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					    Experience of the BRAIN and MIND
       Projects in Development of
           IP Mobility Solutions
                        draft-mihailovic-brain-mind-00.txt
              At: http://www.ctr.kcl.ac.uk/Pages/Members/Mihailovic/


    Andrej Mihailovic, Philip Eardley, Robert
      Hancock, Tapio Suihko, Mark West
  IRTF Micromobility Routing Research Group
                 18th July 2002
File name: BCMP-IRTF.ppt                                  Status:
Originator: Robert Hancock (Siemens/RMR)                  Page 1
Structure
•   Project context and network overview
•   The role of ‘micromobility’
•   Solution framework
•   Gory details
     –    Paging and idle mode
     –    Address assignment
     –    Handover management
     –    Path updates
• Current status – modelling, implementation
• Conclusions


File name: BCMP-IRTF.ppt                   Status:
Originator: Robert Hancock (Siemens/RMR)   Page 2
Project Context
• Gestation: 1998 onwards as EU co-funded project
• IST BRAIN (2000-01); IST MIND (2001-02)
• ‘Incubator’ for future research & standardisation
                                              EDGE Intelligence

                                                                                • 11 partners:
              SGSN                 GGSN
                                                                                  BT, FT, DT, DoCoMo;
                         UMTS PS                                                  Siemens, Ericsson,
                                                                                  Nokia, Sony;
                         domain               IP backbone
       UTRAN                                  Diffserv,
       (AAL2/ATM)                             IP macro-mobilty


                                                                                  KCL, Agora,
                                              management




                                                                 Other access
                                                                 networks
                                                                                  INRIA(BRAIN)/UPM(MIND)
              Vertical         IP-based                          (e.g. ADSL)

                                                                                • Applications
 UTRAN        Handover       micro-mobility
Release 00
                                 IP QoS



                                                                                • Access networks
                         BRAIN
                                                                                • Radio interface
                                                                                • ‘Beyond 3G’
File name: BCMP-IRTF.ppt                                                                  Status:
Originator: Robert Hancock (Siemens/RMR)                                                  Page 3
  Network Overview
                                         Another BRAIN              Internet
                                            Access
                                            Network
                                                                  Applications           Scope of the
                                          MG                                            BRAIN Network
    MN
                                                                   TCP/IP
                                                                                            Layer
              AR
                                                                   Protocol
                                                                  Stack with
                                    MG                            enhanced
                                                                                                    Access network
              AR
                                                One or more        mobility        Custom IP
                                               standard fixed                                       supporting QoS
                   BRAIN Access                 IP network s,
                                                                   support         Forwarding        and seamless                  To IP Core
   MN                 Network                     with user
                   (Transport and              mobility support                                      micromobility                  Networks
                      Control)
                                                                    Radio           Radio                                 Link
              AR                                                    Lay ers         Lay ers                              Lay ers

   MN                          MG
                                                                  Terminal       BRAIN Access                        BRAIN Mobility
                                                                                  Router (AR)                        Gateway (MG)



• AN hides all link
  technology and
  terminal mobility
  behaviour
• Network can get
  very large
  File name: BCMP-IRTF.ppt                                                                      Status:
  Originator: Robert Hancock (Siemens/RMR)                                                      Page 4
 Micromobility Priorities

• Already N similarly performing solutions
• Our priorities:
   –   Internal/external decoupling
   –   Extreme scalability (107-8 hosts, nw multihoming)
   –   Mainly user-network traffic flows, AAA
   –   Coexistence with MIP; no critical dependence on v6
• Others: User-user flows; ad hoc infrastructure
• Engineering goal:
   – Look for an ‘IP-style’ solution - little point replicating
     L2 solutions with IP encapsulation
 File name: BCMP-IRTF.ppt                     Status:
 Originator: Robert Hancock (Siemens/RMR)     Page 5
Solution Framework
• We actually have a family of protocols
                                                    •   Address management is
             Address management                         handled between ARs and
                                                        (load-aware) AAA server
                 Path Updates                       •   Paging and handover




                                           Paging
                                                        activation/smoothing is
                                                        handled entirely between ARs
            Handover Framework                          and MNs
                                                    •   Path updating (routing) is
                 MN-AR Protocol
                                                        handled between ARs and the
                                                        interior of the access network
                                                        how you like…

• If the boundaries between the components are right
• Then the components are almost independent
• Routing component can be made functionally small
File name: BCMP-IRTF.ppt                                         Status:
Originator: Robert Hancock (Siemens/RMR)                         Page 6
Details I: Address Management

• A globally routable address is always assigned locally
• Considered an extension to AAA functions
     – Can allocate different classes or numbers of addresses
       (and subnets) based on subscription
                   – Stateless autoconfiguration? DAD?? DIID???
• Address management is decoupled from routing
     – But, exploit it to do feeble TE, give redundancy
• Addresses can be used anywhere / any time
• Background reassignment for route optimisation etc.
     – ‘v6-thinking’ – cf. renumbering, privacy extensions…
• AM assumptions can significantly impact solution

File name: BCMP-IRTF.ppt                                  Status:
Originator: Robert Hancock (Siemens/RMR)                  Page 7
 Details II: Paging and Idle Mode

• Paging in IP is controversial (apparently)
• Our view: still needed for power saving
   – Good path update approach can weaken signalling
     load argument; can’t be pure air i’/f issue
• Solution makes paging an AR-only function
   – ‘Just deliver a packet to this IP address’
   – No implication for network internals
   – Paging area configuration is left open
• Location update = just invoke handover
• Still resilience details to complete (AR loss)
   – Can still be handled in edge
 File name: BCMP-IRTF.ppt                   Status:
 Originator: Robert Hancock (Siemens/RMR)   Page 8
Details III: Handover Management

• Philosophy: handle at
  the edge                                                                    Path
                                                                              Updating
• Mobile is in control of                                      Inter-AR
  state machine                             OAR
                                                           Handover Request
                                                                                          NAR
     – L2 (not MIP) triggered
• Basic variant is                         IP2W Handover
                                           Trigger
                                                               Mobile
                                                                               Registration


  planned, unplanned                                           Node


  as a fallback
                                                     CAR determination         IP2W Handover
                                                            +                  Trigger
                                                    MN Handover Request




File name: BCMP-IRTF.ppt                                            Status:
Originator: Robert Hancock (Siemens/RMR)                            Page 9
Handover Implications for Routing

• Seamlessness means short RTTs for signalling
• Routing efficiency implies re-routing point far from
  the network edge (in long-term)  Hard problem
• Two basic approaches: edge tunnels vs. bicast
• Bicast requires special network infrastructure
     – Also, treating multiservice traffic efficiently is hard
•   So, we assumed edge tunnelling for seamlessness
•    No fast internal path update
•    No need for hierarchy of mobility agents
•    Infrastructure independent of handover details
•    Minimised impact on QoS framework issues
File name: BCMP-IRTF.ppt                         Status:
Originator: Robert Hancock (Siemens/RMR)         Page 10
Consequences for Path Update
Requirements
• Minimised functional reqt: AN has to deliver
  packets to right AR based on MN IP address
     – Scalable, resilient, loop-free, manageable, no
       hard RT requirement, no idle mode requirement
• Comparable scope to IGP problem
     – Expect solutions as simple as OSPF, IS-IS…
• Modularity requirements
     – PU solution can be swapped out, or better
     – PU solutions can co-exist, or best
     – PU solution can be be tuned per-MN
File name: BCMP-IRTF.ppt                   Status:
Originator: Robert Hancock (Siemens/RMR)   Page 11
       Final Overview (“BCMP”)
                                                                                     Connections to
                                                                                     peer networks
                                                                                                      • All transport is
                                                                                                        provided by a
                                             ANP
                                                    MG
                                                                                MG
                                                                                                        standard routed
       AAA Serv er
                                                                                                        network
                         Address allocation                                                           • Anchor points (ANP)
                                                                                                        can be attached
                           f low [Address
                          associated with                       ANP(*)
                               ANP(*)]

                                                                                                        anywhere
'Traditional' pref ix-                 ANP
 routed IP network
                                                                                          MG          • MGs are standard
                                                                                                        border routers
                             AR
                                                                                                      • Paging and handover
                                                                                                        are operated entirely
                          operations




                                                                                                        at the edge
                           Paging




                                                   AR
                                                                                     AR
                                                               AR
                                                                           AR
                                             MN     Handov er operations




        File name: BCMP-IRTF.ppt                                                                         Status:
        Originator: Robert Hancock (Siemens/RMR)                                                         Page 12
Details IV: Path Updates

• Numerous classical routing issues arise
     – Address aggregation, edge mobility, topological
       implications, support for multiple peering points,
       tunnels/source routes
• BCMP uses non-hierarchical tunnels
     – No need for hierarchy (handover approach)
     – Tunnels allow arbitrary ANP placement within an
       arbitrary routed infrastructure
• New issues are then
     – resilience to ANP failure, and
     – secure route installation (and update)

File name: BCMP-IRTF.ppt                   Status:
Originator: Robert Hancock (Siemens/RMR)   Page 13
Path Updates: RT?
• Stability of routing, single point of control, simplified
  QoS handling (in nw multihomed case)
• Uplink traffic can be used as implicit update
     – Requires good security handling (obviously)
     – Updates are rapid and cheap to process
• AR can be nearly ignorant of ANP existence
     – Reduced AR configuration, less MN state at AR
     – Cf. cases where even MN knows about ANP
• Use prefix routing infrastructure to find ‘right’ ANP
  for netmask’s worth of MN addresses
     – No longer a purely mobile issue
• AR & ANP interact with network like standard routers

File name: BCMP-IRTF.ppt                     Status:
Originator: Robert Hancock (Siemens/RMR)     Page 14
 Simulation
• BCMP has been
  extensively simulated
  in ns-2
• Performance results
  are explicable
    – Show importance of
      meshing at edges                                                            TCP Throughput




                                            throughput (MBps)
                                                                 3


• Comparison with                                               2.5


  other micromobility                                            2


  protocols still needed                                        1.5


    – Difficult to design                                        1
                                                                              Configuration   A

      universal scenarios                                       0.5
                                                                              Configuration
                                                                              Configuration
                                                                                              B
                                                                                              C

      or metrics
                                                                              Configuration   D
                                                                 0
                                                                      0   2   4         6           8       10   12          14
                                                                                                                      time (s)




 File name: BCMP-IRTF.ppt                                                                         Status:
 Originator: Robert Hancock (Siemens/RMR)                                                         Page 15
 Implementation Work

• Implemented and
  interoperated (in public!)
   –   Mainly 802.11 so far
   –   IPv4 and IPv6
   –   RT and nRT services
   –   Network controlled h/o
   –   Failure recovery

• Future and non-network layer work
   – RSVP triggering (maybe)
   – Multiple technologies (maybe)
   – Adaptive applications
  File name: BCMP-IRTF.ppt                   Status:
  Originator: Robert Hancock (Siemens/RMR)   Page 16
Conclusions
• Assumptions about paging (scope) and
  address management are critical
• Adaptation can/must be limited to path update
• Multihoming and resilience have major impacts
• Security impact might be less
     – Separate MN-AR and AN internal aspects
• We could not find a path update solution
  without needing edge handover support
     – Maybe there isn’t one? We looked hard, answer
       might be different in other scenarios
• See also: www.ist-brain.org and www.ist-
  mind.org
File name: BCMP-IRTF.ppt                   Status:
Originator: Robert Hancock (Siemens/RMR)   Page 17

				
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