Seamless & Secure Mobility

Nada Golmie

Advanced Networking Technologies Division

National Institute of Standards and Technologies

Gaithersburg, MD 20899

USA

www.antd.nist.gov

2

Seamless Future Networks

IP Based Core Networks

Media Access Systems

Services and Applications

Short RangeConnectivity

cellular

WirelineDSL/modem

WLAN

Interworking

Mobility Management

Roaming

Network of Networks

3

Everyday Usage Scenarios

Internet

EthernetWi-Fi

Cellular

Wi-Fi

Wi-Max

In the office

In the car

Out of Town

Wi-Fi

Wi-Fi

Wi-Fi

AP1AP2

AP3

4

Emergency Response Scenario

Satellite

Satellite3G

WiFi

3G

5

Military Usage Scenario

Satcom

Satcom

GPRS

3G

WiMax

Satcom

WiMax

WiMax

“Always Best Connected”

6

Mobility Granularity

Horizontal Handover

Vertical Handover

Multiple Interface Management

Multiple Flow Management

A handover is initiated when mobile device exits the boundaries of an administrative domain. Single interface is used.

A mobile device does need to move in order to initiate a handover. Multiple interfaces are required, but use one interface at a time.

Simultaneous use of multiple interfaces and access networks. Association of an application with an interface

Ability to split individual flows between links with respect to the requirements of the flows and the user preferences

Co

mp

lexi

ty L

evel

7

Key Challenges Scalability – roaming from any access network to any other

access network (2G, 3G, 4G, Wi-Fi, Wi-Max, Bluetooth, Satellite, Ethernet)

Standard handover interfaces – interoperability between different vendor equipment.

Cross-layer solutions - extensions to layer 1 & layer 2 functionalities in order to optimize higher layer mobility architectures (MIPv4, MIPv6, SIP).

QOS guarantees during handover – no disruption to user traffic: extreme low latency, signaling messages overhead and processing time, resources and routes setup delay, near-zero handover failures and packet loss rate

Security – user maintains the same level of security when roaming across different access networks.

8

Access Scalability

Wide variety of access network technologies including cellular (2G, 2.5G, 3G), wireless (Wi-Fi, Wi-Max, Bluetooth, UWB) and wired (DSL, cable modems, Ethernet)

Data Rate (Mb/s)

IEEE 802.16a

Co

vera

ge

Are

a &

Mo

bil

ity

IEEE 802.11n

IEEE 802.15.1Bluetooth

IEEE 802.15.3a

Local Area

IEEE 802.15.4Zigbee

Metro Area802.3 Ethernet

10 base-T1000 base-T100 base-T

IEEE 802.20

IEEE 802.11a

IEEE 802.15.3

IEEE 802.11g

Personal Area

IEEE 802.11b

0.01 0.1 1 10 100 1000

Wide Area

High Speed Vehicular

Rural

Vehicular

Urban

Pedestrian

Indoor

Fixed Urban

Personal Area

2GGSM, CDMA

2.5GGPRS

3GCDMA2000, UMTS

DSL

Cable Modem

9

Access Media Properties

Different media and coverage areas from few square meters to hundred of kilometers

Different architectures and protocols for routing, transport, mobility management

Different authentication, key management and encryption schemes

Different services offered and user demands ranging from low-data-rate non-real-time applications, to high-speed real-time multimedia applications.

10

Industry and Standards Activities

UMA TechnologySession Initiation Protocol

IP Multimedia SubsystemInternet Engineering Task Force Detecting Network Attachment

Processing Layer 2 Triggers Mip4

Mobile IP version 6 Mip6

Mobile IP version 4 Mipshop

MIPv6 signaling and Handoff Optimization Mobopts

IP Mobility optimizations research group Nemo

Network Mobility

Higher Layers

No single standard interface!

IEEE 802

IEEE 802.21 Media Independent Handovers

IEEE 802.11rIEEE 802.11 Fast handovers

IEEE 802.11uInterworking with external networks

IEEE 802.20Mobile broadband wireless access

Layer 2

Layer 3

FMCA NOKIA

KT

11

Cross-Layer Protocol Interactions

Profile Manager

AccessMedia

Applications

Policy

Mobility Decision

Cellular

PHY

MAC

Link measurements: RSSI, Noise, Interference

Performance Measure.:QOS, ACK

Handover Layer

Network Layer Mobile IP

trig

ger

trig

ger

trig

ger Transport Layer

SCTP

Application Layer SIP

trig

ger

trig

ger

trig

ger

Han

dove

r su

ppor

tWhat are the mobility architectures considered?

What are the protocols and messages needed?

What measurements will be used in the handover decision?

What are the mobility scenarios envisaged?

How can mobility performance be evaluated?

12

Secure Mobility

Level 1

Level 2

Access Net. 1

Level 3

What additional encryption mechanisms and policies should be applied for secure access network transitions?

How to characterize security levels?

Level 2

Level 3

Level 1

Level 2

Level 3

Access Net. 2

Access Net. 3

Eg. GSM

Eg. Wi-Fi Eg. Wi-Max

Encryption + AuthenticationIntegrity Checking

ConfidentialityNon-RepudiationAuthenticationAuthorization

13

•CCM-Mode 128 bit AES data encryption •CCM-Mode 128 bit AES data authentication•ECB mode AES, 128-bit key TEK encryption

•CBC-Mode 56-bit DES data encryption •no data authentication•RSA, 1024 TEK encryption

Comparing Cryptographic Suites

•CBC-Mode 56-bit DES data encryption •no data authentication•3-DES,128 TEK encryption

•No data encryption•no data authentication•RSA, 1024 TEK encryption

•No data encryption, •no data authentication•3-DES,128-bit TEK encryptionWhat are

possiblemappings?

IEEE 802.16

Security offered by different access network technologies does not compare.

CCMP data encryption802.1X authentication802.1X key management

IEEE 802.11

WRAP data encryption802.1X authentication802.1X key management

TKIP data encryption802.1X authentication802.1X key management

WEP-104 data encryption802.1X authentication802.1X key management

WEP data encryption802.1X authentication802.1X key management

CCMP data encryption802.1X authenticationNo key management

WRAP data encryption802.1X authenticationNo key management

TKIP data encryption802.1X authenticationNo key management

WEP-104 data encryption802.1X authenticationNo key management

WEP data encryption802.1X authenticationNo key management

14

Factors Impacting Security

1. Radio Transmission

2. Network Architecture Cellular Mesh

3. Internetworking

4. Shared Medium CSMA/CA Polling

5. Cryptography

6. Mobility

7. Changing Network Topology

8. Limited Energy resources

9. Node Association

10. Power Save Mode

11. Logical channel sensing

12. Retransmission

13. Fragmentation

14. Threat Environment

15

Practical Issues in Secure Mobility

Single administrative domain – pairing of user security levels on different access networks

Multiple administrative domain – need for (re)authentication

Lack of quantitative measures for security performance

Menu driven security options for equipment vendors and service providers increase complexity

Dependence on threat environment, equipment capabilities and usage scenarios.

16

Project Roadmap

Tool Development Protocol Analysis Protocol Development

DeliverablesWhy NIST?

Technology GapLack of measurement tools OpportunityLack of standards

Industry Standards Sponsors

• Plug-and-play simulations- Choice of platform- Extensions- Abstractions• Analytical models• Performance Metrics• Usage Scenarios

IEEE 802 > development of standard interfacesIETF > lower layer meas.

Engage potential customersDetermine need/requirementsAdvertise program

Information Assurance Workshop, Feb. 2005

• Quantify handover performance in terms of latency, loss, signaling, security• Identify protocol cross-layer interactions• Explore and map lower layer measurements• Devise service/ security profiles mappings

• Mobility architecture• Decision algorithms and optimizations• Extensions to existing protocols• Policy Mapping

Start

• Mobility tool & measurement repository• Publication of comparative performance analysis results• User guidelines• Best practices• Contributions to Industry standard developments

Competence

Impact

Strategic

Technical

17

An Approach to Secure Mobility

Transitional Security Security Levels Mappings

Sin

gle

Adm

in.

Dom

ain

Mul

ti-A

dmin

. D

omai

n

Vulnerability analysis:- Are there any additionalthreats and weaknessesposed by the mobility?handover?- What are they?-Under what threat models?- How to mitigate them?

1) Select two technologies as a starting point: for example 802.11b and 802.162) Assess vulnerabilities associated with handover scenarios and related threat models3) Identify security levels or tiers based on weakness analysis available for each

technology4) Devise security level mappings between different technologies5) Extend the analysis to the multi-administrative domain case

Identify levels of security based on protocol description and weakness analysis:-How to map comparable levels of security?-What additional security policies and mechanisms need to be applied in order to maintain the same level of security (or vulnerability)?

Extensions of vulnerability analysis:-Investigate scenario andapplication specific cases- Devise taxonomy

Extensions of security levels: - what are the security policies required for specific mobility and application scenarios?

Start

Co

mp

lexi

ty L

evel

Deliverables arein the form:•Mobility securityrequirements•Security levels andmappings•User Guidelines

•Lessons learned•Limits of technology•Feasibility study

Secure & Seamless Mobility

Action Plan• Develop plug-and-play mobility simulation platform:

- Assess state of the art & availability of tools available in the public domain.

- Build model extensions and abstractions to accurately characterize protocol interactions

• Derive analytical models for evaluating handover latency, and transition blocking probability.

• Devise benchmarks and realistic usage scenarios.

• Devise metrics for quantifying handover performance.

• Devise and evaluate handover protocol optimizations and decision algorithms.

• Devise access link security profiles and mappings across access link technologies.

Technical Approach

Investigate mobility protocols and methods that characterize & improve their performance.Bridging the interconnection gap between heterogeneous

and “stovepipe” access network technologies

Deliverables• Contribute to standard group activities such as

IETF and IEEE 802: conduct comparative performance evaluation of handover mechanisms being considered in IEEE 802

• Create and maintain a repository of tools, benchmarks and performance metrics on NST Web site.

• Publish performance analysis results in conference / journal articles: characterize implications on handover performance including mobility management, QOS, and security.

Key Questions

How to support seamless mobility across different access network technologies?

How to maintain security when handing over a connection from one access link to another access link?

Internet