ip-based mobility and handover optimization (t3)wcnc2011.ieee-wcnc.org/tut/t3.pdf · ip-based...

IP-based Mobility and

Handover Optimization (T3)

Tutorial Authors:H. Anthony Chan, Ph.D.

Huawei Technologies, USA

[email protected]

Ashutosh Dutta, Ph.D.

NIKSUN Innovation Center, NJ, USA

[email protected]

Presented by Ashutosh Dutta

IEEE WCNC 2011Cancun, Mexico

– A name identifies what you want,

– An address identifies where it is,

and

– An route identifies a way to get there

John Shoch, 1978

Outline• Overview of Mobile Wireless Internet

• Mobility Taxonomy

• Systems modeling of mobility event

• Functional components of mobility event

• Overview of Mobility Protocols– Cellular Mobility Protocols

• GSM, IS-41, WCDMA, CDMA2000, LTE

– IP-based Mobility Protocols• MIPv4, MIPv6, ProxyMIPv6, HIP, SIP, DSMIPv6, DMM

•Handoff Optimization Methodologies– Optimization of mobility functions

– Optimization Models

Outline (contd.)• Applicability of Optimization Techniques to different Mobility Protocols

– L2 and L3 Discovery

– L3 Configuration Delay

– Network Detection Delay

– Authentication

– Security Association

– Route Optimization

– Hierarchical binding update,

– Redirection of in-flight data

– Small group multicasting

– Buffering and Copy-Forwarding Technique

• IEEE 802.21 Multi-interface Mobility – Media Independent Handover Functions (MIHF)

• Optimized Handoff Systems (Case studies)– Media Independent Pre-authentication– Multimedia Session Continuity in IMS-based systems– Multicast mobility

• Deployment roaming scenarios

• Petri net based mobility models

• Rules of mobility optimization

• Conclusions

L3 Attachment PointRAP

R

RR

AP

AP

AP

AP

AP

R

Domain

Router

R

RR

RR

Domain

Router

R AP

AP

AP

R

CH

AP

AP

AP

R

RR

AP

AP

AP

AP

AP

R

Domain

Router

R

RR

RR

Domain

Router

RAP

AP

AP

R

MH

AP

AP

AP

CORE

Router

L2 Attachment Point

CORE

Router

An abstract view of mobility

Abstract view of Host Mobility (Terminal Mobility)

A

B

C

Process

SOCKET

End-PointLocator

Process

SOCKET

End-PointLocator

X

Y

Z

PATH

NODE A NODE B

Process

SOCKET

End-PointLocator

Process

SOCKET

End-PointLocator

A

B

C

X

Y

W

PATH

NODE A NODE B

Node B moves

Application T

Application T

Process

SOCKET

End-PointLocator

Process

SOCKET

End-PointLocator

X

Y

Z

PATH

Host A Host B

Process

SOCKET

End-PointLocator

Process

SOCKET

End-PointLocator

A

B

D

X

Y

W

PATH

NODE A NODE B

Nodes A and B

Both move

Application T

Application TA

B

C

As an example

End-Point, Locator could be an IP address

Trajectory of a Packet (Source-Destination)

Source

PCM sample

CompressedpacketT1

T2

T3

T4

T5

T6

T7VoIPPacket (Application)

Receiver

Total E-E delay = ∑T i

Transmission+ Handoff

T1 = Encoding Delay

T2 = Packetization Delay

T3 = Transmission Delay

T4 = Handoff Delay

T5 = Jitter buffer delay (mobile)

T6 = De-Packetization delay

T7 = Decoding Delay

P1

P1

PN

T4 = 0

P1

T6

T7

P1

P1

P1PN

PN

PN

T5

Total Packet Loss = PN – P1

Time Nohandoff

Handoff

LostPackets

VoIPPacket

No handoff

Handoff

42 Mb/s (DL),

22 Mb/s (UL)

CDMA2000

NX

TACS

NMT

AMPS

SMR

GPRS EDGEGSM

IS-136

IS-95 (A)

iDEN

PDC

IS-95 (B)CDMA2000

1X

WCDMA

1 G 2 G 2.5 G 3 G 4 G

144 kb/s, 384

kb/s, 2 Mb/s

144 kb/s, 384

kb/s, 2 Mb/s

JTACS

54 kb/s 236 kb/s

144 kb/s

50 UL, 100 DL

9.6 kb/s

9.6 kb/s

48.6 kb/s

42 kb/s

NTT

24 kb/s

IEEE 802.16

802.20

EHSPA

UMB

LTE

80 Mb/s (UL), 360 Mb/s

280 Mb/s

80 Mb/s

115 kb/s

1980 1990 19952000

2008

Evolution of mobility protocols

Cellular Access CharacteristicsGeneration System Channel

spacing

Access type Uplink data

rate

1G AMPS 30 kHz FDMA N/A

TACS 25 kHz FDMA N/A

NMT 25 kHz FDMA N/A

NTT 25 kHz FDMA N/A

2G GSM 200 kHz TDMA 9.6 kb/s

PDC 30 kHz TDMA 42 kb/s

IS-136 30 kHz F/TDMA 48 kb/s

IS-95 (A) 1.25 MHz F/CDMA 14.4 kb/s

iDEN 25 kHz F/TDMA 24 kb/s

2.5G GPRS 200 kHz TDMA 45 kb/s

EDGE 200 kHZ TDMA 236 kb/s

IS-95 (B) 1.25 MHz F/CDMA 115 kb/s

CDMA2000 1X 1.25 MHz CDMA 144 kb/s

3G UMTS/WCDM

A

5 MHz CDMA/TD

MA

2 Mb/s

CDMA2000

1xEV-DO

1.25 MHz CDMA 2 Mb/s

4G LTE 20 MHz OFDMA 50 Mb/s

WiMAX 2.5 GHz OFDM 40 Mb/s

UMB 5 MHz OFDMA 75 Mb/s

MH

nPoAoPoABTS A

MSC

BSC 1

Serving

Cell

BSC 2

Target

Cell

VLRAUC

Move

EIR

BSS

nPoA nPoA

HLR

Cellular mobility – GSM – an example

BTS B BTS CBTS D

HLR – Home Location RegisterMSC - Mobile Switching Center

AUC – Authentication CenterBSC – Base Station ControllerBSS – Base Station SystemBTS – Base Transceiver StationEIR – Equipment Identity Register

VLR – Visitor Location Register

GSM Mobility

BSC

MSC

MS

BTS BTS

OLD NEW

Switching Point BSC

MSC

MS

BTS BTS

OLD NEW

Switching Point

BSC

OLD

OLD

NEW

NEW

Switching Point

BSC

MSC

MS

BTS BTS

OLD NEW

BSC

MSC

OLD

OLD

Anchor MSC Relay MSC

Switching Point

BSC

MSC

MS

BTS BTS

OLD NEW

BSC

MSC NEW

NEW

Relay MSC Relay MSC

MSCAnchor MSC

NEW

NEW

Switching Point

BSC

MSC

MS

BTS BTS

OLD NEW

BSC

MSC

OLD

OLD

Relay MSC Anchor MSC

Old Path

New Path

1. Intra BSC Handover 2. Inter BSC/intra-MSC Handover

3.Inter-MSC handover (anchor-to-relay)

4. Inter-MSC handover (relay-to-relay)

5. Inter-MSC handover (relay-to-anchor)

MH

nPoAoPoA

CDMA

BTS A

MSC

BSC 1

Serving

Cell

BSC 2

Target

Cell

HLR

Move

SMS-SC

CDMA

BTS B

AC

VLR

EIR

External

Network

PSTN

and

ISDN

IS95 (2G)IS95-based architecture

IS-41 Handoff (Mobile Assisted Handoff)

Serving

BS/MSC

Target

BS/MSC

Mobile

StationPilot Strength

Measurement

Message

(T_ADD)

Pilot Strength

Measurement

Message

(T_COMP)

Facilities Directive INVOKE

Facilities Directive

Return RESULT

Handoff Direction Message

Handoff Completion Message Mobile On-Channel

INVOKE

Searches

for Pilot (discovery phase)

Resource

Assignment

MH

nPoAoPoANode B

MSC/VLR

RNC1

Serving

Cell

RNC2

Target

Cell

HLRGGSN

Move

SGSN

RNS1

nPoA nPoA

GMSCPSTN/

ISDN

IP

Network

L3 PoA

RNS2SGSN

WCDMA architecture

Mobility State Model for GPRS/UMTS

IDLE READY STANDBY

GPRS

Attach

GPRS Detach/

RAU Reject/

GPRS Attach

Reject

READYTimer expiryForce to Stanbdy

PDU

transmission

PMMDETACHED

PMMIDLE

PMMCONNECTED

PS Attach PS SignalingConnectionRelease

PS SignalingConnectionEstablish

Implicit PS Detach

1. MS MM States for GPRS2. MS MM States for UMTS

IDLE READY STANDBY

GPRS

Attach

GPRS DetachRAU ReadyGPRS Attach Reject


PDU

Reception

PS Detach

RAU Reject

PS Attach Reject

PMMDETACHED

PMMConnected

STANDBY

PS

Attach

GPRS DetachRAU ReadyGPRS Attach Reject


PS Signaling

Connection Establish

PS Detach

RAU Reject

PS Attach Reject

Cancel Location

PS

Detach3. SGSN MM States for GPRS

4. SGSN MM States for UMTS

GPRS UMTS

Home Agent

BSC1 BSC2 BSC3 BSC4

PCF1 PCF3 PCF4

PDSN2PDSN1

PCF2

FA1FA2

MSC

PSTN

GMSC

HLR

AC

A B CD F

BTS1

E

L3 PoA L3 PoA

L2 PoA BTS3 L2 PoA

VLR

CDMA2000 architecture

Mobility State Model for CDMA

DORMANT

NULL/

INACTIVE

ACTIVE/

CONNECTED

MS Powers off

MS Powers ON

MS Powers off

Packet Data Inactivity,

Timer Expires

MS or network initiates packet

call reactivation

Source

eNB

Target

eNBCandidate

eNB

MME

Serving

Gateway

(S-GW)PDN-GW

UEUE

UE

SGSN

E-UTRAN

IP-basedIMS

network

Enhanced Packet Core (EPC)

UEUE

ePDG

Untrusted

Non-3GPP

Trusted

Non-3GPP

(WiFI, WiMAX)

UTRAN

SAE/LTE (4G)

HSSPCRF

SGiS5

S11

S1-U

S1-MME

S4

S7

S6a

S3

S2a

S2b

AAA

S6c

Wm

Wn

PCEP

Rx+

Wx

S10

X2

X2 X2

MME S-GWUE Source

eNBTarget

eNB

Data packets

Measurement

report

Handover request

Handover AckRRC

Reconfigure

Detach old

and

Sync new

Buffering

for

forwarding

Data forwarding

Buffer source

eNB packets

RRC Reconfiguration complete

Path switch

request

Modify bearerEnd-of-marker packets

Stops

forwarding

data

Status Transfer

UE context releaseModify bearer ACK

Path switch

Request ACK

Switch

DL

path

Release

resource End of marker

New Data packetsData packets

SAE Handoff

What are Characteristics of Next

Generation Networks?• Heterogeneous networks, many access networks

– Access-independent converged IP network

• Order-of-magnitude increases in bandwidth

– MIMO, smart antennas

– Increase in video and other high bandwidth traffic

• New terminals

• New services and service enabling platforms

• Large range of cell sizes, coverage areas

– PAN, LAN, WAN

– Pico-cellular, micro-cellular, cellular

• Changes in traffic and traffic patterns

– Rise in video on demand? Requires good high-bandwidth

multicast

One Vision of 4G

IP-BasedCore Network

Media Access SystemMedia Access System

Cellular(2G)

Cellular(2G)

Packet-Based

(2.5G)

Packet-Based

(2.5G)

IMT-2000(3G)

IMT-2000(3G)

WLANType

WLANType

New RadioInterface

New RadioInterface

Services &ApplicationsServices &

Applications

Fixed

Wireless

Fixed

Wireless

Services &ApplicationsServices &

Applications

Mobile Wireless Internet: A Scenario

802.11a/b/g

Bluetooth

IPv6

Network

UMTS/CDMA

Network

InternetDomain1

Domain2

UMTS/

CDMA

PSTN gateway

Hotspot

CHRoaming

User Ad Hoc

Network

PAN

LAN

WAN

WAN

LAN

PSTN

802.11 a/b/g

Backbone

Administrative

Domain B

L2 PoA

Corresponding

Host

128.59.10.7

IPch

207.3.232.10

210.5.240.10

128.59.11.8

N2

N1N1

N2

N1- Network 1 (802.11)

N2- Network 2 ( CDMA/GPRS)

Configuration

Agent

L3 PoA

207.3.232.10

MobileHost

AuthenticationAgent

Authorization Agent

RegistrationAgent

RegistrationAgent

Administrative

Domain A

Configuration

Agent

Authorization Agent

SignalingProxy

AuthenticationAgent

SignalingProxy

Layer 3

PoA

L2 PoALayer 2

PoA

Layer 2

PoAL3 PoA

Mobility Illustration in IP-based 4G network

128.59.9.6

L3 PoA

A

B

CD

900 ms media interruption

802.11 802.11

h/o delay900 ms

802.11 802.11

4 Seconds media interruption h/o delay 4 s

Handoff Delay~ 18 s

802.11 CDMA

18 Seconds media interruptionh/o delay18 s

23

Non-optimized handoff results

Handoff between heterogeneous access(802.11 – CDMA)

Handoff between homogeneous access(802.11 – 802.11)

c. SIP-based non-optimized

handoff between 802.11 networks

802.11 802.11Handoff

Delay 4 s

Handoff Delay

~ 18 s

802.11 CDMA

Handoff Delay

16 s

802.11 CDMA

a. MIP-based Non-optimized handoff

b. SIP-based Non-optimized handoff

Performance Degradation – Non-optimized

Handoff

Mobility TaxonomyIP Mobility

PersonalTerminal Service

Application

Layer

Network

Layer

Session

• Systems

Optimization

MIPv4 Cellular IPHAWAIIIDMP MIP-LR MIPV6ProxyMIPv6

SIPMM

MIP-LR(M)

Proxy

Transport

Layer

MSOCKS,

Migrate

mSCTP

Shim Layer

HIP

Issues

• Host controlledvs.

Mobile Controlled

• Mobility pattern

Several concepts of mobility• Terminal mobility, e.g., supported by Mobile IP

IP-based Network

CH

Subnet 1MH

Subnet 2

IP-based Network

CH

Subnet 1

MH

Subnet 2• Typically, you don’t

just have terminals

– Users/Persons

– Sessions

• Mobility of users, sessions?

Personal Mobility: Registration

IP-based Network

CH

Subnet 1

Subnet 2

registrar

IP-based Network

CH

Subnet 1

Subnet 2

registrar

• When lady in red moves, she

– leaves her laptop behind

– Uses another machine

– Logs in

• User registration performed

[email protected]

[email protected]

Personal Mobility: simultaneous

registration of multiple bindings

IP-based Network

CH

Subnet 1

Subnet 2

Registrar

& proxy

IP-based Network

CH

Subnet 1

Subnet 2• When lady in red moves,

she

– leaves her laptop

behind

– Uses another machine

• She can still be located

[email protected]

[email protected]

Registrar

& proxy

[email protected]

[email protected]

Session Mobility

IP-based Network

CH

Subnet 1

MH

Subnet 2

IP-based Network

CH

Subnet 1

Subnet 2

INVITE2

3

1

Service Mobility• Service Mobility allows a roaming user to get the same

view of the network as when he is at home

• At the time of registration

–User’s service profile is retrieved from the home

network

–The service profile is shared with the responsible entity

at home and in the foreign network (wholly or partially)

• The foreign network provides some of the service

required

• The home network still retains responsibility for other

services

• Examples of entries in the profile of interest may be

address book, call handling features, buddy lists, etc.

Key Functions Characteristics

Handoff • May take place between cell, subnet or domain

• Need to optimize the handoff delay and transient data loss ( e.g., end-to-

delay up to 200 ms, 3%-5% packet loss, jitter, for real-time VoIP traffic)

• May use soft-handoff feature of CDMA, but need fast-handoff mechanisms

for other technologies (e.g., 802.11)

• Need to support session based applications for TCP and RTP traffic

Configuration •Should be configured within few milliseconds

•Configures IP address and other server parameters (e.g, DNS, SIP server, Gateway)

Registration • Assist pre-session mobility

• Hierarchical nature will make the registration faster

• Helps location management functionality

Quality of Service

•Need to maintain same QoS during its subnet/domain movement

Location Management

•Allow user to maintain same URI irrespective of point of attachment

Technical issues for mobility management

Motivation for Handover Optimization• Mobility adds complexity to the wireless access

• Cellular-based mobility systems do not suffer from performance degradation

• IP-based systems contribute to performance degradation due to movement across access technologies, domains, and mobility at multiple layers

• Currently there are ad hoc solutions for IP mobility optimization, not engineering practice

– No formal methodology to systematically discover or

evaluate mobility optimizations

– No methodology for systematic evaluation of "run-time"

cost/benefit tradeoffs

Sample IP-based mobility protocols

ForeignSubnet

j.k.l

CH

HomeNetwork

HomeSIP Server

MH

Foreign/visited

network

Outbound

SIP server

2. INVITE

3. MOVED

6. Data

7. Move

1. REGISTER

3a. INVITE

4. OK

5. ACK

ForeignSubnet 2p.q.r

8. RE-INVITE/

RegisterRe-REGISTER

Re-INVITE9. Data

ForeignSubnet

j.k.l

CH

HomeNetwork

HomeSIP Server

MH

Foreign/visited

network

Outbound

SIP server

2. INVITE

3. MOVED

6. Data

7. Move

1. REGISTER

3a. INVITE

4. OK

5. ACK

ForeignSubnet 2p.q.r

8. RE-INVITE/

RegisterRe-REGISTER

Re-INVITE9. Data

ForeignSubnet 1

CH

HomeSubnet

HA

MH

foreign/visited

network

4b. binding update

(MH.IP->MH.COA2)

ForeignSubnet 2

1. REGISTER

2. Data

2a. Tunneled Data

3. Move

4. DATA<CH.IP, MH COA2)

ForeignSubnet 1

CH

HomeSubnet

HA

MH

foreign/visited

network

4b. binding update

(MH.IP->MH.COA2)

ForeignSubnet 2

1. REGISTER

2. Data

2a. Tunneled Data

3. Move

4. DATA<CH.IP, MH COA2)

Mobile IPv4

Application layer mobility (SIP)Proxy MIPv6

Mobile IPv6

ForeignSubnet 1

CH

HomeSubnet

HA

<CH.IP, MH.IP>

<MH.IP, CH.IP>

MH

<HA.IP, M

H.COA.IP<CH.IP

, MH.IP

>>foreign/visited

network1. Registration

ForeignSubnet 2

4. Re-registration

5. New tunneledData

3. Move

2a. Tunneled Data

2. Data

FA

Data

ForeignSubnet 1

CH

HomeSubnet

HA

<CH.IP, MH.IP>

<MH.IP, CH.IP>

MH

<HA.IP, M

H.COA.IP<CH.IP

, MH.IP

>>

<HA.IP, M

H.COA.IP<CH.IP

, MH.IP

>>foreign/visited

network1. Registration

ForeignSubnet 2

4. Re-registration

5. New tunneledData

3. Move

2a. Tunneled Data

2. Data

FA

Data

Data

Signal

CN

HA MN

R1

(PMA1)

R2

(PMA2)

5. PMIP Tunnel 1

11. PMIP Tunnel 2

AAA

Move

2. AAA Request/Reply

1. Access

Initiation

3. Proxy BU

4. AAA Query/Reply

4. Proxy ACK

7. Access

Initiation

6. Home Prefix

advertisement


9. Proxy BU

10. AAA Query/Reply

12. Home Prefix

advertisementHome

Network

Visited 1

Visited 2

CN

HA MN

R1

(PMA1)

R2

(PMA2)

5. PMIP Tunnel 1

11. PMIP Tunnel 2

AAA

Move


1. Access

Initiation

3. Proxy BU

4. AAA Query/Reply

4. Proxy ACK

7. Access

Initiation

6. Home Prefix

advertisement


9. Proxy BU

10. AAA Query/Reply

12. Home Prefix

advertisementHome

Network

Visited 1

Visited 2

Mobility/

Function

Access

Type

Network

Discovery

Resource

Discovery

Triggering

Technique

Detection

Technique

Configuration Key

exchange/

Authentic

ation

Encryption Binding

Update

Media

Rerouting

GSM TDMA BCCH FCCH Channel

Strength

SCH TMSI SRES/A3 DES MSC

Contld.

Anchor

WCDMA CDMA PILOT SYNC

Channel

Channel

Strength

Frequency TMSI SRES/A3

AES Network

Control

Anchor

IS-95 CDMA PILOT SYNC

channel

Channel

Strength

RTC TMSI Diffie-

Hellman

AKA

Kasumi MSC

Contld.

Anchor

MSC

CDMA

1X-

EVDO

EVDO PILOT

Channel

SYNC

Channel

Channel

Strength

RTC TMSI Diffie-

Hellman/

CAVE

AES MSC PDSN/MSC

802.11 CSMA/

CA

Beacon

11R

11R

802.21

SNR at

Mobile

Scanning.

Channel

Number,

SSID

SSID,

Channel

number

Layer 2

authentic

ate

802.1X

EAP

WEP/WP

A

802.11i

Associate IAPP

Cell IP Any Gateway

beacon

Mobile

msmt.

AP

beacon

ID

GW Beacon MAC

Address

AP address

IPSec IPSec Route

Update

Intermediat

ey

Router

MIPv4 Any ICMP

Router

adv.

FA adv.

ICMP

Router

Adv.

FA adv.

L2

triggering

FA adv FA-CoA

Co-CoA

IKE/PA

NA

AAA

IPSec MIP

Registratio

n

FA

RFA

HA

MIPv6 Any Stateless

Proactive

CARD

802.21

11R

Router

Adv.

Router

Prefix

CoA IKE/PA

NA

AAA

IPSEC MIP

update

MIP RO

CH

MAP

HA

SIPM Any Stateless

ICMP

Router

802.21

11R

L3

Router

Adv.

Router

Prefix,

ICMP

CoA

AOR

Re-Register

INVITE

exchange

/AAA

IPSEC/

SRTP/

S/MIME

Re-INVITE B2BUA

CH

RTPtrans

Abstraction of mobility functions

35

HandoverEvent

Network discovery &selection

Networkattachment

Configuration Securityassociation

Bindingupdate

Mediareroute

Channel

discoveryL2

association

Router

solicitation

Domain

Advertisement

Identifier

acquisition

Duplicate

Address

Detection

Address

ResolutionAuthentication

(L2 and L3)

Key

derivation

Identifier

update

Identifier

mapping

Binding

cache

Tunneling

Buffering

Forwarding

Bi-casting/

Multicasting

Server

discovery

Identifier

Verification

Subnet

discover

y

P1 P2 P3 P4 P5P6

P11

P13

P12

P21

P22

P23

P31

P32

P33P41

P42P51

P52

P53

P54

P61 P62

P63

P64

System decomposition of handover process

36

Handoff components of a Mobility Event• Network Discovery

– Discover the new networks around the current network• Resource discovery in the new network

– New frequency, QoS parameters• Network Selection

– Handoff decision to switch access networks

• Detection of new point of attachment– Detection at several layers

• Configuration of network identifier– Obtain new temporary connection Identifier (e.g. new IP address, )

• Authentication and authorization– Authentication of identity

• Security Association– Key derivation process between by the mobile upon every move results in signaling

exchange over the air – Processing delay at the end client

• Binding Update– Associate new network identifier for rerouting of data

• Media redirection– Rerouting of data from CN– Encapsulation/decapsulation– Buffering

Handover: Distributed operation across multiple layers

Time

L2PoA

L3PoA

Discovery Detection Configuration

SecurityAssociation

p11

p12

p21

p31

p32 p42

p41Server(Proxy,/HA)

p22

Binding Update

MediaRerouting

p51p31

p32

p41 p42

p42p63

p62

p13p23

p31

p33

MN

p11 p12 p21 p22p31 p41

p61p32 p42

p13 p23p33

p51

p51

p52

p52

CN

p42p52

p61p54

p53 p54

p61

p61p62

p64p51

Inter-domain Handoff Delay Analysis (example)

Operation

L2 Delay

L 2 Scanning

Association

L2 security

L3 Delay

Address Acquisition

DuplicateAddress Detection

ARPUpdate

Local Authentication

AAAProfile

BindingUpdate

Media RedirectionApplication

LayerDelay

-Reduce the handoff delay

-Reduce the packet Loss

Handoff Latency with associated Protocols (example)

AP1 AP2Next

Access

Router

Router Advertisement

DHCP server

PPP

DHCP/PPP

HA/SIP Server

Binding Update

CN

Media

New Media

Binds to AP1

Layer 2 Association

Dual mode

MN

Stateless Auto-configuration

AAA

DAD/ARP

AAA

Server

Layer 2 Security

VPN

VPN

GW

∆∆∆∆1- L2 Hand-over Latency Delay

∆∆∆∆2 – Delay due to

IP Address Acquisition and

Configuration, authentication, authorization

∆∆∆∆3 – Binding update and

Media Redirection delay

∆∆∆∆1

∆∆∆∆2

∆∆∆∆3

∆∆∆∆

∆∆∆∆ =T4

∆∆∆∆1

∆∆∆∆2

∆∆∆∆3

IGMP/RTCP

Mobility Event Systems Modeling with Distributed State (an example)

MN

L2PoA

L3PoA

CN

MobilityAgent

Discovery (Job1)

Detection (Job 2)

Configuration (Job 3)

Binding Update ( Job 5)

Job1 Job2 Job3 Job4

Time

j11

j12

j13

j13

j21

j22

j23j31

j31

j32

j42

j42

j44

j41

Server

j22

Job5 Job6

J53

J51

J51

J52

J61

J61

J62

Security Association (Job 4)

Media redirection ( Job 6)

j32

j31

j32

j43 j44

j41 j42 j43

j43

j42j31

j33 J53 J62

J63

J52

Case I: Mobility Event Systems Modeling with Distributed State (Security Optimization)

MN

L2PoA

L3PoA

CN

MobilityAgent

Discovery (Job1)

Detection (Job 2)

Configuration (Job 3)

Binding Update ( Job 5)

Job1+part of

Job4 overlapped Job2 Job3 Job4 reduced

Time

j11

j12

j13

j13

j21

j22

j23j31

j31

j32

j42

j42

j44

j41

Server

j22

Job5 Job6

J53

J51

J51

J52

J61

J61

J62

Security Association (Job 4)

Media redirection ( Job 6)

j32

j31

j32

j43 j44

j41j42

j43

j43

j42j31

j33 J53 J62

J63

J52

A layered approach to mobility

N

N-1

N-2

N-3

N-4

N-5

N-6

Mobile Mobile

N

N-1

N-2

N-3

N-4

N-5

N-6

MacroMicro

Mobile

N

N-1

N-2

N-3

N-4

N-5

N-6

N

N-1

N-2

N-3

N-4

N-5

N-6

Mobile

Inter-domain Move

N

N-1

N-2

N-3

N-4

N-5

N-6

Mobile

N

N-1

N-2

N-3

N-4

N-5

N-6

Mobile

Layers on the mobile Not Affected due to mobility

Layers on the mobile Affected due to mobility

Layers on the correspondent host

Micro Mobility

N

N-1

N-2

N-3

N-4

N-5

N-6

CH

N

N-1

N-2N-3

N-4

N-5

N-6

Mobile

t1 t2 t3

t1 = processing time in CH

t3 = processing time in Mobile

t2 = transmission time before movement

t3a = L2 reconfiguration+ processing time

t2a = new transmission time

N

N-1

N-2

N-3

N-4

N-5

N-6

Mobile

CH

Internet

AP1 AP2

Mobile

R

Mobile

N

N-1

N-2

N-3

N-4

N-5

N-6

CH

t1 t2a t3a

Old Data Path

New Data Path

L2 move

Domain 1

Subnet 1

Macro Mobility

N

N-1

N-2

N-3

N-4

N-5

N-6

Mobile

Mobile

N

N-1

N-2

N-3

N-4

N-5

N-6

CH

Internet

AP1 AP2

Mobile

R1

Mobile

R2

AP3 AP3

N

N-1

N-2

N-3

N-4

N-5

N-6

CH

t1 t3t2

N

N-1

N-2

N-3

N-4

N-5

N-6

CH

t1 t2b t3b



t2 = transmission time in static mode

t3b = (L2+L3) reconfiguration+ processing

time on the mobile

t2b = new transmission time

L3 move

Old Data Path

New Data Path

Domain 1

Subnet 1Subnet 2

R – Router

AP – Access Point

Inter-domain Mobility

N

N-1

N-2

N-3

N-4

N-5

N-6

MobileInter-domain Move

Mobile

N

N-1

N-2

N-3

N-4

N-5

N-6

N

N-1

N-2

N-3

N-4

N-5

N-6

CH

N

N-1

N-2

N-3

N-4

N-5

N-6

CH

t1 t2 t3

t1 t2c t3c

CH

Internet

AP1 AP2

Mobile

R1

Mobile

R2

AP3 AP3

Domain 1 Domain 2



t2 = transmission time in static mode

t3c = (L2+L3) reconfiguration+ processing

time on the mobile

t2c = new transmission time

Security

Security

Old Data Path

New Data Path

Inter-domain Move

Handoff Operation Across LayersHandoff

Operations

Layer 2 Layer 3 Application

Layer

Discovery Scanning Router

Advertisement

AAA Domain

Advertisement

Authentication Open Auth

EAPoL

IKE, PANA S/MIME

Security

Association

802.11i

4-way handshake

IPSEC TLS

SRTP

Configuration ESSID

Beacon

DHCP

Stateless

URI

(Universal Resource

Identifier)

Address

Uniqueness

MAC

Address

ARP

DAD

SIP

Registration

Binding update Cache

Update

Update CN,

HA

SIP

Re-INVITE

Media Routing IAPP Encapsulation

Tunneling, Forwarding, Bi-casting

Direct

Routing

Handover Taxonomy

Inter-subnet

Intra-subnet

Intra-tech &

Inter-domain

Intra-tech & Intra-domain

Inter-tech &

Inter-domain

Inter-tech &

Intra-domain

Intra-tech &

Intra-domain

802.11 (provider X) to CDMA (provider X)

802.11 (provider X) to CDMA (provider Y)

802.11b (provider X) to 802.11n (provider X)

802.11b (provider X) to 802.11n (provider Y)

Inter-tech & Intra-domain

802.11 (provider X) to CDMA (provider X)Some scenario could be homogeneous as well,

e.g., intra-tech & intra-domain

Multiple Interface Case (802.11b – CDMA1XRTT) – MIP as mobility protocol

802.11 802.11CDMAHandoff19 s

Single Interface Case (802.11b – 802.11b) – SIP as mobility

802.11 802.11Handoff

4 s

Handoff

17 s802.11 CDMA 802.11

Multiple Interface Case (802.11b – CDMA1XRTT) – SIP as mobility protocol

Effect of handoff delay during non-optimized mobility management (experimental results)

Mobility protocols in IETF working groups• DNA: Detecting Network Attachment

• Mip4: Mobility for IPv4

– deployment issues and an addressing known deficiencies and shortcomings in the protocol that have come up as a result of deployment experience

– AAA, enterprise environments, etc.

• MEXT (Mobility Extension) – recently formed– mip6

• Address issues related to MIPv6 inter-operability testing

• Modularize the MIPv6 specifications (route optimization, etc.)

• Dual stack MIPv6

– nemo: network mobility

• Security, routing issues for network mobility

– MONAMI6 (multi-homed)

– DMM – Distributed Mobility Management

• MOBOPTS: Mobility OPtimization– IRTF Research Group

• Netlmm : Network-based Localized Mobility Management– ProxyMIPv6

• mipshop: Mobility for IP: Performance, Signaling and Handoff Optimization

– Reducing overhead and handoff latency for MIPv6, using HMIPv6 and FMIPv6

• Seamoby (old): context transfer, handoff candidate discovery, and dormant mode host alerting

• 3GPP– VCC, MMSC

• IEEE 802.21• 3GPP2

Network Layer Mobility

Motivations• Internet originally designed for fixed nodes

• Routing

– Host-based is not scalable

– Hierarchical

• Assumes geographical/topological clustering of addresses

• Small routing tables

• Mobility

– When do we want to keep IP address?

– IP address for identity vs. routing

– Need two IP addresses?

IP-based Network

CH

HomeSubnet

MH

ForeignSubnet

Towards an IP Mobility Solution• Mobile Host – MH

–2 IP addresses

• MH.IP: original home address

• MH.COA.IP: foreign network care-of address, for

routing

• Home Agent

–In home network

–Has binding between MH.IP and MH.COA.IP

• Intercepts packets for MH.IP and re-directs them

• Foreign Agent

–In foreign network

–Handles foreign network aspects, e.g. un-encapsulation

• Tunneling concept

Mobile IP Basic Operations

IP-based Network

CH

HomeSubnet

HA

<CH.IP, MH.IP>

<MH.IP, CH.IP>

MH<CH.IP, MH.IP>

FA<MH.IP, CH.IP>

� CH to MH

� CH sends packet to MH home address as usual

� HA in home subnet intercepts packet, tunnels it to FA

� FA un-encapsulates packet, forwards to MH

� MH to CH

� Normal IP routing from foreign network

home

network

foreign/visited

network

Mobile IP Registration – FA mode

IP-based Network

HomeSubnet

HA

MH

FA

1. (optional) agent solicitation

2. Agent advertisement

3. MIP registration request


5. MIP registration reply


home

network

foreign/visited

network

12

364

5

ForeignSubnet

Mobile IP Basic Operations: with co-located

COA

IP-based Network

CH

HomeSubnet

HA

<CH.IP, MH.IP>

<MH.IP, CH.IP>

MH

� CH to MH


� HA in home subnet intercepts packet, tunnels it to COA of MH

� MH un-encapsulates packet, processes it

� MH to CH


home

network

foreign/visited

network

Foreign Subnet

Mobile IP Registration: with co-located

COA

IP-based Network

HomeSubnet

HA

MH

DHCP server

1. Obtain IP address in foreign/visited network, e.g. using DHCP



home

network

foreign/visited

network

23

Mobile IP Assessment

•Pros

–Overlay on IP

–Transparent to higher layers

• Applications don’t

need to be changed

–No changes needed in CH

• No awareness of

mobility needed in

legacy hosts

• Cons

– Routing efficiency

• Triangular routing

– Encapsulation overhead

– Update latency

– Single point-of-failure

• What is home agent

goes down?

– Signaling overhead

Mobile IPv6

ForeignSubnet

Mobile IPv6 basics

IP-based Network

CH

HomeSubnet

HA

<MH.IP, CH.IP>

MH

� Address auto-configuration is inherent in IPv6

� No FA, no triangular routing

� Use of source routing through MH.COA.IP, avoids/reduces

encapsulation overhead

� But if any packets go through HA, would still be tunneled to MH

� Binding update can be piggybacked on data packets

home

network

foreign/visited

network

<CH.IP, MH.IP

(through MH.COA.IP)>

binding update (MH.IP->MH.COA.IP)

binding update

Mobile moves between visited subnets4a. binding update

Foreign

Subnet 1

CN

Home

Network

HA

MN

4b. binding update

(MN.IP->MN.CoA2)

Foreign

Subnet 2

1. REGISTER

2. Data

2a. Tunneled Data

3. Move

4. DATA

(CN.IP, MN CoA2)

Foreign/visited

network

4a. binding update

Foreign

Subnet 1

CN

Home

Network

HA

MN

4b. binding update

(MN.IP->MN.CoA2)

Foreign

Subnet 2

1. REGISTER

2. Data

2a. Tunneled Data

3. Move

4. DATA

(CN.IP, MN CoA2)

Foreign/visited

network

ForeignSubnet

Mobile IPv4: Route Optimization

IP-based Network

CH

HomeSubnet

HA

<MH.IP, CH.IP>

MH

� Removes triangular routing

� CH to MH

� In this illustration, we assume co-located COA is used

� CH sends packet to MH.COA.IP directly

� MH to CH


home

network

foreign/visited

network

<CH.IP, MH.COA.IP >

binding update (MH.IP->MH.COA.IP)

ProxyMIPv6• ProxyMIPv6 is a Network-based Localized

Mobility Management Protocol with following goals:– Handover Performance Improvement

– Reduction in Handover-Related Signaling Scheme

– Location Privacy

– Limit the overhead in the network

– Simplify Mobile Node Mobility Management

– Link Technology Agnostic

– Support for Unmodified Nodes

– Localized Mobility Management

– Support for IPv4 and IPv6

– Configurable Data Plane Forwarding

ProxyMIPv6

CN

HA MN

R1

(PMA1)

R2

(PMA2)

5. PMIP Tunnel 1

11. PMIP Tunnel 2

AAA

Move


1. Access

Initiation

3. Proxy BU

4. AAA Query/Reply

4. Proxy ACK

7. Access

Initiation

6. Home Prefix

advertisement


9. Proxy BU

10. AAA Query/Reply

12. Home Prefix

advertisementHome

Network

Visited 1

Visited 2

CN

HA MN

R1

(PMA1)

R2

(PMA2)

5. PMIP Tunnel 1

11. PMIP Tunnel 2

AAA

Move


1. Access

Initiation

3. Proxy BU

4. AAA Query/Reply

4. Proxy ACK

7. Access

Initiation

6. Home Prefix

advertisement


9. Proxy BU

10. AAA Query/Reply

12. Home Prefix

advertisementHome

Network

Visited 1

Visited 2

LMA

Proxy MIPv6 Flow – Initial attachment

MN MAGLMA

MN Attachment

(MN-ID)

MN Attached Event

(Acquire MN-Id

and profile)

PBU (Proxy Binding Update)

Accept PBU

(Allocate MN-HNP, Setup BCE and Tunnel)

Proxy Binding Acknowledgement

Accept PBA

(Setup Tunnel and Routing)Bi-Dir Tunnel Setup

IP Address

Configuration

Stateless/

Stateful

Policy

database

AAA with MN-id

MN’s policy

Router Solicitation


DHCP Request

DHCP Acknowledgement

CN

DataTunneled Data

Data

Proxy MIPv6 Flow – Handoff

MN LMAn-MAG

MN Detached

PBU

Accept PBU

(Start MinDelayBeforeBCEDelete Timer)PBA

Accept PBA

(Setup Tunnel and Routing)Bi-Dir Tunnel

Router Solicitation


MN retains

HoA/HNP

p-MAG

Bi-Dir Tunnel

MN Detached

EventDeReg PBU

MN Attached

MN Attached Event(Acquire MN-Id and profile)

PBU

PBA

CN

Data Data

data

Tunneled data

data

Policy

Database

Proxy MIPv6 in CDMA Network(example)

SIP REGISTER (HoA)

MNPDSN#1

(MAG)

PDSN#2

(MAG)

DHCP

#1LMA

P-CSCF

#1

SIP INVITE

P-CSCF

#2S-CSCF

PPP

DHCP

#2

PCRF

#1

PCRF

#2CN

Router Advertisement (Home Prefix)

DHCP Information Request/Ack (P-CSCF#1)

Proxy Binding Update/Proxy Binding Acknowledgement (Home Prefix)

Media

MN handoff

PPP

Router Advertisement (Home Prefix)

Proxy Binding Update/Binding Acknowledgement (Home Prefix)

SIP REGISTER

DHCP Information Request/Ack (P-CSCF#2)

Gate Open

SIP Re-INVITE

Media

Gate Open

Session Transfer

Handoff

Delay

DSMIPV6 - Dual Stack MIP6

• Mobile nodes will move to networks that might not support IPv6

• Extends MIPv6 capabilities to allow dual stack mobile nodes to request the dual stacked home agent to tunnel IPv4/IPv6 packets addressed to their home addresses

– Both mobile node and Home Agent are IPv4 and IPv6-enabled

– No need to run both MIPv4 and MIPv6 on the client

– MIPv6 is used between mobile and home agent

– Home agent is available using globally unique IPv4 address

• Proposes extension to Binding Updates (RFC 5555)

HA

v6HA_Addrv4HA_Addr

MN v6HoAv4HoA

HA

v6HA_Addrv4HA_Addr

MN v6HoAv4HoA

Proposed New Extension

• DSMIPv6 to support– To address single version home links (e.g., legacy

3GPP)

• IPv4-only Home Network

• IPv6-only Home Network

IPv4-only home network

IPv6 home network is virtualIPv6-only home network

IPv4 home network is virtual

HAv6HA_Addr

MN

v6HoA

v4HA_Addr

v4HoA

HAv4HA_Addr

MN

v4HoA

v6HA_Addr

v6HoA

Global Ipv4/Ipv6

connectivity

HAv6HA_Addr

MN

v6HoA

v4HA_Addr

v4HoA

HAv4HA_Addr

MN

v4HoA

v6HA_Addr

v6HoA

Global Ipv4/Ipv6

connectivity

HAv6HA_Addr

MN

v6HoA

v4HA_Addr

v4HoA

HAv4HA_Addr

MN

v4HoA

v6HA_Addr

v6HoA

Global Ipv4/Ipv6

connectivity

HAv6HA_Addr

MN

v6HoA

v4HA_Addr

v4HoA

HAv4HA_Addr

MN

v4HoA

v6HA_Addr

v6HoA

Global Ipv4/Ipv6

connectivity

Source IETF 71

Network MovementIP11

IP12

Domain 1

IP00

Mobile

Router

Mobile

Network 1

Advertises

MNP1

LANMobile

Router

Mobile

Network 4

LANMobile

Router

Mobile

Network 3

NetworkMovementBetween domains

Domain 2

IP01

Internet

Mobile

Router

Mobile

Network 2

LAN

LAN

Home

Network 1

Home

Network 2Home

Agent 1

Home

Agent 2

Egress

interface

Ingress

interface

Egress

interface

Ingress

interface

Egress

interface

Ingress

interface

Egress

interface

Ingress

interface

Bi-directional

TunnelBi-directional

Tunnel

BCE

BCE:MNP-> MR’s HoA MR’s HoA -> MR’s CoA

Network Mobility

MNP2

Transport Layer Mobility

Solutions

MSOCKS ( Transport Layer Mobility)

• Basic architecture consists of three pieces

– User level MSOCKS proxy running on a proxy machine

– In-Kernel modification on the proxy machine to provide TCP-splice

service

– Shim Msocks library that runs under the application on the mobile

• Built on the top of SOCKS protocol (Firewall Traversal, RFC 1928)

– Addition to support MSOCK’s basic ability to redirect TCP streams to

a mobile’s changing location

– Connection ID to track the logical connection

– MSOCKS Reconnect request

• Mostly suited for local mobility

• Can be integrated with other firewall proxies

• Related work Indirect TCP, Multi-homed TCP, Bullet-proof FTP

MSOCKS Flow DiagramMobile CHProxy

Connect

Addr, Port

Syn

ACK

Auth.

checksSYN

SYN ACK

ACK

Connect ()

Splice

setup

DATA

DATA

DATA

ACKDATA

ACK

Mobile Proxy CH

C DC D

DATA

DATA

DATA, ACK

DATA,ACK

SYN

SYN,Ack

ACK

Reconnect

Conn ID Auth.

checks

Re-splicing

OK

DATA DATA

TCP Migrate Approach• Join together two separate connections

– Unifies context space

– Reference previous connection with token

– Minimal changes in state machine

• Location Update

– Use DYNAMIC DNS

• Seamless connectivity via connection migration

– It notifies current set of correspondent hosts

• Adds a migrate option

– SYN packets of new connection carries it

– It indicates the new connection to be joined with

previous one

• Key negotiation

– Uses Diffie-Hellman Exchange

– Use IPSec or SSH for real security

• Works with NATs/PATs and middle boxes

• Related work

– Extended-TCP (Huitema et al)

– Migratory TCP (Sultan et al)

– Bullet-proof FTP

TCP Connection Migration

SYN

ACK

1

2

3

4

ACK

MN CN

Disconnection

SYN

ACK

5

6

7 ACK

MN – Mobile Node

CN – Correspondent Node

1. Initial SYN

2. SYN/ACK

3. ACK ( with data)

4. Normal Data

5. Migrate SYN

6. Migrate SYN/ACK

7. ACK (with Data)

Initial Key

exchange

After the move

TCP state diagram

LISTEN

SYN_SENTSYN_RECEIVED

ESTABLISHED

CLOSED

MIGRATE_WAIT

appl:passive open

send:(nothing)

recv:SYN

send:SYN,ACK

2MSL timeout

appl:

clo

se o

r ti

meo

ut

Mobile SCTP (Stream Controlled Transport Protocol)

• Mobility Enabled Transport Protocols

– Allows change in IP address when communication is still intact

– Transport layer protocols that allow modification of end-points

– TCP and UDP do not allow that

• Multi-homing feature will allow simultaneous connection to two different networks

– Allows make-before-break, soft-handover

• SCTP supports multi-homing/multistreaming

– SCTP transport addresses can all share the same port number

– SCTP end-point can use multiple IP addresses for an association between two end-points

– Allows the end-points of a single association to have multiple IP addresses

– Allows for independent among data streams

• ADDIP feature makes SCTP a mobility enabled transport protocol

– It allows SCTP end-points to change IP addresses

– Server must use multiple IP addresses and ADDIP implementation

Mobile SCTP• Use Cases

– Assume at least two network interfaces

– Keeping seamless connectivity while switching between different

network technologies

• Wireless LAN in a hotspot and 3G network

– Combination of link layer mobility and transport layer mobility for

smooth handover

– Provides multiple paths to the server adding redundancy

• Mobile servers

– Servers can move also (e.g, ftp server, streaming server)

– Dynamic assignment of IP addresses of the mobile servers

• Dynamic DNS takes care of it

– Mobile SCTP does not handle simultaneous handover of both

SCTP end-points

– It handles only if they happen sequentially

HIP(Host Identity Protocol)

Basics of HIP• Host identity namespace consists of host

identifiers– Identity, identifier

• Host identifier is cryptographic in nature– public key of an asymmetric pair

– Usually stored as • DNS RR similar to IPSECKEY RR

• PKI

• HIP base exchange uses cryptographic HI to set up pair of ESP SAs

• SA is not bound to the IP address

• HIP is middle-box friendly

Host Identity Protocol (HIP)

A

B

Process

SOCKET

End-Point

NODE A

Application T

IP

Address

Locator

Application T

Service

A

B

Process

SOCKET

End-Point

NODE A

IP

AddressLocator

Host

identity

Service

A

B

Process

SOCKET

End-Point

NODE A

IP

AddressLocator

Host

identity

Service

NODE A

A

B

Process

SOCKET

End-Point

IP

AddressLocator

Host

identity

Service

Node A moves

Host identity does not change

but IP address changes

Regular Stack

HIP Stack

Node A moves

HIP Mobility

• HIP decouples the transport from the internetworking layer– Binds the transport associations to Host Identities through HIT or

LSI

– Decoupling makes end-host mobility and multi-homing easier

– TCP and ESP are bound to HITs not IP addresses

• HIP mobility includes IP address change by either party– PPP, DHCP, IPv6 prefix, NAT

– IP addresses are used only for routing

• Since SA is not bound to the IP address– Internal control of SA is done by HITs

– SA is not changed when any mobility protocol is used

• Rendezvous mechanism to locate the end-points– Helps during simultaneous mobility

• Re-establishment of mobile handover will not require HIP negotiation or disruption of transport services

HIP mobility - scenario

TCP (Sockets bound to HITs)

ESP (HIT_s,HIT_d) SPI

HIP {HIT_s, HIT_d, SPI} {IP_s, IP_d, SPI}MH

IP




IP




IP

Mobile

Host

Peer

Host

UPDATE (ESP_INFO, LOCATOR, SEQ)

UPDATE (ESP_INFO, LOCATOR, ACK, ECHO_REQUEST)

UPDATE (ACK, ECHO_RESPONSE)

Mobile

Host

Peer

Host

UPDATE (ESP_INFO, LOCATOR, SEQ)

UPDATE (ESP_INFO, LOCATOR, ACK, ECHO_REQUEST)

UPDATE (ACK, ECHO_RESPONSE)

IP

Address

changes

Application Layer Mobility

SIP-based Mobility Management

SIP Signaling Components

UAC

UAS

UAS

UAC

SIP server

RegistrarProxy

Location

Database

UDP/5060 (Signaling)

UDP/5060 (Signaling)

SIP UA

CH

SIP UA

MH

Outside

Media

Application

RAT

WB

VIC

CHAT

VNC

RAT

WB

VIC

CHAT

VNC

audio

video

white board

text

desktop sharing

Real-time Application

RTP/UDP

RTCP

P0 P0

P0+1 P0+1

Redirect

Proxy

With permission from Xiaotao Wu

SIP Mobility - Basics

CH

HA

FA

Home Network

MN

Tunnelled data

data

data

CH

SIP

Server

Home Network

MN

1

2

3

4

5

Plain Mobile IP

CH

SIP

Server

Home Network

MN

movesMN

Foreign Network

SIP Personal Mobility

SIP Mid-session mobility

1

2

3

4

1. SIP INVITE

2. 302 client moved

3. SIP INVITE

4. SIP OK

5. Data

1. MN moves

2. MN re-invites

3. SIP OK

4. Data

CH

SIP

Server

Home Network

MN

movesMN

Foreign Network

SIP

ServerCH

When both move

SIP-based Mobility FeaturesPersonal

Mobility� One address to many potential terminals – forking

proxy

� Many addresses reaching one terminalService

Mobility� Allows users to maintain access to their services while moving

� Maintain speed dial list, address books, buddy lists, incoming call handling

(e.g, CPL)Session

Mobility� Allows a user to maintain an on going media session even while changing

terminals– Use of MGCP/Megaco– Third-party Call control– Refer Mechanism

Pre-

session

mobility

� pre-session mobility by means of unique URI

� use of SIP proxy, redirect, registrar

� Hierarchical registration for faster registration updateMid-session

Mobility

(RTP/ UDP)

� Move between cells, subnets, domains, supports fast-handoffs

� SIP Re-invite, RTP SSRC/IP address

� RTP translator for fast hand-off within a domain

� Duration limited multicast between subnet handoff

� use of RTSP to control multi-media stream server

TCP � Mobility Proxy, Mangling (MIP-LR), IDMP(DMA)

SIP Mobility Key Design Features• Mobility as part of application layer signaling

– No need to install Mobile IP stack

– Interaction with DNS, HTTP, LDAP for location management

– personal mobility by means of unique URI

– Re-Invite CH for terminal mobility, via SIP server when CH also moves

• Redundancy/survivability

– Determine multiple SIP servers during auto-configuration

• Via DRCP configuration option, multicast discovery, use of SRV record in DNS

• Retransmission during call setup by switching over to secondary server in case of a failure

• Hierarchical SIP registration

– No need to go back to home registrar, register in the visiting domain - less delay

– Registration gets proxied to other SIP servers - Hierarchical registrars - Optimized

• Performance

– No triangular routing—reduces delay

– No IP-IP tunneling—reduces network load and saves overhead

• When SIP server also moves

– Use Dynamic DNS

SIP-based subnet and domain Mobility handoff results (from experiment)

CH MH

59.521 - 10.1.4.162

00.478RTP2

RTP1

00.652

00.701

RTP2 00.938

RTP1

00.949

00.960

01.031

01.151

(De-REG+REG) (01.049, 01.052)

01.37

00.759 - 10.1.1.130

PANA

OK

ACK

Pr

Pr = 220 ms

RTP1

01.52 – 10.1.1.130

Pr

Time

Sec

Handoff timing with more granularity

Operation DRCP PANA SIP MediaRTP

Subnet

Handoff

79 ms 2 ms 228

ms

1490

ms

Domain

Handoff

81 ms 45 ms 289

ms

1656

ms

Fig 1. Handoff Factors for SIP-based mobility

Table 1. subnet/domain handoff

Experimental values

∆∆∆∆2 ∆∆∆∆3 ∆∆∆∆3 ∆∆∆∆

Handoff

(L2+DRCP+PANA)

CHMH

Old IP address IP1

New IP

address IP2

Re-Invite

X

RTP to IP1

RTP to IP2

OK

ACK

RTP to IP1

Voice

20 msec

time interval

X

Pr

Pr

Pr

Handoff

(L2+DRCP+PANA)

CHMH

Old IP address IP1

New IP

address IP2

Re-Invite

X

RTP to IP1

RTP to IP2

OK

ACK

RTP to IP1

Voice

20 msec

time interval

X

Pr

Pr

Pr

Operational comparison with Mobility

Protocols

Intra-domain

encapsulation

Inter-domain

encapsulation

Changes

to end-systems

Triangle

routing

Infrastructure

change

Fast

handoff

MIP * Yes Yes No Yes No No

MIP-RO Yes Yes Yes No No No

MIP-RR Yes Yes No Yes Yes Yes

MIP-FF Yes Yes Yes Yes Yes Yes

CIP * No No Yes No Yes Yes

HAWAII No No Yes No Yes Yes

MIP-LR * No No Yes No No No

IDMP * Yes Yes No Yes Yes Yes

SIP * No No No No No Yes

MIPv6 * No No Yes No Yes Yes

Protocols

Proxy MIPv6 No No No No Yes Yes

HIP No No Yes No No

Mobility Optimization

Packet Loss, Jitter, Latency

1 2 3 4 5 6

1 3 5

1 2 3 3 4

1 2 3 4

Sender

Receiver(Packet Lost)

Receiver(Jitter)

Receiver(Delay)

Motivation for Optimization• Handoff contributes to

– Change in network connection path between communicating nodes– Discrete Sate Event change at different layers– Rebinding of common set of properties (e.g., association, endpoint address, locator)– Associated delay and packet loss due to these discrete events and rebinding

• Limit jitter, delay and packet loss for real-time applications during different types of handoff

– 150 ms end-to-end delay and 3% packet loss for interactive traffic such as VoIP

– ITU-T G.114

• Essential to reduce handoff delay across layers during re-association and mitigate the effect of handoff delay (i.e., packet loss)– Currently it takes between 4s – 17 s– Packet loss depends upon the CODEC, packet generation rate (G711, G729)

• The challenge is even greater when moving between– Heterogeneous domains – Heterogeneous access technologies (e.g., CDMA, 802.11)– Simultaneous mobility

It is desirable to have a common optimization framework and set of formal methodologies for mobility optimization

Performance Requirement• Limit value of end-to-end delay, jitter and packet loss

• Performance requirement varies based on the traffic class

• ITU-T G.114 recommends 150 ms as the upper limit for most applications

• 3GPP TS23.107 defines 4 application classes– Conversational, Streaming, Interactive, Background

• One way delay tolerance for video conference is 200 - 300 ms

• Several performance parameters determine QoS– Transmission Rating Factor (R factor)– End-to-end (One way mouth-to-ear)– Call Blocking ratio

• Different standards bodies define the performance requirement varies based on the type of traffic

Mobility Event Distributed Tasks (Sample)

Operation

(Job)

Task1 Task2 Task3 Task 4

Discovery (J1) Scanning

J11

Beaconing

J12

Association

J13

Open Auth

J14

Detection

(J2)

Beaconing (L2),

Router

Advertisement (L3)

J21

Solicitation

J22

Link Switch

J23

Configuration

(J3)

Identifier

Acquisition

J31

Duplicate

Address

Detection

J32

Mapping

Identifier

J33

Security Association

(J4)

Key distribution

J41

Authenticatio

n

J42

Encryption

J43

Decryption

J44

Binding

Update

(J5)

Tunneling

J51

Mapping

IP addresses

J52

Caching

J53

Media

Redirection (J6)

Encapsulation

J61

Decapsulatio

n

J62

Buffering

J63

Forwarding

J64

Optimization of Network Discovery and Selection

Layer 2 discovery process (802.11)

State1 UnauthenticatedUnassociated

State 2Authenticated

Unassociated

State 3AuthenticatedAssociated

SuccessfulAuthentication

SuccessfulAuthentication orRe-association

Disassociation

Notification

De-authentication

Notification

De-authenticationNotification

Class 1

Frames

Class 1 & 2

Frames

Class 1, 2 &3

Frames

Class 1 Frames –Control Frames

Class 2 Frames –Management Frames

Class 3 Frames –Data Frames

State1 UnauthenticatedUnassociated

State 2Authenticated

Unassociated

State 3AuthenticatedAssociated

SuccessfulAuthentication

SuccessfulAuthentication orRe-association

Disassociation

Notification

De-authentication

Notification

De-authenticationNotification

Class 1

Frames

Class 1 & 2

Frames

Class 1, 2 &3

Frames

Class 1 Frames –Control Frames

Class 2 Frames –Management Frames

Class 3 Frames –Data Frames

Discovery

Scanning

Authentication Association

Beaconing

MN

L2PoA

MN L2

PoAMN L2

PoA

Discovery

Scanning

Authentication Association

Beaconing

MN

L2PoA

MN L2

PoAMN L2

PoA

Layer 2 Handoff Delay (802.11)

• Discovery Phase

– Active scanning

• MN probes AP

– Passive scanning

• AP sends beacons

periodically

• Authentication Phase

– Open authentication

– Shared authentication

– 802.11i – 4 way handshake

• Association Phase

Station performing handoff All APs within

range on all channels

MN

Probe Request

Probe Response

(broadcast)

New

AP

Reassociation

Request

De-authentication

Authentication

Request

Authentication

Response

Re-association

Request

Re-association

Request

Re-association

Response

Probe

Delay

De

-au

the

ntica

tio

n

De

lay

Authentication

Delay

Re-association

Delay

Chan 1

Chan N

Sample Layer 2 and Layer 3Delay

Under

study

100 ms4-5

s

1 – 2

s

150 ms4-5

s

Time

∆∆∆∆2

Proactive

IP

StaticAuto

IP

FA

COA

DHCP (v6)DHCP

ARP w/o

Method

(Linux)

Under

study

100 ms4-5

s

1 – 2

s

150 ms4-5

s

Time

∆∆∆∆2

Proactive

IP

StaticAuto

IP

FA

COA

DHCP (v6)DHCP

ARP w/o

Method

(Linux)

300- 400

ms

DRCP

160ms

500ms

PPP

7-8s

L3 Delay

SA SF

Under

study

100 ms4-5

s

1 – 2

s

150 ms4-5

s

Time

∆∆∆∆2

Proactive

IP

StaticAuto

IP

FA

COA

DHCP (v6)DHCP

ARP w/o

Method

(Linux)

Under

study

100 ms4-5

s

1 – 2

s

150 ms4-5

s

Time

∆∆∆∆2

Proactive

IP

StaticAuto

IP

FA

COA

DHCP (v6)DHCP

ARP w/o

Method

(Linux)

300- 400

ms

DRCP

160ms

500ms

PPP

7-8s

L3 Delay

SA SF

14 msHostap (Managed)

5 msMADWIFI

250 msOrinoco +Windows

300 msCentrino + Linux (Passive scanning)

400 – 600 msDLink +Linux

100 – 160 msOrinoco+Linux

200 – 300 msAiroNet +Linux

L2 HandoffH/W - OS

14 msHostap (Managed)

5 msMADWIFI

250 msOrinoco +Windows

300 msCentrino + Linux (Passive scanning)

400 – 600 msDLink +Linux

100 – 160 msOrinoco+Linux

200 – 300 msAiroNet +Linux

L2 HandoffH/W - OS

L2 Delay

Layer 2 Discovery Optimization

General techniques:• Reduce the scanning time• Caching of ESSID• Use of second interface• 802.11 specific discovery• Proactive Discovery (no scanning)

Proposed Solutions:• Shin et al introduces selective

scanning and caching strategy• Montavont et al propose periodic

scanning• Velayos et al propose reduction of

beacon interval and performs search in parallel with data transmission

• Brik et al propose to use a second interface to scan while communicating with the first interface

• 802.11u, 802.11k• Forte and Schulzrinne• Application Layer proactive

discovery (e.g., Dutta et al)

Network Detection Mechanisms

• Detection of Layer 2

– SNR drops below a threshold

– Promiscuous Mode to detect other Access Point overlapping

– Proactive Layer 2 handoff

– Beacon Interval

– Client polling interval

• Detection at layer 3

– Enabling L2 handoff event to trigger L3 handoff

• Network Initiated, Mobile Initiated by L2 trigger

– Lazy Cell Switching, Prefix matching, Eager Cell Switching

– ICMP Subnet Router Advertisement

– FA server advertisement

• Application layer detection

– Monitoring an incoming data stream

– Based on GPS co-ordinates of the terminal

• Proposed optimization techniques– Cross layer triggers help detect

the PoA at upper layer

– Passing layer 3 information as part of layer 2 information

– Hybrid scanning to detect the loss of access point

Optimization of Layer 3 Configuration

Components that affect L3 configuration and optimization techniques for layer 3 configuration

• Layer 3 address

acquisition

– Proactive caching

• Duplicate Address

Detection

– Optimistic DAD,

Proactive DAD,

Passive DAD,

– Router Assisted DAD

• NUD (Neighbor

Unreachability Detection)

– Aggressive Router

Selection

Configuration

Identifier

AcquisitionDuplicateAddressVerification

IdentifierMapping

Layer 2

Layer 3

Mobile

NodeServer Network

Mobile

Node L3 POA Network

MNServer

L3

PoA

Configuration

Identifier

AcquisitionDuplicateAddressVerification

IdentifierMapping

Layer 2

Layer 3

Mobile

NodeServer Network

Mobile

Node L3 POA Network

MNServer

L3

PoA

IP Address Discovery Methods• Static

– Works only when a set of possibly visited networks is known in advance

– Each Mobile can be pre-assigned a fixed set of IP addresses for use on these frequently visited networks

• Stateful– DHCP Server, Relay Agent, DRCP

– PPP Server

– MIP Care-of-address (MIP-COA)

• Stateless– IPV6 provides this option

– Combination of link-local prefix and network prefix computes an address of global scope

• Auto-IP– Zero-conf scenario provides 169.154/16 Network address for the local link

– But is not globally routable

• GPS-IP

– Obtains an IP address based on the GPS location, machine ID and MAC address

– Supposed to help the fast-handoff

IP Discovery methods/Timing/ Triggering

FactorsOS DHCP

∆∆∆∆2

DHCP(w/o

ARP)

∆∆∆∆2

DRCP

∆∆∆∆2

(v6)∆∆∆∆2 PPP

∆∆∆∆2

MIP (∆∆∆∆2)FA CoCOA COA

AutoIP∆∆∆∆2

L2 switch (∆∆∆∆1)802.11 CDMA

Static

IP (∆∆∆∆2)

Linux

Windows

Triggering

Method

Triggering

Method

GPS

IP

∆∆∆∆2

7-8

Sec

~4-15

sec

300-

400 msec~ 100

msec

L2

(client)

L2

(client)

L2 (client)

L3 (Server)

L2/

Client

L3/

serverN/A

15 Sec

L2

(client)N/A

L2

/Client

100-150 ms

(Beacon

Interval)

~27 ms

SNR

Threshold

Pilot

Signal

State

less

DH

CP

L3

L3

H. Time/

T. Methods

Handoff

Time

(∆∆∆∆2/∆∆∆∆1)

Handoff

Time (∆∆∆∆2/∆∆∆∆1)

160

msec

TBD

~15sec ~4sec N/A TBD TBD

N/A100-

200 ms

TBD

(~100ms)

L2/L3

L3/

GPS

coordinate

based

L2

(client)

Server

Server

~ 3-5Sec

1-2 sec

Same

as

DHCP’

DRCP/

PPP

Server

N/A

N/A

5sec DHCP 15 sec

Client

Threshold

~27 ms

(Soft

HO)

L3/

server

Server

~500ms

- 1 sec

SNR

Threshold

Pilot

SignalL2/L3

** Some of the numbers shown above are based on experiment in lab environment and may vary based on the processing

power and load in the network

∆∆∆∆1 - L2 Detection

∆∆∆∆2 - IP address Discovery

∆∆∆∆3- Media Redirection

Soft

h/o

Optimizing Layer 3 - in IPv6 - SIPv6 and MIPv6

MNNew

Router

RouterAdvertisement

200 OK

detachment fromold access medium

attachment tonew access medium

handoffdetection

handoff completion(signaling)

Re-INVITE

CN

handoff completion(media)

Delay on Media

UDP packet

ACK

DAD

D1

D2

D3

Signaling (ms) Media (ms)

H123890 3854

H233932

HANDOFFCASE

SIP(DAD)

SIPNDAD

MIPv6NDAD

SIPDAD

SIPNDAD

MIPv6NDAD

171.4 1.5 420.8 21.1

H31

161.6 2.0 4187.7 418.6 30.3

1934.7 161.1 1.0 1949.4 408.4 25.3

Effect of DAD Handoff Delay

Handoff Flow

NUD

Optimizing L3 configuration in IPv4Standard DHCP timing

Message time (Absolute timing) Discover 11.931577

Offer 11.944456

Request 11.994972

ACK 12.099620

ARP Check 12.106605

ARP Reply 27.114676

Total time 15.183099

Without ARP checking

Average Minimum Maximum

436.75 ms 303 ms 535 ms

With Application

Application Average Min Max Ave. rate A Loss.

RAT 1416.46 ms 1363 ms 1524 ms 4515.92 Bps 6396.63

Bytes

vic 1314.23 ms 1273 ms 1368 ms 5298.33 Bps 6963.23 Bytes

Authentication Optimization

How security related protocols affect

performance

• Security protocols have an impact on the performances of the network

– End-to-end latency

– Throughput

– Handoff delay

• Main components that affect the performance

– Authentication/authorization, Key Derivation, Encryption

• Security related delays may affect all the layers

• Layer 2 (e.g., 802.11i, WEP)

• Layer 3 (IPSEC/IKE)

• Upper Layers (e.g., TLS, SRTP)

Security

Association

KeyDistribution Authentication Encryption

Layer 2

Layer 3

Layer 4

ServerMobile Network

MN

MN Server

L3

POA

Security

Association

KeyDistribution Authentication Encryption

Layer 2

Layer 3

Layer 4

ServerMobile Network

MN

MN Server

L3

POA

Authentication Optimization

• Authentication mechanism requires 802.1x message exchange with the authenticator in the target network

• Number of round trip signaling and key derivation process need to be minimized

• Low latency re-authentication

• Authentication can be done proactively

• Context can be transferred

• Layer 3 authentication bootstraps layer 2 authentication process

Optimizing authentication Related Work

• IEEE Standards– IEEE 802.11i provides pre-authentication at link-layer in the

distribution system (DS)– IEEE 802.11r improves 11i by introducing a new key hierarchy but it

does not work between DSs either.

• Context transfer solutions (Bargh et al, Georgiades et al, Duong et al)– Security problems such as “domino effect”– Assume certain trust relationships which might not be possible in

certain scenarios.– Oriented towards the same technology

• Re-authentication

• Pre-installation based on movement pattern (Mishra et al, Pack et al )– AAA assisted key installation– Works within the same administrative domain

• MIPv6 and AAA assisted (Ruckforth et al)– Limited to MIPv6 and within the same domain

• Cooperative Roaming (Forte et al)– Works within a domain

802.11i – Pre-authentication Flow

1x controlled port enabled & IP traffic

EAPOL Start

EAPOL-Request(EAP-Req/ident)

EAPOL-Response(EAP-Resp/ident)

IEEE 11i

Pre-Authentication

STA Current AP Target AP

EAPOL-Request(EAP-TLS/Start)

EAPOL-Response(EAP-TLS/Client-Hello)

EAPOL-Request(EAP-TLS/ServCert)

EAPOL-Response(EAP-TLS/ClientCert)

EAPOL-Request(EAP-TLS/ChangeSpec)

EAPOL-Response(EAP-TLS/Ack)

EAPOL-Request(EAP-TLS/Sucess)

EAPOL Key: Message 1




Associated

(Re)Association

PMKsta-targetAP

4-way hanshake

AAAHAAAv

AAA prot-ans (EAP-TLS/Start)

AAA prot-req (EAP-Resp/Ident)

AAA prot-ans (EAP-TLS/ServCert)

AAA prot-req (EAP-TLS/Client-Hello)

AAA prot-req (EAP-TLS/ClientCert)

AAA prot-ans (EAP-TLS/ChangeSpec)

AAA prot-ans (EAP-Success)

AAA prot-req (EAP-TLS/Ack)

RoamingNon-roaming

PMKsta-targetAP


EAPOL Start

EAPOL-Request(EAP-Req/ident)

EAPOL-Response(EAP-Resp/ident)

IEEE 11i

Pre-Authentication

STA Current AP Target AP

EAPOL-Request(EAP-TLS/Start)

EAPOL-Response(EAP-TLS/Client-Hello)

EAPOL-Request(EAP-TLS/ServCert)

EAPOL-Response(EAP-TLS/ClientCert)

EAPOL-Request(EAP-TLS/ChangeSpec)

EAPOL-Response(EAP-TLS/Ack)

EAPOL-Request(EAP-TLS/Sucess)





Associated

(Re)Association

PMKsta-targetAP

4-way hanshake

AAAHAAAv









RoamingNon-roaming

PMKsta-targetAP

Network-Layer Assisted

Pre-Authentication Technique

• Assists link-layer optimization mechanism

to work accross subnets and domains

• It is independent of link-layer technology

(e.g., 802.11, CDMA)

• It does not suffer from context transfer

security problems and only assumes basic

trust relationship

• It supports handover across inter-

technology, inter-subnet and inter-domain.

Experimental Testbed

Home AAA

Domain

IEEE 802.11i

Pre-authentication

nAR/PAA

AAAv

AAAh

pAR165.254.55.116/24

165.254.55.115/24

155.54.204.82

10.1.30.1/24

10.1.30.3/2410.1.30.2/24

10.1.10.2/24

10.1.10.1/2410.1.20.2/2410.1.20.1/24

MN

PSK PSK

AP0AP1AP2

Radius/Diameter

PANA pre-auth

Association

&

4-way handshake

Network A Network B

PANA Pre-authentication

Roaming AAA

Domain*

* Roaming AAA Domain in roaming case.

For non-roaming case, it acts as MN’s home AAA

domain.

Non-Roaming: [email protected]: [email protected]

Network Pre-authentication Flows

PANA-Client-Initiation(PCI)

PANA-Start-Request (PSR) [EAP Req/Ident]

PANA-Start-Answer(PSA) [EAP Resp/Ident]

PANA-Auth-Request (PAR) [EAP-TLS/Start]

PANA-Auth-Answer (PAN) [EAP-TLS/Client-Hello]

PANA-Binding-Request[AUTH] (PBR) (EAP-Success)

PANA-Binding-Answer (PBA)

PaC target PAAtarget APx AAAH

SNMPv3-Set(PSK, PaC’s MAC address)


SNMPv3-Ack

PaC’s

Movement





PSKx PSKx


Network-Layer

Pre-authentication

EAP skipped


Pre-configuration

PSK

installation

AAAv



PANA-Auth-Answer (PAN) [EAP-TLS/ClientCert]

PANA-Auth-Request (PAR) [EAP-TLS/ServCert]



PANA-Auth-Answer (PAN) [EAP-TLS/Ack]

PANA-Auth-Request (PAR) [EAP-TLS/ChangeSpec]



(Re)Association

Associated

current APx

Non-roaming Roaming

4-way hanshake

PANA-Client-Initiation(PCI)

PANA-Start-Request (PSR) [EAP Req/Ident]

PANA-Start-Answer(PSA) [EAP Resp/Ident]

PANA-Auth-Request (PAR) [EAP-TLS/Start]

PANA-Auth-Answer (PAN) [EAP-TLS/Client-Hello]

PANA-Binding-Request[AUTH] (PBR) (EAP-Success)

PANA-Binding-Answer (PBA)

PaC target PAAtarget APx AAAH

SNMPv3-Set(PSK, PaC’s MAC address)


SNMPv3-Ack

PaC’s

Movement





PSKx PSKx


Network-Layer

Pre-authentication

EAP skippedEAP skipped


Pre-configuration

PSK

installation

AAAv



PANA-Auth-Answer (PAN) [EAP-TLS/ClientCert]

PANA-Auth-Request (PAR) [EAP-TLS/ServCert]



PANA-Auth-Answer (PAN) [EAP-TLS/Ack]

PANA-Auth-Request (PAR) [EAP-TLS/ChangeSpec]



(Re)Association

Associated

current APx

Non-roaming Roaming

4-way hanshake

Key Derivation Process

AAA

PAA

MN

AAA

MSK

AP

MSK

MSK�

PaC-EP-Master-Key �

PSK

MNMSK�

PaC-EP-Master-Key �

PSK�PMK

4-way handshake (PTKs) 4-way handshake (PTKs)

PSKap

PSKap�PMK

MSK� PMK

MSK� PMK

AP

802.11i

Pre-auth

Network-Layer Preauth

AAA

MN

AP

MSK

4-way handshake (PTKs)

MSK� PMK

MSK� PMK

AP

Post-auth

AP

AuthenticationServer

Authenticator

WPA SupplicantWPA Supplicant

Authenticator

AuthenticationServer

Results (II)

Security Association Optimization

Key principles for SA optimization

• Avoid the key exchange by maintaining the end-point address identifier

• Avoid tear down and re-establishment of Security Association

• Reduce the number of signaling messages that help rekeying

• Anchor-based security association

• Clients behind NAT are shielded from IP address change

Description of the Solution (1)

Dynamic Tunnel Management at MN

DMZ

Internal (protected) External (unprotected)

CN

Internal Home

Network

VPN tunnel x-MIP tunnel

VPN

GW x-HA

Based on its current location, MN dynamically establishes/changes/terminates tunnels

without changing current standards of IPsec VPN or Mobile IP.

Triple encapsulation tunnel is constructed by:

• i-HA (Internal Home Agent): Forwards IP packets to MN’s current internal location

• VPN GW: Protects (encrypts and authenticates) IP packets transmitted in external networks

• x-HA (External Home Agent): Forwards IP packets to MN’s current external location

MN

i-MIP tunnel

Internal Visited

Network

i-HA

MNMN MN

ExternalNetwork 1

ExternalNetwork N

Mobike-based solution

Re-Invite

DMZ


CN

Internal Home

Network

VPN tunnel

VPN

GW

MN

Internal

VisitedNetwork

Home

Proxy

MNMN MN

ExternalNetwork 1

ExternalNetwork N

COA1TIA (Tunnel address)

COA2

MOBIKE(modifies SA)

Re-register (IP1)1 2

(IP0) (IP1)

Register (TIA)Register (TIA)

Re-Invite(TIA)

Re-Invite

DMZ


CN

Internal Home

Network

VPN tunnel

VPN

GW

MN

Internal

VisitedNetwork

Home

Proxy

MNMN MN

ExternalNetwork 1

ExternalNetwork N

COA1TIA (Tunnel address)

COA2

MOBIKE(modifies SA)

Re-register (IP1)1 2

(IP0) (IP1)

Register (TIA)Register (TIA)

Re-Invite(TIA)

Results: Mobile IP-VPN

N o n -M a k e -b e fo re -b re a k

3 15 0 0

3 20 0 0

3 25 0 0

3 30 0 0

3 35 0 0

3 40 0 0

3 45 0 0

3 50 0 0

0 5 0 1 00 1 5 0 20 0 2 5 0 3 00

T im e in S e c o n d s

RT

P S

eq

ue

nc

e

R TP S e q ue n c e

8 0 2 .1 1(e n te rp r ise )

C e l lu la r

80 2 .1 1(e n te rp r is e )

P ac k e t L o s sD u e to N o n -m a k e -b e fo r e - b r e ak

N o n -m a k e -b e fo re -b r ea k

N o n -M a k e -b e fo re -b re a k

3 15 0 0

3 20 0 0

3 25 0 0

3 30 0 0

3 35 0 0

3 40 0 0

3 45 0 0

3 50 0 0

0 5 0 1 00 1 5 0 20 0 2 5 0 3 00

T im e in S e c o n d s

RT

P S

eq

ue

nc

e

R TP S e q ue n c e

8 0 2 .1 1(e n te rp r ise )

C e l lu la r

80 2 .1 1(e n te rp r is e )

P ac k e t L o s sD u e to N o n -m a k e -b e fo r e - b r e ak

N o n -m a k e -b e fo re -b r ea k

80 2.1 1-C ellu lar S e cured H an doff

1800

1900

2000

2100

2200

2300

2400

2500

2600

0 20 40 60 80 100 120 140 160 1 80

Time in Se co nd s

RT

P P

ac

ke

t

Se

qu

en

ce

RTP sequence during

handoff

O ut-of-order-packet802.11(en te rprise)

Ce llular 802.11(enterprise)

80 2.1 1-C ellu lar S e cured H an doff

1800

1900

2000

2100

2200

2300

2400

2500

2600

0 20 40 60 80 100 120 140 160 1 80

Time in Se co nd s

RT

P P

ac

ke

t

Se

qu

en

ce

RTP sequence during

handoff

O ut-of-order-packet802.11(en te rprise)

Ce llular 802.11(enterprise)

MNVPN GW

Visite d Network 2(802.11)

V isited Network 1(Cellular)

CN

Tunne l (RTP)

MOBIKE

MOBIKE

13.377

13.342 ( 802.11 is up)

13.554 (First packet o n 802.11)

47.881

51.519

MOBIKE

51.977

PacketLoss

(No-Break-b efore-make)

RTP

Visited Netwo rk 1

(Cellu lar)

13.667 (Last packet on cellular)

MOBIKE

43.103 (Last packet on 802.11)

VP N traffic in 802.11

VP N traffic in cellular

Mobike in cellular

Mobike in 802.11

IP0 is primary address



IP0 – address of 802.11 interface

IP1 – address of cellular interface

MNVPN GW

Visite d Network 2(802.11)

V isited Network 1(Cellular)

CN

Tunne l (RTP)

MOBIKE

MOBIKE

13.377

13.342 ( 802.11 is up)

13.554 (First packet o n 802.11)

47.881

51.519

MOBIKE

51.977

PacketLoss

(No-Break-b efore-make)

RTP

Visited Netwo rk 1

(Cellu lar)

13.667 (Last packet on cellular)

MOBIKE

43.103 (Last packet on 802.11)

VP N traffic in 802.11

VP N traffic in cellular

Mobike in cellular

Mobike in 802.11




IP0 – address of 802.11 interface

IP1 – address of cellular interface

Hand-off with no-make-before break(internal-external-internal) with make-before-break

H o m e -C e l lu la r -H o t s p o t h a n d o ff

5 0 0

1 5 0 0

2 5 0 0

3 5 0 0

4 5 0 0

5 5 0 0

0 1 0 0 2 0 0 3 0 0 4 0 0

T i m e i n S e c o n d s

RT

P S

eq

ue

nc

e

R T P S e q u e n c e

Home802.11

CellularExternal

Hotspot802.11

H o m e -C e l lu la r -H o t s p o t h a n d o ff

5 0 0

1 5 0 0

2 5 0 0

3 5 0 0

4 5 0 0

5 5 0 0

0 1 0 0 2 0 0 3 0 0 4 0 0

T i m e i n S e c o n d s

RT

P S

eq

ue

nc

e

R T P S e q u e n c e

Home802.11

CellularExternal

Hotspot802.11

Home-external-external handoff Mobike-based handoff (cellular-hotspot-cellular)

Optimizing Route between CH and MH

What is RO Optimization?• What is it?

– Ability to maintain direct route between the communicating hosts

– Avoid triangular route for the media traveral

– Most of the mobility protocols in their current form are not route optimized

• Key Principle

– Maintain direct path between the end points for signaling and media

• Proposed Solutions

– Application Layer Mobility

– MIPv6 inherently supports route optimization

– CGA-based route optimization

– Route Optimization in ProxyMIPv6

– Interceptor-assisted packet modifier

– Midcom-proxy assisted route optimization

Trombone Routing (MIPv4, PMIPv4)

Home Network

a) SIP REGISTER

P-CSCF FA/PMA

HAS-CSCF

Home Network

P-CSCF

HAS-CSCF

b) SIP INVITE

MN MN

CN

I-CSCF

Visited Network Visited Network

Core NetworkCore Network

FA/PMA

Trombone Routing (MIPv6, PMIPv6)

Home Network

a) SIP REGISTER

P-CSCFAccess Router/

MAG

HA/LMAS-CSCF

Home Network

S-CSCF

b) SIP INVITE

MN MN

CN

I-CSCF

Visited Network

Core NetworkCore Network

P-CSCFAccess Router/

MAG

Visited Network

HA/LMA

Trombone routing mitigation

P-CSCFS-CSCF

AS

HSS

I-CSCF

PDSN

HA

AP01

802.11b

Home NetworkVisited Network 1

DHCP

cdma2000

RAN Emulator

Mobile Node

192.168.20.0/24

Router

192.168.6.0/24

20.4 20.3 20.2

6.26.1

20.1

10.1

30.1

30.230.330.420.22

192.168.30.0/24

Delay Controller

CN

192.168.30.33

P-CSCF

AP02

802.11b

Visited Network 2

DHCP

192.168.10.0/24

10.4 10.3 10.2

8.28.1

192.168.8.0/24

cdma2000

RAN Emulator

Delay Controller

Optimized SIP Signaling between MN and P-CSCF

Non Optimized SIP Signaling between MN and P-CSCF

• Trombone routing mitigation for SIP signaling

– Non-Optimized

– Selective Reverse Tunneling

Effect of distance on signaling

Types

Of Handoff

Proactive Handoff

(Linearized Values)

Reactive Handoff

(Linearized Values)

Non-optimized Handoff

(Linearized Values)

Emulated

Delay

beween

Home and

Visited

(ms)

SIP, AKA,

Context

Transfer

Delay

(ms)

MIP

Update

Delay

(ms)

L2

PPP

Delay

(ms)

SIP,

AKA,

Context

Transfer

Delay

(ms)

MIP

Update

Delay

(ms)

L2

PPP

Delay

(ms)

SIP,

AKA,

Context

Transfer

Delay

(ms)

MIP

Update

Delay

(ms)

L2

PPP

Delay

(ms)

0 0 51 2736 1.010 62 1523 3,999 41 2,239

50 0 152 2693 1,375 161 1744 4,584 145 2,217

100 0 252 2650 1,741 261 1964 5,170 248 2,194

150 0 352 2607 2,107 360 2184 5,756 352 2,172

200 0 453 2563 2,472 459 2405 6,342 455 2,150

250 0 553 2520 2,838 558 2625 6,927 559 2,128

300 0 654 2477 3,203 658 2845 7,513 663 2,106

350 0 755 2434 3,569 757 3066 8,099 766 2,084

400 0 855 2391 3,935 856 3286 8,685 870 2,061

450 0 956 2347 4,300 955 3506 9,270 973 2,039

500 0 1,057 2304 4,666 1,055 3726 9,856 1077 2,017

Trombone routing mitigation results

0 .0 0 1 .0 0 2 .0 0 3 .0 0 4 .0 0 5 .0 0 6 .0 0 7 .0 0 8 .0 0 9 .0 0 1 0 .0 0

M itig a tio n

N o M itig a tio n

H a n d o ff T im e [m s e c ]

P P P D is c o n n e c tio n L 2 H a n d o ff P P P C o n n e c tio n M IP U p d a te

D H C P fo r n e w P - C S C F S IP R e g is tra tio n S IP R e - IN V IT E

Figure 2: Effect of Trombone routing mitigation

Components Optimized

Components Optimized

(A) PMIP route optimization(Intra-LMA)

HA/LMA

MAG1 MAG2

MN1 MN2

MAG3

MN2

Network Configuration

Non-optimizedDate path

OptimizedPath (MN1 – MN2)

OptimizedPath (MN1-MN2)After handoff

(E) PMIP route optimization(Multiple LMA/HA)

HA1/LMA1

MAG1 MAG2

MN1

MAG3

Network Configuration

HA2/LMA2

MAG4 MAG5

MN2 MN2

MAG6

CORENetwork

Route

Optimized path

after

Hand over

Route

Optimized

path

Non-OptimizedPath

PMIP Domain1PMIP Domain 2

Optimizing a) Binding Updateb) Media Rerouting

Optimizing Binding Update

• Techniques– Reduce the latency due to

longer binding update when the communicating host is far away

– Limit the binding update within a domain

• Proposed Solutions– IDMP– Regional registration-based

Mobile IP– HMIPv6– Anchor-based Application

Layer• B2BUA

– Proactive Binding Update

Binding

Update

Tunneling Mapping Caching

Mobile Network Anchor Mobile CN

Anchor

PointCN

Binding

Update

Tunneling Mapping Caching

Mobile Network AnchorMobile Network Anchor Mobile CN

Anchor

PointCN

“Low Latency Handoffs” Approach Malki et al

• Original MIP makes no assumptions on L2, therefore

– MIP registration can only start after L2 handoff has completed

– MH is not able to communicate before registration process completes

• Cross-layer cooperation, L2 and L3

• Pre-Registration handoff technique

– Proxy route advertisement (and possibly proxy route solicitation) through old FA triggered by “L2 trigger” in old FA (or in MH, for solicitation)

– With some exceptions, MH starts registration through old FA

– Registration may be global or regional

• Post-Registration handoff technique

– Use of Bidirectional Edge Tunnels (BET) between old and new FAs

• Set up after “L2 trigger” in old FA or new FA

• Forwarding begins based on reception of another “L2 trigger” at old FA

– Old FA acts as “anchor FA”, while MH registers with new FA

– Use of BET ends after MIP registration is complete

• Combination

– Use both for maximum protection!

– If pre-registration doesn’t complete in time, use the BET

ForeignSubnet old

Mobile IPv4: Media redirection

ForeignSubnet new

IP-basedNetworkCH

HomeSubnet

HA

MH

� CH to MH

� In this illustration, we assume co-located COA is used

� Forwarding of packets from old FA

� “mid-flight”, or from any CH that does not receive/process binding update

� reduces lost packets due to handoff

home

network

foreign/visited

network

FA, new

FA, old

<CH.IP, MH.IP>binding update

PFANE

IPv4 Proactive Handoff (Malki et al)

oFA nFA

Internet

Mobile

•Allows MN to communicate with

nFA while under oFA

• Provide for data delivery at nFA even

before registration is complete

• Server Initiated/Mobile Initiated

Domain

HA/GFA

Rt. Adv (2)

Rt. Sol (1)

Proxy

Rt. Sol

Proxy

Rt. adv

34

5

Reg

Req

6.

Reg. Req

CH

IPv6 pro-active handoff (FMIPV6)

• Handover Initiation•Mobile initiated

•Server initiated

• Tunnel establishment

• ForwardingPAR

NAR

Internet

Mobile Mobile

Bi-directional Tunnel

CH

PAR: Previous Access

Router

NAR: New Access

Router

1 RtSolPr2 PrRtAdv

3 F-BU

4. HI (Pcoa, Ncoa)

5. HACK

BR

Tunneled data

FMIPv6 Flow (Predictive)

MN

PAR NAR

RtSolPr

PrRtAdv

FBUHI

HAck

FBackFBack

Forward packets

disconnect

Connect

UNA

Packets buffered

Deliver packetsPackets flushed

FMIPv6 Flow (Reactive)

MN

PAR NAR

RtSolPr

PrRtAdv

FBU

HI/Hack if necessary

disconnect

Connect

Deliver packets

In-flight packets forwarded

UNA

FBU

Forward packets including FBAck

Non-optimized (MIPv6)Handoff (no 802.11i)

MIPv6 Non-optimized Handoff

1320

1340

1360

1380

1400

1420

1440

1460

27 29 31 33 35 37 39

Packet arrival time in seconds

Packet

Seq

uen

ce n

um

ber

Series1Handoff delay

Average packet loss = 70 pkts

Reactive FMIPv6 Handoff (Reactive)

FMIPV6 Reactive Handoff

540

560

580

600

620

640

42 43 44 45 46 47 48 49 50

Packet arrival time in seconds

Packet

seq

uen

ce n

um

bers

Series1

HandoffDelay

Average packet loss = 16 pkts

FMIPV6 predictive handover

FMIPv6 Predictive Handover

795

800

805

810

815

820

825

830

835

15 16 17 18 19

Packet Time arrival in seconds

Packet

Seq

uen

ce

Series1

Handoff Delay

Buffered packetsAt NAR

No packet loss

MH2

(2nd)

MH1

(1st)

MH2

(1st)

Domain 2a Domain 2b

SIP

Server 2

SIP

Server 1MH1

(2nd)

Home

Domain 1

Home

Domain 2Domain 1a Domain 1b

Both hosts cannot find the other!

(Figure 7.2)

Communication session

(in normal state):

Exchanging IP packets

Simultaneous mobility in SIP

Home

Domain A

Home

Domain B

A

(2nd)

Domain B1 Domain B2

Home

Agent A

A

(1st )

Domain A2 Domain A1

Home

Agent B

B

(1st )

B

(2nd)

CTIHTI

Communication session

(in normal state):

Exchanging IP packets

A’s binding update is lost as are B’s CTI and HTI

(Figure 7.3)

HTCT

CTIHTI

Simultaneous mobility for MIPv6

Node 1Forwarding

Proxy Node 2

Node 1Redirecting

Proxy Node 2

Node 1Intercepting forwarding

proxy

Node 2

Node 1InterceptingRedirecting

proxy

Node 2

Figure 7.6

Abstract functions of the location proxies

0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150 200 250 300

Probability

of

failure

Inter-handoff time in seconds

Simultaneous mobility probability

Probability of failure vs. inter-handoff time

(One way latency = 50 ms)

0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150 200 250 300

Probabilityof

failure

One-way latency (ms)

Failure probability (N = 3)

Probability of failure (PN) vs. one-way-packet delay

Media redirection and optimized

binding update for SIP-based mobility

• Capture the transient packets in-flight and redirects to the mobile– SIP Registrar and NAT-like functionality

• RTPtrans (RTP translator an application layer Translator)

• Mobility Proxy (Linux iptables)

– Outbound SIP proxy server

• Local SIP proxy captures outbound packets

• Limit the signaling due to Intra-domain Mobility– B2B SIP UA

• Emulates Third Party Call control

– Multicast Agent

– Small group multicast

– Duration limited locally scoped Multicast

SIP-based Fast-Handoff

MN

Internet

Visited Domain

MN

MN

Public SIP Proxy

Public SIP Proxy

Public SIP Proxy

IP0

IP1

IP2

Visited

Proxy

Home SIP

Proxy

RTP

Media

(Existing SIP

Session)

OKACK

CNHome

Domain

Subnet

S0

Subnet

S1

Subnet

S2

RTP

Media after

Re-Invite

Register

1

2

3

4

5

Translator

Translator

Translator

Optimized media redirection SIP fast-handoff mechanism -RTPtrans

R

SIPServer/Registrar

RT1RT2RT3

MHMHMH

IP1IP2IP3

CH

IPR1IPR2IPR3

Mapping Database

Register

1

IP1:p1IP2:p1

2’

DelaySimulator

IP2 -> IPR1IP3 -> IPR2...

3

Intra- Domain SIP based fast-handoff(RTP-Trans/NAT based approach)

Domain -D1

4

RT1,RT2,RT3 - RTP Translators

4’

2a Re-Invite

MH CHVisited SIP

Registrar

Media

RT1 RT2 RT3

IP1

IP2

(New Address)

Re-INVITE (2)

REGISTER 2’

Forward

traffic

(IP1:p1 ---> IP2:p1)

New traffic

IP3

(New Address)

Re-INVITE

Re-REGISTER

Forward

traffic(IP2:p1 ---> IP3:p1)

Transient

Traffic during the move

(1)

SIP-CGI (3)

Transient

Traffic during

the move

First move

Second move

IP2

Delay

Box

SIP fast-handoff media redirection Protocol

flowServer

Localized-Binding

Update

ForeignSubnet

ForeignSubnet

Hierarchical Mobile IP

IP-based Network

CH

HomeSubnet

HA

<CH.IP, MH.IP>

<MH.IP, CH.IP>

MH

RFA

� CH to MH


� HA in home subnet intercepts packet, tunnels it to GFA

� GFA un-encapsulates packet, tunnels it to RFA

� RFA un-encapsulates packet, sends to MH

home

network

GFA coverage area

GFA

RFA

IDMP Fundamentals • Every MN is assigned 2 CoAs

– Global CoA (GCoA)- is globally reachable and remains unchanged as long as the MN moves within a domain.

– Local CoA (LCoA)- has only domain-wide scope and changes with every change in point of attachment.

• Mobility Agent acts as a domain-wide point of packet redirection.

– Packets from outside (addressed to the GCoA) arrive at the MA.

– MA intercepts such packets and tunnels them to the MN's current LCoA.

• During movement inside the domain, the MN only sends a intra-domain BindingUpdate to the MA.

– No need for global signaling (to HA or other servers) unless the GCoA changes.

– Hierarchy reduces the latency of most updates, and significantly lowers the global signaling traffic load.

Hierarchical Mobility Management

IDMP+MIPHome Network

1

2

1

3

2

MA

SA

MN

• All packets from the global Internet tunneled (re-directed) to the

GCoA and are intercepted by the MA.

• MA tunnels each packet to the MN’s current LCoA.

CN

SASA

HADomain

Hierarchical Mobility Management

(IDMP+SIPMM)

MA

MA

HA

CHINTERNET

Intra-Domain

Inter-DomainIntra-Domain

MNMN

LCOA

SIP RE-INVITE (GCOA)

SIP Registrar SIP Registrar

Initial Domain-Based Registration Procedure

Subsequent Intra-Domain Registration

Anchor-based localized binding update SIP-based mobility

RouterCH

Delay

Simulator

SIP

UAC

SIP MA (B2B)

MHMHMH

MoveIP1(Initial position before move)IP2

IP3

IPch

SIP

UAS

SIP

UAS

SIP

UAC

Packets gain for SIP optimized handoff

0

10

20

30

40

50

60

0 20 40 60 80 100 120 140 160

Distance between CH and MH

(Hops)

Nu

mb

er

of

pa

ck

ets

Packets gain for SIP

optimized handoff

Optimizing Binding – SIP Fast-handoff (Results)

HMIPv6 OverviewHomeHomeAgentAgent

Internet

CN

MAP1

RCoA1

AR1 AR2

Movement

LCoA1:RCoA1 LCoA2:RCoA1

Home Networkis far away

MAP2

RCoA2

AR3 AR4

LCoA2:RCoA2 LCoA3:RCoA2

HMIPv6 Protocol Operation

• Mobile has two addresses

– RCoA, LCoA

– RCoA � stateless auto-configuration interfaceid+subnet prefix in MAP option

• Needs update on the implementation only

• HA and CN are unchanged

• MAP performs the function of “local” HA

that binds mobile node’s RCoA to LCoA

Protocol Flow for HMIPv6

MN CNR1 R2MAP1 HA

RA w MAP

option

LCoA and RCoAConfiguration

Local Binding Update (LBU)

MAPPerformsDAD

Local Binding Acknowledgement (LBacK)

BU

BU

MN-MAP Tunnel

RA w MAP option

MobileHands over

Local Binding Update (LBU)

Local Binding Acknowledgement (LBacK)

Tunnel

Data

DataTunneled Data

Cellular IPHomeHomeAgentAgent

Correspondent

HostInternet

(with Mobile IP)

Gateway AGateway A

Cellular IP

Node

Cellular IP

Node

CIP

Node

CIP

Node

CIP

Node

CIP

Node

Gateway BGateway B

Cellular IP

Node

Cellular IP

Node

CIP

Node

CIP

Node

CIP

Node

CIP

Node

Domain A

Domain B

MIP

registration

CIP updateMedia

Inter Domain handoff

(SIP/MIP variants)

Optimization for Media Redirection

• Forwarding of in-flight data

– Buffering

– Small group multicasting

– Copy and Forwarding

Related Work• Buffering at the source

– Rosenberg et al, Collins et al – FEC, AVT

• Buffering at the destination

– Playout Buffer for RTP

• Buffering in the middle of the network

– Perkins et al – RFC 2354, Optimized Smooth Handover (MIPv4)

– N. Moore et al, Krishnamurthy et al – MIPv6

– M. Khalil et al - MIPv4

– Mobility Anchor Point

• Buffering at the edges

– Koodli et al – FMIPv6

– IAPP ( Layer 2 – 802.11)

Overview of Buffering Scenarios

Buffer Node

Post Handoff Traffic

with route optimization

Pre Handoff

Traffic

Buffered traffic

New Network Previous Network

Mobile Node

Correspondent Node

Flushed Traffic after

handoff


with care-of-address

Signaling

Access

Router (BN)

Access Router

Buffering Node

Pre Handoff

Traffic

Buffered traffic

New Network Previous Network

Mobile Node

Correspondent Node

Flushed Traffic after

handoff


Signaling

Access

Router (BN)

Access Router

Buffering Model with Previous Access

Router as BN

Packet Buffering with Next Access Router

as BN

Buffer Node


Pre H andoff

Traffic Buffered traffic

New Network Previous Netw ork

Mobile Node

Correspondent Node

Signaling

Access

Router Access Router

Buffer Node

Buffered traffic

New NetworkOldPrevious Network

Mobile Node

Correspondent Node

Flushed Traffic after handoff

Signaling

Access Router (BN) Access Router

Buffer Node

Buffered traffic

New NetworkOldPrevious Network

Mobile Node

Correspondent Node

Flushed Traffic after handoff

Signaling

Access Router (BN) Access Router

End System Buffering

Buffering during handoff

Source

Mobile

Buffer Length (B)

Packet 1 throughN (Pre-handoff)

Mobile

N+1

N+2

N+3

StartBuffer Flush

Buffer

Packet N+4 onwards(post-handoff)

1…NN+1, …

End-to-end packet delay due to buffering

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Packet Number

En

d-t

o-e

nd

dela

y

End-to-end packet

delay due to buffering

IDMP Fast Handoff

Fundamentals•On detecting the impending change in point of attachment, the MN (or optionally SA) sends a MovementImminent message to the MA.–No additional information keeps the message very

short.

•On receiving this message, the MA starts multicasting all inbound packets by tunneling them to all neighboring SAs.–Pre-configured list of SAs to which MN can move.

Fast Handoff Operational View

Fast Handoff in MA-based

GCoA mode

MovementImminentMovementImminent

MN_addrMA data

MN_addr

Multi-cast MN_addr data

Multicasting Begins

Buffered Packets

Agent Advt.

Local Regn Request

Local Regn Response

Data Packets

MASA_oldMN

SA_new

Cross Layer TechniquesIEEE 802.21

Scope of IEEE 802.21

•The current scope includes a Media Independent Handover Function (MIHF) consisting of three basic components– Event Service (ES)– Command Service (CS) – Information Service (IS)

•Support for multiple access technologies (e.g., 802.3, 802.11, 802.16, and Cellular (3GPP and 3GPP2))

•Support for both network and device initiated handovers

What is Media Independent Handover?

•Media Independent Handover (MIH) is to facilitate handover optimization between heterogeneous media by providing

–Link layer intelligence and

–Network information to upper layers

• Media Independent Handover (MIH) is not to design another mobility management protocol rather help them to perform handover seamlessly by offering a better user experience

IEEE 802.21 OverviewThe goal of IEEE 802.21 is to facilitate mobility management protocols such that following handover requirements are fulfilled

• Service Continuity –Minimize the data loss and break time without user intervention

• Application Class–Supporting applications of different tolerance characteristics

• QoS–Specify means of obtaining QoS information of the neighboring networks

• Network Discovery and Selection –Network information could include information such as link type, link

identifier, link availability, link quality

–Selection of appropriate network based on required QoS, cost, user preference

• Security–Specify means of security information to be made available to the upper

layers

• Power Management–Real-time link status, efficient scanning provide proper battery power

management

MIHF and Its Interactions with Lower and Upper Layers

Lower Layers (L2 and below)

MIH Function

802.3 802.11 802.16 3GPP(WCDMA)

3GPP2(CDMA2000)

Upper Layers (L3 and above)

SIP MIPv4 MIPv6 HIP L3MP

MIH Events

Link Events Link Commands

MIH Commands Information Service

Information

Service

Cross-layer feedback in IETF Multimedia Protocol Stack

Application (Audio, Video, Data)

Codecs (H.261)SAP SIP

RTP RTCP

H.323

TCPUDP

SCTP

SDP

MIP MIPv6 ICMP IGMP

PPPAAL 3/4

CDMA/GPRS802.3802.11

CSMA/CA CSMA/CD

SONETTX powerModulation

BER

SNR,

switchingLINK status

RoutingHandoff

TCP Retransmission,

RTCPFeedback

Re-negotiate

Bw, codec

Adaptive Application User Needs, Requirement

CIP

User

AAL3/4

RIP OSPF

Petri-Net Modeling for Mobility Systems

Net-within-a-System net

Layer 2

Layer 3

Application

Layer

Layer 2Event

Layer 3Event

Layer 4Event

Enter Mobility Event

Leave layer 2

Disconnected

Leave layer 3

Leave mobilityevent

Enter layer 3

Enter layer 2

transition

Connected

SNR goes belowa threshold

State

Service

discovery

Scanning is performed

Selected

L2 authenticationperformed

Authenticated

Location

L3 discovery

L3 addressacquisition

DAD

configuration

L3 authenticationperformed

authenticated

Extraneous action

buffering

BU performed

Forwarding

Use Case: Using Multiple Radios

Ne

tw

or

k

Ty

pe

S

SI

D/

C

ell

ID

B

S

SI

D

Op

er

at

or

Se

cu

rit

y

N

W

C

ha

nn

el

Q

o

S

Ph

ysi

cal

La

yer

Dat

a

Rat

e

GSM

13989

N/A

AT&T

NA NA 1900

N/A

N/A 9.6 kbps

802.16d

NA

NA

T-Mobile

PKM

EAP-PEA

P

11

Yes

OFDM

40 Mbp

s

Wakeup WLANDownload over WLANShutdown GPS

Café

Airport

Zone 1 Zone 2 Zone 3

Zone 4 Zone 5 Zone 6

Zone 7 Zone 9

Wi-Fi

Wi-MAX

WLAN Link Going Down.

Switch to WiMAXDownload over WiMAXShutdown WLANWakeup GPS

Zone 8

Wi-Fi

Connect to WLAN

Battery level lowShutdown WiMAXDownload over GSM/GPRS

Wakeup WLAN

Wi-MAX

Shutdown GPSStart Download over WLAN

Network

Type

SSID/

Cell ID

BSSID Operator Security NW Channel QoS Physical

Layer

Data Rate

GSM 13989 N/A AT&T NA NA 1900 N/A N/A 9.6 kbps

Network

Type

SSID/

Cell ID

BSSID Operator Security NW Channel QoS Physical

Layer

Data Rate

GSM 13989 N/A AT&T NA NA 1900 N/A N/A 9.6 kbps

802.11b Café 00:00:… Café .11i EAP-PEAP

6 .11e OFDM 11 Mbps

Network

Type

SSID/

Cell ID

BSSID Operator Security EAP

Type

Channel QoS Physical

Layer

Data Rate

GSM 13989 N/A AT&T NA NA 1900 N/A N/A 9.6 Kbps

802.11b Airport 00:00:… Airport .11i EAP-PEAP

6 .11e OFDM 11 Mbps

Radio State

GSM

WLAN

WiMAX

GPS

Radio State

GSM

WLAN

WiMAX

GPS

Radio State

GSM

WLAN

WiMAX

GPS

Radio State

GSM

WLAN

WiMAX

GPS

Radio State

GSM

WLAN

WiMAX

GPS

Radio State

GSM

WLAN

WiMAX

GPS

Radio State

GSM

WLAN

WiMAX

GPS

802.21 and MP Enabled Seamless Mobility Deployment Scenario

Courtesy: Vivek Gupta, IEEE 802.21 chair

Link Layer Events

Event

Identifier

Event Type Event Name

1 State Change Link Up

2 State Change Link Down

3 Predictive Link Going Down

4 State Change Link Detected

5 State Change Link Parameters Change

6 Administrative Link Event Rollback

7 Link Transmission Link SDU Transmit Success

8 Link Transmission Link SDU Transmit Failure

9 Link Synchronous Link Handoff Imminent

10 Link Synchronous Link Handoff Proceeding

11 Link Synchronous Link Handoff Complete

Link CommandsNo Link Command Local,

Remote Media Types

Comments

1 LinkPowerUp L All Power Up a link

2 LinkPowerDown L All Power down a link

3 LinkConfigure L All Configure a specific interface

4 LinkConnect L All Connect on a specific link

5 LinkDisconnect L All Disconnect the connection on specified link

6 LinkSleep L All Put link into sleep mode

7 LinkScan L All Scan the link for network PoA

8 LinkPoll L All Poll a specific link

MIH Command List

No MIH Command Local,

Remote

Media Types

1 MIH Poll L, R All

2 MIH Switch L, R All

3 MIH Configure L, R All

4 MIH Scan L, R All

List of GNI Information Elements Name of the information element Description Media

Types

List of networks available List all network types that are available given a location or POA information

All

Location of POA Geographical Location, Civic address, PoA ID All

Network standards supported List of all available transmission technologies available

All

Network Identifier Unique ID of the network or network provider All

Operator Name of the network provider All

IP Version Indicates the version Internet Protocol used All

Roaming Partners List of direct roaming agreements All

Cost Indication of costs for service/network usage All

SLAList Service level Agreement list All

List of LLI Information Elements

Name of the Information Element Description Media Types

Neighbor Information Neighboring network information, measurement report

All

Security Link layer security supported All

Quality of Service Link QoS parameters All

AccessRouterInfo Access Router Parameters All

List of HLI Information Elements

Name of the Information Element Description Media Types

IMS Access (MMS, SMS, Presence, Instant Message, Push-to-Talk, …)

Indication whether specific service is supported or not

N/A

ISP Supported Internet Service Provider that provides the access to internet

N/A

Location based services List of Local services that are available given a location

N/A

VPN Supported Network enables VPN services

N/A

MIP Supported Network enables MIP version and services

N/A

Use of NAT NAT is used for internet access

N/A

Optimization Case Studies

Initial Experimental Results on Mobility Optimization(Systems Evaluation)

Experimental Validation of Mobility OptimizationCase Studies

Following are the experimental case studies where we have been able

optimize the handoff delay and reduce the packet loss by deploying several

Optimization Techniques discussed above

• Case I - Optimizing data path between CH and MH

• Case II - Optimizing Binding Update

• Case III - Optimizing Layer 3

• Case IV - Optimizing Security Association

• Case V - Make-before-Break Technique

• Case VI - Maintaining Security Association

• Case VII - Media Independent Pre-authentication proactive handover and buffering

• Case VIII – Optimized IMS Handoff• Case IX - Multicast Mobility

Media-independent Pre-Authentication

• MPA is:

–a mobile-assisted higher-layer authentication,

authorization and handover scheme that is

performed a-priori to establishing L2 connectivity to

a network where mobile may move in near future

• MPA provides a secure and seamless mobility

optimization that works for

–Inter-subnet handoff

–Inter-domain handoff

–Inter-technology handoff

•Use of multiple interfaces

• MPA works with any mobility management protocol

Functional Components of Proactive

Handoff

1) Pre-authentication/authorization

– Used for establishing a security association (SA) between the

mobile and a network to which the mobile may move

2) Pre-configuration

– Used for obtaining parameters (e.g., an IP address) from the

network to which the mobile may move

– The SA created in (1) are used to perform secured configuration

procedure

3) Secured Proactive Handover (PH)

– Used for sending/receiving IP packets from the current network

using the pre-configured parameters of the new network

Media-independent Pre-Authentication (MPA)• MPA is a mobile-assisted higher-layer authentication,

authorization and handover scheme that is performed a-priori to establishing L2 connectivity to a network where mobile may move in near future

• MPA provides a secure and seamless mobility optimization that works for Inter-subnet handoff, Inter-domain handoff and Inter-technology handoff

• MPA works with any mobility management protocol

TimeConventional

Method

AP DiscoveryAP DiscoveryAP DiscoveryAP DiscoveryAPAPAPAP

SwitchingSwitchingSwitchingSwitching

MPA

Pre-authentication

IP address

configuration

& IP handover

Time

Client

Authentic

ation

Packet Loss Period

Media Independent Pre-authentication -

Seamless Handoff (a deployment scenario)

AA CA

MN-CA keyAR

Network 3

AR

AA CA

MN-CA key

Network 2

INTERNETInformation

Server

Mobile

Current

Network 1AR

AP1 Coverage Area AP 2 & 3 Coverage Area

AR

Network 4

CN

AP3AP2AP1 CTN

TN

CTN – Candidate Target Networks

TN – Target Network

Home

Network HA

MPA Overview

CN: Correspondent NodeMN: Mobile NodeAA: Authentication AgentCA: Configuration AgentAR: Access Router

AA CA

A(X)

2. DATA [CN<->A(Y)] over proactive handovertunnel [AR<->A(X)]

AR

L2 handoff procedure

Domain X Domain Y

CN

Data in new

domain

1. DATA[CN<->A(X)]

MN-CA key

Preconfiguration

pre-authentication

MN-AR key

3. DATA[CN<->A(Y)]

Data in old

domain

MN

A(Y)

BU

Proactive handovertunneling end

procedure

Tunneled Data

MN

Proactive Handoff Experimental Results (Case III) Mobility Type MIPv6

Handoff

Parameters

Buffering Disabled

+ RO Disabled

Buffering

Enabled

+ RO

Disabled

Buffering Disabled

+ RO

Enabled

Buffering

Enabled

+ RO

Enabled

Buffering

Disabled

Buffering

Enabled

L2 handoff (ms)

4.00 4.33 4.00 4.00 4.00 5.00

Avg. packet loss

1.33 0 0.66 0 1.50 0

Avg. inter-packet interval (ms)

16.00 16.00 16.00 16.00 16.00 16.00

Avg. inter-packet arrival time during handover (ms)

n/a 45.33 n/a 66.60 n/a 29.00

Avg. packet jitter (ms)

n/a 29.33 n/a 50.60 n/a 13.00

Buffering period (ms)

n/a 50.00 n/a 50.00 n/a 20.00

Avg. Buffered Packets

n/a 2.00 n/a 3.00 n/a 3.00

SIP Mobility

Performance (MPA-Non-MPA) – Single

I/F• MPA

– No packet loss during pre-authentication, pre-configuration and pro-active handoff before L2 handoff

– Only 0 packet loss, 4 ms delay during handoff mostly transient data

• Includes delay due to layer 2, update to delete the tunnel on the router

• We also reduced the layer 2 delay in hostap

Driver

• L2 delay depends upon driver and chipset

• non-MPA

– About 200 packets loss, ~ 4 s during handover

• Includes standard delay due to layer 2, IP address acquisition, Re-Invite, Authentication/Authorization

– Could be more if we have firewalls also set up

MPA Approach

Non-MPA Approach

handoff

802.11 802.11

4 s

Handoff Delay

~ 18 s

802.11 CDMA

Handoff Delay

16 s

802.11 CDMA

a. MIP-based Non-optimized handoff

b. SIP-based Non-optimized handoff

c. MPA and 802.21 assisted optimizedhandoff

802.11 CDMA

Optimized handoff delay with MPA (Multiple I/F)

Optimized Handoff - Audio

Optimization in IMS Testbed

P-CSCFP-CSCF S-CSCF

AS

HSS

I-CSCF

PDSN HA

VN1-re2VN2-re3

802.11b 802.11b

Visited Network 1

Visited Network 2

DHCPDHCP

RAN Emulator

Mobile Node

K6Router

192.168.6.0/24192.168.8.0/24

6.2

6.1

8.2HN-HA

HN-AS-SCSCFHN-HSS-ICSCF

VN1-PCSCF

VN1-DHCP

VN2-PCSCF

VN2-DHCP

VN2-PDSN

VN1-PDSN

VN1-RE-12

PDSN

RAN Emulator

VN2-RE-21

8.1

Mobile Node

Domain: kddi.testbed

VN1-re1

802.11b

Home Network

IPTV Server

HN-IPTVServer

RAN Emulator

VN1-RE-11

6.3

PDIF

VN2-PDIF

VN2-re4

802.11b

::5::10::15::25::5::10::15

3ffe:2::/64

3ffe:1::/643ffe:5::/64

::1

::1

::1

::10::5

3ffe:5::30

(Mobile IP case) mh2

3ffe:5::35

(Mobile IP case)

::20::15::25

PDIF

VN1-PDIF

VN1-re5

802.11b

<PPP address on PDSN>

mh1 3ffe:11::MAC/64

mh2 3ffe:11::MAC/64

<PPP address on PDSN>

mh1 3ffe:22::MAC/64

<Address on PDIF>

mh1 3ffe:33::MAC/64

<Address on PDIF>

mh1 3ffe:44::MAC/64

PCRF

VN2-PCRF

::30

VN1-PCRF

::30

PCRF

To visited domain

mh3

3ffe:5::40

(Mobile IP case)

Mobile NodeMobile Node3ffe:5::30

(Mobile IP case)

Current demonstration• P-CSCF fast handover

– Non-Optimized– Reactive– Proactive

• Optimized Roaming– Dual anchoring– Home address anonymity

Functions-Protocol MappingFunctions Protocols

Signaling, Personal Mobility SIP

Policy Control, Feature Interaction

Diameter

Mobility Management MobileIP[v4,v6], SIP, ProxyMIPv6

Security IPSec, L2 Security

Server Configuration DHCP

Address configuration Stateless Autoconfig, DHCPv6

Streaming, IPTV RTSP

Name Resolution DNS

Multicast Routing PIM-SM

Multicast Mobility Remote Subscription based

Non-Optimized Mode of Operation

MIP Registration Request

MN old P-CSCF new P-CSCF S-CSCF

401 Auth. (Reg.) - new Key, vector

REGISTER (MN address)

Medialoss

Radio

handoff

old DHCP new DHCP HA

MIP Registration Reply

Non Encrypted

Non Encrypted

new SA setupnew SA setup

Open Gate

Createa new context

Re-INVITE

401 Auth. (Reg.) - vector

Encrypted by new SA 200 OK (Reg.)

REGISTER (Auth, MN address)

200 OK (Reg.)

REGISTER (Auth, MN address)Encrypted by new SA

Encrypted by new SA

Encrypted by new SA

REGISTER (MN address)

DHCP Inform (pcscf, pcscf-neighbor)

DHCP Ack (new P address, neighbor P addresses)

200 OK (Reg.)

Re-INVITE

200 OK (Reg.)

Reactive Mode of Operation

M IP Registra tion Request

M N old P -C S C F new P -C SC F S-C SCF

Do C on text T ransfer (new P address, M N address)

401 Au th. (R eg.) - new K ey, vec tor

C ontext T ransfer (M N In form ation)

REG ISTE R (MN address )

Med ia

loss

R adio

hando ff

O pen G ate

R EG IST ER (MN address)

o ld D HC P new DHC P H A

M IP Registra tion Reply

R e-C reatethe context

Non

Encrypted

Non

Encrypted

new SA setup

401 A uth. (R eg.) - vec tor

Encryp ted by

new SA200 O K (R eg.)

REG ISTE R (Auth, M N address )

200 O K (Reg.)

REG IST ER (Auth, M N address)Encryp ted by

new SA

new SA s etup

C ontext T ransfer Ack (MN address)

DH C P Inform (pcscf, pcscf-neighbor)

DH C P Ack (new P address, neighbor P addresses)

Proactive Mode of Operation

M IP R eg istra tion Request

M N old P-C SC F new P-C SCF S-CSCF

M oveNotify (new P address, MN address)

401 Auth . (Reg.) - new Key, vector

Context Transfer (old Key, M N Inform ation)

R EG ISTER (M N address)

new SA setup

Re-Createthe context

Media

loss

Radiohandoff

O pen G ate

401 Auth . (Reg.) - vector

REG ISTER (MN address)

old DHC P

Encrypted by

new SA

new DHCP HA

M IP R eg istra tion Reply

Encrypted by

old SA

o ld SA setupEncrypted by

old SA

Encrypted by

old SA

200 OK (Reg.)

R EG ISTER (Auth , M N address)

200 O K (Reg.)

REGISTER (Auth, MN address)Encrypted by

new SA

new SA setup

Context Transfer Ack (M N address)

D HCP Inform (pcscf, pcscf-neighbor)

D HCP Ack (new P address, neighbor P addresses)

Basic Functional Components During

Handoff in IMS/MMD

•Handoff related functions in IMS

– Layer 2 Configuration

– Layer 3 Configuration

– Mobility Binding

– Session Registration

– Security Association

– Session Maintenance

– Media control on PDSN

0 3000 6000 9000 12000

Proactive

Reactive

Non-Optimized

Typ

es o

f H

andoff

Time in ms

PPP Termination

Layer 2 Delay

PPP Activation

MIP-Solicitation

MIP-Binding Update

DHCP Trigger

DHCP Inform

SIP Trigger

SIP+Security

Media Redirection

Figure 1: Levels of Optimization

MIPv6-SIPM-ProxyMIPv6 in IMS

0 2000 4000 6000 8000 10000

Proxy MIPv6 (cdma2000)

Proxy MIPv6 (WiFi)

SIP mobility (cdma2000)

SIP mobility (WiFi)

MIPv6 (cdma2000)

MIPv6 (WiFi)

Handoff time [ms]

IEEE 802.11b handoff PPP negotiation

Layer 3 address configuration Binding update

SIP server address configuration SIP Registration

SIP re-INVITE/Gate open

MIPv6-SIP-ProxyMIPv6 results –effect of RAN delay

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

50 100 150 200 250 300 350 400 450 500

RAN delay [ms]

Han

doff

tim

e [m

s]

MIPv6 SIP mobility Proxy MIPv6

Multicast Mobility (remote Subscription)

Internet

Home Network

HA

MN

Visited Network 1

DHCP

MN

Multicast Tree

Visited Network 2

MN

MR1 MR2

DHCP

Handover

Source

Fast-handoff with Multicast mobility

S1 S2p1 p2

BS0BS1

Sources

Backbone

Ad server

Local

Server

m1

m2

Local

Program

RTSP

Ad server

Local

Server

m1

m2

Local

Program

RTSP

BS2

M-Proxy

(P1,a1) (P2,a2)P2,a2

P2,a3

S0

S1

(a1,a2)

(a3)

• Fast-handoff for the mobiles

• QoS negotiation

RTCP

IGMP

Layer 2 Handoff for Multicast

0

1

2

3

4

5

0 200 400 600 800

Time in Seconds

Pro

toc

ols RTP

DRCP

Router Query

Q.Response

IGMP-802.11 (Subnet) Handoff

0

1

2

3

4

5

0 200 400 600 800 1000

TIme in Seconds

Pro

toc

ols

In

sta

nc

e a

t M

ob

ile

RTP

DRCP

Router Query

Q.Response

JOIN Latency JOIN Latency

Subnet

handoff

Subnet

handoff

Ping-Pong Ping-Pong

There is no JOIN Latency but Leave latency

inherent

JOIN Latency is about 60 seconds

Proxy assisted subnet handoff

0

1

2

3

4

5

0 200 400 600 800

Time in Seconds

Pro

toc

ols

at

mo

bil

e

RTP

DRCP

Router Query

Q.Response

JOIN latency is almost zero

Leave latency is still an issue

LEAVE latency during 802.11subnet handoff

0

1

2

3

4

5

120 180 240 300 360 420 480 540 600

Timr in Seconds

Pro

toc

ols RTP

DRCP

Router Query

Ping Mobile

Maximum leave latency is about 3 min.

Leavelatency

Proactive Proxy-based handoff for Multicast in 802.11

environment (Case III)

Bluetooth

APCDMA

Corresponding Host

Router/ Foreign Agent Router/ Foreign Agent

802.11

AP

Home Agent

BackboneNetwork

Visiting Network A Visiting Network B

Home Network

Ether

Bridge

Video StreamVideo Stream

Multi-Interface Mobility Management (Make-before-Break)

IntraIntra--Subnet MobilitySubnet MobilityInterInter--SubnetSubnet

MobilityMobility

Movement type Cellular-802.11b

802.11b –

Cellular

Handoff

Trials

#1 #2 #1 #2

INVITE -> OK 0.12 s

0.12 s

1.32 s 6.64 s

INVITE ->

1st Packet

0.39 s

0.41 s

2.54 s 7.18 s

Re-transmission

None None Yes Yes

Operation Timing

PPP setup 10 sec

X-MIP 300 ms

VPN Tunnel

setup

6 Sec

I-MIP 400 ms

I-MIP (Home) 200 ms

IPSEC 60 ms

DHCP 3 Sec

TransmissionDelay 5 ms 802.11

2.5 s cellular

Packet Transmission Delay for Voice Traffic

0.00000010

0.00000100

0.00001000

0.00010000

0.00100000

0.01000000

0.10000000

1.00000000

36

46

0

37

80

0

39

14

0

40

48

0

41

82

0

43

25

2

45

58

6

49

31

7

52

62

4

56

93

3

60

94

0

62

28

0

63

62

0

Packet Numbers

Tra

ns

mis

sio

n D

ela

y i

n (

Lo

g S

ca

le)

Transmission Delay

802.11

Cellular

802.11

Packet Transmission Delay for Voice Traffic

0.00000010

0.00000100

0.00001000

0.00010000

0.00100000

0.01000000

0.10000000

1.00000000

36

46

0

37

80

0

39

14

0

40

48

0

41

82

0

43

25

2

45

58

6

49

31

7

52

62

4

56

93

3

60

94

0

62

28

0

63

62

0

Packet Numbers

Tra

ns

mis

sio

n D

ela

y i

n (

Lo

g S

ca

le)

Transmission Delay

802.11

Cellular

802.11

Inter-Packet Delay Variation betw een CH and MH (Voice)

0.0010

0.0100

0.1000

1.0000

10.0000

36

46

0

37

48

4

38

50

8

39

53

2

40

55

6

41

58

0

42

60

4

44

01

2

46

01

9

48

86

7

51

67

1

54

17

2

58

27

9

60

85

2

61

87

6

62

90

0

Packet Numbers

Inte

r-P

ac

ke

t D

ela

y d

iffe

ren

ce

(lo

g s

ca

le)

Delay Variation

802.11 802.11

Inter-Packet Delay Variation betw een CH and MH (Voice)

0.0010

0.0100

0.1000

1.0000

10.0000

36

46

0

37

48

4

38

50

8

39

53

2

40

55

6

41

58

0

42

60

4

44

01

2

46

01

9

48

86

7

51

67

1

54

17

2

58

27

9

60

85

2

61

87

6

62

90

0

Packet Numbers

Inte

r-P

ac

ke

t D

ela

y d

iffe

ren

ce

(lo

g s

ca

le)

Delay Variation

802.11 802.11

(a) Packet Transmission Delay(b) Inter-packet departure and arrival delay variation for

CBR (Voice)

Mobile IP with VPN

SIP-based multi-interface mobility management

Experimental results for handoff delay with multiple Interfaces

without optimization

SIP Mobility (MIMM) – Make-before-break (802.11 – CDMA)

MN: WLAN - Eth0 – 10.1.10.2CDMA - PPP0 – 166.157.116.186

CN – 165.254.55.2

•Jitter observed in Cellular Network-Several Re-INVITE retransmissionin CDMA network-Packets are received in eth0 duringSIP Re-INVITE sequence- No packets are lost during the handoff

MNCN

(ppp0)

RTP (28790)16.202

16.240

16.242RTP (28791)

(eth0)

(ppp0)

(eth0)

Re_INVITE (IP1)

Re-INVITE (Re-trans) –IP116.750(ppp0)

RTP (28792)16.285(eth0)

16.322

16.362

RTP (28793)

RTP (28794)

Re_invite (Re-trans)- IP117.761

RTP

RTP

(eth0)

(eth0)OK

19.639(ppp0)RTP

(eth0)

19.758ACK

(ppp0)RTP

RTP(eth0)

(eth0)28888

RTP 2888920.549(ppp0)

20.122

20.669(ppp0)RTP 28890

Handoffdelay

20.769(ppp0)

20.869

(eth0)

(eth0)

MIP with Make-before-break (802-11-CDMA)MN HA CN

RTP 644407eth0 39.594

RTP 644408eth0 39.630

RTP 644405

RTP 644406

Mobile IP (reg)eth0 39.514

ppp0 39.520

eth0 39.551

RTP 644409eth0 39.674

RTP 644410ppp0 40.059

ppp0 40.119RTP 644411

Mobile IP (Rep)

ppp0 40.219

ppp0 40.339RTP 644412

ppp0 40.629RTP 644413

RTP 644414ppp0 40.649

RTP 644415ppp0 40.659

Tunnlled data

Non-tunneled data

Signaling

CN – 207.3.232.223, MN – WLAN – eth0 – 10.1.10.2

CDMA – PPP0 – 166.157.32.161

Data Sentat 40 ms interval

Jitter in cellular

eth0 – wavelan InterfacePpp0 – cellular interface

Deployment Roaming Scenarios

vDHCPvP-CSCF

hMN

hAGW

hMN

Home domainVisited domain

vS-CSCF

vASvAAA

hMNhMN

Home Local MobilityGlobal MobilityVisited Local Mobility

Internet

hMN hMN

hAGWhAGW

Trust domain

vPCRF

hDHCPhP-CSCF

hS-CSCF

hAShAAA

hPCRF

vAGWvAGWvAGW

hHAvHA

Roaming Movement Matrix

MIPv6

PMIPv6/MIPv6

PMIPv6/MIPv6

Simple IPv6MIPv6 (Case IV)

MIPv6

PMIPv6/MIPv6 (Case VI)

Simple IPv6PMIPv6/MIPv6 (Case III)

MIPv6

PMIPv6/MIPv6

Simple IPv6Simple IPv6CMIPv6

MIPv6

Simple IPv6MIPv6

MIPv6

PMIPv6/MIPv6

Simple IPv6 PMIPv6/MIPv6 (Case II)

MIPv6

PMIPv6/MIPv6 (Case V)

Simple IPv6 Simple IPv6 (Case I)Simple IPv6

Visited DomainHome DomainMN Stack

This case may not happen.

Multi-Media Session Continuity (3GPP)• The MMSC solution will provide IMS level multimedia session

continuity when the user is moving between 3GPP access systems or when the user is moving between 3GPP and non-3GPP access systems with minimum disruption

• Two basic scenarios are PS-PS and PS-PS in conjunction to PS-CS

Non-3GPP

(e.g. WiMAX)

E-UTRAN

Intermediate

IMS elements

MGCF

P-CSCF-a1

Voice + data

Voice + data

P-CSCF-a2

UE-1

UE-2

Voice + data

WLAN

UTRAN/

GERAN

Intermediate

IMS elements

MGCF

P-CSCF-a1

Voice + data

Voice + data

Data

P-CSCF-a2

Voice

UE-1

UE-2

PS-PS Scenario

PS-PS in conjunctionto PS-CS Scenario

Mobility Modeling

217

Scheduling

of handover

operations

Relevant

optimization

principles

Example experimental mobility systems Potential

Target

Mobility

System

SIP-based

Fast

handoff

Mobile

VPN

Media

Independent

Pre-authentication

Simultaneous

Mobility

Optimized

handoff

In IMS

Muti-layer

Mobility

Multicast

fast

handoff

Sequential Direct path between

CH and MH X

Limit binding update

between CH and MH X X

Maintain Security

association

between end-points

X

Anchor-based

ForwardingX X

Post-handoff triggers X

Proactive Pre-handoff triggers X X

Proactive network

discovery X

Proactive

authentication X

Proactive identifier

configuration X

Proactive

binding updateX X

Dynamic Buffering X

Proactive context

transfer X

Parallel Discovery of Layer 2

and Layer 3 PoA X

Binding update X

Optimized mobility system design

Mobility model Problem: In the absence of any formal mechanism it is difficult to predict or

verify the systems performance of un-optimized handover or any specific handoff optimization technique

Proposal

• Analyze the basic primitives of a handoff event

• Model the handoff-related processes as Discrete Event

Dynamic Systems (DEDS)

• Deterministic Timed Transition Petri Net (DTTPN) to build various un-optimized mobility models and their associated optimization techniques

Key advantages :

• This model can predict systems performance for optimized handoff operations

• This model can design optimal path for sequence of execution of events based on expected performance and resource constraints

• This model can verify systems behavior (e.g., deadlocks) during handover

218

Framework for Systems Optimization

Design a Generalized Systems Model to characterize

Mobility Optimization

• List a common set of properties that get affected (changed)

during different types (micro, macro, domain) mobility

• Need a generalized Systems Model to represent these

Mobility experiments

– A Systems Model for mobility optimization can be

characterized as a Discrete Event Systems Model

– An FSM model can be used to model the state transition

for mobility optimization

• Conduct a performance evaluation using this generalized

model (e.g., Timed Petri Net)

Systems Optimization Approach • We model mobility events as a set of discrete state transition events

within a layer and between layers

• Mobility events contribute to the change in state (e.g. Discrete State Events) within a mobile due to layered transition

• State transitions take place within a layer and between layers during mobility events

• We propose various handoff optimization techniques – Proactive, Reactive, Parallel– That help reduce the handoff delay at different layers– Mitigates effect of handoff delay (i.e., packet loss), jitter

• We map our optimization techniques to the mobility system model

• We perform experiments and simulation to show the implementation results for the following cases

Pa Pb

Pa Pb

Pa

Pb

Pa

Pb

tc

Pa

Pb

pb

pa

tc

tc

ta tc tb

ta tbta

tc tb

tc ta

tb

ta

tb

pa starts before pb

pa meets pb

pa overlaps pb

pa during pb

pa starts pb

pa finishes pb

pa starts with pbpa

pb

tc

tb

tc ta

ta

tb

Timing Diagram for sequence of events

Petri Net Primitives

t1 t2

b. Conflict

P1

p1

p2

p1

p2

t1

p1

p2

t1

t2

t3

d. Synchronization

f. Confusion

P1 t1 t2 P3

a. Sequential

c. Concurrent

p1

p2

t1

t2

P3

e. Merging

p1

p2 p3

t1

t2

g. Mutual exclusiveh. Priority

Sample Handover OptimizationExample (1) - Proactive Handover

Mobility Type

Mobile IPv6 SIP mobility

Handoff

Parameters

Bufferin

g

Disable

d

+ RO

Disable

d

Buffering

Enabled

+ RO

Disabled

Buffering

Disabled

+ RO

Enabled

Buffering

Enabled

+ RO

Enabled

Buffering

Disabled

Buffering

Enabled

L2 handoff (ms)

4.00 4.0 4.00 4.00 4.00 4.00

L3 handoff

(ms)

1.00 1.00 1.00 1.00 1.00 1.00

Avg. packet loss

1.3 0 0.7 0 1.50 0

Avg. inter-packet interval (ms)

16.00 16.00 16.00 16.00 16.00 16.00

Avg. inter-packet arrival time during handover (ms)

21 45 21 67 21 29.00

Avg. packet jitter (ms)

n/a 29.00 n/a 51.00 n/a 13.00

Buffering period (ms)

n/a 50.00 n/a 50.00 n/a 20.00

Avg. Buffered Packets

n/a 2.00 n/a 3.00 n/a 3.00

Results: Media independent proactive handoff

802.11802.11

4 s

223

Non-optimized handoff (200 packets loss, ~ 4 s handover delay)

Media Independent Pre-auth handoff (No packet loss – 5 ms handoff delay)

802.11 802.11Interruption

AAA

nAR

L3 PoA

MN

AP1

L2 PoA

AP0

(L2 PoA)

Pre-authentication

Network ANetwork B

Pre-configuration

pAR

L3 PoA

Core

Network DHCPserver PANA

server

Buffering

module

Tunneling

module

MN

HA (MIP)Home

Network

Proactive

Handover

Tunnel

CN

Network C Network D

224

Sample Handover Optimization: Example (2) -

IMS

0 3000 6000 9000 12000

Proactive

Reactive

Non-Optimized

Typ

es o

f H

andoff

Time in ms

PPP Termination

Layer 2 Delay

PPP Activation

MIP-Solicitation

MIP-Binding Update

DHCP Trigger

DHCP Inform

SIP Trigger

SIP+Security

Media Redirection

DOMAIN

research.telcordia.com

P-CSCF P-CSCFS-CSCF

ASI-CSCF I-CSCFHSS

SPE

I-CSCF

InternetInternet

HUB

HUB

HUB

192.168.10.0/24

Mobile

Phone

Mobile

Phone

SIP-UA

mh3

URI: user3

SIP-UA

mh1

URI: user1

SIP-UA

mh2

URI: user2

PDSN

Gateway

FA

Gateway

PDSN

FA

HA

Sample Testbed

kddiv1kddiv2

802.11b802.11b

CH 8 CH 8

Home NetworkVisited Network 1Visited Network 2

Database Monitor

Packet Snooper

DHCP

HUB

CDMA 2000

RAN

Emulator

kddiw2

DHCP

HUB

CDMA 2000

RAN

Emulator

Mobile

192.168.20.0/24

192.168.30.0/24

Router

192.4.30.0/24

192.168.6.0/24

192.168.7.0/24

192.168.8.0/24

192.168.9.0/24

10.5

10.4 10.3 10.2

20.5 20.4 20.3 20.2

6.2

6.1

7.1

8.2

8.1

9.1

20.1

10.1

30.1

30.230.330.4

kddi1

kddi2

kddi3

kddi4kddi5kddi6

kddi7kddi8kddi9

kddigw2

kddigw1

kddiw1

213-111

Figure 2: Handoff delay with 3 levels of optimization

Figure 1: IMS Experimental Testbed

Components optimized

ConnectedP8

Disconnected

NetworkDiscovered

NetworkSelected

MobileConfigured

AuthenticatedSecurityAssociationEstablished

Updated

NetworkResourceDiscovery Network

SelectionDetectionProcess

NetworkConfiguration

AuthenticationProcess

Binding Update

MediaForwarding

P1 P2 P3

P4P5P6

P0

t1 t2t3

t4

t5t6t7

P7

Intra-domainBinding update

t8t9

BufferingRedirection

t0

p01

p02

p03

t01

t02

t03

t013

t04

Security AssociationProcess

Modeling Mobility Event as Discrete Event Dynamic Systems (DEDS)

Description of Places and TransitionsPlace Description

P0 Mobile is in disconnected state

P1 Network and resources discovered

P2 Target network selected

P3 Mobile is configured and registered

P4 Mobile is authenticated

P5 Security Association is established

P6 Binding Update is complete

P7 Intra-domain binding update is complete

P8 Mobile is connected state

Transition Description Time Delay

t0 Mobile gets disconnect trigger 1t

t1 Mobile discovers the network and resources at the new PoA 2t

t2 Mobile selects the network 3t

t3 Mobile goes through configuration and registration 4t

t4 Mobile goes through authentication process 3t

t5 Mobile goes through key derivation and security association process 2t

t6 Mobile goes through binding update process 6t

t7 Mobile goes through hierarchical binding update 5t

t8 Mobile gets redirected to the mobile 2t

t1

p1p0 t2

p2t3

Layer 2association

Router Solicitation Domain

advertisement

2

Mobile connected

p6

p3p4

p5

Channelavailable

(Resource: Battery Power) (Resource: CPU Cycles)(Resource: Bandwidth)

Petri net modeling: Handoff attachment process

t1p1

p0 t2p2

t3

p4p3 p5

3

1

IdentifierAcquisition

Duplicate Address Detection Address

Resolution

12

2

MobileConfigured

MobileAuthenticated

(Resource: Battery Power) (Resource: CPU cycles)(Resource: Bandwidth)

p6

Petri net modeling - Handoff configuration process

Dependency analysis among handover operations

Handoff Process Precedence Relationship

Data it depends on

P11 – Channel Discovery P00 Signal-to-Noise Ratio valueP12 – Subnet discovery P21,P22 Layer 2 beacon ID

L3 router advertisementP13 – Server discovery P12 Subnet address

Default router addressP21- Layer 2 association P11 Channel number

MAC address Authentication key

P22- Router solicitation P21, P12 Layer 2 bindingP23- Domain advertisement P13 Server configuration

Router advertisementP31 – Identifier acquisition P23,P12 Default gateway

Subnet address Server address

P32 – Duplicate addressdetection

P31 ARPRouter advertisement

P33 – Address resolution P32, P31 New identifierP41 – Authentication P13 Address of authenticatorP42 – Key Derivation P41 PMK (Pairwise Master Key) P51 – Identifier update P31,P52 L3 Address

Uniqueness of L3 addressP52 – Identifier verification P31 Completion of COTIP53 – Identifier mapping P51 Updated MN address

at CN and HAP54 – Binding cache P53 New Care-of-address mappingP61 – Tunneling P51 Tunnel end-point address

Identifier addressP62 – Forwarding P51, P53 New address of the mobileP63 – Buffering P62, P51 New identifier acquisition P64 – Multicasting/Bicasting P51 New identifier acquisition

229

Resource usage per mobility eventsSub transitions

Sub-operations Resource Consumption

Bytes exchanged

CPU samples

Power due to transmission(nanojoules)

t00 Layer 2 un-reachability test 43 5 51600

t01 Layer 3 unreachability 86 3 103200

t11 Discover layer 2 channel 109 3 130800

t12 Discover layer 3 subnet 110 4 132000

t13 Discover server 126 5 540000

t21 Layer 2 association 99 2 118800

t22 Router solicitation 70 4 84000

t23 Domain advertisement 226 4 271200

t31 Identifier acquisition 1426 5 1711200

t32 Duplicate address detection 164 6 196800

t33 Address resolution 60 3 72000

t41 Layer 2 open authentication 94 3 112800

t42 Layer 2 EAP 2842 6 3410400

t43 Four-way handshake 504 4 604800

t51 Master key derivation (PMK) 0 10 0

t52 Session key derivation (PTK) 0 6 0

t61 Identifier update 204 4 422400

t62 Identifier verification 148 6 177600

t63 Identifier mapping 0 8 0

t64 Binding cache 0 3 0

t71 Fast binding update 110 3 132000

t72 Local caching 0 6 0

t81 Tunneling 60 2 72000

t82 Forwarding 100 2 120000

t83 Buffering 120 3 144000

t91 Local id mapping 40 4 48000

t92 Multicasting/bicasting 192 2 230400 230

Petri net modeling of handoff processes

P00 t01

t11

t41

p11

p41

t13

p13

t42

p42

t21

p21

t22

p22

t12

p12

t23

p23 P52

t52 t51 P51

t53 p53

t64p64

t62

p62

t63

p63

t54 p54

p61

t31 t32 t33

p31 p32 p33

t70

Resource network capacity

Resource Battery

Resource CPU

PotentialParallelOperation

Connected

Verification of handover systems performance in Petri net

1.Reachability analysis to study behavioral characteristics (e.g., deadlocks)

2.Cycle time of Deterministic Timed Petri net

– Minimum cycle time (C) is an indicator of maximum system performance (delay vs. resource)

3.Floyd algorithm– S matrix is formed out of token loading matrix, transition

matrix and distance matrix

– Inspection of the diagonal elements of matrix “S” indicates whether systems meets the required performance

Scheduling of handoff operations

233

Association

Network

discovery

P11

t11

PA2

4-way

Handshake

(SA)

t1

t4 t5

P2 P3

Connected

Dis

connected

Pre-authentication

Current Network Target Network

PA1

PC

PB1

PD

t12

t13

AP

Key installation

P12

P1

Resources CPU

PC

Resource s

Battery

PB

4-way

handshake

completet3

t4 t5

P2

P3

t2

Scanning

Authentication

Network

Discovered

4-way

Handshake

Operation

P1

Resources

Network capacity

Mobile

Authenticated

Connected

Association

P0

P01

P02

2 2

t1

PA

PC CPU

Battery

PB

t3

t4

t5

P2

t2

Scanning

Authentication

Network

Discovered

4-way

Handshake

P1

Resources

Network Capacity

Mobile

Authenticated

Connected

P0

P01

P02

2

t1

P03

P3Association

4

PA

C. Proactive operations

B. Parallel operations – Level of concurrency =2

D. Parallel operations – Level of concurrency = 3

A. Sequential operations

Batterypower

scanning Authentication 4-way

Handshake

t2 t3 t4 t5

P2 P3 P4

Association

Connected

Mobile

Disconnected

Network capacity

CPUcycles

P1

PA

PB

PC

P0

t1Disconnection

Network

Discovered

Mobileauthenticated

1 token

Deadlocks in HandoffPA

CPU

Memory

PB

4-way handshakecompletet2

t3 t4

P2

P3

t1

Scanning

Authentication

Network

Discovered

4-wayHandshakeOperation

P1

ResourcesNetwork b/w

Mobile

Authenticated

ConnectedAssociation

P0

P01

P02

2

2

a. Deadlock due to resource constraint

Deadlock

b. Deadlock avoidance with additional resources

No -Deadlock

Deadlock analysis for simultaneous mobility

235

Deadlock Scenario (non-optimized) Deadlock verification (deadlock exists)

Deadlock avoidance with retransmission Deadlock verification (No deadlock)

Deadlock

Deadlock

01/06/2009 HICSS-42 236

Results from Cycle Time-based approach

Proactive

Concurrent

Sequential

Optimization

schedule

17117P1t1P2t4P3t5P1

4201420p0t1p01t2p1t3p3t4p0

4701470p0t1p1t2p2t3p3t4p4t5p0

Max Di/Ni

Minimum cycle

Time (ms)

NiDiRelevant

loop in Petri Net

t5

t4

t3

t2

t1

Transition

5 msAssociation

10 ms4-way handshake

50 msAuthentication

400 msScanning

5 msDisconnection

Trigger

Experimental

Results

Handoff

operation

C. Proactive – meets systems performance C=100

A. Sequential : Does not meet systems performance Cycle

time C =100

B. Concurrent: does not meet systems performance for C= 100

D. Concurrent– meetssystems performance C= 410

Verification of handoff systems performance using Floyd algorithm

237

Summary of rules of handoff optimization• In general, handoff event can be described as Discrete Event Dynamic Systems

where optimization at each sub-component level contributes to the overall optimization process

• Optimization techniques can primarily be defined as the following category– Sequential– Parallel– Predictive

• Minimize execution time by maximizing parallelism between various functional components– A system that introduces parallelism into a sequential program in such a way as to

maintain correct results is called determinate

• Reduction of signaling overhead during handoff operation at component level– Caching– Local redirection to reduce the traversal of signaling

• Proactive execution of handoff events• Cross layer triggers• Optimal buffering strategy to reduce packet loss• Local agent assisted media redirection• Research Issues

– Resource utilization for proactive handoff operations– Extent of parallelism between operations– Optimum handoff strategy

Conclusions• Several types of IP-based mobility protocols have evolved over the years

– End-to-end – Infrastructure-assisted – Mobile controlled vs. Network controlled– Mobility across layers

• There is no one-size-fit all solution for all types of application and deployment environment

• A specific mobility protocol needs to be chosen based on the following:– Type of application (e.g., Real-time, Non-Real-time)– Operating environment (e.g., intra-domain vs. inter-domain)– Extent of operator control

• Mobility protocols in their current form are not sufficient to support many of the delay sensitive real-time communication

• Optimization is needed at each layer to provide cellular like handoff quality• Optimization framework and fundamental rules of optimization can be applied to

any type of mobility protocol • Any deployment strategy needs to look at the fundamental rules of optimization

during the design process

ip-based mobility and handover optimization (t3)wcnc2011.ieee-wcnc.org/tut/t3.pdf · ip-based...

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