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Mobilité IP



              1
Plan
• Introduction
       – Qu’est-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
       – Découverte d’agent
       – Enregistrement
       – Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP & 3G
• Conclusion


                                          2
Différents types de mobilité




                               3
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



                                                4
Mobilité IP ≠ LANs sans fil
               (WLAN)
• LANs sans fil aujourd’hui :
     – 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 d’un même sous-réseau IP)
• Mobilité IP ≠ Interface sans fil
                                               5
Mobilité IP ≠ LANs sans fil
          (WLAN)




                              6
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

•Session Mobility
    - Allows to interrupt sessions and to resume them later, possibility from another terminal or another
     network




                                                                                                                   7
Différents types de mobilité




                               8
Mobilité




           9
Introduction Mobile IP (1)
• Sillage des réseaux GSM
       – Mobilité = nécessité pour les utilisateurs
             d’un 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 : l’une des principales
             sources d’information

                                                  10
Introduction Mobile IP (2)
• Échelle planétaire :
      – Quasi-totalité des réseaux fournissent une entrée au
        réseau Internet
      – Avec mobilité : garantie d’un accès universel, simple
        d’emploi et pratique
• Groupe de travail de l’IETF : proposition IP
      Mobile
      – Proposer une localisation planétaire par l’adresse IP
        (à l’instar du roaming du GSM)
• IP préexiste au concept nomade
      – GSM doté dès l’origine de telles fonctions
      – IP : « bricolage » de solutions pour ajouter la mobilité



                                                                   11
Cahier des charges pour
   l’architecture 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




                                                               12
Problématique de la mobilité
           dans IP
• Difficultés pour intégrer à IP de nouvelles
fonctions devant offrir la mobilité




                                            13
Why isn’t 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



                                                                     14
IP mobility: routing




                       15
Why isn’t IP mobility simple? (2)
• The first use supposes that a host’s IP address should
  never change since the DNS should always point to the
  same IP address
• The second use supposes that a host’s 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 host’s 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



                                                            16
Why isn’t 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 host’s IP address is
   changed, all TCP sessions involving this host should be
   dropped and reinitialized with the new IP address

                                                                     17
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



                                                                        18
PLAN

• Introduction
– Qu’est-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
– Découverte d’agent
– Enregistrement
– Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP & 3G
• Conclusion
                                        19
Overview of the IP mobility
       architecture




                              20
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 node’s
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 node’s
visited network that collaborates with the Home agent to
complete the delivery of datagrams to the mobile node while
it is away from home




                                                                  21
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)




                                                                22
Plan
• Introduction
– Qu’est-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
– Découverte d’agent
– Enregistrement
– Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP & 3G
• Conclusion
                                        23
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
                                                         24
Mobile IP




            25
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)




                                                       26
Protocol overview
4. The mobile registers its COA with its home agent
5. The Home Agent sends ARP on the Home Network
(IP@ <-> MAC@). 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


                                                          27
IP mobility mechanisms

    Agent discovery
     Registration
      Tunneling




                         28
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

                                                         29
Agent Solicitation Message




                             30
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




                                                              31
Mobile Agent Discovery
          Getting 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




                                                                   32
Agent Advertisement Message




                              33
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
                                                 34
Mobile Agent Discovery
              Mobility Agent Advertisement Extension


• Flags:
– R=Registration required at the Foreign Agent
– B=Busy
– H=Home Agent
– F=Foreign 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



                                                                             35
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 the«ForeignAgent»
– With the temporary address of the mobile



                                                                    36
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
                                          37
Registration




               38
Registration
  request




               39
Registration




               40
Registration
               Registration Request

                                  • Flags :
      – S=Simultaneous Registrations (multiple Care-of Adresses)
                              – B=Broadcast
          – D=Care-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



                                                                           41
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


                                                                   42
Registration
                 Registration 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




                                                                           43
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
                                                          44
Registration
  Reply




               45
Registration
  Reply




               46
Registration
• Via le Foreign Agent :




                           47
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
                                                48
Exemple




          49
Exemple




          50
Exemple

Annuler l’enregistrement (au retour au
réseau home) :




                                         51
Exemple




          52
De-registration




                  53
Discovering the HA's address


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




                                           54
Learning the HA address




                          55
Learning the HA address




                          56
Learning the HA address




                          57
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
                                            58
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



                                                              59
Interception by the HA

              • 2 possibilities
    – Accessibility advertisement :
only on HA routers with several interfaces
         – Using the proxy ARP
      Mobile's IP@ <-> HA's MAC@
  Updated by the HA and by the mobile
        node when it returns on its
              home network
                                         60
Packet interception
   by the HA




                      61
Home Network configurations




                              62
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 node’s 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




                                                                  63
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




                                                                          64
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




                                                                       65
Firewalls and packet filtering
        problems (1)




                                 66
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 Address=Care-of Address this
      is a loosing proposition because it runs counter to the
                            architecture
   – Send datagrams encapsulated in an outer IP header with
         Source Address=Care-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
                                                                   67
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


                                                                    68
Datagram Tunneling

• A Correspondent Node sends datagrams to a Mobile Node with
the Destination Address field containing the Mobile Node’s 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

                                                                     69
Reminder : IPv4 header
       format




                         70
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 Node’s 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 won’t transport the Mobile
Node’s Home Address used at the Foreign Agent to send the
decapsulated datagram on the right data link




                                                                    71
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


                                                                  72
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
                                                                        73
Plan

• Introduction
– Qu’est-ce que la mobilité IP ?
• Architecture Mobile IP
• Mécanismes de mobilité IP
– Découverte d’agent
– Enregistrement
– Tunnelage
• Fonctionnalités avancées
• Micro-mobilité
• Support de mobilité fourni par IPv6
• Mobile IP & 3G
• Conclusion
                                        74
Enhanced functionnalities


    • Optimisation du routage
        • Smooth handoff




                                75
Routing optimisation


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

                                         76
Triangle Routing




                   77
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


                                                                  78
Route optimization (2)




    Correspondent Node

                         79
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

                                                         80
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

                                                           81
Smooth Handoff
     (1)




Correspondent Node

                     82
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




                                                                              83
Smooth Handoff
     (3)




 Correspondent Node

                      84
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




                                                                          85
Plan
             • Introduction
    – Qu’est-ce que la mobilité IP ?
       • Architecture Mobile IP
    • Mécanismes de mobilité IP
         – Découverte d’agent
           – Enregistrement
               – Tunnelage
     • Fonctionnalités avancées
           • Micro-mobilité
• Support de mobilité fourni par IPv6
           • Mobile IP & 3G
              • Conclusion




                                        86
Micro mobility: Différents
   types de mobilité




                             87
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 => need to
                 ditinguish
           micro/macro mobility
• The mobile registers with the HA when it
  moves to a new mciro mobility domain
                                               88
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


                                                                          89
Micro mobility




                 90
Macro / Micro mobility




                         91
Solutions de micro mobilité
    • Enregistrements régionaux
                 HMIP
            • Cellular IP
               • Hawaii




                                  92
Regionalized registration (1)




                                93
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




                                                                          94
Solutions de micro mobilité
    • Enregistrements régionaux
                • HMIP
            • Cellular IP
               • Hawaii




                                  95
HMIP: Hierarchical Mobile IP
• Problem: a mobile
registers with its HA
 every time it moves
   • Goal: reduce
 registration time by
   using regional
     registrations


                                 96
HMIP: Registration(1)




                        97
HMIP: Registration(2)




                        98
HMIP: Routing




                99
HMIP: Ericsson(1)
    • Several levels in the
          hierarchy
• FA sends advertisements
 @FA7,@FA3,@FA1@GF
         A (pour FA7)
@FA6,@FA4,@FA2,@GF
         A (pour FA6)
   • The MN registers the
            GFA@
          with its HA
   • IP tunnels are set up
       between the FAs

                                   100
HMIP: Ericsson(2)
  • When it moves, the mobile
       checks the routes to
      determine if it is in the
         same hierarchy
   @FA7,@FA3,@FA1@GFA
            (for FA7)
@FA6,@FA4,@FA2,@GFA (for
              FA6)
   • Fast handoffs : a mobile
    may register with several
               FAs
 • The packets are bicasted by
            the GFA
                                  101
Solutions de micro mobilité
    • Enregistrements régionaux
                 HMIP
            • Cellular IP
               • Hawaii




                                  102
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


                                                                        103
Cellular IP:principes

     • Caches distribués
   – Position des mobiles
  – Information de routage




                             104
IP cellulaire

                 • Base Stations
           – Wireless Access Points
  – IP routing replaced by Cellular IP routing
                    • Gateways
               – Mobile IP support
    – Mobile Nodes use the GW@ as COA
                  • Mobile Node
– Inside the Cellular IP network, mobile nodes
                        are
       identified with their home address
                                             105
Architecture IP cellulaire




                             106
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

                                                                  107
Architecture IP cellulaire




                             108
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



                                                                         109
Objectifs de Cellular IP

             • Migration facile
           • Bonne connectivité
        • Support du soft handoff
• Passage à l’échelle avec une complexité
                 minimale




                                       110
Cellular IP

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




                                       111
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
                                        112
Mappings

• Paging cache/Routing Cache




                               113
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

                                                                  114
Localisation d’un 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)
                                                        115
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




                                                                116
Identification d'un terminal
             oisif




                               117
Caches de paging




                   118
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




                                                                119
Routage




          120
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


                                                                    121
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


                                         122
123
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
                                         124
Summary

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



                                      125
Solutions de micro mobilité

    • Enregistrements régionaux
                 HMIP
            • Cellular IP
               • Hawaii




                                  126
Hawaii




         127
Hawaii




         128
Routing Update ( 1)




                      129
Routing Update ( 2)




                      130
Hawaii




         131
Plan

             • Introduction
    – Qu’est-ce que la mobilité IP ?
       • Architecture Mobile IP
    • Mécanismes de mobilité IP
         – Découverte d’agent
           – Enregistrement
               – Tunnelage
     • Fonctionnalités avancées
           • Micro-mobilité
• Support de mobilité fourni par IPv6
           • Mobile IP & 3G
              • Conclusion



                                        132
IPv4 vs IPv6




               133
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)
                                              134
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

                                                       135
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 subnetwork’s
                          prefix
   • Combination of this prefix with the MAC address
    • Movement detection is also accomplished with
                         Neighbor
                 Discovery procedures
                     • Multi-homing



                                                    136
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



                                                                137
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
                                       138
The IETF model




                 139
BU format




            140
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
                                                          141
Binding Request & Home
         address
• Allows the correspondents to update
their bindings


• Store the principal address of the mobile




                                              142
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

                                             143
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

                                           144
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


                                                   145
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


                                                                    146
IPv6 and mobility (2)




    Correspondent Node

                         147
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


                                                              148
HMIPv6
      • MAP (Mobility Anchor Point)
– Minimizes interruptions due to handoffs
  • The mobiles use the MAP's IP@ as
                   COA
• MAP receives the packets and delivers
                   them
              to the mobile
      • The access routers send the

                                            149
HMIPv6
 • The access routers send
   the MAP's IPv6@ 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




                                150
HMIPv6




IPv6MobHA
IPv6MobCOA   151
Plan
             • Introduction
    – Qu’est-ce que la mobilité IP ?
       • Architecture Mobile IP
    • Mécanismes de mobilité IP
         – Découverte d’agent
           – Enregistrement
               – Tunnelage
     • Fonctionnalités avancées
           • Micro-mobilité
• Support de mobilité fourni par IPv6
           • Mobile IP & 3G
              • Conclusion


                                        152
MIP-UMTS standardized
     architecture




                        153
MIP-UMTS other solutions
        (1/2)




                           154
MIP-UMTS other solutions
        (2/2)




                           155
3GPP Network Reference
   Architecture – R5




                         156
Mobile IP in UMTS




                    157
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


                                                              158

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77232345 cours-ip-mobile

  • 2. Plan • Introduction – Qu’est-ce que la mobilité IP ? • Architecture Mobile IP • Mécanismes de mobilité IP – Découverte d’agent – Enregistrement – Tunnelage • Fonctionnalités avancées • Micro-mobilité • Support de mobilité fourni par IPv6 • Mobile IP & 3G • Conclusion 2
  • 3. Différents types de mobilité 3
  • 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 4
  • 5. Mobilité IP ≠ LANs sans fil (WLAN) • LANs sans fil aujourd’hui : – 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 d’un même sous-réseau IP) • Mobilité IP ≠ Interface sans fil 5
  • 6. Mobilité IP ≠ LANs sans fil (WLAN) 6
  • 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 •Session Mobility - Allows to interrupt sessions and to resume them later, possibility from another terminal or another network 7
  • 8. Différents types de mobilité 8
  • 10. Introduction Mobile IP (1) • Sillage des réseaux GSM – Mobilité = nécessité pour les utilisateurs d’un 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 : l’une des principales sources d’information 10
  • 11. Introduction Mobile IP (2) • Échelle planétaire : – Quasi-totalité des réseaux fournissent une entrée au réseau Internet – Avec mobilité : garantie d’un accès universel, simple d’emploi et pratique • Groupe de travail de l’IETF : proposition IP Mobile – Proposer une localisation planétaire par l’adresse IP (à l’instar du roaming du GSM) • IP préexiste au concept nomade – GSM doté dès l’origine de telles fonctions – IP : « bricolage » de solutions pour ajouter la mobilité 11
  • 12. Cahier des charges pour l’architecture 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 12
  • 13. Problématique de la mobilité dans IP • Difficultés pour intégrer à IP de nouvelles fonctions devant offrir la mobilité 13
  • 14. Why isn’t 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 14
  • 16. Why isn’t IP mobility simple? (2) • The first use supposes that a host’s IP address should never change since the DNS should always point to the same IP address • The second use supposes that a host’s 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 host’s 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 16
  • 17. Why isn’t 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 host’s IP address is changed, all TCP sessions involving this host should be dropped and reinitialized with the new IP address 17
  • 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 18
  • 19. PLAN • Introduction – Qu’est-ce que la mobilité IP ? • Architecture Mobile IP • Mécanismes de mobilité IP – Découverte d’agent – Enregistrement – Tunnelage • Fonctionnalités avancées • Micro-mobilité • Support de mobilité fourni par IPv6 • Mobile IP & 3G • Conclusion 19
  • 20. Overview of the IP mobility architecture 20
  • 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 node’s 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 node’s visited network that collaborates with the Home agent to complete the delivery of datagrams to the mobile node while it is away from home 21
  • 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) 22
  • 23. Plan • Introduction – Qu’est-ce que la mobilité IP ? • Architecture Mobile IP • Mécanismes de mobilité IP – Découverte d’agent – Enregistrement – Tunnelage • Fonctionnalités avancées • Micro-mobilité • Support de mobilité fourni par IPv6 • Mobile IP & 3G • Conclusion 23
  • 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 24
  • 25. Mobile IP 25
  • 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) 26
  • 27. Protocol overview 4. The mobile registers its COA with its home agent 5. The Home Agent sends ARP on the Home Network (IP@ <-> MAC@). 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 27
  • 28. IP mobility mechanisms Agent discovery Registration Tunneling 28
  • 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 29
  • 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 31
  • 32. Mobile Agent Discovery Getting 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 32
  • 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 34
  • 35. Mobile Agent Discovery Mobility Agent Advertisement Extension • Flags: – R=Registration required at the Foreign Agent – B=Busy – H=Home Agent – F=Foreign 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 35
  • 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 the«ForeignAgent» – With the temporary address of the mobile 36
  • 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 37
  • 41. Registration Registration Request • Flags : – S=Simultaneous Registrations (multiple Care-of Adresses) – B=Broadcast – D=Care-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 41
  • 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 42
  • 43. Registration Registration 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 43
  • 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 44
  • 47. Registration • Via le Foreign Agent : 47
  • 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 48
  • 49. Exemple 49
  • 50. Exemple 50
  • 51. Exemple Annuler l’enregistrement (au retour au réseau home) : 51
  • 52. Exemple 52
  • 54. Discovering the HA's address • Manual configuration on the mobile • Automatically – By broadcasting a registration request 54
  • 55. Learning the HA address 55
  • 56. Learning the HA address 56
  • 57. Learning the HA address 57
  • 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 58
  • 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 59
  • 60. Interception by the HA • 2 possibilities – Accessibility advertisement : only on HA routers with several interfaces – Using the proxy ARP Mobile's IP@ <-> HA's MAC@ Updated by the HA and by the mobile node when it returns on its home network 60
  • 61. Packet interception by the HA 61
  • 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 node’s 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 63
  • 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 64
  • 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 65
  • 66. Firewalls and packet filtering problems (1) 66
  • 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 Address=Care-of Address this is a loosing proposition because it runs counter to the architecture – Send datagrams encapsulated in an outer IP header with Source Address=Care-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 67
  • 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 68
  • 69. Datagram Tunneling • A Correspondent Node sends datagrams to a Mobile Node with the Destination Address field containing the Mobile Node’s 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 69
  • 70. Reminder : IPv4 header format 70
  • 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 Node’s 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 won’t transport the Mobile Node’s Home Address used at the Foreign Agent to send the decapsulated datagram on the right data link 71
  • 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 72
  • 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 73
  • 74. Plan • Introduction – Qu’est-ce que la mobilité IP ? • Architecture Mobile IP • Mécanismes de mobilité IP – Découverte d’agent – Enregistrement – Tunnelage • Fonctionnalités avancées • Micro-mobilité • Support de mobilité fourni par IPv6 • Mobile IP & 3G • Conclusion 74
  • 75. Enhanced functionnalities • Optimisation du routage • Smooth handoff 75
  • 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 76
  • 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 78
  • 79. Route optimization (2) Correspondent Node 79
  • 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 80
  • 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 81
  • 82. Smooth Handoff (1) Correspondent Node 82
  • 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 83
  • 84. Smooth Handoff (3) Correspondent Node 84
  • 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 85
  • 86. Plan • Introduction – Qu’est-ce que la mobilité IP ? • Architecture Mobile IP • Mécanismes de mobilité IP – Découverte d’agent – Enregistrement – Tunnelage • Fonctionnalités avancées • Micro-mobilité • Support de mobilité fourni par IPv6 • Mobile IP & 3G • Conclusion 86
  • 87. Micro mobility: Différents types de mobilité 87
  • 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 => need to ditinguish micro/macro mobility • The mobile registers with the HA when it moves to a new mciro mobility domain 88
  • 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 89
  • 91. Macro / Micro mobility 91
  • 92. Solutions de micro mobilité • Enregistrements régionaux HMIP • Cellular IP • Hawaii 92
  • 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 94
  • 95. Solutions de micro mobilité • Enregistrements régionaux • HMIP • Cellular IP • Hawaii 95
  • 96. HMIP: Hierarchical Mobile IP • Problem: a mobile registers with its HA every time it moves • Goal: reduce registration time by using regional registrations 96
  • 100. HMIP: Ericsson(1) • Several levels in the hierarchy • FA sends advertisements @FA7,@FA3,@FA1@GF A (pour FA7) @FA6,@FA4,@FA2,@GF A (pour FA6) • The MN registers the GFA@ with its HA • IP tunnels are set up between the FAs 100
  • 101. HMIP: Ericsson(2) • When it moves, the mobile checks the routes to determine if it is in the same hierarchy @FA7,@FA3,@FA1@GFA (for FA7) @FA6,@FA4,@FA2,@GFA (for FA6) • Fast handoffs : a mobile may register with several FAs • The packets are bicasted by the GFA 101
  • 102. Solutions de micro mobilité • Enregistrements régionaux HMIP • Cellular IP • Hawaii 102
  • 103. 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 103
  • 104. Cellular IP:principes • Caches distribués – Position des mobiles – Information de routage 104
  • 105. IP cellulaire • Base Stations – Wireless Access Points – IP routing replaced by Cellular IP routing • Gateways – Mobile IP support – Mobile Nodes use the GW@ as COA • Mobile Node – Inside the Cellular IP network, mobile nodes are identified with their home address 105
  • 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 107
  • 109. 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 109
  • 110. Objectifs de Cellular IP • Migration facile • Bonne connectivité • Support du soft handoff • Passage à l’échelle avec une complexité minimale 110
  • 111. Cellular IP • Réseau distribué • Les noeuds ne connaissent pas la topologie • Pas de base de données centralisée • Bon passage à l’échelle 111
  • 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 112
  • 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 114
  • 115. Localisation d’un 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) 115
  • 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 116
  • 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 119
  • 120. Routage 120
  • 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 121
  • 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 122
  • 123. 123
  • 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 124
  • 125. Summary • Use of the home address • No temporary address • No encapsulation • The mobile sends the gateway address to the HA • GW@ is learnt by the BS 125
  • 126. Solutions de micro mobilité • Enregistrements régionaux HMIP • Cellular IP • Hawaii 126
  • 127. Hawaii 127
  • 128. Hawaii 128
  • 129. Routing Update ( 1) 129
  • 130. Routing Update ( 2) 130
  • 131. Hawaii 131
  • 132. Plan • Introduction – Qu’est-ce que la mobilité IP ? • Architecture Mobile IP • Mécanismes de mobilité IP – Découverte d’agent – Enregistrement – Tunnelage • Fonctionnalités avancées • Micro-mobilité • Support de mobilité fourni par IPv6 • Mobile IP & 3G • Conclusion 132
  • 133. IPv4 vs IPv6 133
  • 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) 134
  • 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 135
  • 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 subnetwork’s prefix • Combination of this prefix with the MAC address • Movement detection is also accomplished with Neighbor Discovery procedures • Multi-homing 136
  • 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 137
  • 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 138
  • 140. BU format 140
  • 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 141
  • 142. Binding Request & Home address • Allows the correspondents to update their bindings • Store the principal address of the mobile 142
  • 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 143
  • 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 144
  • 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 145
  • 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 146
  • 147. IPv6 and mobility (2) Correspondent Node 147
  • 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 148
  • 149. HMIPv6 • MAP (Mobility Anchor Point) – Minimizes interruptions due to handoffs • The mobiles use the MAP's IP@ as COA • MAP receives the packets and delivers them to the mobile • The access routers send the 149
  • 150. HMIPv6 • The access routers send the MAP's IPv6@ 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 150
  • 152. Plan • Introduction – Qu’est-ce que la mobilité IP ? • Architecture Mobile IP • Mécanismes de mobilité IP – Découverte d’agent – Enregistrement – Tunnelage • Fonctionnalités avancées • Micro-mobilité • Support de mobilité fourni par IPv6 • Mobile IP & 3G • Conclusion 152
  • 153. MIP-UMTS standardized architecture 153
  • 156. 3GPP Network Reference Architecture – R5 156
  • 157. Mobile IP in UMTS 157
  • 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 158