Cours IP Mobile

8/3/2019 Cours IP Mobile

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Mobilit IP


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PlanIntroduction

Quest-ce que la mobilit IP ?Architecture Mobile IPMcanismes de mobilit IP

Dcouverte dagent

Enregistrement TunnelageFonctionnalits avancesMicro-mobilitSupport de mobilit fourni par IPv6Mobile IP & 3GConclusion


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Diffrents types de mobilit


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Diffrents types de mobilit Nomadisme (DHCP) Ordinateurs mobiles (Mobile IP, IEEE

802. 11) Rseaux mobiles (rseaux Ad-hoc) Besoin de protocoles fournissant un service

de localisation


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Mobilit IP LANs sans fil

(WLAN) LANs sans fil aujourdhui : IEEE 802. 11, Bluetooth

AP IEEE 802.

11 AP = pont entrele rseau fixe et le rseau sans fil handoffs de niveau2 supports mais PAS la

mobilit IP (les handoffs sont supportsau sein dun mme sous-rseau IP) Mobilit IP Interface sans fil


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Mobilit IP LANs sans fil(WLAN)


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Diffrents types de mobilitTerminal Mobility

- Wireless connection between a terminal and access point (base station) or between several terminals(adhoc 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


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Diffrents types de mobilit


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Mobilit


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Introduction Mobile IP (1) Sillage des rseaux GSM

Mobilit = ncessit pour les utilisateursdun systme de communication

Tous les rseaux existants se donnentpour mission de proposer ce service Standard TCP/IP : rseau le + tendu au

monde Principe Anywhere, Any Time, Network

Access Rseau IP : lune des principalessources dinformation


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Introduction Mobile IP (2 )

chelle plantaire : Quasi-totalit des rseaux fournissent une entre au

rseau Internet Avec mobilit : garantie dun accs universel, simple

demploi et pratique

Groupe de travail de lIETF : proposition IPMobile Proposer une localisation plantaire par ladresse IP

( linstar du roaming du GSM) IP prexiste au concept nomade

GSM dot ds lorigine de telles fonctions IP : bricolage de solutions pour ajouter la mobilit


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Cahier des charges pour larchitecture de mobilit IP

Two major requirements arise when considering IP mobility: Application transparency : Dealing witha mobile

configuration should not necessitate a mobile-awareapplication . This is needed in order to avoid applicationreplacement on all Internet hosts!

Seamless roaming : When a user goes out of hiscorporate network and roams around in the Internet, therequirement 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 toanswer the above requirements


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Problmatique de la mobilit

dans IP Difficults pour intgrer IP de nouvellesfonctions devant offrir la mobilit


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Why isnt IP mobility simple? (1) The complexity comes from the current use of IP addresses. An IP address is used to identify a particular end-system . In this respect, IP

addresses are equivalent to FQDNs (Fully Qualified Domain

Names) and the equivalence is maintained in a DNS, DomainName Server identify a particular TCP session in an IP host since a TCP

socket consists of a (destination IP address, destination portnumber) couple

determine a route to a destination IP host .

The first two uses come into contradiction with the third usewhen mobility is considered


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IP mobility: routing


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Why isnt IP mobility simple? (2 ) The first use supposes that a hosts IP address shouldnever change since the DNS should always point to thesame IP address The second use supposes that a hosts IP address should

never change during a TCP session otherwise thesession would be lost The third use supposes that when the host is roamingoutside its home network (the network which has theprefix of the hosts IP address),it should change itsaddress (and take an address with a prefix given by thevisited network ) in order to receive the datagramsdestined to it


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Why isnt IP mobility simple? (3 ) A possible answer to the third constraint would be to use aDHCP (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 hoston the visited network. This may be very dangerous on asecurity standpoint!

Second, this solution can not provide a seamless continuousmobility capability since when the mobile hosts IP address ischanged, all TCP sessions involving this host should bedropped and reinitialized with the new IP address


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Mobile IP standardization

process The standardization of Mobile IP is being mainly carried out at theIETF (Internet Engineering Task Force) The IP Routing for Wireless/Mobile Hosts (MobileIP ) Working

Group is in charge of defining and specifying the Mobile IParchitecture and protocols The major architecture components are already in the standardstrack (Request For Comments, RFCs 2002-2006 )

Some very interesting enhanced functionalities are stillconsidered as work in progress and specified in Internet Drafts

These documents and other related information may be found atthe mobileip WG home page on the Web :http://www.ietf .org/html.charters/mobileip-charter .html


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PLAN

Introduction Quest-ce que la mobilit IP ?

Architecture Mobile IPMcanismes de mobilit IP

Dcouverte dagent Enregistrement Tunnelage

Fonctionnalits avances

Micro-mobilitSupport de mobilit fourni par IPv6Mobile IP & 3GConclusion


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0

Overview of the IP mobilityarchitecture


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Functional entities

Mobile node : A host or a router that roams from onenetwork or subnetwork to another outside its home networkwithout changing its long term IP address (the home address)

Home agent : This is typically a router on a mobile nodeshome network which delivers datagrams to departed mobilenodes, and maintains current location information for each

Foreign agent : This is typically a router on a mobile nodesvisited network that collaborates with the Home agent tocomplete the delivery of datagrams to the mobile node whileit is away from home


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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 thetwo first IP addresses constraints) The Care-of address is a temporary address used toroute the datagrams destined to the mobile host to thecurrent attachment point of this host (answers the last IPaddresses constraint)


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PlanIntroduction

Quest-ce que la mobilit IP ?Architecture Mobile IPMcanismes de mobilit IP





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Main FunctionsAgent Discovery :

Home Agents & Foreign Agents send advertisementson thelink. A mobile can ask for advertisements to be sent .

Registration : When a mobile is away, it registers its temporaryaddresswith its home agent

Tunneling : The packets for the mobile are intercepted by the HAandtunnelled to the mobile


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Mobile IP


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Protocol overview

1. Home Agent & Foreign Agent broadcast or multicastagent advertisements on their respective links .2. Mobile nodes listen to Agent Advertisements. Theyexamine the contents of these advertisements todetermine whether they are on the home or on avisited network3. A mobile node on a visited network acquires atemporary address (care of address)


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Protocol overview

4. The mobile registers its COA with its home agent5 . The Home Agent sends ARP on the Home Network(IP@ MAC@). The packets for the mobile areintercepted and sent to the current position of themobile6 . The packets arrive to the COA and are decapsulatedinorder to extract the original packet7 . The packets from the mobile are sent directly to thecorrespondents


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IP mobility mechanisms

Agent discoveryRegistrationTunneling


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Agent Discovery

Process by which the mobile detects where it isattached(home or visited network)

Allows the mobile to determine a COA when themobile is on avisited network

Based on 2 types of messages: Agent Advertisement : broadcast or multicast by theagents

Agent Solicitation : sent by a mobile which does notwant towait for an AA

Message authentication


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Agent Solicitation Message


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Mobile Agent Discovery

An extension, called theMobility Agent extension , isappended to ICMP Router Advertisement to constitute theAgent 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 aMobile Node knows when it hasreturned to its HomeNetwork

A Mobile Node is allowed to sendICMP Router Solicitationmessages in order to elicit a Mobility Agent Advertisement


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Getting a COA

A Care-of Address may be obtained from the Foreign Agent byan 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 andnot to a Mobile Node through a Foreign Agent. For a collocated Care-of Address, the tunnel terminates at the

Mobile Node interface


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Agent Advertisement Message


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Mobile Agent Discovery

It is based upon an extension of the ICMP(InternetControl Message Protocol) Router Discovery

protocol A router periodically broadcastsICMP Router Advertisement messages on the differentdirectlyattached subnetworks

This allows the hosts on these subnets todiscover therouter


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Mobile Agent DiscoveryMobility 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


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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

thetype of registration to be done

Two registration procedures With the ForeignAgent With the temporary address of the mobile


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Registration

Once the Mobile Node receives a Care-of Address, it shouldregister its (Home Address, Care-of Address) binding athis Home Agent

This is done using2 messages :

Registration Request Registration Reply They both use aUDP/IP service


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Registration


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Registrationrequest


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Registration


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RegistrationRegistration 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 thebinding

Identification is used to protect against replay attacks and allows tocorrelate a Registration Request with a Registration Reply message The Mobile-Home authentication extension is used to authenticate

the Mobile Node at the Home Agent


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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


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RegistrationRegistration Reply

Type identifies the Registration message Lifetime specifies the duration of the mobility addresses binding

Home Address identifies the Mobile Node to which this message isrelated

Home Agent identifies the Home Agent having registered thebinding

Identification is used to protect against replay attacks and allows tocorrelate 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 , 7 0... : registration denied by the Foreign Agent 13 0, 13 1, 133... : registration denied by the Home Agent


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Registration Reply

The FA receives a registration reply If the RR is invalid, the agent sends a Registration

Reply describing the reasonwhy 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 tochange its registrationprocedure

Otherwise the mobile updates its routing table


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RegistrationReply


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RegistrationReply


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Registration

Via le Foreign Agent :


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Exemple

Adresse home du mobile node =12 9 .34. 7 8. 5 HA du mobile node = 12 9 .34. 7 8.2 5 4

FA address = 13 7 .0.0.11

FA care of address = 9 .2.2 0.11 Home node source port =434

Mobile node source port = 109 4

FA source port = 1105 Care-of-address registration lifetime =6 0000 s HA granted lifetime =3 5 000 s


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Exemple


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Exemple


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Exemple

Annuler lenregistrement (au retour aurseau home) :


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Exemple


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De-registration


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Discovering the HA's address

Manual configuration on the mobile Automatically

By broadcasting a registration request


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Learning the HA address


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Movement detection

Using the lifetime field If the lifetimeexpires, the mobile

supposes it has attachedto a new link or the agent has failed. It

waits for an Agent Advertisement or sends an Agent

Sollicitation Detection using the network prefix

Routing


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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 anddelivered to the mobile

Interception by the HA


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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 itshome network

Packet interception


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Packet interceptionby the HA


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Home Network configurations


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Proxy and Gratuitous ARP Proxy

In the cases A and B above, the Home Agent should intercept thedatagrams intended to Mobile Nodes using a Proxy ARPmechanism

In the case C, all datagrams intended to Mobile nodes will benaturally intercepted by the Home Agent. Here, all the hosts are

outside their Home Network which become aVirtual Network

Gratuitous ARP should be used by the Home Agent in order tochange the ARP cache entry for a roaming Mobile nodes Home

Address on the Home Network When the Mobile Node gets back to its Home Network, Gratuitous

ARP should again be used by the Mobile Node itself to restore the ARP cache entry


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Security aspects (1)

The security issue is fundamental for registration messages otherwiseimpersonation and session hijacking attacks would be trivial

Authentication should be applied to these messages The Mobile IP architecture specifies its own security mechanisms for usewith IPv4 since IPsec, the new standardized security architecture, is not

mandatory with IPv4

An authentication extension is thus appended to each of the abovemessages The default authentication algorithm is a keyed-MD5 in prefix + suffix

mode The result of the authentication is thus a 12 8 bit message digest

transmitted in the authentication extension


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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

authenticationextension


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Firewalls and packet filteringproblems (1)


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Firewalls and packet filteringproblems (2 )

Ingress filtering is often applied in the border gateway of acorporate network playing the role of a firewall

This prevents Mobile Node generated datagrams to reach theInternet coming from the Visited Network

Solutions Send datagrams with Source Address=Care-of Address this

is a loosing proposition because it runs counter to thearchitecture

Send datagrams encapsulated in an outer IP header withSource Address=Care-of Address this is a better

proposition but the Correspondent Nodes are not required tobe able to do the decapsulation Encapsulated datagramsmay be sent to the Home Agent which sends them back to the

Correspondent Node this is a suboptimal solution on therouting standpoint

f


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Firewalls and packet filteringproblems (3 )

Correlated problem : the firewall on the Home Networkside 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 beaccepted

Otherwise, a protocol between the Home Agent and theFirewall may be necessary

Finally, a solution may consist in tunneling all such datagramsto the Home Agent which should play the role of a bastionhost and be attached to a DMZ for safety

l


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Datagram Tunneling

A Correspondent Node sends datagrams to a Mobile Node withthe Destination Address field containing the Mobile Nodes Home

Address Based on the destination address, these datagrams reach the

Home Network There, theHome Agent intercepts the datagrams and

encapsulates them into an outer IP header that tunnels theinitial 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

Reminder : IPv4 header


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Reminder : IPv4 header format

IP-within-IP encapsulation


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IP within IP encapsulation

Theoriginal IP header remains unchanged when transmitted inthe tunnel (the TTL field is decremented) Source Address : Correspondent Node Address Destination Address : Mobile Nodes Home Address

Thenew IP header has :

Source Address : Home Agent Address Destination Address : Care-of Address Whenfragmentation is needed, it should be done at the inner IP

datagram level otherwise the fragments wont transport the MobileNodes Home Address used at the Foreign Agent to send thedecapsulated datagram on the right data link

Minimal encapsulation


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Minimal encapsulation

S indicates the presence of the Original Source Address field Minimal encapsulationlimits the number of supplementarybytes necessary for tunneling

It prevents however from performing fragmentation

S f T l S


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Soft Tunnel State

It is interesting to maintain at the Home Agent level (the entrypoint

of the tunnel) a number of parameters on the state of eachestablished 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 thenrelay ICMP error messages to theCorrespondent Node source of the tunneled datagrams

Typically,ICMP host unreachable messages are sent back totheCorrespondent Node when the datagrams are not delivered

throughthe tunnel

Plan


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Plan






Enhanced functionnalities


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Enhanced functionnalities

Optimisation du routage Smooth handoff

Routing optimisation


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Routing optimisation

Goal: Avoid triangle routing Idea:

Tell the correspondents the currentposition of the mobilenode

Problem: Change the correspondent's IP stack

T i l R i


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Triangle Routing

R t ti i ti (1)


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Route optimization (1)

The basic Mobile IP mechanisms create aTriangle Routingbetween the Correspondent Node, the Home Agent and the

Mobile Node. This Triangle Routing isfar from being optimal especially inthe case of a Correspondent Node very close to the Mobile

NodeRoute optimization consists of eliminating this problem

This is done by updating the Correspondent Node giving it themobility binding (Home Address, Care-of Address) of the

Mobile Node

For security purposes, it is theresponsibility of the HomeAgent to send the mobility binding to the CorrespondentNodes that need them

R t ti i ti (2 )


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Route optimization (2 )

Correspondent Node

R t ti i ti (3 )


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Route optimization (3 )

Binding updates are authenticated by a routeoptimization

authentication extension (same as for the Mobile-Home

authentication extension) Route optimization offers an efficient routing technique

butsupposes that the Correspondent Nodes are able to

implement the route optimization protocol

This may be the main reason why this mechanism hasnot yet

been definitively adopted as an RFC

H d ff


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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 (avoidlosses and retransmissions)

Protocol: The mobile registers with the new FA and tells theaddress of its

old FA The new FA sends a BU to the old FA so that it

forwards thepackets to the new location of the mobile

Smooth Handoff


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(1)

Correspondent Node

Smooth Handoff


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(2 ) During the handoff, it is important that the datagrams intended to theMobile Node and received by the previous Foreign Agent not be lost Asmooth handoff may be obtained if the previous Foreign Agent

receives a binding update with the new Care-of Address of the MobileNode allowing it to relay the datagrams to the new Foreign Agent This is best achieved if it remains alocal mechanism between the

Mobile Node and both the current and previous Foreign Agents (theHome 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 securityassociation be established between the Mobile Node and the Foreign

Agents

Smooth Handoff


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(3 )

Correspondent Node

Smooth Handoff


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(4 ) If the previous Foreign Agent does not hold the new mobility bindingfor the Mobile Node, it maysend back the decapsulated datagram

to the Home Agent . This may createrouting loops if the Foreign Agent has lost the traceof the Mobile Node and the Mobile Node is not connected elsewhere

The Foreign Agent shouldre-encapsulate the decapsulated

datagram into a Special Tunnel getting it back to the Home Agentwith 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 thedatagram or not thus avoiding routing loops

Plan


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Plan



Dcouverte dagent

Enregistrement TunnelageFonctionnalits avances

Micro-mobilitSupport de mobilit fourni par IPv6

Mobile IP & 3GConclusion

Micro mobility: Diffrents


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ytypes de mobilit

Micro mobility


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Micro mobility

A mobile has to register with its HA everytime it moves

Macro mobility (Mobile IP)

Micro Mobility (Hawaii, Cellular IP ) Smaller cells + more mobiles => need to

ditinguishmicro/macro mobility

The mobile registers with the HA when itmoves to a new mciro mobility domain

Micro mobility IP


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Micro mobility IP

Fonctionnement en mode paquet Diffrence par rapport aux autres rseaux cellulaires publics GSM, UMTS, CDMA2 000 : interfaces radio majoritairement en

mode circuit Universalit du protocole IP

Infrastructures rpandues dans le monde entier Micromobilit : va devenir une donne primordiale des rseaux

Protocole de micro mobilit = complmentaire d'IP mobile Macromobilit : possibilit pour un utilisateur de quitter son rseaud'abonnement pour se rendre dans un autre domaine du rseau IP

Adresse temporaire dans le nouveau domaine Enregistrement auprs de l'agent local de sa zone

d'abonnement Gnration d'un temps de latence

change de nombreux messages de signalisation Micro mobilit : mobilit locale Transparente pour le rseau d'abonnement de l'utilisateur

mobile

Micro mobility


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Micro mobility

Macro / Micro mobility


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Macro / Micro mobility

Solutions de micro mobilit


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Enregistrements rgionauxHMIP

Cellular IP Hawaii

Regionalized registration (1)


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Regionalized registration (1)

Regionalized registration (2 )


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Regionalized registration (2 )

Regionalized registration is a solution to thereduction of theregistration traffic between a Home and a Visited Network over theInternet in order to update the mobility binding of the Mobile Nodes

The idea is to construct ahierarchy of Foreign Agents , each FAregistering a Care-of Address for the Mobile Node at its father FA levelMultiple 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 registrationshould only be sent to FA4 and the tunnel FA4 FA7 would be replaced by

a tunnel FA4 FA8 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 wouldbe replaced accordingly



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Enregistrements rgionaux HMIP

Cellular IP Hawaii

HMIP: Hierarchical Mobile IP


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HMIP: Hierarchical Mobile IP

Problem: a mobileregisters with its HAevery time it moves

Goal: reduceregistration time by

using regional

registrations

HMIP: Registration(1)


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HMIP: Registration(1)

HMIP: Registration(2 )


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HMIP: Registration(2 )

HMIP: Routing


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HMIP: Routing

HMIP: Ericsson(1)


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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 upbetween the FAs


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Cellular IP Hawaii

Mobile / IP cellulaire


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IP cellulaire n'intervient que sur le rseau d'accs Aucun routeur du rseau de c ur n'a conscience de l'existence d'IPcellulaire

Systme peu coteux l'installation car pas de modification pour les routeurs

Fonctionnement simple

Dfinition d'une passerelle ou GW (Gateway) Accs au rseau Internet Situe la racine du domaine : joue le rle d'agent tranger

Possde une adresse IP qui sert de COA (Care-Of Address) tous les visiteurs du domaine

la rception de paquets encapsules, la GW te l'en-tteadditionnel

IP cellulaire met en uvre des techniques qui lui sont proprespour transfrer le paquet vers le mobile adquat

Grce aux adresses IP permanentes

Cellular IP:principes


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Caches distribus Position des mobiles

Information de routage

IP cellulaire


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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 nodesareidentified with their home address

Architecture IP cellulaire


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Rseau d'accs contient des stations de base Couverture de microcellules (id GSM)

Couverture de picocellules, desservies par de petitesantennes dans des espaces privatifs

Souplesse de fonctionnement grce IP Mthode de transmission sur l'interface radio indpendantedes oprations lies au routage et la gestion de la mobilit

Dtection du passage d'une cellule une autre Diffusion priodique d'une signature de chaque station de

base : voie balise

Signal pilote servant mesurer la puissance du signal radiomis par chaque station de base Stations de base cbles de manire hirarchique

Sommet = racine du domaine = passerelle



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Oprations dans le rseau


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Oprations dans le rseau

3 oprations principales Paging

Localisation d'un utilisateur lors de l'arrive de paquets destination Routage

Acheminement des paquets vers l'utilisateurs travers lesprincipaux lments du rseau d'accs Handoff

Gestion des dplacements de l'utilisateur via le rseau d'accs IP cellulaire se comporte comme un systme sans fil

Les terminaux choisissent toujours la station de base qui diffuse lesignal pilote le plus puissant

Handoff : changement de station de base Mise jour de tous les RC lorsque la route est nouvelle

Objectifs de Cellular IP


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Objectifs de Cellular IP

Migration facile Bonne connectivit

Support du soft handoff Passage lchelle avec une complexit

minimale

Cellular IP


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Cellular IP

Rseau distribu Les noeuds ne connaissent pas la

topologie

Pas de base de donnes centralise Bon passage lchelle

Cellular IP


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Cellular IP nodes do not know the exactlocation of a

mobile

Hop by hop routing IP addresses are mapped to ports on

Cellular IP

nodes Soft state mappings

Mappings


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Paging cache/Routing Cache

tat de l'utilisateur


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tat actif Utilisateur en train d'envoyer ou de recevoir des paquets Initialis la suite d'un paging ou d'une demande d'mission

Position du terminal dtermine la cellule prs tat oisif (ou idle)

Permet de rduire la signalisation sur le lien radio L'utilisateur peut rester attach au rseau d'accs tout en tant

inactif Localis dans un groupement de cellules

Permet d'accueillir un grand nombre de visiteurs dans unmme domaine

Pas d'enregistrement chaque passage dans chaque cellule Si un utilisateur oisif reoit des paquets, on s'appuie sur unpaging

l'initiative du n ud cherchant localiser l'utilisateur

Localisation dun utilisateur


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2 exigences pour la russite d'une localisation Laisser toute la libert un terminal oisif Ne pas le contraindre se signaler

Mettre en uvre un mcanisme optimal pour atteindre le

terminal oisif un cot moindre lorsqu'il devient actif 2 procdures employes pour rpondre ces besoins

Enregistrement de la localisation de temps autre encas

d'activit Cache de routage ou RC (Routing Cache)

Emploi de paging en cas d'oisivet Cache de paging ou PC (Paging Cache)

Caches de paging


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Libert 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 installs dans certains n uds ou stations debase

Connaissance partielle de la localisation des mobiles Complte par le paging

Mise jour des Paging Caches Par l'envoi vers la racine d'un paquet vide : paging-update

Paging-update transmis de manire priodique

Identification d'un terminali if


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oisif

Caches de paging


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Cache de routage


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Permet d'acheminer le flux de paquets versl'utilisateur Routage saut par saut (hop by hop)

Enregistrement du chemin l'initiative de l'utilisateur Lorsqu'il envoie un paquet vers la racine, tous les n uds

intermdiaires retiennent le chemin pour l'utiliser en sensinverse

Si l'utilisateur cesse son activit rseau Possibilit de se maintenir dans les RC

Transmission de paquets vides : route-update, vers laracine

Sinon, effacement sur temporisation

Routage


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Route discovery


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y

When the mobile receives PP, it sends a Route-Update Packet tothe base station F which forwards it towards GW

All the RCs on the route are updated

Downlink routing


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If there is no PC on the GW: GW buffers the packet

GW sends a Paging Packet with themobile's id

If the nodes have paging caches, hopby hop routing,

otherwise, the packet is broadcast


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Handoff


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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 anew route

The packets are send to the old and newBS during acertain time

Summary


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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



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Cellular IP Hawaii

Hawaii


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Hawaii


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Routing Update ( 1)


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Routing Update ( 2 )


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Hawaii


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Plan


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Fonctionnalits avancesMicro-mobilit

Support de mobilit fourni par IPv6Mobile IP & 3G

Conclusion

IPv4 vs IPv6


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Mobile IPv6


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IPv6 mobility relies on: New functionnalities in IPv6 A native support of mobility

A global and unique IPv6 address is assignedto each

mobile node: the Home Address This address identifies the mobile

A mobile is able to communicate directly withmobile

nodes (no triangle routing)

Main functionnalities in IPv6


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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 (RoutingHeader) TheHA must

Be a router on the mobile's home network Intercept the packets on the home network

Tunnel (IPv6 encapsulation) these packets directlyto the mobile

Reaching the mobile


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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 subnetworksprefix

Combination of this prefix with the MAC address Movement detection is also accomplished with

Neighbor Discovery procedures

Multi-homing

IPv6 Destination options


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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 willsoon expire

Binding Acknowledgement Sent by the HA. Acknowledges a BU containing the COA Home Address

Included in every IPv6 packet from the mobile to itscorrespondent

The packet is supposed to be originated from the home networkand not the visited network

Uses 1 44 bits in the header of every packet

management


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Every time a mobile moves it sends aBinding Update (BU): The BU includes a lifetime

The mobile keeps a list of thecorrespondents towhich it sent a BU

The temporary address sent to the HA iscalled the

principal COA

The IETF model


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BU format


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message


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ACK message based on a destinationheader extension

Sent if the A bit is set in the BU sent by the mobile Also includes an authentication header

address


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Allows the correspondents to updatetheir bindings

Store the principal address of the mobile

IPv6 Nodesdli bili f h d


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Handling IPv6 mobility forces the nodes toimplement somefunctionnalities:

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

IPv6 routers


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At least one router on the mobile's homenetwork may actas a HA

A HA must:

Maintain a Binding table Intercept packets in the mobile's homenetwork

Encapsulate these packets and sendthem to the mobile's COA

HA discovery


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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 (1message/sec)

Send a BU (with the H bit set) to the anycastaddress of the HAs

IPv6 and mobility (1)


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IPv 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 awidely 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 theMobile Nodes directly to Correspondent Nodes very efficiently

This simplifies the smooth handoff procedure

IPv6 and mobility (2 )


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IPv and mobility ( )

Correspondent Node

Data mobility perspectives


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The Mobile IP architecture isbeing finalized at the IETFwith its basic mechanisms already terminated and someenhanced functionalities being added progressively Themarket opportunities for this architecture are huge

and should follow the explosive growth of bothcomputer/Internet industries on the one hand and mobile

telephony on the other hand Some work still has to be done however to integrate bothapproaches 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 aconsolidated network infrastructure trend for publicnetworks

HMIPv6


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MAP (Mobility Anchor Point) Minimizes interruptions due to handoffs

The mobiles use the MAP's IP@ asCOA

MAP receives the packets and deliversthem

to the mobile The access routers send the

HMIPv6


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The access routers send

the MAP's IPv6 @ in RAs The mobile may roam and

keep the same MAP

If the mobile changes itsMAP, it sends a new BU toits HA and correspondents

HMIPv6


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15 1IPv6 MobHAIPv6 MobCOA

PlanI t d ti


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Dcouverte dagent Enregistrement

TunnelageFonctionnalits avancesMicro-mobilit

Support de mobilit fourni par IPv6Mobile IP & 3G

Conclusion

MIP-UMTS standardizedhi


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architecture

MIP-UMTS other solutions(1/ )


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(1/2 )

MIP-UMTS other solutions( / )


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(2 /2 )

3 GPP Network ReferenceA hi R


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Architecture R5

Mobile IP in UMTS


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Data mobility perspectives


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The Mobile IP architecture isbeing finalized at the IETF

with its basic mechanisms already terminated and someenhanced functionalities being added progressively Themarket opportunities for this architecture are huge

and should follow the explosive growth of bothcomputer/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 aconsolidated network infrastructure trend for publicnetworks

Cours IP Mobile

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Transcript of Cours IP Mobile