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 Mesh Networks � Enhanced Mobility Management (EMM) � MeshDV vs EMM � Conclusion 1

Mobility Wireless Mesh Networks •Detect Clients movement � Flexibility •Keep alive established � Easy deployment connections � Low cost •No software installation 2

MeshDVNet – MeshDVNet architecture: � Soekris net4521 box � Based on Linux (Crux) � IPv6 – only � MeshDV software: – Python modules – Click software � Iperf tool 3

MeshDVNet – Mobility Management (problem 1) BOX 09 BOX 01 CRREP UDP Packet MCREQ Connect _ to PcB But where is PcB? BOX 05 PcA UDP Packet UDP Packet PcB MCREQ: Multicast Client REQuest CRREP: Client Request REPly 4

MeshDVNet – Mobility Management (problem 1) Reason: NDP cache not refreshed 5

MeshDVNet – Mobility Management (problem 2) BOX 09 BOX 01 REPLY CRREP REPLY MCREQ REQUEST But where is PcB? BOX 05 Ping PcB _ PcB REQUEST REQUEST PcA MCREQ: Multicast Client REQuest CRREP: Client Request REPly 6

MeshDVNet – Mobility Management (problem 2) BOX 09 But where is PcA? CWIT BOX 01 MCREQ REPLY CRREP BOX 05 PcB Ping PcB _ REQUEST MCREQ: Multicast Client REQuest CRREP: Client Request REPly CWIT: Client WIThdraw PcA 7

MeshDVNet – Mobility Management (problem 2) Reason: wireless card driver timeout 8

MeshDVNet – Problems’ cause � Cause 1: – NDP cache is not refreshed instantaneously � Cause 2: – MeshDV is based on wireless card driver detection (3 minutes timeout) 9

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] 10

EMM – EMM Overview BOX 09 BOX 01 CERR (PcA is not here) CIP CREQ CIP CRREP ACK 2 UNA(MAC 1 , CIP) CREQ ACK 3 CWIT (PcA has moved) CRREP But where is PcB? Send TCP NS PcA BOX 05 Packets to (addr src _ PcB PcB == CIP) CIP TCP Request 2 TCP Request 1 PcA TCP Request 3 UNA(MAC 5 , CIP) CERR: Client ERRor CRREP: Client Request REPly CREQ: Client REQuest CWIT: Client WIThdraw Reply to (CIP, MAC 1 ) 11

EMM – EMM performance (UDP) 12

EMM – EMM performance (TCP) 13

EMM – Resuming the results ~3s <1s ~40s 14

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 15

Thank you for your attention