Distributing Mobility Agents Hierarchically under Frequent Location Updates

Distributing Mobility Agents Hierarchically

under Frequent Location Updates

D. Forsberg, J.T. Malinen, J.K. Malinen,

T. Weckström, M. Tiusanen

TSE-Institute

Telecommunications and Software Engineering

Laboratory of Information Processing Science

Helsinki University of Technology

Finland

HELSINKI UNIVERSITY OF TECHNOLOGY

Introduction

• a need to support efficient and seamless roaming with e.g. multimedia applications

• scaling mobility over the subnet boundaries

• independent of link-layer techniques• real testbed, not only simulated• testing environment for further ideas


Our solution

HA

Home Network

Mobile Node

CNInternet

FA4 FA5

FA2

HFA1

FA1

FA3 FA6

IEEE 802.11WLAN

Foreign Network,FA hierarchy

Mobile Node

Mobile Node

• partly distributed HA functionality

– ability to send registration replies– tunnel updates within the organization– private addresses may be used within the FA hierarchy


Signaling

• scales to multiple levels of hierarchy– localized registration are only sent as high

in the hierarchy as needed

• HA's binding lifetime updated separately (forced registration)

• tear-down (session key reset)

• potential race condition


Security

• shared secret between HA and MN

• session key distribution and usage– session key used for localized registrations– HA as KDC – public key encryption or shared secret

between HA and FA organization– local replay protection


Localized location update

CN HAInternet

Home Network

WLAN

FA5

FA2

HFA1

FA1

FA3 FA6

Mobile NodeMobile NodeMobile Node

FA4

SFA

FA4FA3

FA1 Foreign Network

FA4


Localized location update

CN HAInternet

Home Network

WLAN

FA5

FA2

HFA1

FA1

FA4FA3 FA6FA4

Mobile Node

FA5

FA2

SFA

FA2

FA5

FA1

FA4

HFA1

Foreign Network


Feasible scenarios

• rapidly changing connection type (e.g. GPRS--WLAN)

• Need for optimized location updates

• vehicle connection

• multi-channel environment

• latency between FAs (e.g. radio links between access points)


Testbed

HA

Home NetworkCN Switch

Delayhost

IEEE 802.11 WLAN

HFA1

FA1 FA2

FA3

FA13 FA14

FA4 FA5

FA15

FA6

Organization 1,Foreign Network 1

Mobile NodeIEEE 802.11 WLAN

HFA2

FA7 FA8

FA9

FA16

FA10 FA11 FA12



• wireless connection between the MN and the FAs– Lucent's IEEE 802.11

compatible 2 Mbps WLAN adapters in ad hoc mode

• wired connections between mobility agents

• delay host to generate additional latency

HA

CN Switch

Delayhost

HFA1

FA2

FA3

FA13 FA14

FA4

FA15

FA6


FA1

Home Network

IEEE 802.11 WLAN

FA5

Testbed


Mobile Node

• two foreign networks • a separate four node non-

hierarchical configuration• mobile node able to roam

within and between the networks

HA

CN Switch

Delayhost

HFA1

FA2

FA3

FA13 FA14

FA4

FA15

FA6


FA1

Home Network

IEEE 802.11 WLAN

FA5

Testbed


Mobile Node

• HA & HFAs: Intel Pentium II and Pentium desktops

• lower FAs: 486-based embedded access points (Martnodes)

• MN: Intel Pentium II laptop• all nodes running Linux 2.2

kernels

HA

CN Switch

Delayhost

HFA1

FA2

FA3

FA13 FA14

FA4

FA15

FA6


FA1

Home Network

IEEE 802.11 WLAN

FA5

Testbed


Mobile Node

Test methods

• forced location updates

• handoff latency measured in the MN

• data throughput measured with netperf– maximum TCP throughput and paced UDP

streams (about 1.4 Mbps)


Tests, Handoff times

HA


Delayhost

HFA1

FA2

FA3

FA13 FA14

FA4 FA5

FA15

FA6

Organization 1

IEEE 802.11 WLAN

HFA2

FA7 FA8

FA9

FA16

FA10 FA11 FA12

Organization 2

FA1



HA


Delayhost

HFA1

FA2

FA3

FA13 FA14

FA4 FA5

FA15

FA6

Organization 1

FA1FA1 FA2

FA3 FA5

FA13 FA15

Location update latencies for some transitions

OLD FA

NEW FA

Average in ms

FA1 FA2 24.0FA3 FA5 43.3

FA13 FA15 62.6


0

100

200

300

400

0 20 40 60

CN Switch

Delayhost

HFA1

FA2

FA3

FA13 FA14

FA4 FA5

FA15

FA6

Organization 1

FA1FA1 FA2

FA3 FA5

FA13 FA15

HA

Home Network




HA


Delayhost

HFA1

FA2

FA3

FA13 FA14

FA4 FA5

FA15

FA6

Organization 1

FA1

Location update latencies for some transitions

FA1 FA2

FA3 FA4

FA13 FA14

OLD FA

NEW FA

Average in ms

FA1 FA2 24.0FA3 FA4 29.8

FA13 FA14 28.7


Tests,TCP, no latency

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

0,1 1,0 10,0 100,0

locupds/s

Mb

ps

hierarchy

no-hierarchy


Tests, UDP, no latency

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

0,1 1,0 10,0 100,0

locupds/s

Mb

ps

hierarchy

no-hierarchy


Tests, TCP, 100ms lat.

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

0,1 1,0 10,0 100,0

locupds/s

Mb

ps

hierarchy

no-hierarchy


Tests, UDP, 100ms lat.

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

0,1 1,0 10,0 100,0

locupds/s

Mb

ps

hierarchy

no-hierarchy


Discussion

• possible to extend Mobile IP to work with frequent local location updates

• possible to construct deeper hierarchies

• packets lost during tunnel establishment– can be optimized when soft handoff is used– performance sensitive to small changes in order of

operations


Conclusions

• hierarchical FA network has advantages over basic RFC 2002 operations

• our extensions can be useful in settings where latencies exist and fast mobility is required

• possibility to use private addresses






TSE-Institute

Telecommunications and Software Engineering

Laboratory of Information Processing Science

Helsinki University of Technology

Finland






Email{dforsber, jtm, jkmaline, tweckstr, mikko}@cs.hut.fi

WWW

http://www.cs.hut.fi/Research/Dynamics/


Documents

Distributing Mobility Agents Hierarchically under Frequent Location Updates