Network Initiated Handovers

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Network Initiated Handovers

• T. Melia, J. Korhonen, R. Aguiar,
• S. Sreemanthula, V. Gupta

Based on draft-melia-mipshop-niho-ps-00
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Motivation

• Deployment of heterogeneous access systems
  combined with IP convergence (WLAN, WiMax, 3G)
  requires enhanced network controlled mobility
• Inter system handovers
• WLAN deployments lack network control of roaming
  users
• Steering of roaming NAPs do not belong to mobile
  operators (inter domain)
• We have solutions for Mobile Initiated and
  network assisted (L2 triggers, FMIv6 alike
  solutions)
• Need to understand Network Initiated Handover
• i.e. the trigger generates in the network
• ?NEED for a flexible framework supporting both
  kind of handovers

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Definition of network initiated handover

• Action taken in the network to initiate the
  handover based on
• Link events originated in the mobile node
• radio link variations (e.g. RSSI, SNR)
• powering on of new network devices
• new service requirements
• Events generated in the network
• resource management reasons
• optimization based on location/services
• multi homed devices

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Assumptions (i)

• Reusing existing security mechanisms as much as
  possible
• All mobile nodes within the scope of this
  document are expected to support at least one
  (potentially modified) existing or future IP
  mobility enabling protocol.
• MNs and mobility management nodes are expected
  to understand or support network initiated and
  assisted handovers. CNs may not.
• The network initiated handover concept relies on
  the presence of a functional entity.

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Assumptions (ii)

• To provide adequate scalable support, additional
  distributed functions are required to support the
  functional entity.
• See functional components described in the
  document
• It is envisioned the presence of multi wireless
  access, such as 802.11, 802.16, UMTS, forming an
  heterogeneous composition of macro and micro
  cells.
• Performing network initiated handover has the
  main implication that the network has first to
  assess the terminal view of the network. Signal
  level evaluation is a important matter when
  coming down to user mobility.
• Neighborhood discovery relates to the above
  assumption when neighborhood scanning is
  requested from the network. It is expected these
  functions to be available on the terminal side.

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Issues to consider for NIHO feasibility

• Mobility Application Area
• Efficiency of measurement functions for signal
  level reports
• Location of decision functions (RTT)
• Network can control the handover
• Resource Application Area
• Overlapping and Coverage of (different) wireless
  access technologies
• Resource optimization or administrative decisions
• Network can trigger the handover
• Application for inter-domain handover
• Steering of roaming

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NIHO with IEEE 802.21

• IS, ES and CS as enablers for network initiated
  and assisted handover scenarios
• Consider the Mobility and Resource Optimization
  (opportunistic handover) application area
• Two steps approach
• Network selection
• MIHF at the terminal discovers available networks
• MM in the network decides which is favorable
• Handover control
• MM sends a CS-switch request to initiate the
  handover

? Simulation results available on request
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Goals

• Independent of the IP mobility management
  mechanism
• Work over administrative domains e.g. in
  inter-domain handover cases or when a multi-homed
  host is attached to multiple ISPs
• Provide inter technology handover
• Provide similar degree of security as existing
  with the current solutions.

Non Goals

• Designing a new security framework in order to
  enable network initiated and assisted handover
  triggering.
• Initial bootstrapping problem -- The mechanism to
  gain the initial access to some network is out of
  scope of.

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Questions?
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ScenariosSingle administrative domain
MRMH
NIHO Triggers generated in the home network
Mobile Operator Home Network
ISP
NIHO Triggers generated locally in the access
network Transparent to the home network
NAP A
NAP B
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ScenariosMultiple administrative domain
Mobile Operator Home Network
MRMH
NIHO Triggers generated in the home network also
over administrative domain
ISP
ISP
GMP
NIHO Triggers generated locally in the access
network Transparent to the home network
NAP A
NAP B
NAP B