Presentation is loading. Please wait.

Presentation is loading. Please wait.

Enhancing DTN capacity with Throwboxes (work-in-progress) Wenrui Zhao, Yang Chen, Mostafa Ammar, Mark Corner, Brian Levine, Ellen Zegura Georgia Institute.

Similar presentations


Presentation on theme: "Enhancing DTN capacity with Throwboxes (work-in-progress) Wenrui Zhao, Yang Chen, Mostafa Ammar, Mark Corner, Brian Levine, Ellen Zegura Georgia Institute."— Presentation transcript:

1 Enhancing DTN capacity with Throwboxes (work-in-progress) Wenrui Zhao, Yang Chen, Mostafa Ammar, Mark Corner, Brian Levine, Ellen Zegura Georgia Institute of Technology University of Massachusetts Amherst

2 Delay Tolerant Networks (DTN) DTNs: non-Internet-like networks Intermittent connectivity Large delays High loss rates Examples of DTNs Tactical networks, disaster relief, peacekeeping Interplanetary networks, rural village networks Underwater acoustic networks DTN features Store-Carry-and-forward Message switching

3 Capacity Limitation in DTNs DTNs are intermittently connected Potentially low throughput, large delay Question: enough capacity for applications? What if not?

4 Use radios with longer range Deploy a mesh network as infrastructure Message ferrying This presentation: Throwboxes Enhancing DTN Capacity MF S M D

5 Our Work on MF/DTN Ferry Route Design Problem [FTDCS 03] MF with Mobile Nodes [MobiHoc 04] Efficient use of Multiple Ferries [INFOCOM 05] The V3 Architecture: V2V Video Streaming [PerCom 05] Ferry Election/Replacement [WCNC 05] MF as a power-savings device [PerCom 05] Multipoint Communication in DTNs/MF [WDTN 05, WCNC 06] Power Management Schemes in DTNs/MF [SECON 05, PerCom 05] Road-side to Road-side relaying using moving vehicles [WCNC 06]

6 Throwboxes Basic idea: add new devices to enhance data transfer capacity between nodes Deploy throwboxes to relay data between mobile nodes Throwboxes are: small, inexpensive, possibly dispensable, battery- powered wireless devices Some processing and storage capability Easy to deploy and replenish

7 Throwboxes ProcessorIntel PXA MHz Memory64MB SDRAM 32MB Flash Power consumption < 500mA Size3.5 x 2.5 Weight47g

8 Example: DTN w/out Throwboxes

9 Example: DTN w/ Throwboxes

10 UMassDiesel DTN Example w/out TB w/ TB Total contact duration (sec) Effective capacity (Kbps) Delay (sec) Data transmission between bus 38 and bus 45 A single throwbox achieves an improvement factor of 19 for both capacity and delay

11 Main Question How to best deploy s Where? How to route through them? When? -- Later work

12 Throwbox Deployment & Routing Framework Objective: throughput enhancement Important to deliver data May improve delay too Deployment issue Where to place throw-boxes? Routing issue How data are forwarded? Contact-oblivious Contact-based Traffic and Contact based Single path routing Multi-path routing Epidemic routing

13 Network Model DTN consists of mobile nodes Relative traffic demand between nodes b ij Total throughput λ Given inherent capacity (w/out TBs) as a function of: Contacts – dictated by mobility patterns Data rate

14 Throwbox Assumptions Sufficient energy supplies No interaction between throwboxes Deployed to a given set of potential locations Center of Grid Cells Deployment Vector (0/1 vector)

15 Throwbox Deployment & Routing Framework Contact oblivious Contact based Traffic & Contact based Multi-path routing Single path routing Epidemic routing Deployment approach Routing approach Random or Regular Deployment

16 Throwbox Deployment & Routing Framework Contact oblivious Contact based Traffic & Contact based Multi-path routing Single path routing Epidemic routing Deployment approach Routing approach Random or Regular Deployment

17 Multi-Path Routing – Traffic and Contact-Aware Deployment Need to determine Deployment locations of throwboxes Routing paths and traffic load on each path Performance objective Given m throwboxes, maximize total throughput λ such that traffic load λb ij is supported from node i to j

18 Multi-Path Routing – Traffic and Contact-Aware Deployment Formulated as an 0/1 linear programming problem Throwbox deployed at location 1 Solution also gives optimal flow vector describing use of multiple paths NP-hard to solve optimally

19 Greedy Heuristic Deploy throwboxes one by one Given throwbox locations, (2) is a concurrent flow problem Solved by network flow techniques or linear programming tools (1) for i=1 to m do (2)find location L that maximizes λ (3)deploy a throwbox at location L (4) end (5) compute routing

20 Throwbox Deployment & Routing Framework Contact oblivious Contact based Traffic & Contact based Multi-path routing Single path routing Epidemic routing Deployment approach Routing approach Random or Regular Deployment

21 Multi-Path Routing – Contact-Based Deployment Throwbox deployment is based on contact information, but not traffic information Benefits varying traffic patterns May not be optimal for specific traffic Maximize Absolute contact enhancement Maximize absolute enhancement of contact between nodes Relative contact enhancement Maximize relative enhancement of contact between nodes

22 Throwbox Deployment & Routing Framework Contact oblivious Contact based Traffic & Contact based Multi-path routing Single path routing Epidemic routing Deployment approach Routing approach Random or Regular Deployment

23 Single Path Routing Single path routing Data for a S-D pair follow a single path Adapt greedy algorithm for multi-path routing by enforcing the single path requirement

24 Throwbox Deployment & Routing Framework Contact oblivious Contact based Traffic & Contact based Multi-path routing Single path routing Epidemic routing Deployment approach Routing approach Random or Regular Deployment

25 Epidemic Routing Epidemic routing (ER) Difficult to characterize traffic load among nodes because of flooding ER exploits all paths to propagate data Multi-path heuristic Proportional allocation heuristic

26 Performance Evaluation Objectives Utility of throwboxes in performance enhancement Performance impact of various routing and deployment approaches ns simulation deployment/routing computation traffic demand node mobility throwbox locations routing path/load

27 Simulation Settings Node mobility models Predictable/constrained: UMass model based on measured bus trace Random/unconstrained: Random waypoint model Random/constrained: Manhattan model Simulation Parameters 9 nodes in a 25Km x 25 Km area MAC, radio range: 250m, bandwidth: 1Mbps 20 source-destination pairs, message size is 1500 bytes, Poisson message arrival with same data rate FIFO buffer, buffer size is messages

28 Delivery Ratio vs. Number of Throwboxes Multi-path routing

29 Delivery Ratio vs. Number of Throwboxes Single path routing Message delivery ratio Number of throw-boxes T & C Aware AbsoluteContact RelativeContact Random Grid

30 Delivery Ratio vs. Number of Throwboxes Epidemic routing

31 Delay vs. Number of Throwboxes (High Traffic Load) Multi-path routing

32 Delay vs. Number of Throwboxes (Low Traffic Load) Multi-path routing Message delay (second) Number of throw-boxes T & C AbsoluteContact RelativeContact Random Grid

33 Summary of Simulation Results RWP mobility Manhattan mobility UMass mobility Multi-path routing Single path routing Epidemic routing Delay improvement (high traffic load) Throughput improvement Delay improvement (low traffic load)

34 Contact based T & C Multi-path routing Single path routing Epidemic routing Contact oblivious T & C/ Contact based T & C / Contact based Contact oblivious Contact oblivious High Low Throughput improvement Routing approach Summary of Simulation Results (2)

35 Summary Study the use of throwboxes for capacity enhancement in mobile DTNs Develop algorithms for throwbox deployment and routing Routing: multi-path, single path, epidemic Deployment: traffic and contact, contact-based, contact-oblivious Evaluate the utility of throwboxes and various routing/deployment approaches Throwboxes are effective in improving throughput and delay, especially for multi-path routing and predictable node mobility

36 Questions?

37 Message Ferrying D MF M S S M D


Download ppt "Enhancing DTN capacity with Throwboxes (work-in-progress) Wenrui Zhao, Yang Chen, Mostafa Ammar, Mark Corner, Brian Levine, Ellen Zegura Georgia Institute."

Similar presentations


Ads by Google