Ohne Fehl und Kabel – Mobilität Ubiquitär und Sicher · Hotspots, Roaming in Netzwerken Hannover 22.03.2004 D. Tavangarian, Universität Rostock 1 Ohne Fehl und Kabel – Mobilität

Hotspots, Roaming in Netzwerken Hannover 22.03.2004

D. Tavangarian, Universität Rostock 1

Ohne Fehl und Kabel –Mobilität Ubiquitär und Sicher

D. Tavangarian

University of Rostock Department of Computer ScienceInstitute of Computer EngineeringAlbert-Einstein-Str. 21, D-18059 Rostock / GermanyTel: +49 (0)381 498 3385, Fax: +49 (0)381 498 3440Email: [email protected]: http://wiss.informatik.uni-rostock.de

Berlin, 2. Dezember 2002

2D. Tavangarian, Rostock

Wireless Communication Techniques

WLAN/802.11b

IRDA

GSM

TETRA- Systems

Satellite transmission

GPRS

Distance

Bandwidth

Bluetooth

Power BluetoothDECT

WLAN 802.11g

Kbit range Mbit range

500-1000 km

10-50 km

5-15 m

1-1,5 m

1-6 km

20-500 m

UMTS

WLAN/802.11a

EDGEEGPRS

Wide-Area / Low BW Local-Area / High BW

HYBRID COMMUNICATION

WiMax 802.16




WLAN-standards

MAC-Layer

PHY-Layer

IEEE 802.11

802.11f: Inter Access Point Protocol (IAPP)

802.11e: QoS Enhancement802.11i: Security Enhancement

802.11g2,4 GHz

>54Mbit/s

802.11b2,4 GHz

11 Mbit/s

802.112,4 GHz2 Mbit/s

Current subjects of Standardisation

802.11a5 GHz

54 Mbit/s

802.11h Power Transmit

Control

1996 1999 2000 2002


• Ad-hoc Mode without Access Point

WLAN Architectures IAccess Point

Mobile Station

• Autonomous wireless Networks with one einemAccess Point only




WirelessNetworks

Bac

kbon

e

Switch

Server

Switch

Switch

ServerWired Net

• Extension of the available IP-Netze with WLAN

WLAN Architectures IIAccess Point

Mobile Station

EigenerVLAN-Bereich

für dasFunknetz

BestehendesFestnetzdient als

Backbone

WirelessNetworks

Wired Net


What is a WLAN Hotspot?

An area to get high speed Internet access with laptops or PDAsover locations with a 802.11x wireless connection to the communication networksExamples: Airports, Airline Clubs, Cafés, Hospitals, Universities, Store Buildings etc.

54 Mbit /s2.4 MHz802.11b

ISP

Internet




Kind of WLAN Hotspots

• Public Hotspots (billing needed)– Open Community (Conferences, Hotels, …)– Selected Users (Airport, Pre-paid, subscribers, tickets

….)

• Private Hotspots (no billing needed)– Closed Communities (Universities, Enterprise,

Hospitals, Companies, …)


PublicWLAN

Airport

Railway Station

Campus

Semi-publicWLAN

OfficeHospital

Congress hall,Hotel

HomeWLAN

Remote Access

PlantCorporate

WLAN

Office

MobileVehiclesMobile

Vehicles

WLAN HotspotApplication Fields




• 8 Building areas (approx. 350 buildings)

• Distributed over the whole city• Hystorical buildings

• Primary part:– Fiber optic backboone star topology– About 70 km fiber optics (20 / 28

Fasern)– ATM with 155 Mbps and Gigabit-

Ethernet• Secondary part:

– Fiber optics within the building complexes

– ATM with 155 Mbps or Gigabit-Ethernet

Wireless Communications network of theUniversity of Rostock

First stage of development April 2000

Computer poolDepartment of Computer ScienceFaculty of Engineering

Mechanical engineeringElectrical engineering

Faculty of Engineeering

Electrical engineeringMain buildingFaculty of Science

PhysicsChemistry

Faculty of Economic SciencesFaculty of PhilosophyFaculty of ArgriculturalsciencesFaculty of LawAudio Visual Media CentreDepartment of Biology

WLAN at the University of Rostock

The first European university-wide Hotspot


Our experiences• WLAN is available since April 2000• More than 200 Access Points are installed• About 3000 registered users, 3000 hour daily access• Secure communication network with VPN and IPSec• Mobility of the users within the whole university• Access to internet from

– lecture, meeting and working rooms, Labs etc.,– dormitories,– student restaurants and cafes,– libraries, – neighborhood of the university, etc.

• High availability of the wireless AP and robust systems




Goals:

Realization of an Ubiquitous Mobility

Roaming Models


Advances and Needs of Mobility

• Smart-Equipments (Appliances)– Smart PDA– Smart Phone– Tablet-PC– Notebook

• Communication– Wired global Networks– Wireless local Networks– Ubiquitous of electronic Communication

(asynchronous, synchronous)• Didactical Enhancements

– from view of the learners – from view of the instructors– from the knowledge view

• Intensified knowledge need– Individualizing and Personalizing– reinforcement of content and communication – collaboration and/or group work




An active service is continued without interruption on another terminal.

An active session of a user is continued without interruption on another terminal.

What Means Mobility?

• user-Mobility• terminal mobility• session mobility• service mobility The communications equipment

can change thus its place? whether with or without its user

The communication services follow a user. Typical example: Call forwarding at the telephone or a www service, which the user can use from each Internetable computer and whose surface looks always alike.


Roaming Between Different Networks

Subnetwork Subnetwork

Subnetwork

SubnetworkSubnetwork

Subnetwork

PublicWLAN

WLAN

WLAN

Ethernet

Ethernet

Public or private Network

Internet

Roam Roam

RoamRoam Roam

Hybrid Roaming

Enterprise Network

Wirelesswide area networkCDMA, GPRS, 3G

Roam




Low Security

AuthenticationSupplicant

Enhanced-802.1x Security

VPN client

Enhanced-VPN Security

VPN client

Public Wireless LAN

User authentificationand VPN tunneling

Wired Ethernet backbone

VPNgateway


SSID, MAC filtering, static WEP encryption

WLAN card

User authentificationand VPN tunneling


notebookcomputers with bullit-in

WLAN adapters

Public WLANaccess controller


Internet

Radiusserver

Intranet

Security Policies


Roaming between the Roaming between the UniversitiesUniversities(Inter University Roaming) (Inter University Roaming)




WLAN Communication in German universities

• A great number of universities have a university-wide WLAN, more than 100.

• The main goal is the use of WLAN hotspots for an ubiquitous University

• More than 40% of students use own notebooks

• More than 70% of research and teaching staff use a notebook

• There are several portals for e-learning, digital libraries and other services in Germany


Intera-University Roaming

• A RADIUS servers supports domain-based AAA proxying

• RADIUS servers support 802.1X via different authentication methods (EAP-MD5, EAP-TLS, EAP-TTLS ...)

• Access Controllers and wireless access points are hardware that support RADIUS protocol for AAA purposes

• Standard based equipment should be used in order to achieve vendor independency and easier management

© Wirlab Research Center




Local Roaming

Internet

Local NetworkAP

AP LocalAccessControl

Services

1

4

32

56

o: powerpoint/wlan-tav.ppt

MobileClient


Global Roaming between Universities

InternetLocal

AccessControl

DFN as Clearing CenterGlobalAccessControl

GlobalSerrvices

UniversityB

LocalAccessControl

LocalServices

UniversityA

LocalServicesAP AP

5

6 7

4

3

2 9

8

1 Moving Client




Roamingbetween the University Hotspots

Example: German Universities:• University of Aachen• Universities in Berlin • University of Bremen• University of Erlangen • Techn. University of Darmstadt • Techn. University of Dresden • University of Frankfurt • University of Feiburg• University of Hamburg• University of Karlsruhe• University of Luebeck• University of Mannheim• Universities in Munich• University of Paderborn• University of Rostock • University of Saarbruecken• University of Wuerzburg

Berlin

Frankfurt

Karlsruhe

Rostock

Dresden

Munich

Hamburg

Hannover

Erlangen

Freiburg

BremenLuebek

Saarbrücken

Dortmund

Aachen Paderborn

Mannheim

Darmstadt

DFN


Next Steps ….

• Horizontal Roaming between European Universities and Research Centers

• Vertical Roaming for Students and Staffs

• Availability of Services (e. g. Teachware)




Global Roaming in Europe

European Clearing Center

Country Clearing Center

Country Clearing Center

…

University A

…University

B

University N

University A

…University

B

University N


Seemless Hybrid Roaming

InternetISDN, ATM,

Wired-Network

Intranet

WWW-Server

SAP/Metaphase Server

Firewall

Mobile Client

Wired-NW

GSM/GPRS or UMTS

Transmitter

Phone Network

ISPWired-NW

Wired-NW

WLAN-Hotspot

Access Point

WWW-Server ISDN, ATM, Wired-Network




Realization of the Hybrid Roaming

Method of Socket-Tunneling


Conclusions:Adaptive and Secure Wireless Architectures

• Scalability (AP, Clients, Servers…)• Germany- and Europe-wide Seamless Roaming

– Parameter-based organization (Security, Bandwidth, Cost, Throughput, …)

• User Accounting • Available Security (Firewall, VPN, IPSec, …)• World-wide ubiquitous access is possible

– To the resources– To the data

• Stable systems (MTBF > 105 hour)




Conclusion:

Get More from the Mobile Life• HIGH-SPEED wireless Internet access in convenient public locations • POWERFUL SERVICES like download the email attachments,

watch a live web-cast, or listen to streaming audio • ROBUST NETWERKS with a full connection at every location • EASY USE of either a laptop or PDA etc. • SEAMLESS integration with existing Internet tools. • FAST–CONNECTION to the Internet or the own corporate intranet • RELIABLE - Get a high quality communication services in every

location• AFFORDABLE - Use it a little, use it a lot • CONVENIENT - There are no busy signals, no searching for phone

jacks, no waiting, easily and instantly connection.


Vielen Dank für Ihre Aufmerksamkeit

• KontaktProf. Dr.-Ing. habil. D. TavangarianUniversität RostockFakultät für Informatik & ElektrotechnikLehrstuhl für RechnerarchitekturAlbert-Einstein-Str. 2118059 RostockTel. +49 381 498 3386Fax. +49 381 498 3440

Web: http://wwwra.informatik.uni-rostock.de

Documents

Ohne Fehl und Kabel – Mobilität Ubiquitär und Sicher · Hotspots, Roaming in Netzwerken Hannover 22.03.2004 D. Tavangarian, Universität Rostock 1 Ohne Fehl und Kabel – Mobilität