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Enhanced Mobility Management in Wireless Mesh Networks
Mehdi BEZAHAF, Luigi IANNONE, Serge FDIDA
- JDIR 2008
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Enhanced Mobility Management in Wireless Mesh Networks Mehdi - - PowerPoint PPT Presentation
Enhanced Mobility Management in Wireless Mesh Networks Mehdi - - PowerPoint PPT Presentation
Enhanced Mobility Management in Wireless Mesh Networks Mehdi BEZAHAF, Luigi IANNONE, Serge FDIDA JDIR 2008 Outline Introduction Mobility Management in
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Mobility Wireless Mesh Networks
Flexibility Easy deployment Low cost
- Detect Clients movement
- Keep alive established
connections
- No software installation
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MeshDVNet – MeshDVNet architecture:
Soekris net4521 box Based on Linux
(Crux)
IPv6 – only MeshDV software:
– Python modules – Click software
Iperf tool
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BOX 09 BOX 01
MeshDVNet – Mobility Management (problem 1)
PcA But where is PcB? BOX 05 PcB UDP Packet MCREQ CRREP UDP Packet UDP Packet CRREP: Client Request REPly MCREQ: Multicast Client REQuest _ Connect to PcB
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MeshDVNet – Mobility Management (problem 1)
Reason: NDP cache not refreshed
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PcB BOX 09 BOX 05 PcA _ Ping PcB REQUEST But where is PcB? MCREQ CRREP BOX 01
MeshDVNet – Mobility Management (problem 2)
REQUEST REPLY CRREP: Client Request REPly MCREQ: Multicast Client REQuest REQUEST REPLY
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PcB BOX 09 BOX 05 BOX 01 PcA _ Ping PcB REQUEST REPLY CWIT But where is PcA? MCREQ CRREP
MeshDVNet – Mobility Management (problem 2)
CRREP: Client Request REPly MCREQ: Multicast Client REQuest CWIT: Client WIThdraw
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MeshDVNet – Mobility Management (problem 2)
Reason: wireless card driver timeout
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Cause 1:
– NDP cache is not refreshed instantaneously
Cause 2:
– MeshDV is based on wireless card driver
detection (3 minutes timeout)
MeshDVNet – Problems’ cause
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Enhanced Mobility Management (EMM)
All routers use the same address called
Common IP (CIP)
Client NDP “cookies”
– Cookie=(CIP, Mac)
Uses UNA packet (Unsolicited Neighbor
Advertisement) [RFC 2461]
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PcB BOX 09 BOX 05 PcA _
Send TCP Packets to
PcB
But where is PcB? CREQ CRREP BOX 01 UNA(MAC1, CIP) CIP NS PcA (addr src == CIP) Reply to (CIP, MAC1) CWIT (PcA has moved)
EMM – EMM Overview
CERR (PcA is not here) CRREP CREQ CIP CIP TCP Request 2 ACK 2 TCP Request 3 ACK 3 TCP Request 1 UNA(MAC5, CIP) CRREP: Client Request REPly CREQ: Client REQuest CWIT: Client WIThdraw CERR: Client ERRor
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EMM – EMM performance (UDP)
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EMM – EMM performance (TCP)
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EMM – Resuming the results
~3s ~40s <1s
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Conclusion
Enhanced Mobility Management (EMM)
– Based on NDP cache cookies – Important improvement:
- 80% gain for TCP
- 99.5% gain for UDP
Future Work:
– Sub-seconds analysis – DHT based lookup
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