Mobilit

1

• Mobilité IP

2
Plan

• Introduction
• Quest-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
• Découverte dagent
• Enregistrement
• Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP 3G
• Conclusion

3
Différents types de mobilité
4
Différents types de mobilité

• Nomadisme (DHCP)
• Ordinateurs mobiles (Mobile IP, IEEE 802.11)
• Réseaux mobiles (réseaux Ad-hoc)
• Besoin de protocoles fournissant un service de
  localisation

5
Mobilité IP ? LANs sans fil (WLAN)

• LANs sans fil aujourdhui
• IEEE 802.11, Bluetooth
• AP IEEE 802.11 AP pont entre
• le réseau fixe et le réseau sans fil
• handoffs de niveau 2 supportés mais PAS la
• mobilité IP (les handoffs sont supportés au
  sein dun même sous-réseau IP)
• Mobilité IP ? Interface sans fil

6
Mobilité IP ? LANs sans fil (WLAN)
7
Différents types de mobilité

• Terminal Mobility
• Wireless connection between a terminal and
  access point (base station) or between several
  terminals(ad hoc network)
• Keeps registration/call between customer and
  network while in motion
• Enabling fonctions handover, paging
• Personal Mobility
• Enables a customer to be identifiable regardless
  of the terminal, the terminal type, the
  operator/provider
• domain, and the type of network he is currently
  registered with
• User profiles are available across
  terminal/network/operator boundaries
• Number portability
• Service Mobility
• - Enables usage of tailored and
  personalized services even if the customer is
  roaming to foreign networks
• - Includes service portability

8
Différents types de mobilité
9
Mobilité
10
Introduction Mobile IP (1)

• Sillage des réseaux GSM
• Mobilité nécessité pour les utilisateurs
  dun système de communication
• Tous les réseaux existants se donnent pour
  mission de proposer ce service
• Standard TCP/IP réseau le étendu au monde
• Principe Anywhere, Any Time, Network Access
• Réseau IP lune des principales sources
  dinformation

11
Introduction Mobile IP (2)

• Échelle planétaire
• Quasi-totalité des réseaux fournissent une
  entrée au réseau Internet
• Avec mobilité garantie dun accès universel,
  simple
• demploi et pratique
• Groupe de travail de lIETF proposition IP
  Mobile
• Proposer une localisation planétaire par
  ladresse IP
• (à linstar du roaming du GSM)
• IP préexiste au concept nomade
• GSM doté dès lorigine de telles fonctions
• IP bricolage de solutions pour ajouter
  la mobilité

12
Cahier des charges pour larchitecture de
mobilité IP

• Two major requirements arise when considering
  IP mobility
• Application transparency Dealing with a
  mobile
• configuration should not
  necessitate a mobile-aware
• application. This is needed in
  order to avoid application
• replacement on all Internet
  hosts!
• Seamless roaming When a user goes out of his
  corporate network and roams around in
  the Internet, the requirement is to assure
  a seamless Internet communication between
  this user and his correspondents whatever the
  access network used by the mobile roaming user
• Dealing with mobility at the IP layer provides
  a way to
• answer the above requirements

13
Problématique de la mobilité dans IP

• Difficultés pour intégrer à IP de nouvelles
  fonctions devant offrir la mobilité

14
Why isnt IP mobility simple? (1)

• The complexity comes from the current use of IP
  addresses.
• An IP address is used to
• identify a particular end-system. In this
  respect, IP
• addresses are equivalent to FQDNs (Fully
  Qualified Domain
• Names) and the equivalence is maintained in
  a DNS, Domain
• Name Server
• identify a particular TCP session in an IP
  host since a TCP
• socket consists of a (destination IP
  address, destination port
• number) couple
• determine a route to a destination IP host.
• The first two uses come into contradiction with
  the third use
• when mobility is considered

15
IP mobility routing
16
Why isnt IP mobility simple? (2)

• The first use supposes that a hosts IP address
  should
• never change since the DNS should always point
  to the
• same IP address
• The second use supposes that a hosts IP
  address should
• never change during a TCP session otherwise
  the
• session would be lost
• The third use supposes that when the host is
  roaming
• outside its home network (the network which
  has the
• prefix of the hosts IP address), it should
  change its
• address (and take an address with a prefix
  given by the
• visited network) in order to receive the
  datagrams
• destined to it

17
Why isnt IP mobility simple? (3)

• A possible answer to the third constraint would
  be to use a
• DHCP (Dynamic Host Configuration Protocol)
  server in order
• to obtain an address on the visited network
• This however poses a problem with the first two
  constraints
• First, the IP address of a host having
  changed, the DNS in
• the home network should be updated by the
  mobile host
• on the visited network. This may be very
  dangerous on a
• security standpoint!
• Second, this solution can not provide a
  seamless continuous
• mobility capability since when the mobile
  hosts IP address is
• changed, all TCP sessions involving this
  host should be
• dropped and reinitialized with the new IP
  address

18
Mobile IP standardization process

• The standardization of Mobile IP is being
  mainly carried out at the
• IETF (Internet Engineering Task Force)
• The IP Routing for Wireless/Mobile Hosts
  (MobileIP) Working
• Group is in charge of defining and specifying the
  Mobile IP
• architecture and protocols
• The major architecture components are already
  in the standards
• track (Request For Comments, RFCs 2002-2006)
• Some very interesting enhanced functionalities
  are still considered as work in progress and
  specified in Internet Drafts
• These documents and other related information
  may be found at the mobileip WG home page on the
  Web
• http//www.ietf.org/html.charters/mobileip-charter
  .html

19
PLAN

• Introduction
• Quest-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
• Découverte dagent
• Enregistrement
• Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP 3G
• Conclusion

20

• Overview of the IP mobility architecture

21
Functional entities

• Mobile node A host or a router that roams
  from one
• network or subnetwork to another outside its home
  network
• without changing its long term IP address (the
  home address)
• Home agent This is typically a router on a
  mobile nodes
• home network which delivers datagrams to departed
  mobile
• nodes, and maintains current location information
  for each
• Foreign agent This is typically a router on a
  mobile nodes
• visited network that collaborates with the Home
  agent to
• complete the delivery of datagrams to the mobile
  node while
• it is away from home

22
The Mobile IP basic concept

• The Mobile IP basic concept The Mobile IP basic
  concept
• The Mobile IP architecture resolves the above
  contradiction
• by using 2 IP addresses for a mobile host
• The Home address is a permanent address used to
• identify uniquely the IP host on the Internet
  (answers the
• two first IP addresses constraints)
• The Care-of address is a temporary address used
  to
• route the datagrams destined to the mobile host
  to the
• current attachment point of this host (answers
  the last IP
• addresses constraint)

23
Plan

• Introduction
• Quest-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
• Découverte dagent
• Enregistrement
• Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP 3G
• Conclusion

24
Main Functions

• Agent Discovery
• Home Agents Foreign Agents send
  advertisements on the
• link. A mobile can ask for advertisements to be
  sent.
• Registration
• When a mobile is away, it registers its
  temporary address
• with its home agent
• Tunneling
• The packets for the mobile are intercepted by
  the HA and
• tunnelled to the mobile

25
Mobile IP
26
Protocol overview

• 1. Home Agent Foreign Agent broadcast or
  multicast
• agent advertisements on their respective links.
• 2. Mobile nodes listen to Agent Advertisements.
  They
• examine the contents of these advertisements to
• determine whether they are on the home or on a
• visited network
• 3. A mobile node on a visited network acquires a
• temporary address (care of address)

27
Protocol overview

• 4. The mobile registers its COA with its home
  agent
• 5. The Home Agent sends ARP on the Home Network
• (IP_at_ lt-gt MAC_at_). The packets for the mobile are
• intercepted and sent to the current position of
  the
• mobile
• 6. The packets arrive to the COA and are
  decapsulated in
• order to extract the original packet
• 7. The packets from the mobile are sent directly
  to the
• correspondents

28

• IP mobility mechanisms
• Agent discovery
• Registration
• Tunneling

29
Agent Discovery

• Process by which the mobile detects where it is
  attached
• (home or visited network)
• Allows the mobile to determine a COA when the
  mobile is on a
• visited network
• Based on 2 types of messages
• Agent Advertisement broadcast or multicast by
  the agents
• Agent Solicitation sent by a mobile which
  does not want to
• wait for an AA
• Message authentication

30
Agent Solicitation Message
31
Mobile Agent Discovery

• An extension, called the Mobility Agent
  extension, is
• appended to ICMP Router Advertisement to
  constitute the
• Agent Advertisement message
• A Foreign Agent uses the Agent Advertisement
  message in order
• to indicate the Care-of Address to a Mobile Node
• A Home Agent uses the Agent Advertisement
  message so that a
• Mobile Node knows when it has returned to its
  Home
• Network
• A Mobile Node is allowed to send ICMP Router
  Solicitation
• messages in order to elicit a Mobility Agent
  Advertisement

32
Mobile Agent DiscoveryGetting a COA

• A Care-of Address may be obtained from the
  Foreign Agent by
• an Agent Advertisement.
• It may also be obtained from a RAS (Remote
  Access Server)
• implementing PPP or from a DHCP server on a
  foreign LAN.
• In this case the Care-of Address is said to be
  collocated
• since it is directly assigned to the Mobile Node
  interface and
• not to a Mobile Node through a Foreign Agent.
• For a collocated Care-of Address, the tunnel
  terminates at the
• Mobile Node interface

33
Agent Advertisement Message
34
Mobile Agent Discovery

• It is based upon an extension of the ICMP
  (Internet
• Control Message Protocol) Router Discovery
  protocol
• A router periodically broadcasts ICMP Router
• Advertisement messages on the different directly
• attached subnetworks
• This allows the hosts on these subnets to
  discover the
• router

35
Mobile Agent DiscoveryMobility Agent
Advertisement Extension

• Flags
• RRegistration required at the Foreign Agent
• BBusy
• HHome Agent
• FForeign Agent
• M,G,V indicate the encapsulation type
• Type identifies the Mobility Agent
  Advertisement extension
• Length is the total length of this extension
  which depends on the number
• of Care-of Addresses
• Lifetime specifies the duration of the Care-of
  Address support on the
• Foreign Agent
• For a Home Agent, Zero Care-of Address is
  advertised
• For a Foreign Agent, typically one Care-of
  Address is advertised
• Sequence Number is incremented at each
  Advertisement

36
Registration

• Functionnalities
• Ask for routing functionnalities of the FA
• Tell the HA the new location of the mobile
• Update a binding which is about to expire
• De-register the mobile when it is back on its
  home network
• Triggered as soon as the mobile detects it
  changed its point of
• attachement
• Use of the information obtained by agent
  discovery to determine the
• type of registration to be done
• Two registration procedures
• With theForeignAgent
• With the temporary address of the mobile

37
Registration

• Once the Mobile Node receives a Care-of
  Address, it should
• register its (Home Address, Care-of Address)
  binding at
• his Home Agent
• This is done using 2 messages
• Registration Request
• Registration Reply
• They both use a UDP/IP service

38
Registration
39
Registrationrequest
40
Registration
41
RegistrationRegistration Request

• Flags
• SSimultaneous Registrations (multiple Care-of
  Adresses)
• BBroadcast
• DCare-of Address collocated with the Mobile
  Node
• M,G,V indicate the encapsulation type
• Type identifies the Registration message
• Lifetime specifies the duration of the mobility
  addresses binding
• Home Address is bound to the Care-of Address
• Home Agent identifies the Home Agent that
  should register the
• binding
• Identification is used to protect against
  replay attacks and allows to
• correlate a Registration Request with a
  Registration Reply message
• The Mobile-Home authentication extension is
  used to authenticate
• the Mobile Node at the Home Agent

42
Registration Reply

• Registering with the FA
• The FA receives the message and may reject it
• Invalid authentication
• The lifetime value exceeds what may be accepted
  by the FA
• The mobile wishes to use a tunneling type not
  supported by the
• FA
• The FA has not enough resources
• Otherwise, it forwards the request to the HA
• Registering with the HA
• The HA also checks the registration should be
  accepted (same
• conditions)
• If it is accepted, the HA
• Updates its binding table
• Sends a proxy ARP message on the local link

43
RegistrationRegistration Reply

• Type identifies the Registration message
• Lifetime specifies the duration of the mobility
  addresses binding
• Home Address identifies the Mobile Node to
  which this message is
• related
• Home Agent identifies the Home Agent having
  registered the
• binding
• Identification is used to protect against
  replay attacks and allows to
• correlate a Registration Request with a
  Registration Reply message
• The Mobile-Home authentication extension is
  used to authenticate
• the Home Agent at the Mobile Node
• Code gives the result of the registration
• 0 registration accepted
• 66, 69, 70... registration denied by the
  Foreign Agent
• 130, 131, 133... registration denied by the
  Home Agent

44
Registration Reply

• The FA receives a registration reply
• If the RR is invalid, the agent sends a
  Registration Reply describing the reason
• why the registration was rejected
• Otherwise, theagent
• Updates its binding table
• Forwards the message to the mobile
• Starts to handle the messages for the mobile
• Reception of the RR by the mobile
• If the registration was rejected, the mobile
  tries to change its registration
• procedure
• Otherwise the mobile updates its routing table

45
Registration Reply
46
Registration Reply
47
Registration

• Via le Foreign Agent

48
Exemple

• Adresse home du mobile node 129.34.78.5
• HA du mobile node 129.34.78.254
• FA address 137.0.0.11
• FA care of address 9.2.20.11
• Home node source port 434
• Mobile node source port 1094
• FA source port 1105
• Care-of-address registration lifetime 60000 s
• HA granted lifetime 35000 s

49
Exemple
50
Exemple
51
Exemple

• Annuler lenregistrement (au retour au réseau
  home)

52
Exemple
53
De-registration
54
Discovering the HA's address

• Manual configuration on the mobile
• Automatically
• By broadcasting a registration request

55
Learning the HA address
56
Learning the HA address
57
Learning the HA address
58
Movement detection

• Using the lifetime field
• If the lifetimeexpires, the mobile supposes it
  has attached
• to a new link or the agent has failed. It waits
  for an Agent
• Advertisement or sends an Agent Sollicitation
• Detection using the network prefix

59
Routing

• To the home network
• The packets for a mobile are always sent to its
  home
• network
• No specific routing conventional routing
• If the mobile sends data, it behaves as any
  other node on
• the Internet
• To a visitednetwork
• A router on the local link broadcasts an ARP
  request to
• inform the packets for the mobile should be sent
  to it.
• The packets are intercepted by the HA and
  tunnelled to
• the mobile's COA(s)
• At the end of the tunnel, they are decapsulated
  and
• delivered to the mobile

60
Interception by the HA

• 2 possibilities
• Accessibility advertisement
• only on HA routers with several interfaces
• Using the proxy ARP
• Mobile's IP_at_ lt-gt HA's MAC_at_
• Updated by the HA and by the mobile node when it
  returns on its
• home network

61
Packet interceptionby the HA
62
Home Network configurations
63
Proxy and Gratuitous ARP Proxy

• In the cases A and B above, the Home Agent
  should intercept the
• datagrams intended to Mobile Nodes using a Proxy
  ARP
• mechanism
• In the case C, all datagrams intended to Mobile
  nodes will be
• naturally intercepted by the Home Agent. Here,
  all the hosts are
• outside their Home Network which become a Virtual
  Network
• Gratuitous ARP should be used by the Home Agent
  in order to
• change the ARP cache entry for a roaming Mobile
  nodes Home
• Address on the Home Network
• When the Mobile Node gets back to its Home
  Network, Gratuitous
• ARP should again be used by the Mobile Node
  itself to restore the
• ARP cache entry

64
Security aspects (1)

• The security issue is fundamental for
  registration messages otherwise
• impersonation and session hijacking attacks would
  be trivial
• Authentication should be applied to these
  messages
• The Mobile IP architecture specifies its own
  security mechanisms for use
• with IPv4 since IPsec, the new standardized
  security architecture, is not
• mandatory with IPv4
• An authentication extension is thus appended to
  each of the above
• messages
• The default authentication algorithm is a
  keyed-MD5 in prefix suffix
• mode
• The result of the authentication is thus a 128
  bit message digest
• transmitted in the authentication extension

65
Security aspects (2)
Type identifies the authentication extension
(Mobile-Home, Home Agent- Foreign Agent,...)
SPI specifies the authentication context
(algorithm, mode, key...) The Authenticator is
calculated over the entire message this
authentication extension
66
Firewalls and packet filtering problems (1)
67
Firewalls and packet filtering problems (2)

• Ingress filtering is often applied in the
  border gateway of a
• corporate network playing the role of a firewall
• This prevents Mobile Node generated datagrams
  to reach the
• Internet coming from the Visited Network
• Solutions
• Send datagrams with Source AddressCare-of
  Address this
• is a loosing proposition because it runs counter
  to the
• architecture
• Send datagrams encapsulated in an outer IP
  header with
• Source AddressCare-of Address this is a better
• proposition but the Correspondent Nodes are not
  required to
• be able to do the decapsulation Encapsulated
  datagrams
• may be sent to the Home Agent which sends them
  back to the
• Correspondent Node this is a suboptimal solution
  on the
• routing standpoint

68
Firewalls and packet filtering problems (3)

• Correlated problem the firewall on the Home
  Network
• side should also filter all datagrams coming from
  the Internet
• with a Source Address corresponding to an inner
  address
• (with the same prefix as the Home Network)
• Solutions
• If the Home Agent is collocated with the
  Gateway/Firewall,
• the firewall will know when such datagrams should
  be
• accepted
• Otherwise, a protocol between the Home Agent
  and the
• Firewall may be necessary
• Finally, a solution may consist in tunneling
  all such datagrams
• to the Home Agent which should play the role of a
  bastion
• host and be attached to a DMZ for safety

69
Datagram Tunneling

• A Correspondent Node sends datagrams to a
  Mobile Node with
• the Destination Address field containing the
  Mobile Nodes Home
• Address
• Based on the destination address, these
  datagrams reach the
• Home Network
• There, the Home Agent intercepts the datagrams
  and
• encapsulates them into an outer IP header that
  tunnels the
• initial datagrams to the Foreign Agent or
  directly to the Mobile
• Node (in the case of a collocated Care-of
  Address)
• Multiple encapsulation schemes may be used
  including
• IP-within-IP encapsulation
• Minimal encapsulation
• The datagrams sent by the Mobile Node reach
  directly the
• Correspondent Node

70
Reminder IPv4 header format
71
IP-within-IP encapsulation
The original IP header remains unchanged when
transmitted in the tunnel (the TTL field is
decremented) Source Address Correspondent
Node Address Destination Address Mobile
Nodes Home Address The new IP header has
Source Address Home Agent Address Destination
Address Care-of Address When fragmentation is
needed, it should be done at the inner
IP datagram level otherwise the fragments wont
transport the Mobile Nodes Home Address used at
the Foreign Agent to send the decapsulated
datagram on the right data link
72
Minimal encapsulation
S indicates the presence of the Original Source
Address field Minimal encapsulation limits the
number of supplementary bytes necessary for
tunneling It prevents however from performing
fragmentation
73
Soft Tunnel State

• It is interesting to maintain at the Home Agent
  level (the entry point
• of the tunnel) a number of parameters on the
  state of each
• established tunnel.
• These parameters constitute the Soft Tunnel
  State and include
• The Path MTU on this tunnel for fragmentation
  purposes
• The state of the tunnel (broken or not)
• The Correspondent Node using the tunnel
• The Home Agent may then relay ICMP error
  messages to the
• Correspondent Node source of the tunneled
  datagrams
• Typically, ICMP host unreachable messages are
  sent back to the
• Correspondent Node when the datagrams are not
  delivered through
• the tunnel

74
Plan

• Introduction
• Quest-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
• Découverte dagent
• Enregistrement
• Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP 3G
• Conclusion

75
Enhanced functionnalities

• Optimisation du routage
• Smooth handoff

76
Routing optimisation

• Goal Avoid triangle routing
• Idea
• Tell the correspondents the current position of
  the mobile
• node
• Problem
• Change the correspondent's IP stack

77
Triangle Routing
78
Route optimization (1)

• The basic Mobile IP mechanisms create a
  Triangle Routing
• between the Correspondent Node, the Home Agent
  and the
• Mobile Node.
• This Triangle Routing is far from being optimal
  especially in
• the case of a Correspondent Node very close to
  the Mobile
• Node
• Route optimization consists of eliminating this
  problem
• This is done by updating the Correspondent Node
  giving it the
• mobility binding (Home Address, Care-of Address)
  of the
• Mobile Node
• For security purposes, it is the responsibility
  of the Home
• Agent to send the mobility binding to the
  Correspondent
• Nodes that need them

79
Route optimization (2)
Correspondent Node
80
Route optimization (3)

• Binding updates are authenticated by a route
  optimization
• authentication extension (same as for the
  Mobile-Home
• authentication extension)
• Route optimization offers an efficient routing
  technique but
• supposes that the Correspondent Nodes are able to
• implement the route optimization protocol
• This may be the main reason why this mechanism
  has not yet
• been definitively adopted as an RFC

81
Foreign Agent - Smooth Handoff

• When a mobile moves, it registers with a new FA
• Goal Tell the old FA the current position so
  that the
• packets in transit are redirected to the mobile
  (avoid
• losses and retransmissions)
• Protocol
• The mobile registers with the new FA and tells
  the address of its
• old FA
• The new FA sends a BU to the old FA so that it
  forwards the
• packets to the new location of the mobile

82
Smooth Handoff(1)
Correspondent Node
83
Smooth Handoff(2)

• During the handoff, it is important that the
  datagrams intended to the
• Mobile Node and received by the previous Foreign
  Agent not be lost
• A smooth handoff may be obtained if the
  previous Foreign Agent
• receives a binding update with the new Care-of
  Address of the Mobile
• Node allowing it to relay the datagrams to the
  new Foreign Agent
• This is best achieved if it remains a local
  mechanism between the
• Mobile Node and both the current and previous
  Foreign Agents (the
• Home Agent is too far to perform this binding
  update)
• This poses however a security problem since it
  is highly improbable,
• in the current state of Internet security, that
  an authentication security
• association be established between the Mobile
  Node and the Foreign
• Agents

84
Smooth Handoff(3)
Correspondent Node
85
Smooth Handoff(4)

• If the previous Foreign Agent does not hold the
  new mobility binding
• for the Mobile Node, it may send back the
  decapsulated datagram
• to the Home Agent.
• This may create routing loops if the Foreign
  Agent has lost the trace
• of the Mobile Node and the Mobile Node is not
  connected elsewhere
• The Foreign Agent should re-encapsulate the
  decapsulated
• datagram into a Special Tunnel getting it back to
  the Home Agent
• with the Care-of Address as the source address of
  the outer header
• This allows the Home Agent to compare the
  current registration with
• the returned Care-of Address and decide whether
  it should tunnel the
• datagram or not thus avoiding routing loops

86
Plan

• Introduction
• Quest-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
• Découverte dagent
• Enregistrement
• Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP 3G
• Conclusion

87
Micro mobility Différents types de mobilité
88
Micro mobility

• A mobile has to register with its HA every
• time it moves
• Macro mobility (Mobile IP)
• Micro Mobility (Hawaii, Cellular IP )
• Smaller cells more mobiles gt need to
  ditinguish
• micro/macro mobility
• The mobile registers with the HA when it
• moves to a new mciro mobility domain

89
Micro mobility IP

• Fonctionnement en mode paquet
• Différence par rapport aux autres réseaux
  cellulaires publics
• GSM, UMTS, CDMA 2000 interfaces radio
  majoritairement en
• mode circuit
• Universalité du protocole IP
• Infrastructures répandues dans le monde entier
• Micromobilité va devenir une donnée
  primordiale des réseaux
• Protocole de micro mobilité complémentaire
  d'IP mobile
• Macromobilité possibilité pour un utilisateur
  de quitter son réseau
• d'abonnement pour se rendre dans un autre domaine
  du réseau IP
• Adresse temporaire dans le nouveau domaine
• Enregistrement auprès de l'agent local de sa
  zone
• d'abonnement
• Génération d'un temps de latence
• Échange de nombreux messages de signalisation
• Micro mobilité mobilité locale
• Transparente pour le réseau d'abonnement de
  l'utilisateur
• mobile

90
Micro mobility
91
Macro / Micro mobility
92
Solutions de micro mobilité

• Enregistrements régionaux
• HMIP
• Cellular IP
• Hawaii

93
Regionalized registration (1)
94
Regionalized registration (2)

• Regionalized registration is a solution to the
  reduction of the
• registration traffic between a Home and a Visited
  Network over the
• Internet in order to update the mobility binding
  of the Mobile Nodes
• The idea is to construct a hierarchy of Foreign
  Agents, each FA
• registering a Care-of Address for the Mobile Node
  at its father FA level
• Multiple successive tunnels are thus
  constructed to reach the Mobile
• Node from the Home Agent
• When a Mobile Node moves from the region of FA7
  to FA8, a registration
• should only be sent to FA4 and the tunnel FA4FA7
  would be replaced by
• a tunnel FA4FA8
• When a Mobile Node moves from the region of FA7
  to FA9, a registration
• should be sent to FA1 (and not to the Home Agent)
  and the tunnels would
• be replaced accordingly

95
Solutions de micro mobilité

• Enregistrements régionaux
• HMIP
• Cellular IP
• Hawaii

96
HMIP Hierarchical Mobile IP

• Problem a mobile
• registers with its HA
• every time it moves
• Goal reduce
• registration time by
• using regional
• registrations

97
HMIP Registration(1)
98
HMIP Registration(2)
99
HMIP Routing
100
HMIP Ericsson(1)

• Several levels in the
• hierarchy
• FA sends advertisements
• _at_FA7,_at_FA3,_at_FA1_at_GFA (pour FA7)
• _at_FA6,_at_FA4,_at_FA2,_at_GFA (pour FA6)
• The MN registers the GFA_at_
• with its HA
• IP tunnels are set up
• between the FAs

101
HMIP Ericsson(2)

• When it moves, the mobile
• checks the routes to
• determine if it is in the
• same hierarchy
• _at_FA7,_at_FA3,_at_FA1_at_GFA
• (for FA7)
• _at_FA6,_at_FA4,_at_FA2,_at_GFA (for FA6)
• Fast handoffs a mobile
• may register with several
• FAs
• The packets are bicasted by
• the GFA

102
Solutions de micro mobilité

• Enregistrements régionaux
• HMIP
• Cellular IP
• Hawaii

103
IP cellulaireCouplage IP Mobile / IP
cellulaire

• IP cellulaire n'intervient que sur le réseau
  d'accès
• Aucun routeur du réseau de cœur n'a conscience
  de l'existence d'IP
• cellulaire
• Système peu coûteux à l'installation car pas de
  modification pour
• les routeurs
• Fonctionnement simple
• Définition d'une passerelle ou GW (Gateway)
• Accès au réseau Internet
• Située à la racine du domaine joue le rôle
  d'agent étranger
• Possède une adresse IP qui sert de COA (Care-Of
  Address) à
• tous les visiteurs du domaine
• À la réception de paquets encapsulées, la GW
  ôte l'en-tête
• additionnel
• IP cellulaire met en œuvre des techniques qui
  lui sont propres
• pour transférer le paquet vers le mobile adéquat
• Grâce aux adresses IP permanentes

104
Cellular IPprincipes

• Caches distribués
• Position des mobiles
• Information de routage

105
IP cellulaire

• Base Stations
• Wireless Access Points
• IP routing replaced by Cellular IP routing
• Gateways
• Mobile IP support
• Mobile Nodes use the GW_at_ as COA
• Mobile Node
• Inside the Cellular IP network, mobile nodes
  are
• identified with their home address

106
Architecture IP cellulaire
107
Architecture IP cellulaire

• Réseau d'accès contient des stations de base
• Couverture de microcellules (id GSM)
• Couverture de picocellules, desservies par de
  petites
• antennes dans des espaces privatifs
• Souplesse de fonctionnement grâce à IP
• Méthode de transmission sur l'interface radio
  indépendante
• des opérations liées au routage et à la gestion
  de la mobilité
• Détection du passage d'une cellule à une autre
• Diffusion périodique d'une signature de chaque
  station de
• base voie balise
• Signal pilote servant à mesurer la puissance du
  signal radio
• émis par chaque station de base
• Stations de base câblées de manière
  hiérarchique
• Sommet racine du domaine passerelle

108
Architecture IP cellulaire
109
Opérations dans le réseau Opérations dans le
réseau

• 3 opérations principales
• Paging
• Localisation d'un utilisateur lors de l'arrivée
  de paquets à
• destination
• Routage
• Acheminement des paquets vers l'utilisateurs à
  travers les
• principaux éléments du réseau d'accès
• Handoff
• Gestion des déplacements de l'utilisateur via
  le réseau d'accès
• IP cellulaire se comporte comme un système sans
  fil
• Les terminaux choisissent toujours la station
  de base qui diffuse le
• signal pilote le plus puissant
• Handoff changement de station de base
• Mise à jour de tous les RC lorsque la route est
  nouvelle

110
Objectifs de Cellular IP

• Migration facile
• Bonne connectivité
• Support du soft handoff
• Passage à léchelle avec une complexité
  minimale

111
Cellular IP

• Réseau distribué
• Les noeuds ne connaissent pas la topologie
• Pas de base de données centralisée
• Bon passage à léchelle

112
Cellular IP

• Cellular IP nodes do not know the exact
  location of a
• mobile
• Hop by hop routing
• IP addresses are mapped to ports on Cellular IP
• nodes
• Soft state mappings

113
Mappings

• Paging cache/Routing Cache

114
État de l'utilisateur

• État actif
• Utilisateur en train d'envoyer ou de recevoir
  des paquets
• Initialisé à la suite d'un paging ou d'une
  demande d'émission
• Position du terminal déterminée à la cellule
  près
• État oisif (ou idle)
• Permet de réduire la signalisation sur le lien
  radio
• L'utilisateur peut rester attaché au réseau
  d'accès tout en étant
• inactif
• Localisé dans un groupement de cellules
• Permet d'accueillir un grand nombre de
  visiteurs dans un
• même domaine
• Pas d'enregistrement à chaque passage dans
  chaque cellule
• Si un utilisateur oisif reçoit des paquets, on
  s'appuie sur un paging
• À l'initiative du nœud cherchant à localiser
  l'utilisateur

115
Localisation dun utilisateur

• 2 exigences pour la réussite d'une localisation
• Laisser toute la liberté à un terminal oisif
• Ne pas le contraindre à se signaler
• Mettre en œuvre un mécanisme optimal pour
  atteindre le
• terminal oisif à un coût moindre lorsqu'il
  devient actif
• 2 procédures employées pour répondre à ces
  besoins
• Enregistrement de la localisation de temps à
  autre en cas
• d'activité
• Cache de routage ou RC (Routing Cache)
• Emploi de paging en cas d'oisiveté
• Cache de paging ou PC (Paging Cache)

116
Caches de paging

• Liberté de mouvement pour les utilisateurs
• Ne facilite pas leur localisation
• Il faut retrouver un mobile oisif pour lui
  transmettre un
• paquet
• Surplus de signalisation
• Caches installés dans certains nœuds ou
  stations de
• base
• Connaissance partielle de la localisation des
  mobiles
• Complétée par le paging
• Mise à jour des Paging Caches
• Par l'envoi vers la racine d'un paquet vide
  paging-update
• Paging-update transmis de manière périodique

117
Identification d'un terminal oisif
118
Caches de paging
119
Cache de routage

• Permet d'acheminer le flux de paquets vers
• l'utilisateur
• Routage saut par saut (hop by hop)
• Enregistrement du chemin à l'initiative de
  l'utilisateur
• Lorsqu'il envoie un paquet vers la racine, tous
  les nœuds
• intermédiaires retiennent le chemin pour
  l'utiliser en sens
• inverse
• Si l'utilisateur cesse son activité réseau
• Possibilité de se maintenir dans les RC
• Transmission de paquets vides route-update,
  vers la
• racine
• Sinon, effacement sur temporisation

120
Routage
121
Route discovery
When the mobile receives PP, it sends a
Route-Update Packet to the base station F which
forwards it towards GW All the RCs on the route
are updated
122
Downlink routing

• If there is no PC on the GW
• GW buffers the packet
• GW sends a Paging Packet with the mobile's id
• If the nodes have paging caches, hop by hop
  routing,
• otherwise, the packet is broadcast

123
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124
Handoff

• Initiated by the mobile
• When a mobile gets close to a new BS, it
  redirects its
• packets to the new BS
• The first packet redirected configures a new
  route
• The packets are send to the old and new BS
  during a
• certain time

125
Summary

• Use of the home address
• No temporary address
• No encapsulation
• The mobile sends the gateway address to the HA
• GW_at_ is learnt by the BS

126
Solutions de micro mobilité

• Enregistrements régionaux
• HMIP
• Cellular IP
• Hawaii

127
Hawaii
128
Hawaii
129
Routing Update ( 1)
130
Routing Update ( 2)
131
Hawaii
132
Plan

• Introduction
• Quest-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
• Découverte dagent
• Enregistrement
• Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP 3G
• Conclusion

133
IPv4 vs IPv6
134
Mobile IPv6

• IPv6 mobility relies on
• New functionnalities in IPv6
• A native support of mobility
• A global and unique IPv6 address is assigned to
  each
• mobile node the Home Address
• This address identifies the mobile
• A mobile is able to communicate directly with
  mobile
• nodes (no triangle routing)

135
Main functionnalities in IPv6

• The correspondents must
• Have a binding in their binding cache
• Learn the location of the mobile by handling
• Binding Updates
• Route the packets directly to the mobile
  (Routing
• Header)
• TheHA must
• Be a router on the mobile's home network
• Intercept the packets on the home network
• Tunnel (IPv6 encapsulation) these packets
  directly
• to the mobile

136
Reaching the mobile

• A mobile can always be reached via its HA
• A mobile on a visited network always has a COA
  (selfconfiguration)
• The Router Advertisement indicates the
  subnetworks
• prefix
• Combination of this prefix with the MAC address
• Movement detection is also accomplished with
  Neighbor
• Discovery procedures
• Multi-homing

137
IPv6 Destination options

• Binding Update
• To inform the HA or the correspondents of the
  new COA
• Binding request
• Ask for a BU. Used when a correspondent thinks
  its binding will
• soon expire
• Binding Acknowledgement
• Sent by the HA. Acknowledges a BU containing
  the COA
• Home Address
• Included in every IPv6 packet from the mobile
  to its correspondent
• The packet is supposed to be originated from the
  home network
• and not the visited network
• Uses 144 bits in the header of every packet

138
Cache association management

• Every time a mobile moves it sends a Binding
  Update (BU)
• The BU includes a lifetime
• The mobile keeps a list of the correspondents
  to
• which it sent a BU
• The temporary address sent to the HA is called
  the
• principal COA

139
The IETF model
140
BU format
141
Binding Acknowledge message

• ACK message based on a destination header
  extension

Sent if the A bit is set in the BU sent by the
mobile Also includes an authentication header
142
Binding Request Home address

• Allows the correspondents to update their
  bindings

Store the principal address of the mobile
143
IPv6 Nodes

• Handling IPv6 mobility forces the nodes to
  implement some
• functionnalities
• Be able to receive and handle BUs
• SendBAs
• Use RoutingHeader
• Maintain a Binding Cache
• An IPv6 node must be able to
• Do IPv6 decapsulation
• Send BUs and receive BAs
• Maintain a list of BUs sent

144
IPv6 routers

• At least one router on the mobile's home network
  may act
• as a HA
• A HA must
• Maintain a Binding table
• Intercept packets in the mobile's home network
• Encapsulate these packets and send them to the
  mobile's COA

145
HA discovery

• Modification of the Routing Advertisement (RA)
  message of Neighbor
• Discovery
• Add an option to the RA message
• Modify the minimal time (3 seconds) between two
  RAs (1
• message/sec)
• Send a BU (with the H bit set) to the anycast
  address of the HAs

146
IPv6 and mobility (1)

• IPv6 represents an almost perfect protocol
  basis for mobile
• networking
• First, the attendant address configuration
  protocols allow each
• Mobile Node to obtain a Care-of Address without
  the need for
• Foreign Agents which disappear from the
  architecture
• Second, IPsec implementation is mandatory to
  IPv6 compliant
• systems. This resolves security pitfalls by
  providing a
• widely available and standardized security
  architecture
• Particularly, mobility bindings are now done by
  the Mobile
• Nodes themselves
• Third, the destination options IPv6 header
  extension provides
• means to sending mobility bindings updates from
  the
• Mobile Nodes directly to Correspondent Nodes very
  efficiently
• This simplifies the smooth handoff procedure

147
IPv6 and mobility (2)
Correspondent Node
148
Data mobility perspectives

• The Mobile IP architecture is being finalized
  at the IETF
• with its basic mechanisms already terminated and
  some
• enhanced functionalities being added
  progressively
• The market opportunities for this architecture
  are huge
• and should follow the explosive growth of both
• computer/Internet industries on the one hand and
  mobile
• telephony on the other hand
• Some work still has to be done however to
  integrate both
• approaches by having a single network
  infrastructure for
• both Mobile IP and other mobility approaches such
  as the
• third generation of Mobile Cellular Networks
  (UMTS)
• This conforms to the global service
  integration over a
• consolidated network infrastructure trend for
  public
• networks

149
HMIPv6

• MAP (Mobility Anchor Point)
• Minimizes interruptions due to handoffs
• The mobiles use the MAP's IP_at_ as COA
• MAP receives the packets and delivers them
• to the mobile
• The access routers send the

150
HMIPv6

• The access routers send the MAP's IPv6_at_ in RAs
• The mobile may roam and
• keep the same MAP
• If the mobile changes its
• MAP, it sends a new BU to
• its HA and correspondents

151
HMIPv6
IPv6MobHA IPv6MobCOA
152
Plan

• Introduction
• Quest-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
• Découverte dagent
• Enregistrement
• Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP 3G
• Conclusion

153
MIP-UMTS standardized architecture
154
MIP-UMTS other solutions (1/2)
155
MIP-UMTS other solutions (2/2)
156
3GPP Network Reference Architecture R5
157
Mobile IP in UMTS
158
Data mobility perspectives

• The Mobile IP architecture is being finalized
  at the IETF
• with its basic mechanisms already terminated and
  some
• enhanced functionalities being added
  progressively
• The market opportunities for this architecture
  are huge
• and should follow the explosive growth of both
• computer/Internet industries on the one hand and
  mobile
• telephony on the other hand
• Some work still has to be done however to
  integrate both
• approaches by having a single network
  infrastructure for
• both Mobile IP and other mobility approaches such
  as the
• third generation of Mobile Cellular Networks
  (UMTS)
• This conforms to the global service
  integration over a
• consolidated network infrastructure trend for
  public
• networks