performance validation of mobile ip wireless networks presented by syed shahzad ali advisor dr. ravi...
TRANSCRIPT
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Performance Validation of Mobile IP Wireless NetworksPresented bySyed Shahzad Ali
Advisor Dr. Ravi Pendse
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AgendaObjectiveMotivationIntroductionProblems : IP Addresses, Location, Routing Solution: Mobile IP ProtocolNs-2 test-bed and resultsRouters Lab setup Test-bed and resultFuture Work
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ObjectivePerformance validation of mobile IP based wireless networks by collecting results on NS-2 simulator and by working in the LAB.Validate the effects of mobility on the transport layerImplement a test bed for the measurement of various parameters that might impact wireless network performance
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MotivationIncreasing mobile workforceDramatic improvement in size, weight, and sophistications of notebook computersTo correctly predict current and future use of Internet technology
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Wireless NetworkingWireless networking is the use of Radio Frequency (RF) technology to connect workstations in a Local Area Network (LAN) or LAN's in a Wide Area Network (WAN).
This technology allows ethernet speed with a limited or no wired connections. It transmits and receives information over the air.
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What is Mobile IP?MIP defines how MN change their Point Of Attachment to the Internet without changing their IP addressEach MN is always identified by its home IP addressHA sends datagrams for MN through a tunnel to the COANo protocol enhancement is required in other hosts or routers
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What if Node MovesRouting decisions are based upon the network-prefix portion of the IP Destination Address10.10.0.1/16130.10.1.0/24Router
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Problem Due to MobilityInternetMobile Node130.1.1.1130.1.x.xABC?Route Next 130.1.x.x BRoute Next 130.1.x.x ACNCN
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Mobile IP ProcessAgent Discovery to find AgentHome agent and foreign agents periodically advertise agent advertisementsThey also respond to solicitation from mobile nodeMobile Node selects an agent and uses Care-Of-Address for further communication
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Care-Of-AddressIP Address associated with a mobile node that is visiting a foreign networkIt generally changes every time MN moves from one foreign network to anotherA FA COA can be any one of the FAs IP AddressA FA COA can be shared by many MN simultaneously
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Mobile IP Process (Contd.)RegistrationMobile Node registers its COA with home agent either directly or through foreign agent.Home agent then sends a reply back to mobile node via FA about successful COA registrationEach mobility binding has a negotiated life time limitTo continue further working in FN, registration must be done within lifetime
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Overview of MobileIP Functionality1. MN discovers agent2. MN obtains COA (Care Of Address)3. MN registers with HA4. HA tunnels packets from CN to MN5. FA forwards packets from MN to CNHA FA1. and 2.3.MNCN5.4.
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Encapsulation/ TunnelingHome Agent Intercepts mobile nodes datagrams and forwards them to COAHome Agent tells all hosts to send mobile nodes datagram to itHome Agent then send it to FA via TunnelDecapsulation: Datagram is extracted by FA and sent to mobile node
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Encapsulation/TunnelingIP CloudHome NetworkNew Network/Foreign NetworkHome AgentForeign AgentMobile NodeMobile NodeCorrespondent Node
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Network SimulatorsSimulation: a common technique used by researchers Test scenarios that yet not occurred in real worldPredict performance to aid technology designImprove validation of the behavior of existing protocols
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NS-2 SimulatorObject oriented, discrete event simulatorNS development is supported by DARPA (Defense Advanced Research Project Agency)NS-2 is written in C++ and Otcl (Object tool command language)Network scenarios are written into Tcl languageLarge and complex trace files are generatedSoftware package extracts the data from trace fileComplicated and long process
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Trace File Formatr 68.423159 3 1 tcp 1020 ------- 2 0.0.0.1 2.0.0.1 6319 12983+ 68.423159 1 2 tcp 1020 ------- 2 0.0.0.1 2.0.0.1 6319 12983- 68.423159 1 2 tcp 1020 ------- 2 0.0.0.1 2.0.0.1 6319 12983r 68.423209029 _6_ AGT --- 12976 tcp 1000 [a2 3 1 800] ------- [0:0 4194305:2 28 4194305] [6316 0] 1 0s 68.423209029 _6_ AGT --- 12996 ack 40 [0 0 0 0] ------- [4194305:2 0:0 32 0] [6316 0] 0 0r 68.423346 4 2 ack 60 ------- 2 1.0.1.2 0.0.0.0 6313 12989+ 68.423346 2 1 ack 60 ------- 2 1.0.1.2 0.0.0.0 6313 12989- 68.423346 2 1 ack 60 ------- 2 1.0.1.2 0.0.0.0 6313 12989r 68.424037 0 1 tcp 1000 ------- 2 0.0.0.0 1.0.1.2 6322 12988+ 68.424037 1 3 tcp 1000 ------- 2 0.0.0.0 1.0.1.2 6322 12988- 68.424037 1 3 tcp 1000 ------- 2 0.0.0.0 1.0.1.2 6322 12988+ 68.424559 4 2 ack 60 ------- 2 1.0.1.2 0.0.0.0 6314 12990- 68.424559 4 2 ack 60 ------- 2 1.0.1.2 0.0.0.0 6314 12990r 68.425271 2 1 ack 60 ------- 2 1.0.1.2 0.0.0.0 6311 12984+ 68.425271 1 0 ack 60 ------- 2 1.0.1.2 0.0.0.0 6311 12984- 68.425271 1 0 ack 60 ------- 2 1.0.1.2 0.0.0.0 6311 12984+ 68.425611 4 2 ack 60 ------- 2 1.0.1.2 0.0.0.0 6315 12992- 68.425611 4 2 ack 60 ------- 2 1.0.1.2 0.0.0.0 6315 12992r 68.426802 2 1 ack 60 ------- 2 1.0.1.2 0.0.0.0 6312 12986+ 68.426802 1 0 ack 60 ------- 2 1.0.1.2 0.0.0.0 6312 12986- 68.426802 1 0 ack 60 ------- 2 1.0.1.2 0.0.0.0 6312 12986+ 68.427576 4 2 ack 60 ------- 2 1.0.1.2 0.0.0.0 6316 12996- 68.427576 4 2 ack 60 ------- 2 1.0.1.2 0.0.0.0 6316 12996r 68.428204 1 0 ack 60 ------- 2 1.0.1.2 0.0.0.0 6307 12977+ 68.428204 0 1 tcp 1000 ------- 2 0.0.0.0 1.0.1.2 6327 12997
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Network Setup (NS-2)
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Test Bed Setup Flow
Mobile IP Scenario File written in TCL Language
The trace file generated by ns2.
A program written in AWK language grab only TCP information out of the ns2 Trace File. Save the information into another file named tcp_info.tr
Another AWK program examines every line of the tcp_info.tr file and generates latency behavior.
A Program in C++ (delay_avg2.cpp), further normalizes the results
A Program (create.sh) control the whole process of calculating delay out of a raw trace file format of ns2 simulator
Finally a program (final_avg.sh) takes the averages.
Another program automatically email the results to me.
while (!all tcl files run )
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Results NS-2
BW
Link Delay
Queue Length
Complete Avg.Delay
Avg. DelayHA-FA1
Avg. DelayFA1-FA2
Tunnel Overhead
MB
ms
ms
ms
ms
Ms
1
2
50
63.459
65.856
61.282
43.459
1
2
100
63.413
64.507
31.222
53.353
1
2
150
63.109
64.299
30.39
52.849
1
5
50
85.967
60.021
56.399
59.967
1
5
100
66.331
60.021
50.848
53.331
1
5
150
66.368
59.473
50.316
53.368
1
10
50
67.529
55.957
36.857
49.529
1
10
100
67.431
53.642
36.857
49.431
1
10
150
67.513
55.111
36.921
49.513
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Result NS-2 (cont.)
BW
Link Delay
Queue Length
Complete Avg. Delay
Avg. Delay HA-FA1
Avg. Delay FA1-FA2
Tunnel Overhead
MB
ms
ms
ms
ms
ms
5.5
2
50
29.29
29.322
30.685
9.381
5.5
2
100
29.619
29.322
30.685
9.718
5.5
2
150
29.619
29.322
30.685
9.718
5.5
5
50
32.909
32.036
34.016
10.45
5.5
5
100
32.459
32.049
34.016
9.559
5.5
5
150
32.459
32.036
34.76
9.559
5.5
10
50
37.458
36.998
38.093
21.004
5.5
10
100
37.458
36.998
38.093
21.004
5.5
10
150
36.998
38.09
36.998
20.544
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Result NS-2 (Contd.)
BW
Link Delay
Queue Length
Complete Avg. Delay
Avg. Delay HA-FA1
Avg. Delay FA1-FA2
Tunnel Overhead
MB
ms
Ms
Ms
ms
ms
11
2
50
23.076
22.78
24.406
2.954
11
2
100
23.076
22.77
24.321
2.954
11
2
150
23.011
22.67
24.136
2.889
11
5
50
26.027
25.737
27.629
5.3
11
5
100
26.027
25.739
27.631
5.573
11
5
150
26.198
25.322
27.823
5.93
11
10
50
30.984
30.597
31.879
13.418
11
10
100
30.984
30.688
24.548
14.184
11
10
150
30.83
30.597
31.879
11.103
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Lab Setup
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Lab Results
Bandwidth
Link Delay
Queue Length
CompleteAverage Delay
Average DelayHA-FA1
Average DelayFA1-FA2
Tunnel Overhead
MB
ms
ms
ms
ms
ms
1
2
50
55.023
50.715
59.156
24.903
1
2
100
64.991
61.795
69.488
34.371
1
2
150
65.87
62.552
69.45
35.75
1
5
50
56.112
50.551
59.767
25.422
1
5
100
65.735
61.93
62.553
35.615
1
5
150
54.427
50.717
58.577
24.287
1
10
50
66.172
61.541
56.612
35.552
1
10
100
66.807
61.913
61.448
36.117
1
10
150
53.948
60.723
64.608
23.828
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Lab Results (Cont.)
Bandwidth
Link Delay
Queue Length
Complete Average Delay
Average DelayHA-FA1
Average DelayFA1-FA2
Tunnel Overhead
MB
ms
ms
ms
ms
ms
5.5
2
50
42.705
29.398
51.518
26.575
5.5
2
100
44.99
31.164
44.207
28.37
5.5
2
150
44.112
31.125
51.868
27.432
5.5
5
50
47.631
42.736
51.92
31.511
5.5
5
100
45.309
31.37
38.141
29.159
5.5
5
150
43.124
31.124
52.303
27.004
5.5
10
50
42.35
31.062
52.196
25.39
5.5
10
100
46.522
31.18
51.949
30.402
5.5
10
150
35.262
31.017
38.554
19.142
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Lab Results (Contd.)
Bandwidth
Link Delay
Queue Length
Complete Average Delay
Average DelayHA-FA1
Average Delay FA1-FA2
Tunnel Overhead
MB
ms
ms
ms
ms
ms
11
2
50
35.86
39.131
43.389
21.718
11
2
100
34.892
28.824
48.749
20.767
11
2
150
35.02
28.704
37.538
20.895
11
5
50
37.24
39.145
45.621
23.115
11
5
100
34.964
39.257
52.762
20.839
11
5
150
35.891
39.13
54.185
21.765
11
10
50
33.103
39.454
54.328
18.939
11
10
100
37.313
39.068
48.525
23.151
11
10
150
34.187
28.657
52.792
20.062
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1MB Bandwidth
Chart2
55.02363.459
64.99163.413
65.8763.109
56.11285.967
65.73566.331
54.42766.368
66.17267.529
66.80767.431
53.94867.513
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet1
CompleteComplete Avg.
Average Delay LABDelay Sim
msms
55.02363.459
64.99163.413
65.8763.109
56.11285.967
65.73566.331
54.42766.368
66.17267.529
66.80767.431
53.94867.513
Sheet1
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet2
Sheet3
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5.5 MB Bandwidth
Chart3
42.70529.29
44.9929.619
44.11229.619
47.63132.909
45.30932.459
43.12432.459
42.3537.458
46.52237.458
35.26236.998
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet1
1mb
CompleteComplete Avg.
Average Delay LABDelay Sim
msms
55.02363.459
64.99163.413
65.8763.109
56.11285.967
65.73566.331
54.42766.368
66.17267.529
66.80767.431
53.94867.513
Sheet1
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet2
5.5MB
Complete Average Delay LABComplete Avg. Delay Sim
msms
42.70529.29
44.9929.619
44.11229.619
47.63132.909
45.30932.459
43.12432.459
42.3537.458
46.52237.458
35.26236.998
Sheet2
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet3
-
11 MB Bandwidth
Chart4
35.8623.076
34.89223.076
35.0223.011
37.2426.027
34.96426.027
35.89126.198
33.10330.984
37.31330.984
34.18730.83
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet1
1mb
CompleteComplete Avg.
Average Delay LABDelay Sim
msms
55.02363.459
64.99163.413
65.8763.109
56.11285.967
65.73566.331
54.42766.368
66.17267.529
66.80767.431
53.94867.513
Sheet1
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet2
5.5MB
Complete Average Delay LABComplete Avg. Delay Sim
msms
42.70529.29
44.9929.619
44.11229.619
47.63132.909
45.30932.459
43.12432.459
42.3537.458
46.52237.458
35.26236.998
Sheet2
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet3
11MB
Complete Average Delay LABComplete Avg. Delay Sim
msms
35.8623.076
34.89223.076
35.0223.011
37.2426.027
34.96426.027
35.89126.198
33.10330.984
37.31330.984
34.18730.83
Sheet3
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet4
1MB
Tunnel Overhead SimTunnel Overhead Lab
msms
43.45924.903
53.35334.371
52.84935.75
59.96725.422
53.33135.615
53.36824.287
49.52935.552
49.43136.117
49.51323.828
Sheet4
Tunnel Overhead Sim ms
Tunnel Overhead Lab ms
Sheet5
5.5MB
TunnelTunnel Overhead LAB
Overhead Sim msms
9.38126.575
9.71828.37
9.71827.432
10.4531.511
9.55929.159
9.55927.004
21.00425.39
21.00430.402
20.54419.142
Sheet5
Tunnel Overhead Sim ms
Tunnel Overhead LAB ms
Sheet6
11MB
Tunnel Overhead LABTunnel
msOverhead Sim ms
21.7182.954
20.7672.954
20.8952.889
23.1155.3
20.8395.573
21.7655.93
18.9393.418
23.15114.184
20.06211.103
Sheet6
Tunnel Overhead LAB ms
Tunnel Overhead Sim ms
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1 MB Bandwidth
Chart5
24.90343.459
34.37153.353
35.7552.849
25.42259.967
35.61553.331
24.28753.368
35.55249.529
36.11749.431
23.82849.513
Tunnel Overhead Lab ms
Tunnel Overhead Sim ms
Sheet1
1mb
CompleteComplete Avg.
Average Delay LABDelay Sim
msms
55.02363.459
64.99163.413
65.8763.109
56.11285.967
65.73566.331
54.42766.368
66.17267.529
66.80767.431
53.94867.513
Sheet1
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet2
5.5MB
Complete Average Delay LABComplete Avg. Delay Sim
msms
42.70529.29
44.9929.619
44.11229.619
47.63132.909
45.30932.459
43.12432.459
42.3537.458
46.52237.458
35.26236.998
Sheet2
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet3
11MB
Complete Average Delay LABComplete Avg. Delay Sim
msms
35.8623.076
34.89223.076
35.0223.011
37.2426.027
34.96426.027
35.89126.198
33.10330.984
37.31330.984
34.18730.83
Sheet3
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet4
1MB
Tunnel Overhead LabTunnel Overhead Sim
msms
24.90343.459
34.37153.353
35.7552.849
25.42259.967
35.61553.331
24.28753.368
35.55249.529
36.11749.431
23.82849.513
Sheet4
Tunnel Overhead Lab ms
Tunnel Overhead Sim ms
Sheet5
5.5MB
TunnelTunnel Overhead LAB
Overhead Sim msms
9.38126.575
9.71828.37
9.71827.432
10.4531.511
9.55929.159
9.55927.004
21.00425.39
21.00430.402
20.54419.142
Sheet5
Tunnel Overhead Sim ms
Tunnel Overhead LAB ms
Sheet6
11MB
Tunnel Overhead LABTunnel
msOverhead Sim ms
21.7182.954
20.7672.954
20.8952.889
23.1155.3
20.8395.573
21.7655.93
18.9393.418
23.15114.184
20.06211.103
Sheet6
Tunnel Overhead LAB ms
Tunnel Overhead Sim ms
-
5.5 MB Bandwidth
Chart6
26.5759.381
28.379.718
27.4329.718
31.51110.45
29.1599.559
27.0049.559
25.3921.004
30.40221.004
19.14220.544
Tunnel Overhead LAB ms
Tunnel Overhead Sim ms
Sheet1
1mb
CompleteComplete Avg.
Average Delay LABDelay Sim
msms
55.02363.459
64.99163.413
65.8763.109
56.11285.967
65.73566.331
54.42766.368
66.17267.529
66.80767.431
53.94867.513
Sheet1
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet2
5.5MB
Complete Average Delay LABComplete Avg. Delay Sim
msms
42.70529.29
44.9929.619
44.11229.619
47.63132.909
45.30932.459
43.12432.459
42.3537.458
46.52237.458
35.26236.998
Sheet2
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet3
11MB
Complete Average Delay LABComplete Avg. Delay Sim
msms
35.8623.076
34.89223.076
35.0223.011
37.2426.027
34.96426.027
35.89126.198
33.10330.984
37.31330.984
34.18730.83
Sheet3
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet4
1MB
Tunnel Overhead LabTunnel Overhead Sim
msms
24.90343.459
34.37153.353
35.7552.849
25.42259.967
35.61553.331
24.28753.368
35.55249.529
36.11749.431
23.82849.513
Sheet4
Tunnel Overhead Lab ms
Tunnel Overhead Sim ms
Sheet5
5.5MB
Tunnel Overhead LABTunnel
msOverhead Sim ms
26.5759.381
28.379.718
27.4329.718
31.51110.45
29.1599.559
27.0049.559
25.3921.004
30.40221.004
19.14220.544
Sheet5
Tunnel Overhead LAB ms
Tunnel Overhead Sim ms
Sheet6
11MB
Tunnel Overhead LABTunnel
msOverhead Sim ms
21.7182.954
20.7672.954
20.8952.889
23.1155.3
20.8395.573
21.7655.93
18.9393.418
23.15114.184
20.06211.103
Sheet6
Tunnel Overhead LAB ms
Tunnel Overhead Sim ms
-
11 MB Bandwidth
Chart3
21.7182.954
20.7672.954
20.8952.889
23.1155.3
20.8395.573
21.7655.93
18.9393.418
23.15114.184
20.06211.103
Tunnel Overhead LAB ms
Tunnel Overhead Sim ms
Sheet1
1mb
CompleteComplete Avg.
Average Delay LABDelay Sim
msms
55.02363.459
64.99163.413
65.8763.109
56.11285.967
65.73566.331
54.42766.368
66.17267.529
66.80767.431
53.94867.513
Sheet1
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet2
5.5MB
Complete Average Delay LABComplete Avg. Delay Sim
msms
42.70529.29
44.9929.619
44.11229.619
47.63132.909
45.30932.459
43.12432.459
42.3537.458
46.52237.458
35.26236.998
Sheet2
42.70529.29
44.9929.619
44.11229.619
47.63132.909
45.30932.459
43.12432.459
42.3537.458
46.52237.458
35.26236.998
Complete Average Delay LAB ms
Complete Avg. Delay Sim ms
Sheet3
Complete Average DelayComplete Avg. Delay Sim
msms
35.8623.076
34.89223.076
35.0223.011
37.2426.027
34.96426.027
35.89126.198
33.10330.984
37.31330.984
34.18730.83
Sheet3
Complete Average Delay ms
Complete Avg. Delay Sim ms
Sheet4
1MB
Tunnel Overhead SimTunnel Overhead Lab
msms
43.45924.903
53.35334.371
52.84935.75
59.96725.422
53.33135.615
53.36824.287
49.52935.552
49.43136.117
49.51323.828
Sheet4
Tunnel Overhead Sim ms
Tunnel Overhead Lab ms
Sheet5
5.5MB
TunnelTunnel Overhead LAB
Overhead Sim msms
9.38126.575
9.71828.37
9.71827.432
10.4531.511
9.55929.159
9.55927.004
21.00425.39
21.00430.402
20.54419.142
Sheet5
Tunnel Overhead Sim ms
Tunnel Overhead LAB ms
Sheet6
11MB
Tunnel Overhead LABTunnel
msOverhead Sim ms
21.7182.954
20.7672.954
20.8952.889
23.1155.3
20.8395.573
21.7655.93
18.9393.418
23.15114.184
20.06211.103
Sheet6
Tunnel Overhead LAB ms
Tunnel Overhead Sim ms
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ConclusionOverall comparison shows that results are almost same so we can rely on simulator to predict mobile IP wireless networksIn lowest bandwidths, tunnel overhead is more than 50% of the overall network latencyDuring roaming packets are lost and retransmitted
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Conclusion (cont.)Latencies values in lab setup are higher than collected from NS-2 setupIn lab handoff was achieved between networks by changing SSID of mobile nodeIn NS-2 handoff is based on received signal power strengthNetwork performance improved when high bandwidths are used
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ConclusionStrict separation between layer 2 and layer 3 results in increased network latenciesMobile node may only communicate with a directly connected FAMN may only begin registration process after layer 2 handoff to a new FA is completedThe registration process takes some time to complete. During this time MN is not able to send or receive IP packets
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Future WorkIn this research the correspondent node was stationary. A study can be done where CN is also mobileStudy can be done to determine and validate performance with more number of mobile nodesReal time traffic using RTP protocol may be realized
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Thank you very much for attending the presentationQuestions?
Range: The range of the wireless network is an important consideration when using a wireless network. Access point and station adapters have a range of 3280 ft in open space and 200 ft-650 ft indoors. PCMCIA adapters have an open space range of 2200 ft and an indoor range of 300 ft. These ranges are affected by interferences such as microwaves and other radio interferences, as well as interference for structures such as walls and doors.Throughput: The amount of data transferable using wireless devices is important. The amount will not be as great as a standard wired LAN, but will be greater than using a using wireless modems or other such devices. The access point, PCMCIA adapter, and station adapter have a data rate of 3mb. This data rate, however, is not throughput. When data is being transferred via wireless networking it requires a certain amount of overhead which is also included in the data rate. Most networks do not require more throughput than provided by the devices.Integrity: The wireless network is a generally stable form of communication. The robust designs of proven wireless technology and the limited distance over which signals travel result in connections that are far more robust than cellular phone connections and provide data integrity performance equal to or better than wired networking.Interoperability: Wireless device provide the ability to connect to wired LAN with ease. Adapters and access points work like a wired connection, except that no wires are necessary. The computer connects to other computers just as it would for a wired connection, because wireless devices use a "transparent protocol". These devices are compatible with IEEE 802.11 standards, which is the industry standard for wireless devices. Although industry standards are being set, most devices do not work with devices made by another manufacturer. In the future more interoperability will function as industry standards are polished and device become completely interchangeable.Scalability: Wireless networks can be designed to be extremely simple or quite complex. Wireless networks can support large numbers of nodes and/or large physical areas by adding access points to boost or extend coverage.Simplicity of installation and use: Users need very little new information to take advantage of wireless LANs. Because of the nature of a wireless LAN is transparent to a user's network operating system, applications work the same as they do on wired LANs. Wireless devices incorporate a variety of diagnostic tools to address issues associated with the wireless elements of the system; however, products are designed so that most users rarely need these tools.Security: Because wireless technology has roots in military applications, security has long been a design criteria for wireless devices. Security provisions are typically built into wireless LANs, making them more secure than most wired LANs. It is extremely difficult for unintended receivers (eavesdroppers) to listen in on wireless LAN traffic. Complex encryption techniques make it impossible for all but the most sophisticated to gain unauthorized access to network traffic. In general, individual nodes must be security-enabled before they are allowed to participate in network traffic.Battery Life for Mobile Platforms: End-user wireless products are designed to run off the AC or battery power from their host notebook or hand-held computer, since they have no direct wire connectivity of their own. WLAN vendors typically employ special design techniques to maximize the host computer's energy usage and battery life.Safety: The output power of wireless LAN systems is very low, much less than that of a hand-held cellular phone. Since radio waves fade rapidly over distance, very little exposure to RF energy is provided to those in the area of a wireless LAN system. Wireless LANs must meet stringent government and industry regulations for safety. No adverse health affects have ever been attributed to wireless LANs.From : http://aspin.asu.edu/projects/wireless/introduction.htmlLocation DiscoveryMobile IP works because the mobile node is able to discover whether it is at home or away from home. A host determines whether it is on its home network by using extensions to ICMP Router Discovery Protocol (IRDP) (RFC 1256). These IRDP extensions indicate mobility agent information that facilitates agent discovery. Routers acting as home agents (HAs) or foreign agents (FAs) will advertise their existence.HAs are routers located on the mobile node's home network that are capable of tunneling the mobile node's datagrams to it while it is away. FAs are devices on a network that are capable of acting as a detunneling point for datagrams to the mobile node. Agent discovery, like router discovery, works through advertisements, solicitations, and responses. A mobile aware host, which is a host that is capable of utilizing mobile IP, will listen for agent advertisements or solicit them. An agent advertisement will indicate a mobility agent's IP address as well as whether it is able to serve as an HA or FA. Agents will also advertise the registration options they are capable of supporting, as well as their availability, by using the appropriate fields. If the mobile node notices its own HA's advertisement, it knows it is at home and does not need to register or do anything special in order to receive its datagrams.