Shilpi Gautam Chris Haagen Martin Nicholes EEC273 W04 Project Presentation March 22, 2004
Jun 09, 2015
AGAL
A
Seamless
Handoff Protocol
Between
Ad-hoc
802.11 and
GSM/GPRS
AGAL
A
Seamless
Handoff Protocol
Between
Ad-hoc
802.11 and
GSM/GPRS
Shilpi GautamChris Haagen
Martin Nicholes
EEC273 W04Project Presentation
March 22, 2004
OverviewOverview
•Motivation•Previous Work•Our Approach•Methodology•Evaluation•Summary•Future Work•References
MotivationMotivation
•GSM/GPRS users desire an alternative higher bandwidth link to each other
•GPRS bandwidth is expensive
•GSM/GPRS Providersbecome burdened with growing increase in users
Related WorkRelated Work
• UCANUsing AdHoc to find higher bandwidth downlink
• ICARUsing Adhoc as a relay station for load balancing
• WiFi BridgeContinuity between WLAN and GPRS
• Other work all related to connecting GPRS/GSM to WLAN
Our ApproachOur Approach
• AGAL: Ad-hoc to GPRS/GSM Alternate Link
• Mobile host session over GPRS/GSM
• Ad-hoc node detected
• ALRequest transmitted over Adhoc
• ALReply received from target MH
• Alternate Link created
• Alternate Link tear down on failing 802.11 MAC signal (ALDelete is sent)
• TCP adjustment to help with vertical handoff
OSI Protocol StackOSI Protocol Stack
AGAL Protocol AGAL Protocol
ALREQALREPLYALDEL
MethodologyMethodology
• Simulate using NS-2
• AGAL implemented in routing layer
• Scenario (all 802.11 signaling)
• 3 MHs: 2 involved in FTP, 1 is “base station”
• 2 MHs move toward each other, triggering AGAL
• AGAL creates alternate link
• Alternate link deleted based on simulator time
• Graph of throughput was verified
• Graph of TCP trace was verified
• 8 runs with unique random seeds
Evaluation Evaluation
•GSM/GPRS bandwidth approx. 35Kbits/s
•Ad-hoc bandwidth approx. 700Kbits/s
•Successful switch between GSM/GPRS to ad-hoc
ThroughputThroughput
TCP TraceTCP Trace
TCP Trace
0
500
1000
1500
2000
2500
3000
3500
4000
10 30 50 70 90 110 130 150 170 190
Time (s)
Segment Number
TCP Segments
TCP ACKS
TCP Trace
0
500
1000
1500
2000
2500
3000
3500
4000
10 30 50 70 90 110 130 150 170 190
Time (s)
Segment Number
TCP Segments
TCP ACKS
Vertical HandoffVertical Handoff
TCP Trace
125
145
165
185
205
225
245
46 48 50 52 54 56 58
Time (s)
Segment Number
Node 0 TCP Rx
Node 0 ACK Rx
AGAL Events
TCP Trace
125
145
165
185
205
225
245
46 48 50 52 54 56 58
Time (s)
Segment Number
Node 0 TCP Rx
Node 0 ACK Rx
AGAL Events
TCP Trace
3260
3270
3280
3290
3300
3310
3320
89.5 90 90.5 91 91.5 92 92.5 93 93.5 94
Time (s)
Segment Number
Node 0 TCP Tx
Node 0 ACK Rx
AGAL Events
TCP Trace
3260
3270
3280
3290
3300
3310
3320
89.5 90 90.5 91 91.5 92 92.5 93 93.5 94
Time (s)
Segment Number
Node 0 TCP Tx
Node 0 ACK Rx
AGAL Events
Demonstration
SummarySummary
•Seamless handoff from GPRS/GSM to ad-hoc 802.11
•Expected bandwidth increase of the ad-hoc connection
•Movement of traffic to free ad-hoc alternate link
Future WorkFuture Work
•Implement AGAL on testbed system
•Two multihomed mobile hosts and a base station
•Explore interesting applications of protocol
•Enhance authentication for increased security
•Improve scalability of AGAL
ReferencesReferencesA. Calvagna, G. Morabito, A. La Corte. “WiFi bridge: wireless mobility framework supporting session continuity,” Proceedings of the First IEEE International Conference on Pervasive Computing and Communications, 2003.
Haiyun Luo, Ramachandran Ramjee, Prasun Sinha, Li (Erran) Li, Songwu Lu, “Cellular and hybrid networks: UCAN: a unified cellular and ad-hoc network Architecture,” Proceedings of the 9th annual international conference on Mobile computing and networking, September 2003
R. Chakravorty, J. Cartwright, and I. Pratt. “Practical Experience with TCP over GPRS”. Proc. of GLOBECOM, 2002. Vol. 2, pp. 1678-1682.
M. Ye, Y. Liu, and H. Zhang. “The Mobile IP handoff between hybrid networks”. The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 2002. Vol. 1, pp. 265-269.
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