Cellular IP and Comparison with other Mobility Protocols

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Cellular IP and Comparison with other Mobility
Protocols
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Disadvantage of Mobile IP

• Mobile IP is not appropriate, for fast mobility
  and smooth handoff because after each migration a
  local address must be obtained and communicated
  to a possibly distant location directory or home
  agent.
• Even in limited geographical areas, however, the
  number of users can grow to a point where using
  fast lookups for per user data bases is no longer
  viable.
• Mobility management requires mobile hosts to send
  registration information after migration. The
  resulting signaling overhead has significant
  impact on the performance of wireless access
  networks.

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Questions arises ??

• How to deal Fast Handoff (Frequent Handoff)?
• How to Decrease the Signaling Overhead for
  Registration?
• How to separate active and idle users?
• How to extend the Life of the Battery ?

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Mobility Protocols

• Mobile IP - 1996
• Cellular IP May 1998
• Handoff-Aware Wireless Access Internet
  Infrastructure (HAWAII) July 1999
• Hierarchical MIP- 1996

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Cellular IP

• Cellular IP represents a new mobile host protocol
  that is optimized to provide access to a Mobile
  IP enabled Internet support of fast moving
  wireless hosts.
• Micro-mobility
• Mobility in a limited geographical area, with
  hard real-time requirements.
• Probably frequent handovers between pico- or
  nano-cells.
• The Cellular IP network is connected to the
  Internet via a gateway router.
• Mobility between gateways (i.e., Cellular IP
  access networks) is managed by Mobile IP while
  mobility within access networks is handled by
  Cellular IP.

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Protocol overview

• Base station is cellular IPs universal component
  which controls routing for IP packets and
  integrates cellular control functionality.
• The base station also contains the routing and
  paging caches.
• Gateway connects the cellular IP network to the
  internet.
• Gateway also acts as care-of-address to allow
  mobile hosts access to the internet.

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Packets will be first routed to the host's home
agent and then tunneled to the gateway
Packets transmitted by mobile hosts are first
routed to the gateway and from there on to the
Internet
MOBILE IP
The gateway "detunnels'' packets and forwards
them toward base stations
CELLULAR IP
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Routing

• Gateway periodically broadcasts beacon packets on
  the access network.
• Base stations use the interface they receive from
  the gateway beacon packets and route packets
  towards the gateway.
• Base station routing cache stores the mobile
  hosts IP address.
• Mobile hosts need to send regular data packets to
  the gateway to keep a soft-state route between
  the mobile host and the gateway.
• A mobile host can make the base station keep its
  route mapping by sending empty IP packets to the
  gateway.

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Cellular IP
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Differences betweenPaging Cache and Routing Cache

• A paging cache has the same format and operation
  as a routing cache except for two differences.
• First, paging cache mappings have a longer
  timeout period called paging-timeout.
• Second, paging cache mappings are updated by any
  packet sent by mobile hosts including
  paging-update packets.
• Routing cache mappings are updated by data and
  route-update packets sent by mobile hosts.
• This results in idle mobile hosts having mappings
  in paging caches but not in routing caches.
• In addition, active mobile hosts will have
  mappings in both types of cache.

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Cellular IP - Registration
Correspondent Node
Home Agent
(mobile) IP signaling
Gateway
Cellular IP Network
BS
BS
BS
Cellular IP Signaling
CIP signaling
MIP signaling
BS
Mobile Station
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Cellular IP Paging

• Paging occurs when a packet is addressed to an
  idle mobile host and the gateway or base stations
  find no valid routing cache mapping for the
  destination.
• If the base station has no paging cache, it will
  forward the packet to all its interfaces except
  for the one the packet came through.
• Paging cache is used to avoid broadcast search
  procedures found in cellular systems.
• Base stations that have paging cache will only
  forward the paging packet if the destination has
  a valid paging cache mapping and only to the
  mapped interface(s).
• Without any paging cache the first packet
  addressed to an idle mobile host is broadcast in
  the access network. While the packet does not
  experience extra delay it does, however, load the
  access network.
• Idle mobile hosts that receive a packet move from
  idle to active state, start their
  active-state-timer and immediately transmit a
  route-update packet.

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Cellular IP - Paging
Correspondent Node
Home Agent
Gateway
Cellular IP Network
BS
BS
CIP paging
BS
BS
Mobile Station
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Cellular IP Paging Response
Correspondent Node
Home Agent
Gateway
Cellular IP Network
BS
Routing update
BS
BS
BS
Mobile Station
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Cellular IP Data delivery
Correspondent Node
Home Agent
Gateway
Cellular IP Network
BS
BS
BS
BS
Mobile Station
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Handoff

• Cellular IP supports two types of handoff scheme.
• Hard Handoff
• Semisoft handoff

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Hard handoff

• A simple approach that trades off some packet
  loss for minimizing handoff signaling rather than
  trying to guarantee zero packet loss.
• To perform a handoff, a mobile host tunes its
  radio to a new base station and sends a
  route-update packet.
• The route update message creates routing cache
  mappings en route to the gateway configuring the
  downlink route cache to point toward the new base
  station.
• Handoff latency is equal to the round-trip time
  between the mobile host and the crossover base
  station
• In the worst case the crossover point is the
  gateway.

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Cellular IP Hard Handoff
Correspondent Node
Home Agent
Gateway
Cellular IP Network
Packet are dropped
BS
BS
BS
BS
Mobile Station
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Semisoft Handoff

• The routing cache mappings associated with the
  new base station is created before the actual
  handoff takes place by send the semisoft packet
  to new base station, Thus reduces handoff
  latency.
• The path to the old base station remains in place
  until the soft-state cache mappings time out.
• After the mobile host enter into new base
  station, the mobile host performs a regular
  handoff.

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Cellular IP SemiSoft Handoff
Correspondent Node
Home Agent
Before the Handoff taking place the Mobile
station send the Semi Soft message to the New
base station
Gateway
Cellular IP Network
After Time out
BS
BS
BS
BS
Mobile Station
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Security

• Only authenticated packets can establish or
  change cache mappings in a Cellular IP access
  network.
• By authenticating paging and routing update
  control messages, malicious users are prevented
  from capturing traffic destined for mobile hosts.
  
• In Cellular IP access networks, only control
  packets are authenticated.
• Data packets are not authenticated
• Because Control messages establish and change
  existing mappings and data packets can only
  refresh existing mappings.

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Hawaii

• The Hawaii protocol from Lucent Technologies
  proposes a separate routing protocol to handle
  intradomain mobility.
• Hawaii relies on Mobile IP to provide wide-area
  interdomain mobility.
• A mobile host entering a new FA domain is
  assigned a collocated care-of address. The mobile
  node retains its care-of address unchanged while
  moving within the foreign domain thus, the HA
  does not need to be involved unless the mobile
  node moves to a new domain.
• Nodes in a Hawaii network execute a generic IP
  routing protocol and maintain mobility-specific
  routing information as per host routes added to
  legacy routing tables.
• Hawaii nodes can be considered enhanced IP
  routers, where the existing packet forwarding
  function is reused.

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Contd

• Location information (i.e., mobile-specific
  routing entries) is created, updated, and
  modified by explicit signaling messages sent by
  mobile hosts.
• Hawaii defines four alternative path setup
  schemes that control handoff between access
  points.
• The appropriate path setup scheme is selected
  depending on the operators priorities between
  eliminating packet loss, minimizing handoff
  latency, and maintaining packet ordering.
• Hawaii also uses IP multicasting to page idle
  mobile hosts when incoming data packets arrive at
  an access network and no recent routing
  information is available.

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MSF Handoff Management in Hawaii
(0) 1.1.1.1-gtB
A B C
(3) 1.1.1.1-gtC

• Disadvantages
• Mis-ordered packets
• Adversely impact on application like TCP and
  Audio

A B C
A B C
(0) 1.1.1.1-gtA
(0) 1.1.1.1-gtC
(4) 1.1.1.1-gtB
(2) 1.1.1.1-gtA
A B
A B
(0) 1.1.1.1-gtB
(0) 1.1.1.1-gtA
(1) 1.1.1.1-gtA
(5) 1.1.1.1-gtB
OBS
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SSF Handoff management in Hawaii
(0) 1.1.1.1-gtB
A B C

• use a technique we term interfacebased
  forwarding.
• This requires more descriptive routing table
  entries.
• A routing table typically has an entry of the
  form (IP address-gtoutgoing Interface).
• In this scheme, the router must be able to route
  based on an additional field, the incoming
  interface of the packet.

(3) A,C1.1.1.1-gtB
B,1.1.1.1-gtC
(6) ,1.1.1.1-gtC
A B C
A B C
(0) 1.1.1.1-gtA
(0) ,1.1.1.1-gtC
(2) 1.1.1.1-gtB
(4)A,B 1.1.1.1-gtC
C,1.1.1.1-gtA
A B
A B
(0) 1.1.1.1-gtB
(0) 1.1.1.1-gtA
(5) 1.1.1.1-gtA
(1) 1.1.1.1-gtB
OBS
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UNF Handoff Management in Hawaii
(0) 1.1.1.1-gtB
A B C
(3) 1.1.1.1-gtC

• Data packets are diverted at the cross-over
  router to the new base station, resulting in no
  forwarding of packets from the old base station.

A B C
A B C
(0) 1.1.1.1-gtA
(0) 1.1.1.1-gtC
(2) 1.1.1.1-gtB
(4) 1.1.1.1-gtA
A B
A B
(0) 1.1.1.1-gtB
(0) 1.1.1.1-gtA
(5) 1.1.1.1-gtA
(1) 1.1.1.1-gtB
OBS
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MNF handoff management
(0) 1.1.1.1-gtB
A B C
(3) 1.1.1.1-gtB,C
(6) ,1.1.1.1-gtC

• The MNF scheme is very similar to the UNF scheme.
• The main difference is that the cross-over
  router, Router 0, multicasts data packets for a
  short duration.

(0) ,1.1.1.1-gtC
A B C
A B C
(0) 1.1.1.1-gtA
(4)1.1.1.1-gtA
(2) 1.1.1.1-gtB
A B
A B
(0) 1.1.1.1-gtB
(0) 1.1.1.1-gtA
(5) 1.1.1.1-gtA
(1) 1.1.1.1-gtB
OBS
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Hierarchical MIP

• The Hierarchical Mobile IP protocol from Ericsson
  and Nokia employs a hierarchy of FAs to locally
  handle Mobile IP registration.
• In this protocol mobile hosts send Mobile IP
  registration messages to update their respective
  location information.
• Registration messages establish tunnels between
  neighboring FAs along the path from the mobile
  host to a gateway FA (GFA).
• Packets addressed to the mobile host travel in
  this network of tunnels, which can be viewed as a
  separate routing network overlay on top of IP.
• The use of tunnels makes it possible to employ
  the protocol in an IP network that carries
  non-mobile traffic as well.
• Typically one level of hierarchy is considered
  where all FAs are connected to the GFA.
• In this case, direct tunnels connect the GFA to
  FAs that are located at access points.

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Hierarchical Foreign Agents
CH
Binding
HA
MH?FA1
INTERNET
FA1
MH?FA2
MH?FA3
MH?FA6
MH?FA5
FA2
FA3
MH?FA4
FA4
FA5
FA6
FA7
MH?IF
MH?IF
MH?IF
MH
MH
MH
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DESIRABLE PROTOCOL DESIGN ISSUES

• Global connectivity The goal of mobility
  management should ensure continuous and seamless
  global connectivity.
• AAA and security Protocol should support are
  capable of performing accounting, authentication
  and authorization (AAA) services.
• Global roaming facility The mobile user may move
  anywhere throughout the world and still get
  connected to the Internet whenever he/she likes.
• Stable point of attachment The aim of the new
  protocol is to provide a single global IP address
  to the mobile node.
• Real-time traffic management Protocol that
  should support real-time traffic management in
  maintaining larger bandwidth and higher speed of
  operation.
• QoS support The new protocol should support
  integrated QoS management for fulfilling
  bandwidth requirement of the future 4G networks.

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DESIRABLE PROTOCOL DESIGN ISSUES

• Dynamic address allocation For future pervasive
  computing environments where we are likely to see
  the proliferation of networked devices on a large
  scale, need for auto configuration and dynamic
  address allocation will be a must because manual
  configuration proves to be cumbersome and time
  consuming.
• Protocol layers The protocol should be
  implemented at the network layer of the OSI
  model.
• IP Paging support The protocol should support IP
  paging and must be able to distinguish active and
  idle hosts.
• Routing optimization Route optimization may be
  adopted such that routes to mobile nodes from
  their correspondent nodes can be improved if the
  correspondent node has an upto-date mobility
  binding for the mobile node in its routing table.

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DESIRABLE PROTOCOL DESIGN ISSUES

• Mobility management Protocol should support the
  users dynamic mobility, (i.e. the networking
  infrastructure must ensure that they continue to
  gain access to network resources and services.)
• Handoff control while in handoff the packet loss
  should be not be there.
• Low signaling overhead signaling overhead should
  be low.
• Latency The mobility management architecture and
  the new protocol would be able to seamlessly
  redirect packets to the mobile node's new point
  of attachment with minimum latency.
• Location update It is a part of location
  management. Location update procedure would be
  such that the overall signaling overhead on the
  home agent is minimized.

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Reference

• http//comet.columbia.edu
• Design, Implementation, and Evaluation of
  Cellular IP -Andrew T. Campbell, Javier Gomez,
  Sanghyo Kim, András G. Valkó, and Chieh-Yih Wan,
  Columbia University, New York Zoltán R. Turányi,
  Technical University of Budapest
• A Comparative Study of Existing Protocols
  Supporting IP Mobility
• COMPARISON OF IP MICROMOBILITY PROTOCOLS -ANDREW
  T. CAMPBELL, JAVIER GOMEZ, SANGHYO KIM, AND
  CHIEH-YIH WAN, COLUMBIA UNIVERSITY, ZOLTAN R.
  TURANYI AND ANDRAS G. VALKO, ERICSSON RESEARCH
• Enhanced Micro mobility Scheme Kwang Jo Lee,
  Myoung Chul Jung, Jai Yong Lee