DTN Interworking for Future Internet Presented by Chang, Dukhyun

Transcription

1 DTN Interworking for Future Internet Presented by Chang, Dukhyun

2 Contents Introduction Project Progress Future DTN Architecture Summary 2/29

3 DTN Introduction Delay and Disruption Tolerant Networking Delay? Interplanetary networks RTT from Earth to Mars Eight minutes ~ 40 minutes Disruption? Sensor networks Nodes sleep to save power Vehicular networks Mobile devices leaving each others radio ranges Opportunistic networks a sender and receiver make contact at an unscheduled time 3/29

4 Future Internet Introduction Future potential networks do not conform to the Internet s underlying assumptions Intermittent connectivity Long or variable delay Asymmetric data rates High error rates Goal Design DTN Communication Protocol for Future Internet Scenarios 4/29

5 Research Issues Transport Layer Protocol and Congestion Control in DTN Integrating between heterogeneous transport protocols Congestion control Buffer management Delay Tolerant Network Architecture DTN + Future Internet Technology Overall redesign or Extending Bundle Protocol Routing Protocols Transfer Reliability Reducing delay Distributed Caching Reducing delay and traffic Multicast/Anycast Multicast group management Authentication mechanism 5/29

6 Delay Tolerant Network Architecture View Delay & Disruption Tolerant Network Delay & Disruption Tolerant Networking (protocol) Assumptions (In Future Internet) Cognitive Radio Dynamic Wireless Technologies Active Networks Dynamic Protocol Layering and Functions Applications Delay and disruption tolerant internetworking among heterogeneous wireless networks Vehicular Networks (high mobility) not safety app. Heterogeneous Mesh Networks (backbone with different bandwidth) 6/29

7 Possible Solution Approach (1/3) Redesign overall protocol stack Develop DTN-only protocol stack Define basic & essential functions in general DTNs Add extended functions corresponding to specific DTN environments General DTN VANET Heterogeneous Mesh CLO Module Application Transport Management Link Layer PHY (Assumption: CR) Reliable Transport Mobility Management Movement Tracking Congestion Control Topology Management Interference Control Assumption (Reconfigurable Layering) 7/29

8 Possible Solution Approach (2/3) Overlay architecture Similar to DTNRG s bundle layer approach But, assumptions for future Internet Cognitive Radio Dynamic Wireless Technologies Active Networks Dynamic Protocol Layering and Functions Research issues More reliable storage service Unified network management Dynamic multiple overlay gateway Minimized data delivery latency Fair energy consumption Making-route forwarding 8/29

9 Possible Solution Approach (3/3) Summary Redesign Abundant research issues large overhead Overlay Specific research issues Preference to which solution approach? Comment, please 9/29

10 Mobility Assumption Routing Protocols DTN with Vehicles No Mobility Mobility Routine Random Predictable Tendencybased 10/29

11 Routing Protocols Some Strategies Flooding based epidemic routing, spray & wait history-based or utility-based Single-copy scheme Oracle-based scheme Important Metrics delivery probability delivery latency overhead ratio 11/29

12 Our Motivation Existing routing protocols use only past information like contact history, etc. DTN Routing can use additional information & leverages in the future speed, direction, destination of mobile host, etc. We want to propose routing protocol using these additional information & leverages 12/29

13 Potential Approaches Exploiting mobility information Direction of mobile host Location of mobile host s destination Speed of mobile host Location of message s destination Our approaches Direction-based Destination-based Transport-info-based 13/29

14 Our Approach 1 Direction-Based routing protocol Spray & Wait based Number of token is changed by receiver s direction sender s direction 0 hand over -n*angle/180 tokens -90 hand over n*angle/180 tokens hand over n/2 tokens 90 receiver s direction 14/29

15 Our Approach 2 Destination-Based routing protocol Number of tokens for handover n/2*(route distance/max.distance) MAP Receiver s destination Sender s destination 15/29

16 Our Approach 2 Direction-Distance-Hybrid (DDH) Direction Destination Token Handover similar close None similar far A few different close A few different far n/2 C *Direction(d1)*Distance(d2)*Speed(s) C: constant: n/2 Direction(): function ranged [0,1] Distance(): function ranged [0,1] Speed(): function ranged [0,1] d1: difference of direction d2: distance difference of node s destination s: difference of node speed 16/29

17 Simulation results (1/2) Simulator : The ONE The Opportunistic Network Environment simulator Parameter settings Parameters Value Area size (m) 4500 X 3400 Number of nodes 100 (mobile), 10 (static) Transmission range (m) 100 Speed (m/s) 0~18 Buffer size (GB) 1 (mobile), 200 (static) Message size (MB) 0.01 ~ 3 Transmission rate (KB) 250 Movement model Random waypoint 17/29

18 Simulation results (2/2) Comparison b/w S&W and DDH DDH can deliver 18% more packets than S&W * : # of delivered packets per 1000 relayed packets 18/29

19 Problem of Previous Protocols Randomizing problem It is caused by local view of tendency As number of contact is increased, direction or distance is randomized Effect of our protocol is reduced Example case Almost tokens can be distributed to the same direction Tendency of movement becomes meaningless 2 nd contact Angle = 180 handover n/4 tokens Angle = 180 handover n/2 tokens 1st contact 19/29

20 Our Approach 3 - Scenario Model Where to need DTN? DTN need not to be used for communication in a crowd region where communication infrastructure is provided sufficiently => DTN can be used for communication in a poor infrastructure region When to use DTN? DTN can be used for delay tolerant application environmental monitoring, some advertisements 20/29

21 Our Approach 3 - Scenario Model In a region, infrastructure is provided fully There is a need of DTN between regions due to poor infrastructure or delay tolerant application How to dissemination message between regions efficiently Region 1 Region 2 21/29

22 Our Approach 3 - Algorithm Prevention of randomizing problem using history Area is divided into several sub areas Token handover policy When a source creates the message, it assigns fixed number of tokens to the sub-area If the source meets mobile host toward other regions, it sends message to the node with assigned tokens Token can be distributed more evenly than previous protocol 22/29

23 Simulation Settings Simulator: Opportunistic Network Environment (ONE) Area size: 45 X 34km 2 4 sub-area (20x15km 2 for each) # of nodes: 500 Intra-area node & Inter-area node Tx range: 100m Speed: 100km/h, 4~60km/h Snw copies: 32 Packet # of packet: 1000 (2 packets per each node) Packet size: ~ 30kbyte Buffer size: 2gbyte, 100mbyte 23/29

24 Delivery ratio Simulation Results = # of delivered / # of created 0.6 Delivery Probability (10%Inter-area Mobile Nodes) 0.6 Delivery Probability (20% Inter-area Mobile Nodes) b a b ro P ry e liv e D epi_10 snw_10 our_10 Delivery Prob ba epi_20 snw_20 our_ Days Days 24/29

25 Simulation Results Overhead ratio = (# of relayed - # of delivered) / # of delivered Average number of relay nodes tio 250 a R d a200 e r h e v O s e d o n d2.5 e y la 2 r e f o # Epidemic SprayAndWait Region-based 0 Epidemic SprayAndWait Region-based 10% 20% 10% 20% 25/29

26 Simulation Results Avg. latency Med. latency g v A y c n t e a L d e M y c n te a L Epidemic SprayAndWait Region-based Epidemic SprayAndWait Region-based 10% 20% 10% 20% 26/29

27 Summary The Delay and Disruption Tolerant Network will be a a important part of Future Internet. There are many research issues in DTN, specially related future internet New DTN Architecture Routing Protocols We are designing future DTN architecture and new routing protocols which assumes future internet component technologies 27/29