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A Comparison of Mechanisms for Improving Mobile IP Handoff Latency for End-to-End TCP MobiCom 2003 Robert Hsieh and Aruna Seneviratne School of Electrical.

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Presentation on theme: "A Comparison of Mechanisms for Improving Mobile IP Handoff Latency for End-to-End TCP MobiCom 2003 Robert Hsieh and Aruna Seneviratne School of Electrical."— Presentation transcript:

1 A Comparison of Mechanisms for Improving Mobile IP Handoff Latency for End-to-End TCP MobiCom 2003 Robert Hsieh and Aruna Seneviratne School of Electrical Engineering and Telecommunications The University of New South Wales 26 th February, 2004 Presented by Sookhyun, Yang

2 2/25 Contents Introduction Introduction Related Works Related Works Experimental Methodology Experimental Methodology Experimental Results Experimental Results Conclusion Conclusion

3 3/25 Mobility Related Terminology Mobile node (MN) Handoff (Handover) Layer 2 handoff Beacon message Access router (AR) Access network (AN) Mobile IP (MIP) –Handoff latency –Home network (HN) –Foreign (Visited) network –Home Agent (HA) –Foreign agent (FA) –Correspondent node (CN) INTRODUCTION Internet draft:

4 4/25 Mobile IP (MIP) When a MN moves and attach itself to another network –Need to obtain a new IP address –All existing IP connections to the MN need to be terminated and then reestablished Solution to this problem at MIP –Indirection provided with a set of network agents –Handoff latency Address reconfiguration procedure HA registration process –No modification to existing routers or end correspondent nodes Access point (AP) Mobile node (MN) IP IP ’ HA FA COS (Care-of-address) IP Home network (HN) Foreign network (FN) INTRODUCTION binding intercept reconfiguration tunneling CN IP

5 5/25 Motivation Effects of Mobile IP (MIP) handoff latency –Packet losses –Severe End-to-End TCP performance degradation Mitigation of these effects with MIPv6 extensions –Hierarchical registration management –Address pre-fetching –Local retransmission mechanism No comparative studies regarding the relative performance amongst MIPv6 extensions INTRODUCTION

6 6/25 Overview Evaluate the impact of layer-3 handoff latency on End-to-End TCP for various MIPv6 extensions –Hierarchical MIPv6 –MIPv6 with Fast-handover –Hierarchical MIPv6 with Fast-handover –Simultaneous Bindings –Seamless handoff architecture for MIP (S-MIP) Propose an evaluation model examining the effect of linear and ping-pong movement on handoff latency and TCP goodput Optimize S-MIP by further eliminating the possibility of packets out of order INTRODUCTION

7 7/25 Hierarchical Mobile IPv6 (HMIPv6) AR AP CN AP Minimize HA registration delay!! RELATED WORKS AR AP AR Access network AR Internet HA Macro mobility Micro mobility MAP Mobility Anchor Point (MAP) RCOA_1 LCOA’ RCOA_1 RCOA_2 LCOA’’ RCOA_1 LCOA binding Internet draft -

8 8/25 Local Handoff Latency Reduction Low latency address configuration –Reduce address reconfiguration time –Configure an address for MN in an network likely to move to before it moves –Use L2 trigger –Method Pre-registration –Perform L3 handoff before completion of L2 handoff Post-registration –Setup a temporary bi-directional tunnel between oFA and nFA –Allow MN to continue using oFA while registration at the time or later MIPv6 with Fast-Handover –Combined method of pre-registration and post-registration –Three phases 1. Handover initiation 2. Tunnel establishment 3. Packet forwarding RELATED WORKS

9 9/25 MIPv6 with Fast-Handover MN oFA nFA RtSolPr(Router solicitation proxy) PrRtAdv(Proxy router advertisement) F-BU(Fast-binding update) with COA Disconnect HI(Handover initiation)Connect F-NA(Fast neighbor advertisement) Deliver packets L2 trigger F-BAck Beacon F-Back(Fast-binding ack) Hack(Handover ack) Handover initiation Handover initiation 1 Tunnel Establishment btw oFA & nFA Tunnel Establishment btw oFA & nFA 2 Forward packets Packet forwarding phase Packet forwarding phase 3 RELATED WORKS Internet draft -

10 10/25 HMIPv6 with Fast-handover Combine HMIPv6 with Fast-handover Reduce latency due to address configuration and HA registration Relocate the forwarding anchor point from oAR to the MAP RELATED WORKS nAR oAR CN AR MAP AR nAR Access network MAP Internet HA Forwarding

11 11/25 Simultaneous Bindings Reduce packet losses N-casting packets with multiple bindings Forward packets for a short period to the MN’s current location and to n-other locations where the MN is expected move to Forwarding carried by oAR, MAP or HA RELATED WORKS Internet draft- oAR nAR1 nAR2 AP (Access point) MAP Simultaneous binding

12 12/25 Seamless Handoff for MIP (S-MIP) Provide a different approach to solve the timing ambiguity problem Build on HMIPv6 with Fast-Handover Use MN location and movement pattern to instruct MN when and how handoff is initiated Decision engine (DE) –Store the history of MN locations –Determine movement pattern –Make “handoff decision” for MN MAP MN oAR nAR2 nAR1 DE RELATED WORKS

13 13/25 Decision Engine Handoff Decision StochasticLinear MN location Tracking Handoff mechanism <- Signal strength Stationary near the center RELATED WORKS

14 14/25 Handoff Mechanism MAP DE oAR nAR MN S-buffer F-buffer F-packet S-packet Linear movement –Synchronized packet simulcasting (SPS) –Optimized S-MIP Stochastical manner –oAR and nAR are anticipation-mode –Maintain MN’s binding with oAR, nAR before F-NA before F-NA –Reduce unnecessary re-setup Stationary state near the center –Establish multiple bindings with ARs –MN uses more than one COAs RELATED WORKS optimization

15 15/25 Optimized S-MIP Elimination of the possibility of packets out of order –Upon sending the F-BU to the oAR, MN must immediately switch to the nAR –After receiving F-BU, oAR must immediately forward packets to the nAR –oAR only needs to send the FBAck to the nAR IP packet filtering mechanism at nAR –oAR incorrectly forwards IP packets with the S-bit set as f-packets –Compare IP packets within the s-buffer and f-buffer at nAR –Discard identical packets in s-buffer –[optimized] Examine 16 bit identification, fragment offset, and flag fields in IP header RELATED WORKS

16 16/25 Implementation Simulator –Network Simulator version 2 (ns-allinone2.1b6a) Patch with the ns wireless extension module allowing basic MIPv4 Extension to the ns-2 –Mobile IPv6 protocol –Hierarchical Mobile IPv6 protocol –Fast-handover protocol –Simultaneous bindings protocol –Optimized S-MIP protocol Modification –Infrastructure mode: WaveLan with connection monitor (CMon) –Additional handoff algorithm: Midway handoff EXPERIMENTAL METHODOLOGY

17 17/25 Simulation Network Topology EXPERIMENTAL METHODOLOGY Micro mobility Linear / ping-ping Handoff delay TCP goodput CN’s Congestion window Overall handoff delay (D) = time(first-transmitted~retransmitted) +time(CN->MN) Max num of packets received by the receiver in sequence

18 18/25 MIPv6 & HMIPv6 EXPERIMENTAL RESULT – Handoff delay Sender (CN)’s view Time (seconds) TCP sequence number a: MIPv6 (resolution time 100ms) b~e: HMIPv6 (resolution time 100ms) f~I: HMIPv6 (resolution time 200ms) L2 handoff address resolution BU at MAP Out-of-sequence packet MIP’s D = 814ms HMIPv6’s D = 326ms

19 19/25 Fast-Handover EXPERIMENTAL RESULT – Handoff delay Time (seconds) TCP sequence number Sender (CN)’s view f ~ i : fast-handover (resolution time 100ms) L2 handoff BU RtSolPr~PrRtAdv Proportional to distance (FA~HA) D = 358ms Even though forwarding mechanism, MN is unable to receive packets until the binding update is completed

20 20/25 HMIPv6 with Fast-Handover EXPERIMENTAL RESULT – Handoff delay TCP sequence number Time (seconds) Packet loss due to L2 handoff Packet forwarding Out-of-sequence packet send (ack) receive (data) D = 270ms Receiver (MN)’s view

21 21/25 S-MIP EXPERIMENTAL RESULT – Handoff delay Hand off = 100ms No packet loss No out-of-sequence packet TCP sequence number Sender (CN)’s view Time (seconds) TCP sequence number No packet loss Out-of-sequence packet <- Optimized S-MIP Non optimized S-MIP ->

22 22/25 Handoff Delay EXPERIMENTAL RESULT MIP HMIPv6 MIPv6 with Fast-handover MIPv6 with Fast-handover HMIPv6 with Fast-handover HMIPv6 with Fast-handover Simultaneous Bindings Simultaneous Bindings S-MIP (nonop) S-MIP 814ms 326ms 358ms 270ms 268ms 0ms Completely break down Completely break down Affected to a lesser extent Severe throttling Affected to a lesser extent Severe throttling Excellent resilience

23 23/25 TCP Goodput EXPERIMENTAL RESULT MN is stationary near the PAR Linear : 1.447s PP: 14.23s

24 24/25 Congestion Window EXPERIMENTAL RESULT Linear movementPing-ping movement S-MIP Simultaneous Binding Simultaneous Binding

25 25/25 Conclusion Analyze various handoff latency reduction framework Show the possibility of significantly reducing the latency by S-MIP Optimize the S-MIP scheme Future works –S-MIP under multiple connection scenarios –Scalability of the Decision Engine (DE) –Design more sophisticated positioning schemes for S-MIP Correspondent node (CN)


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