Mobile Routers in IPv6

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Mobile Routers in IPv6

• Thierry Ernst - MOTOROLA Labs INRIA (Planete)
• Claude Castelluccia - INRIA (Planete)
• Hong-Yon Lach - Motorola Labs

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Presentation overview

• Foreword
• Mobile Networks
• What applications need mobile routers and
  networks ?
• Definition and terminology
• Requirements (What do we need to support mobile
  routers)
• Current status at the IETF
• Mobile IPv6 and Mobile Networks
• Prefix Scope Binding Updates in Mobile IPv6
• Extended mode in Hierarchical Mobile IPv6
• Ongoing research
• Innovative trends Multicast delivery of Binding
  Updates
• Conclusion

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Foreword

• Most IP devices will be mobile
• always connected to the Internet by some means
• Networks will themselves be mobile
• mobile networks may be of any size, ranging
• from a few IP devices (e.g. PAN)
• to thousands of IP devices (e.g. a train)
• There is no explicit support of mobile networks
  in todays IP specifications
• However, Mobile Networks have
• specific characteristics,
• specific requirements
• specific problems
• Thus, IP needs explicit support for mobile
  networks

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Mobile Networks What applications ?

• Network of sensors deployed in aircrafts, boats,
  cars, trains,
• air-traffic signaling data exchanged with the
  Internet whereas passengers are given access to
  the Internet (web surfing, remote connection to
  office, )

Mobile Router
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Mobile Networks What applications ?

• Personal Area Networks (PANs) connected to the
  Internet
• The mobile network is composed by all IP devices
  carried by humans cellular phone, notebook,
  digital camera,
• Devices in the PAN may be connected using
  Bluetooth
• The device connecting the PAN to the Internet is
  a Mobile Router

Mobile Router
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Mobile Networks the Mobile Network vision

• devices and networks are
• always connected by heterogeneous networks
• unified by IP

Wireless WAN (IEEE 802.11b, GPRS, Bluetooth, ...)
Picocellular MAN
Wired or Wireless LAN (WaveLAN, HiperLAN,..)
john_at_mylovelycar
john_at_street
john_at_work
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Mobile Networks The Mobile Network vision

• mobile networks formed by smaller ones
• A set of mobile devices which compose...
• a PAN which enters ...
• a car which enters in ...
• a queue of cars
• on the motorway, or
• in the Eurostar Shuttle

Mobile Router
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Mobile Networks Internet Definition

• Mobile Node a single node that changes its
  point of attachment
• by means of Mobile IPv6
• Mobile Network an entire network that changes
  its point of attachment
• Mobile Router (MR) its attached Nodes and
  Routers.
• IP subnet or a collection of IP subnets

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Mobile Networks Terminology

• Mobile Router (MR) Border router of the mobile
  network
• nodes in the mobile networks are
• SNs all Stationary Nodes permanently located in
  mobile network ( SNs are not Mobile Nodes !)
• MNs all Mobile Nodes temporarily visiting the
  mobile network
• CNs all nodes communicating with MR, SNs and MNs

MR
MN
SN
SN
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Mobile Network Characteristics

• As we have seen, mobile networks
• are always connected to the Internet through a
  mobile router
• mobile networks may be composed by a set of
  subnets and a set of routers
• size may range for a few (PAN) to hundreds or
  even thousands of nodes and routers (train, etc
  )
• part of a mobile networks may be a sub-mobile
  network

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Mobile Networks Aim of Mobility Support

• to provide continuous Internet connectivity to
  nodes located in the mobile network
• to offer optimal routing between CNs and nodes
  located in the mobile network (both SNs and MNs)

end-system
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IETF Status

• Mobile IP Working Group
• Mobile Networks are not currently supported by
  Mobile IPv6
• Current work
• Prefix Scope Binding Update draft-ernst-mobileip-
  v6-network-01.txt
• HMIPv6 draft-ietf-mobileip-hmipv6-03.txt
• Seamoby Working Group (Context Transfer and
  Micro-mobility routing)
• support of mobile routers and networks is listed
  by the micro-mobility design team
• draft-ietf-seamoby-mm-problem-01.txt
• IPNG Working Group (IP Next Generation or IPv6)
• some discussions in the mailing list
• MANET Working group (Ad-hoc routing)
• No discussion about this subject
• But ad-hoc network that changes its AR is a
  mobile network according to our definition

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IETF Status Mobile IPv6 for mobile nodes (review)

• Working Group Mobile IP at the IETF.
• Allow mobility of end-systems without
  communication disruption
• mobile node MN is identified by its home address
  IP1 (address on the home link)
• a new temporary address IP2 (care-of address or
  CoA) is allocated to MN on each visited foreign
  link and is used for routing.
• Binding between the home address and the CoA
• MN is associated with a Home Agent HA (a router
  on the home link )

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IETF Status Mobile IPv6 for mobiles nodes
(review)

• First packets
• MN obtains CoA IP2 from a router on the foreign
  link
• MN registers its current CoA IP2 with its home
  agent HA.
• CN sends packets to the CoA IP1
• HA intercepts, encapsulates, and redirects
  packets to CoA IP2
• MN decapsulates packets
• Following packets
• MN sends its CoA to CN.
• CN sends packets directly to CoA IP2 using a
  IPv6 Routing Extension Header.

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IETF Status Mobile IPv6 for mobile networks ?

• IETF Mobile IPv6 is a natural candidate to
  support mobile routers and networks
• Specification says that mobile nodes may either
  be Mobile Hosts or Mobile Routers.
• However, no explicitly mention of mobile networks
• Could Mobile IPv6 support mobile networks anyway
  ?
• If we follow the specification, MR
• is a mobile node and operates Mobile IPv6
• has a home address in its home network
• gets a new CoA on each visited link
• registers its new CoA address
• with its HA and its own CNs
• by means of BUs containing current CoA
• gt Packets intended to the MR itself are
  optimally routed from the CN to the MR

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IETF Status Mobile IPv6 for mobile networks ?

• What about packets intended to the SNs ?
• CNs do not have a CoA for SNs
• No optimal routing between CNs and SNs
• Packets intended to SNs are routed to the home
  network
• MRs HA has a binding between MRs home address
  and MRs CoA
• Packets are intercepted by MRs HA (proxy ARP)
• HA does not know that packets intended to SNs
  have to be encapsulated to the MRs CoA
• packets enter a routing loop and get finally
  discarded
• Experiments conducted on FreeBSD has demonstrated
  this
• see draft-ernst-mobileip-network-01.txt
• in some implementations, it may work, but the
  specification does not say what to do for a
  mobile router
• gt communication is not possible at all if the
  implementation strictly follows the specification
• If we want to use Mobile IPv6, it needs
  clarification and extensions

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IETF Status Prefix Scope BU extensions to MIPv6

• Draft-ernst-mobileip-v6.01.txt
• developed by INRIA and MOTOROLA Labs
• Presented at 48th IETF 8/00 and 49th IETF 12/00
• under revision - new version will come before
  next IETF
• Draft addresses 2 issues
• Redirection of packets intended to SNs by the HA
  to the MR
• Optimal Routing between CNs and SNs
• Proposes Mobile IPv6 extensions
• Key idea MR is solely responsible for the
  mobility management of the entire network
• MR acts as any other MN and operates Mobile IPv6
• all interfaces in the mobile network are
  identified by a common network prefix gt the
  Mobile Network Prefix
• Binding between the Mobile Network Prefix and the
  MRs CoA
• Record in Binding Cache network route vs host
  route

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IETF Status Prefix Scope BU extensions to MIPv6

• How
• The Mobile Network Prefix is carried in BUs in
  addition to the CoA
• A BU worth for an entire network, not for a
  single node
• BUs are sent by the MR to the
• MRs HA,
• all CNs of the MR
• all CNs of SNs behind the MR
• We define
• a new sub-Option to record the Mobile Network
  Prefix
• A bit Prefix Scope Registration in the Binding
  Update option that tells BU contains a care-of
  address valid for a mobile network

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IETF Status Prefix Scope BU extensions to MIPv6

• Both CNs and HA are then able to redirect packets
  sent to any node in the mobile network
• all packets with a destination address
  corresponding to mobile network prefix are
  re-routed to the MRs CoA
• using a routing extension header or encapsulation
  
• Security issues
• The sender of the BU is easily authenticated
• Remaining open issue
• Authorization for the MR to manage mobility of
  the entire network
• But same problem as for MNs
• a MN needs to be authorized to send a BU for a
  home address
• a MR needs to be authorized to send a BU for a
  network prefix
• this is presently discussed at the IETF and we
  are waiting for the outcome of this discussion

MR home address gt MRs CoA
Standard Mobile IPv6 Mobile Network prefix
/48 gt MRs CoA our extension
CNs BINDING CACHE
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IETF Status Extended mode in HMIPv6

• Draft-ietf-mobileip-hmipv6-03.txt
• First version around 10/00
• Presented at 49th IETF 12/00
• Developed by INRIA (Planete) and Ericsson
  Research
• Based on original work designed at INRIA
  (Planete) in 1998
• Hierarchical Mobility Management
• separate local mobility management from global
  mobility management
• 2 modes of operation Basic Mode and Extended
  Mode
• Extended Mode
• could be used to support mobile networks
• MR has 2 CoAs
• RCoA is kept as long it remains in the same
  administrative region
• LCoA is topologically correct and changes at each
  new access point
• MR broadcast the RCoA in the mobile network
• MNs (and SNs ?) in the mobile network
• use the RCoA as their CoA
• register RCoA with MAP, their HA, their CNs

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IETF Status Extended mode in HMIPv6

• MR has 2 CoAs
• RCoA is permanent in the site
• LCoA changes at each new Access Router
• MN uses MRs RCoA as its CoA
• MN registers RCoA with MAP, its HA and CNs

RCoA / LCoA1
MR s Home Agent
MR
MR H_at_ gt RCoA
LCoA1, RCoA
MAP
RCoA
MN
RCoA
MN H_at_ gt RCoA
MN s Correspondent
MN H_at_ gt RCoA
MN s Home Agent
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IETF Status Extended mode in HMIPv6
MN does not need to change its CoA as long as MR
remains in the same administrative domain (but it
still needs to send periodic Binding Updates !)
MR s Home Agent
MR H_at_ gt RCoA
LCoA1, RCoA
MAP
LCoA2, RCoA
RCoA
RCoA / LCoA2
MR
MN H_at_ gt RCoA
MN s Correspondent
MN H_at_ gt RCoA
RCoA
MN s Home Agent
MN
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IETF Status

• HMIPv6
• is more appropriate to support MNs visiting the
  mobile network
• mobility management of the MR is not transparent
  to the MNs
• Prefix Scope Binding Updates
• is more appropriate to support SNs permanently
  located in the mobile network
• mobility management of the MR is transparent to
  the SNs
• Both solution may not scale to large mobile
  networks

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Ongoing work How to minimise signalling ?

• Each SN / MN communicate with several CNs
• We want to perform optimal routing
• Current CoA must be sent periodically to each CN
• MRs CoA if we use Prefix Scope Binding Updates
• MRs RCoA if we use HMIPv6 Extended Mode

Binding Update explosion

• Periodic burst due to Binding Updates on the
  first link
• about 6744 bits every 10 seconds if only one CN
• about 198408 bits every 10 seconds if 100 CNs

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Ongoing work Multicast delivery of BUs

• If MR sends Prefix Scope Binding Updates, we note
  that all CNs get an identical copy of the BU
• Multicast delivery of Binding Updates for large
  mobile networks
• an innovative trend

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Ongoing work Multicast delivery of BUs

• Examples on a 1000 nodes topology - CNs are
  selected randomly
• For each number of CN, MR visits the same list
  of ARs
• Graphs show the total number of links and
  bandwidth consumed by Binding Updates during 400
  seconds for each number of CNs

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Conclusion Open issues

• Mobile routers and networks have very specific
  problems and requirements
• They deserve their own solutions
• Many open issues to address
• Mobile Router moving without its attached nodes
• Nested mobility
• Mobile Nodes visiting the mobile network
• the car which enters in the Eurostar Shuttle is a
  MN (phone) in a mobile network (PAN) in a mobile
  network (car) in a mobile network (train)
• impact on routing protocols
• What about
• Router advertisements sent by MR ?
• Multihomed MR
• Network Renumbering

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Conclusion Requirements

• Requirements usually associated with mobility of
  end-systems
• Scalability
• a very large number of mobile networks
• mobile network comprising one or more IP subnets
• very large mobile networks (hundred of SNs or
  MNs)
• Optimal use of network resources
• Optimal Routing between CNs and nodes behind the
  MR (both SNs and MNs)
• Minimal signalling load
• Minimise bandwidth use between MR and access
  router
• Mobility transparency for nodes behind the MR
• As good security as for mobile nodes
  (Authentication, Authorisation,)

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Conclusion In summary

• Mobile IPv6 can not support mobile networks as
  is
• redirection by the HA of packets intended to the
  SNs is not clear
• no optimal routing between CNs and SNs
• Solutions
• Prefix Scope Binding Updates (MOTOROLA / INRIA)
• for SNs permanently in the mobile network
• HMIPv6 Extended Mode (ERICSSON / INRIA)
• for MNs temporarily in the mobile network
• Multicast delivery of Binding Updates (MOTOROLA /
  INRIA)
• for large mobile network
• still a research item

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Thank you

• Fore more information
• http//www.inrialpes.fr/planete/
• Draft, presentation made at the IETF and other
  documents
• IETF web site http//www.ietf.org (MobileIP /
  Seamoby)
• Prefix Scope Binding Update
• draft-ernst-mobileip-v6-network-01.txt
• HMIPv6 Extended Mode
• draft-ietf-mobileip-hmipv6-03.txt
• Seamoby Working Group - micro-mobility design
  team
• draft-ietf-seamoby-mm-problem-01.txt