Chien-Shiu Lin, Wei-Shyh Chang, Ling-Jyh Chen, Cheng-Fu Chou, and Ting-Kai Huang.
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Transcript of Chien-Shiu Lin, Wei-Shyh Chang, Ling-Jyh Chen, Cheng-Fu Chou, and Ting-Kai Huang.
Chien-Shiu Lin, Wei-Shyh Chang, Ling-Jyh Chen, Cheng-Fu Chou, and Ting-Kai Huang
Delay /Disruption Tolerant Networks (DTNS) attracted increasing attention recently.
What’s the crucial factors for a successful routing algorithms in Delay/Disruption Tolerant Networks?
Motivation
2
Analysis of several kinds of routing schemes Epidemic routing PROPHET routing NC routing
Propose two enhancements for PROPHET Contact utilization (PROPHET_CU) Contact duration ratio (PROPHET_CD)
Our contributions
3
“Store, carry and forward” modelUtilize redundancy to increase the success
probabilityBut,
flooding overhead
Epidemic routing
4
Based on Epidemic Routing SchemeUse “delivery predictability” to reduce
flooding overhead
Delivery predictabilityPinit: an initialization constant
Nodes that are often encountered have a high delivery predictability.
PROPHET routing
5
]1,0[ )1( ,),(),(),( initinitoldbaoldbaba PPPPP
The number of contacts vs. the duration of contact
Contact Utilization (Prophet_CU)
PROPHET Enhancements (PROPHET_CU)
6
Total contact duration of pair
(S,D)
1, , /S D S DP T T
Fixed time interval
UPDOWN
UPDOWN
Time line
Contact between A and C
Contact between B and C
T
Super stars avoidance (load balance)Contact Duration Ratio( Prophet CD)
PROPHET Enhancements (PROPHET_CD)
7
1, , ,
1
/N
S D S D S ii
P T T
Total contact
duration of Node S
T
A
B
C D C
C
Time line
Use coding skill to increase success probability
Apply Network Coding on the packet
Network Coding
8
DTNSIM : A Java-based simulatorA Real-world wireless trace
ZebraNet1ZebraNet2 (decreasing 30% contact
durations)
Simulation
9
ZebraNet1 ZebraNet2Avg contact duration/pair/day(sec) 22,211 12,825
Avg # of contacts/pair/day 2.06 2.06Number of nodes 34 34
Trace Name ZebraNet1, ZebraNet2CBR Traffic (1 MB/msg) 1 msg/hour
Contact bandwidth 1 MB/sH (hop count limit) 5
m(computation depth) 4T (time interval) 2 dayNumber of pairs 1, 10, 20, 30
Buffer size 400 MBSimulation time 16 day
Pinit / γ / ω 0.75 / 0.98 / 0.25
Simulation Settings
10
ZabraNet1
PROPHET vs. Enhanced PROPHET
11
CA,C CA,D
CB,
C
Time line
Node ANode B
PROPHET vs. Enhanced PROPHET
12
0
0.2
0.4
0.6
0.8
1
0 200000 400000 600000 800000 1e+006
Del
iver
y R
atio
CC
DF
Latency (seconds)
PROPHETPROPHET_CUPROPHET_CD
30 node pairs
ZebraNet2
PROPHET vs. Enhanced PROPHET
13
Routing comparison
14
Routing comparison: various error rate
16
We propose enhancement schemes on PROPHET.Contact duration is an important factor
We study several DTN routing schemes and suggest suitable network environment for each routing protocol.Epidemic routing is sensitive to network loading.NC has best delivery ration in congestion situation.NC routing is vulnerable in network with high error
rate
Conclusion
17
Thank you
18