General IP Based Mobility Mechanisms

Belghoul Farouk Christain Bonnet

Yan Moret

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Introduction

Today Many Heterogeneous Radio Access Technologies coexist

Typically They are not compatible with each

others

Internet Protocol as Common network layer

4th Generation, ALL-IP wireless and Wireline

network

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IP Mobility Management, definition

Goal: Continuous TCP or UDP connection even MN moves causes IP address changes

• MN move to change its point of attachment and reminds in the network

• MN can change its point of attachment and the network in the same time

Mobile IP process• Location management..??

– IP address is key that defines the Node and its location

• Handover management ( next slide)

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Mobile IPv4, a first proposal

Access Router

Foreign Agent

Home Agent Home network

Foreign network

MN

Internet

1

2

3 1. Connection and foreign agent discovery

2. FA attributes CoA to MN

3. MN registers its COA with HA.

Triangular routingControl traffic load in networkNo specify handover management mechanisms

Correspondentnode

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IP Handover

MN lost phy connections with

its old AR

MN get phy connection

With its new AR

MN process L3 Handover (Location update)

Physical handover

D : Global MN handover Delay

Time

L3 handover

Important issue in mobility management

Efficient way to Manage MN roaming from its Old Access point to the new one.

Handoff management, caused by• signal strength deterioration• user mobility

Old Access Point

Cell A Cell B

New Access Point

IP network

Old Local IP@

New Local IP@

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Mobile IPv4, handover Steps

MN loses the old link

MN obtains new Link

HA

MN gets new CoA & sends BU to HA

MN receives BU from HA (end of registration)

CN

nFA

MN

oFA

Time

MIP4 MIP4

Layer2 handover

L3 New location

registration

L3 new location détection

Dmip = + MIP4+ MIP4

Tmip = TCN,HA+THA,AR+Tradio

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Mobile IPv6

Access Router

Home Agent Home network

Internet

1

2

1. MN Connection , CoA auto-configuration 2. MN registers its COA with both HA and its CNs.

2

3

Correspondent node

CN Binding update avoids triangular routing.No tunneling on MIPv6.Address stateless auto configuration : suppression of FAsIpv6 : enough IP addresses available.Long handoff delay,

MN

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Mobile IPv6

MN loses the old link

MN obtains new Link

HA

MN auto configure its new CoA

MN finish registration with HA and CNs

CN

nAR

MN

oAR

Time

MIP6 MIP4

Layer2 handover

L3 New location

registration

L3 new location détection

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Fast Handover

nAR

MN loses the old link

MN obtains new Link

MN auto configure its new CoA & BU

Layer2 Handover

// L3 handover

HA

CN

MN

oAR

Time

Reduces the handoff delay.Predicts L2 handover to anticipate L3 handover

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Fast handover

5b. MN changes AR

OAR

6. Informs its arrival and

start registration

process

Fast handover, bicasting

NAR

Agent solicitation/advertisement2. MN initiates

Fast handovers

RtSolPr

Reduces the handoff latencyNew L3 Care-of address establishment before the L2 movementIt is based on L2 triggers ( L2 triggers: information on MN L2 connection)

5a. Packets forwarding

7. Packets sent to mobile

1.MN receives L2 triggers to initiate

handover

3. OAR send PrRtAdv:

NAR Subnet @ the MN

4. FBU

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Fast handover , data transmission

oAR

MN

oAR

CN

Time

L2 triggers allows MN to obtain NAR IPv6 prefix

MN loses old link

MN obtains new CoA

MN connects to the new link

oAR forwards packets to NAR

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Fast handover,

Disadvantages:Fast Handoff aims to reduce the handoff latency by using interaction between the radio and IP layers to detect the mobile movements. This can work only if the radio technology allows such interaction between layers.( its not solution for heterogenous wireless network)The packet loss during the handover is * Thp.The handoff process performances, depend of wireless network Radio technologies, it can make problems when mobile node perform roaming between heterogeneous network

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Mobile-IPv6 Soft handover, In order to manage Efficiency mobility across heterogeneous radio access technologies The development of Mobile devices with multiple physical or software-defined interfaces is expected to allow users to switch between different radio accesses technologies In the border of coverage Area, Soft handover allows to improve the low signal level in wireless part of the network by the duplication and the merging of data in IP layer through more than one AR asynchronously, in uplink and downlink.IPv6 Soft handover Solution coexist with MIPv6 and can allows high level of QoS for real- time application.

Access router A

Cell A Cell B

Access Router B

Correspondent Home Agent

Internet

Sub network

Correspondent

WLAN

UMTS

AR1 AR2

Signal strength

Time

Access Router 1

Cell A

Cell B

Access Router 2

Overlapping Region

Bad signal quality

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SHO main process

Registration process

Duplication Process

Merging Process

Handover process

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Mobile registration process

Each mobile is defined by one or more Care of Address CoA.PCoA private CoA is used within MIPv6.LCoA are local addresses, used to define Mobile multiples connections.D&M agent associate PCoA with LCoAs in order to duplicate MN designated packets.The Mobile also duplicate packets to send them throw its multiples ARs to its CN.

Access router A

Cell A

IP Mobile Node

Cell B

Access Router B

D&M agent

Correspondent

Duplicated flows

IPv6 flow

PCoA

LCoA (A) LCoA (B)

Home agent

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Duplication Process

Duplication & Merging agent intercepts all IP packets sent to the MNExtracts destination PCoA, and uses registered corresponding MN LCoAs to duplicate MN designated packets via different Access Routers.Duplicated packets have LCoAs as new destination address .Insertion of merging and control information in all duplicated packets with a sequence number in each packet.Each duplicated packets had the same sequence number and same sender IP address .The MN does the same thing with uplink streams.

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Merging Process

Need to filter duplicated packets at MN and D&MDIO information of received packet are saved in MCT table ( merging control table)MCT table located in MN and D&M, it defines for each correspondent, its LCoA and serial numbers of expected IP packets.At the reception of packet, If the DIO is included and source address has an entry in MCT, and its serial number is not expected in MCT table The packet is discard.First received packet among duplicated packets, is routed to upper layer.

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Soft Handover Process

HA

IP radio

IP radio

D&M

TLC

Tunel 2

AR2

LCoA2

AR1

Merging process deactivated

System closes First MN connection

MN

(MN, PCoA)

LCoA1

PCoA

PCoA

LCoA1

LCoA2

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Handover Processinterface priority choice is dynamic

the primary interface is always the interface with the best connection quality The secondary interface is used to perform the handover and avoid signal strength degradation if possible Two signal strength thresholds are defined. Handover threshold (H_SH), is the threshold used in mobile IPv6 to initiate the handover. Primary threshold (P_SH) is higher threshold, it is used in soft handover to initiate the secondary interface connection process.

AR1 AR2

Handover threshold

primary threshol

d

Signal strength

Time

Access router 1

Cell A

Cell B

Access Router 2

D&M agent

Correspondent

Soft handover

limits

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Advantages of the approach (uplink - downlink)

UplinkNot covered by FHO bi-casting

DownlinkIf more than one link interface

• D&M covers the low signal level period plus the handover period.

• We have 2 chances to receive a packet– Reduces jitter as 1st packet arrives faster and 2nd

packet is destroyed– Divides by 2 the probability to loose a packet

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Where do we place D&M Agent?

In any conventional router located within the data path in the IPv6 network

Preferably located at a median position along the data communication path, between AR1 and AR2 and CN.Could be located in Access Routers.Possibility to distribute the load between several D&M Agents organized in a multilevel hierarchical architecture (see next slide)APs broadcast the address of their D&M agent using RADV.

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Hierarchical topology of D&M Agents

Access router A

Cell A

IP Mobile Node

Cell B

Access Router B

D&M agent

Correspondent

Duplicated flows

IPv6 flow

PCoA

LCoA (A) LCoA (B)

D&M agent

D&M agent

Home Agent

Internet

Sub network

D&M agent

LCoA (c)

LCoA (d)

Correspondent

WLAN

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Simulation model

R9 RaRb Rc

Rd ReR8 Rf

D&M agent

R1

R2

HA

Virtual network

2001::E1

CN

Application UDP :emission debit 1 mb/s

Application

UDP :reception

Virtual network

2001::E2

2001::E0

802.11 11Mb/s

100 m

2001::fa::1

2001::fa::2

We Implement MobileIPv6 with Soft and fast handover in Gemini2, a home made simulatorRadio technology: IEEE802.11b , at 11mb/s

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Simulations Results, delays and jitters

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Simulations Results, throughput

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Prototype Implementation

In Linux Kernel 2.4.19 Based on MIPL 0.9.3.Mobile with two WLAN IEEE802.11 interfaces.Support of Basic Mipv6 handover and Soft HandoverA modified RADVD to dynamically broadcast the presence and the address of D&M agent in the visited network.A support of Multiple DM agent without Hierarchical architecture.

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Testbed

fec0:106:2300::4WLAN AP3 (MURRET)

fec0:106:1300::1fec0:106:2300::3

WLAN AP2 (HECKEL)

fec0:106:1200::1

fec0:106:2700::2Duplication & Merging

Agent (JECKEL)fec0:106:2300::1

Mobile Terminal2 Radio Interfaces

(Radio3)

Correspondent Node

fec0:106:2300::2WLAN AP1

(Radio4)

fec0:106:1100::1

IPV6 subnet 2fec0:106:1200::/64

IPV6 subnet 3fec0:106:1300::/64

IPV6 subnet 1fec0:106:1100::/64

IPv6 Network

IPV6 subnet 5fec0:106:2300::/64

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Testbed2

IPV6 subnet 5fec0:106:2300::/64

IPV6 subnet 3fec0:106:1100::/64IPV6 subnet 1

fec0:106:1200::/64

IPV6 subnet 2fec0:106:1300::/64

WLAN AP2 (MURRET)

WLAN AP1 (HECKEL)

fec0:106:2700::2Duplication & Merging

Agent (JECKEL)fec0:106:2300::1

Mobile Terminal2 Radio Interfaces

(Radio3)

Correspondent Node

WLAN AP3(Radio4)

Home IPV6 subnet

fec0:106:2700::/64

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Conclusion and future work

Solution to manage pure IP mobility in heterogonous network

no handoff effects on real time applicationImproves wireless connexion in overlapping regionImproves MIPv6 micro mobility (Transparency of the MN’s mobility to CNs and HA).Reduces the « ping-pong effect »

Cohabite this solution with QoS mechanisms..?Introduce Checksum to reconstruct two erroneous duplicated packets….?

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Related Publication

“Eurecom IPv6 soft handover “, ICWN 2003, International Conference on Wireless Networks- June 23rd - 26th, 2003 - Las Vegas, USA.“IP-based handover management over heterogeneous wireless networks “, LCN 2003, 28th Annual IEEE Conference on Local Computer Networks, October 20-24, 2003, Bonn, Germany.Journal paper : “Mécanismes de handover pour les réseaux IP sans-fil’ to appear in Technique et Sciences Informatiques, Revue des sciences et technologies de l'information.( TSI journal) . To appear in January 2005.“A Multilevel Hierarchical topology of DM agents for MIPv6 Soft handover »,   World Wireless Congress  SANFRANCISCO, USA 2004 « Performance comparison and analysis on MIPv6, fast MIPv6 bi-casting and Eurecom IPv6 soft handover over IEEE802.11b »     IEEE VTC, MILAN 2004 .“Performance analysis on IP- based soft handover across ALL-IP wireless networks »   IWUC, PORTO, Portugal 2004