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Towards Ubiquitous Mobility in F

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					Towards Ubiquitous Mobility
in Future Wireless Networks

    Ph.D. Dissertation
   Robert C. Chalmers
                                       Committee
                             Prof. Kevin Almeroth
                     Prof. Elizabeth Belding-Royer
                               Dr. Klaus Schauser
Ubiquitous Mobility
                         metropolitan                       expansive coverage


                                                            context-aware services


                campus                      shopping mall


                                                            high-bandwidth access
         physics    engineering               starbucks


                   nmsl       moment                        personalized services




Nov. 29, 2004                   Ph.D. Dissertation                                   2
Key Players in IP Mobility
                               Internet
                                                        access network


    network core




                                                        access router
                                                   AR


                                                   AP
                                                        access point




                mobile node      MN

Nov. 29, 2004                 Ph.D. Dissertation                         3
IP Mobility is Not Seamless
                 Internet            HA     MN’s home agent




                                          end-to-end delay
                                     AR


                                     AP




                         MN

Nov. 29, 2004   Ph.D. Dissertation                           4
Fixing IP Mobility
                 Internet


                                          mobility-enabling services
                                                 • Fast Mobile IP
                                                 • Context Transfers
                                                 • Micro-mobility


                                     AR


                                     AP




                         MN

Nov. 29, 2004   Ph.D. Dissertation                                     5
Broadening the Scope of Mobility

                                                           discovery



                                          ?


                           ?                        ?

                                      MN

                security                                selection



                                                                    selection
Nov. 29, 2004                  Ph.D. Dissertation                               6
A Choke Point
                 ubiquitous mobility
                              voice over ip
                context transfers
                             fast mip


                      selection
                         discovery            key obstacles
                       security




                header compression
                             mobile ip
                  cellular


Nov. 29, 2004        Ph.D. Dissertation                       7
Thesis and Impact
   thesis statement
         The three core obstacles to ubiquitous mobility
          (security, discovery and selection) are tractable
          problems with concrete, deployable solutions.

   impact statement
         By overcoming these core obstacles, we open new
          avenues for future research; provide deployable
          solutions that can be realized in current networks; and
          take a significant step towards making ubiquitous
          mobility a reality in the Internet.



Nov. 29, 2004                  Ph.D. Dissertation                   8
Roadmap

   Introduction
   Securing Services Across Networks
   Discovering Services Dynamically
   Selecting Between Access Networks
   Contributions
   Conclusions

Nov. 29, 2004       Ph.D. Dissertation   9
Who Needs Security?                                                                    security




                         AR1                                           AR2




                AP1                                        goals:                     AP2
                                     MN
                                                           • operate between domains
                                                           • provide authentication
      “Can you help me with AP2 ?”                         • provide authorization
                                                           • complete associations quickly
                                                           • a common architecture across services

Nov. 29, 2004                             Ph.D. Dissertation                                         10
Our Approach                                                                           security



  service-level agreement (SLA)




                AP1                                                                  AP2
                                  MN
                                                        explored approaches:
                                                        • on-demand queries between networks
                                                        • mirrored credentials within each network
                                                        • fully distributed certificates


Nov. 29, 2004                          Ph.D. Dissertation                                            11
Caching Pays Dividends                                       security




                      AR1                             AR2




                AP1                                         AP2
                            MN




Nov. 29, 2004                    Ph.D. Dissertation                     12
Impacting Mobility                                      security




   mobility-enabling services can be deployed with
    explicit authentication and authorization across
    networks

   security associations can be completed quickly
    with minimal delay

   management can be simplified
         new services can be easily developed and deployed
         managing security for a large number of services is less
          complex than individual solutions per service

Nov. 29, 2004                  Ph.D. Dissertation                  13
Roadmap

   Introduction
   Securing Services Across Networks
   Discovering Services Dynamically
   Selecting Between Access Networks
   Contributions
   Conclusions

Nov. 29, 2004       Ph.D. Dissertation   14
Who Needs Discovery?                                                                  discovery




                         AR1                                          AR2




                AP1                                                                  AP2
                                     MN
                                                         goals:
                                                         • map AP identifiers to AR addresses
      “Can you help me with AP2 ?”                       • discover capabilities of neighboring networks
                                                         • pass capabilities on to MNs in a timely fashion


Nov. 29, 2004                             Ph.D. Dissertation                                          15
A Static Approach                                         discovery




                                    AP1  AR1
                      AR1           AP2  AR2       AR2




                               static management




                AP1                                       AP2
                                             MN

                        AP1  AR1
                        AP2  AR2




Nov. 29, 2004                  Ph.D. Dissertation                     16
A Centralized Approach                                           discovery


                                            server


                         AR1                               AR2


                                    AP1  AR1
                                    AP2  AR2




                AP1                                              AP2
                                                    MN

                centralized management
                      (funato’02)




Nov. 29, 2004                         Ph.D. Dissertation                     17
Our Approach                                                          discovery



      dynamic management
                dyCARD
                                  AP1  AR1
                          AR1                            AR2




                 AP1                                                 AP2
                                              MN
                  AP2  AR2

                                                     “I just came from AR1 via AP1.”



Nov. 29, 2004                   Ph.D. Dissertation                                 18
Discovering a Neighbor                                                       discovery




                                           AP1  AR1
                                              down-sampling = true
                                     AR1    context transfers = true
                                                                       AR2
                                              bandwidth = 10 Mbps
                                                  latency = 150 ms




                     AP1                                                     AP2
                                                               MN
           AP2  AR2
                 down-sampling = false
                context transfers = true
                  bandwidth = 15 Mbps
                      latency = 300 ms



Nov. 29, 2004                                   Ph.D. Dissertation                       19
Caching at the Mobile Node                                                             discovery




                                           AP1  AR1
                                             down-sampling = false
                                     AR1    context transfers = true
                                                                       AR2
                                              bandwidth = 10 Mbps
                                                  latency = 150 ms




                     AP1                                                               AP2
                                                               MN
           AP2  AR2                                                     AP1  AR1
                  down-sampling = true                                        down-sampling = false
                context transfers = true                                     context transfers = true
                  bandwidth = 15 Mbps                                          bandwidth = 10 Mbps
                      latency = 300 ms                                             latency = 150 ms
                                                                         AP2  AR2
                                                                               down-sampling = true
                                                                             context transfers = true
Nov. 29, 2004                                   Ph.D. Dissertation             bandwidth = 15 Mbps      20
                                                                                   latency = 300 ms
Simulating Discovery                             discovery




   we compare dyCARD to static and centralized
    approaches
         static
         parallel server
         serial server

   we explore the effect of delay in the access
    network

   we evaluate performance in terms of the cache
    hit rate at the mobile node

Nov. 29, 2004               Ph.D. Dissertation               21
Experimental Setup                                          discovery



   we implemented each approach in ns-2
   simulation parameters:
         600 s. simulation time
         5 topologies generated over 200 X 200 m. grid
                   20 ARs
                   1-3 APs per AR
                   40 meter range per AP
                   120 s. cache lifetimes
         5 mobility patterns (waypoint) for each combination of
                   10, 50, 100 and 150 MNs
                   0.5, 3 and 10 m/s speeds for each MN
   on average, each MN considers 4-6 APs per
    handover
Nov. 29, 2004                          Ph.D. Dissertation               22
Delay Conscious                      discovery




Nov. 29, 2004   Ph.D. Dissertation               23
Cache Efficiency                     discovery




Nov. 29, 2004   Ph.D. Dissertation      extended   24
Impacting Mobility                          discovery




   we serve mobility-enabling services by mapping
    AP identifiers to AR addresses

   by sharing information, networks empower
    mobile nodes with more information to apply
    towards selecting the best network

   since neighbor discovery and mobile resolution
    are decoupled, we achieve low resolution delays



Nov. 29, 2004          Ph.D. Dissertation               25
Roadmap

   Introduction
   Securing Services Across Networks
   Discovering Services Dynamically
   Selecting Between Access Networks
   Contributions
   Conclusions

Nov. 29, 2004       Ph.D. Dissertation   26
Who Needs Intelligence?
                                                                                           ?
                                                                                       ?       ?

                                                                                      selection




                         metropolitan                        expansive coverage


                                                             context-aware services

                campus                  shopping mall

                                                             high-bandwidth access
       physics      engineering          starbucks


                   nmsl      moment                          personalized services



                                                       goals:
                                                       • consider more than just connectivity
                                                       • capture a wide range of user-level requirements
                                                       • account for stale information



Nov. 29, 2004                           Ph.D. Dissertation                                         27
A Selection Pipeline
                                                                                          ?
                                                                                     ?        ?

                                                                                    selection




                               utility 
                                                                                    best pick



                                                 connectivity 
   AP1
   AP2                                     AP2
                                                                        AP2                       AP3
   AP3                                     AP3
                connectivity                            utility         AP3   selection           AP5
   AP4                                     AP5
                                                                        AP5                       AP2
   AP5                                     AP6
   AP6
                  filtering                            filtering              ordering

Nov. 29, 2004                                      Ph.D. Dissertation                               28
                                                                                ?


A Previous Approach to Utility                                              ?

                                                                           selection
                                                                                    ?




policy-enabled handovers (wang’99)


      metrics describing the capabilities of each access network
       •   cost
       •   latency
       •   existence of particular services
       •   properties of each service

                                  utility = f(m1, m2, m3, …)



                utility = w1* ln(m1) + w2* ln(m2) + w3* ln(m3)


 weights reflect the importance                    logarithms used     form of the expression
      of each requirement                          for normalization   assumes proportionality


Nov. 29, 2004                                 Ph.D. Dissertation                        29
Our Approach
                                                                             ?
                                                                         ?       ?

                                                                        selection




       boolean expressions describing application-level requirements
        •   cost < 10 cents/min
        •   latency < 150 ms
        •   down-sampling
        •   down-sampled bandwidth < 1 Mbps


                                utility = f(b1, b2, b3, …)



                        utility = w1* b1 + w2* b2 + w3* b3


 weights reflect the importance                   no need for          no assumption of
      of each requirement                      for normalization        proportionality


Nov. 29, 2004                             Ph.D. Dissertation                         30
Are You Certain?
                                                                                             ?
                                                                                         ?       ?

                                                                                        selection




                                           AP1  AR1
                                             down-sampling = false
                                     AR1    context transfers = true
                                                                       AR2
                                              bandwidth = 10 Mbps
                                                  latency = 150 ms




                     AP1                                                               AP2
                                                               MN
           AP2  AR2                                                     AP1  AR1
                  down-sampling = true                                        down-sampling = false
                context transfers = true                                     context transfers = true
                  bandwidth = 15 Mbps                                          bandwidth = 10 Mbps
                      latency = 300 ms                                             latency = 150 ms
                                                                         AP2  AR2
                                                                               down-sampling = true
                                                                             context transfers = true
Nov. 29, 2004                                   Ph.D. Dissertation             bandwidth = 15 Mbps      31
                                                                                   latency = 300 ms
Modeling Uncertainty
                                                                                 ?
                                                                             ?       ?

                                                                            selection



                                                                            average latency




                                   latency 
  requirement:                                                                              300 ms


    latency <= 200                                             150 ms



                                                            time 
  direct evaluation:
    150 <= 200  true    AR(1)
                                                                     last measurement
                          = 300
                          = 35

  probabilistic evaluation:                     MN
                                                                AP1  AR1
    P(latency <= 200)  0.36                                      down-sampling = false
                                                                 context transfers = true
                                                                   bandwidth = 10 Mbps
                                                                       latency = 150 ms
                 cdf                     expected utility


Nov. 29, 2004                 Ph.D. Dissertation                                              32
Impacting Mobility
                                                  ?
                                              ?       ?

                                             selection




   a pipeline approach allows us to combine
    connection- and user-level requirements into a
    single selection process

   a broader range of user requirements can be
    expressed

   better decisions are possible even in the presence
    of stale information


Nov. 29, 2004           Ph.D. Dissertation                33
Roadmap

   Introduction
   Securing Services Across Networks
   Discovering Services Dynamically
   Selecting Between Access Networks
   Contributions
   Conclusions

Nov. 29, 2004       Ph.D. Dissertation   34
Contributions
   we identify three primary obstacles to achieving
    ubiquitous mobility
         security: we introduce a general model and concrete
          architecture for inter-domain security

         discovery: we provide dynamic service discovery to
          empower mobile devices with service-level information

         selection: we offer a new approach to handover selection
          that integrates connection- and service-level metrics

   we present deployable solutions with a focus on
    minimizing handover delay

Nov. 29, 2004                 Ph.D. Dissertation                  35
Thesis and Impact
   thesis statement
         The three core obstacles to ubiquitous mobility
          (security, discovery and selection) are tractable
          problems with concrete, deployable solutions.

   impact statement
         By overcoming these core obstacles, we open new
          avenues for future research; provide deployable
          solutions that can be realized in current networks; and
          take a significant step towards making ubiquitous
          mobility a reality in the Internet.



Nov. 29, 2004                  Ph.D. Dissertation                   36
Publications
   thesis-specific
         Chalmers, Karpinski, Almeroth & Belding-Royer, Beyond Connectivity
          in Future Wireless Networks, 2005 (to submit).

         Chalmers, Krishnamurthi & Almeroth, Enabling Intelligent Handovers
          in Heterogeneous Wireless Networks, Mobile Networks and
          Applications: The Journal of Special Issues on Mobility of
          Systems, Users, Data and Computing (MONET), 2005 (to appear).

         Chalmers & Almeroth, A Security Architecture for Mobility-Related
          Services, Journal of Wireless Personal Communications, 29 (3-4): 247-
          61, June 2004.




Nov. 29, 2004                      Ph.D. Dissertation                       37
Publications
   thesis-related
         Chalmers & Almeroth, A Mobility Gateway for Small-Device
          Networks, In Proceedings of IEEE International Conference on
          Pervasive Computing and Communications
          (PerCom'04), Orlando, FL, March 2004.

         Trossen, Krishnamurthi, Chaskar, Chalmers & Shim, A Dynamic Protocol
          for Candidate Access Router Discovery, Internet Engineering Task
          Force, March 2003.

         Krishnamurthi, Chalmers & Perkins, Buffer Management for Smooth
          Handoffs in Mobile IPv6, Internet Engineering Task Force, July 2000




Nov. 29, 2004                      Ph.D. Dissertation                           38
Publications
   other work
         Chalmers & Almeroth, On the Topology of Multicast Trees, IEEE/ACM
          Transactions on Networking, 11 (1): 143-65, February 2003.
         Rollins, Chalmers, Blanquer, & Almeroth, The Active Information
          System(AIS): A Model for Developing Scalable Web Services, In
          Proceedings of Internet and Multimedia Systems and Applications
          (IMSA'02), Kauai, HI, August 2002.
         Chalmers & Almeroth, Modeling the Branching Characteristics and
          Efficiency Gains of Global Multicast Trees, In Proceedings of IEEE
          Conference on Computer Communications
          (Infocom'01), Anchorage, AK, April 2001.
         Chalmers & Almeroth, Developing a Multicast Metric, In Proceedings
          of IEEE Global Internet (Globecom'00), San Francisco, CA, December
          2000.


Nov. 29, 2004                     Ph.D. Dissertation                      39
Roadmap

   Introduction
   Securing Services Across Networks
   Discovering Services Dynamically
   Selecting Between Access Networks
   Contributions
   Conclusions

Nov. 29, 2004       Ph.D. Dissertation   40
Conclusions
                         metropolitan                       expansive coverage


                                                            context-aware services


                campus                      shopping mall


                                                            high-bandwidth access
         physics    engineering               starbucks


                   nmsl       moment                        personalized services




Nov. 29, 2004                   Ph.D. Dissertation                                  41
Acknowledgments

   Kevin Almeroth

   Stefan Karpinski

   Govind Krishnamurthi

   Josep Blanquer

   Toni Batchelli

   Folks from the NMSL

   Entire CS Department


Nov. 29, 2004              Ph.D. Dissertation   42
End of the Affair




Nov. 29, 2004   Ph.D. Dissertation   43
Ubiquitous Computing




                                     theater maps
                                     performance previews
                                     ticket auction
Nov. 29, 2004   Ph.D. Dissertation
                                     user reviews           44
Pass It Along                                                                          discovery




                                           AP1  AR1
                                             down-sampling = false
                                     AR1    context transfers = true
                                                                           AR2
                                              bandwidth = 10 Mbps
                                                  latency = 150 ms




                     AP1                                                              AP2
                                                               MN
           AP2  AR2
                  down-sampling = true
                context transfers = true
                  bandwidth = 15 Mbps                                  “Who’s got down-sampling ?”
                      latency = 300 ms



Nov. 29, 2004                                   Ph.D. Dissertation                                   45
Cache Efficiency                     discovery




Nov. 29, 2004   Ph.D. Dissertation       back    46
Mobile Retention                     discovery




Nov. 29, 2004   Ph.D. Dissertation       back    47
Connectivity vs. Utility
                                                                    ?
                                                                ?       ?

                                                               selection




        good utility,                                    area of interest
but poor connectivity   utility 




                                                         good connectivity,
                                                         but poor utility




    not much to offer


                                    connectivity 



Nov. 29, 2004                       Ph.D. Dissertation                        48
A Transforming Effect
                                                                         ?
                                                                     ?       ?

                                                                    selection



                minimum satisfaction




                                                            maximum satisfaction
                          utility 




                                       satisfaction 



Nov. 29, 2004                          Ph.D. Dissertation                          49
Transforming Utility
                                          ?
                                      ?       ?

                                     selection




Nov. 29, 2004   Ph.D. Dissertation                50
To Predict Or Not
                                          ?
                                      ?       ?

                                     selection




Nov. 29, 2004   Ph.D. Dissertation                51
Simple Models
                                          ?
                                      ?       ?

                                     selection




Nov. 29, 2004   Ph.D. Dissertation                52

				
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