLA/CSD

6. Performance Evaluation: Vehicle Scenario
ASOS implemented in QualNet
Virtual Track (VT) mobility model
Battlefield scenario:
7 “switch stations”
4 tank platoons, with 5 tanks each
5 HUMVEEs
5 relay stations
Traffic:
CBR, 5 sources to one destination (command post), all moving
April 6, 2019
UCLA/CSD

7. Instantaneous Throughput
Conventional scheme:
instantaneous throughput always below input rate.
ASOS:
Instantaneous throughput may go above input.
Reason: stored data is transmitted later when connectivity improves.
April 6, 2019
UCLA/CSD

8. Delivery Ratio
Overall, at the end of the data transfer, ASOS manages to deliver twice as much data as the conventional scheme
April 6, 2019
UCLA/CSD

9. Work in progress: DTN Backbone
MB nodes used for storage
Thin BB links vs high speed ground links
dst
src
April 6, 2019
UCLA/CSD

10. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

11. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

12. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

13. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

14. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

15. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

16. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

17. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

18. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

19. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD

20. Delay Tolerant Mobile Backbone
April 6, 2019
UCLA/CSD