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The Göttingen Wireless LAN

gerhard.schneider@gwdg.dehttp://www.gwdg.de/~gschnei2

Gerhard SchneiderGesellschaft für wissenschaftliche Datenverarbeitung Göttingen

and Universität Göttingen

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• The laptop is the (future) working environment (portable!)– And other portable devices

• Outside your office everybody tries to keep you away from the Internet– Where do you find the nearest Internet access point? And may you use it?

• How many access points do you find in this resort??

– are you allowed to access the Internet in your own company/university everywhere??

• In the meeting room to download your digital information• In other departments to read your mail during session breaks• And even if you could (technically), King SysAdmin happens to be far away

– “This is not for everybody”, „you are a security risk“, etc

• So one is dreaming of the Internet and its multi media options but even two inches away from a connected computer you are in Network-Never-Never-Land– and in frustration you use your mobile phone

Motivation -1-

• Fact: The internet is at the desk and files/information are available digitally

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Motivation -2-

• In Göttingen some 4000 dorms are networked, mostly fibre or 100 Mbit/s– Top position in Germany (according to the statistics of the Deutsches

Studentenwerk– Makes dormitories very attractive for students

• Internet access from the bed, but from nowhere else?

– What about private places?

• In a library there is almost no possibility to use the own laptop for online research– Use of existing PC for research is no problem

• (Göttingen offers several hundred “public” terminals, so there is an option) • transfer of the results to a server

– At home download the data onto the private laptop• Which you had with you in the first place

• Even when the weather is fine, surfing the net can only be done in your (dark) room.– Bad social image

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Motivation -3-

• Main problem: Internet access is seen as a local phenomenon, not as a global need.

• Personal vision: always online at little cost and with high performance– Also because of my PDA (personal digital assistant)

• Current twists to synchronise data are far from optimal

• Question: what happens, if you are always online and the tedious search for the net has become history?– Compares with the continous search for food in contrast to always finding a

well laid table

– Remember the Woody Allen film, where a character is constantly calling the secretary to leave his current phone number?

• Now solved by mobile phones...

• First experiments in 1995, using proprietary Breezecom technology

• Now we have a standard 802.11b – new motivation

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20.4.2000first trial „Göttinger FunkLAN“

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Experiences from the trial

• A wireless LAN only makes sense, if it is available (almost) everywhere.– Not just in one building, but really everywhere

– Everywhere means: global management and global operation• Equal access: all net citizens are equal

• In Göttingen, science happens to be everywhere– The scattered buildings scattered over town are a nightmare for networking

people, but a dream for the wireless operator• Many points for transmitters at little extra cost

– In addition all schools are online via fibre optic or ADSL

• So instead of going for a 100% coverage of a few university complex rather go for a (more or less) general coverage of the city– Trick: wireless technology goes in all directions, so a transmitter happens to

cover surrounding areas.

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Göttingen’s Data Network for Science and Research

• University of Göttingen– URL: http://www.uni-goettingen.de

• Max Planck Institute for Aeronomy (in Katlenburg-Lindau, some 30km outside of Göttingen – dark fibre)

– URL: http://www.mpae.gwdg.de

• Max Planck Institute for Biophysical Chemistry

– URL: http://www.mpibpc.gwdg.de

• Max Planck Institute for fluid Dynamics

– URL: http://www.gwdg.de/mpisf

• Institute for the scientific Film– URL: http://www.iwf.de

• Max Planck Institute for Historical Science

– URL: http://www.geschichte.mpg.de

• Max Planck Institute for Experimental Medicine

– URL: http://www.mpiem.gwdg.de

• GWDG– URL: http://www.gwdg.de

• City of Göttingen (since 3/99 – with the local schools)

– URL: http://www.goettingen.de– URL: http://www.goe.ni.schule.de

• Primatenzentrum– URL: http://www.dpz.de

The local high speed networt GöNet, started in 1991, connects the following institutions at gigabit speed:

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LANs in Göttingen

The first data highway:Gauss-Weber 1833: 1 bit/Sek

Backbone1 Gbit/s

Today‘s fibre optic backbone: 1.000.000.000 times faster

• University founded in 1734/37

• Two Campuses and many little buildings scattered all over town.– Observatory of C. F. Gauss

– Oldest Institute for Geophysics in the world.

– World‘s first data highway

Wireless LAN:currently 11.000.000 times faster

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Remarks about the technology

• WAVELAN 802.11b– Unrestricted operation in the 2,4 GHz range– “CB-network” with no guarantee for exclusive access/use– Range restricted by law:

• short range: 100 mW power• long range: 30mW power• 1/20 bis 1/60 of a mobile phone (900 MHz bzw. 1.800 GHz)

– Range up to 300m with normal antennas• Antennas are reasonably invisible (compared with GSM)• Range up to 4km already observed (using special and legal antennas)• Inside of buildings the range is much less

– LAN-connection is still required

– Up to 11 Mbit/s in one cell• Several cells may cover an area, up to 128 users per cell.

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Access Point(connection to the LAN)

Technology (1)

Pccard for the notebook

Antenna

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Technology (2)

12 dBi OmniOMN-120-01

6 dBi PatchDIR-060-01

5.2 dBi Omni (outdoor)OMN-052-02

21 dBi Solid DishDIR-210-01

13.5 dBi YagiDIR-135-01

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Project money from “nds. MWK” and BMBF

• This was what we needed to boost our wireless network: € 250.000– 50% “nds. MWK” = niedersächsisches Ministerium für Wissenschaft und

Kunst = Ministry for Research and Arts, Lower SaxonyMinister Thomas Oppermann

– 50% BMBF: = Bundesministerium für Bildung und Forschung = Federal Ministry for Education and ResearchMinisterin Edelgard Bulmahn

• some 150 Access-Points can be financed– Partly with dual card, i.e. with one access point we can provide service inside

and outside of the buildings by suitably placing the antennas

• some 250 WaveLAN cards for loan to students• A few laptops for loan, including an iPAQ

– Boosts the acceptance of lpatops w.r.t. real computers– Laptops are finally affordable, about €1500 at the food store ALDI

• So far good acceptance from everybody– Colleagues showing off the new infrastructure to visitors!

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The right antennas…

• By use of special antennas larger distances can be covered, provided there is direct (unhampered) visibility– 11 Mbit/s up to 4 km

– Blauer Turm as first long range access point, city hall will follow

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CZ, 8.2.2001Security concepts

• Access is only granted to cards having a valid identification– Check the MAC-adresse against radius database

• Communication between card and access point is encrypted– Generic standard WEP

• This appears far from being secure, thus:– No connection between the Wireless LAN backbone and

the “normal” network GöNET– Only after logging in at a gateway we grant access to the

Internet (VPN-Technology)• Typically used for “external” dial-in

– Connection between user and gateway is encrypted using VPN software and its scientifically approved encryption methods

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Access to the wireless network

• Is this a bottleneck? No!– We can install several gateways

– The backbone offers enough capacity to cope with the incoming wireless traffic

– We can/could talk about separate user groups/users administration• Faculty gateways (but better than a separated net)

• Advantage: Integration of other user groups into the infrastructure– Get more money to expand the network

– Example: companies could also use a relatively wide spread network• Measurement Valley

• local Internet provider

• City radio – use the GöNET for Internet radio

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Wireless LAN – modes of operation

• Central axiom from our point of view:a wireless network is more than a local network– Not an extension of the old idea of a wire based telephone system, but

roaming as we know it from the mobile world

– At this point many institutions commit their central design error!

• Not a centralistic concept, but a concept which scales even for several operators– GWDG-user (science&research), student user, faculty

• Target: one wireless network for all scientists and students in Göttingen– „Internet always on“ – well, “almost everywhere

– Access is possible everywhere, using the same rules

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Wireless LAN – modes of operation

Router

Gateway

GöNETG-WiNShared 11 Mbit/s

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New partners

• The local bank (Sparkasse Göttingen)– Transmitters may be placed inside and outside three “crucial” branch offices

• Connection to GöNET via dark fibres from the bank network

– Easy online banking

• Siemens-Fujitsu– 100 high end laptop computers for students sponsored

• Model B2175 and model E6560 at €1300

• It pays to be a student

• City of Göttingen– Will grant access to the town hall “skyscraper”

– Will donate PCMCIA-WaveLAN-cards to students who take up residence in the city of Göttingen

• (rather than stay in their home town – tax reasons)

• Suddenly our project is affecting the competition of cities

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Future working conditions

Voice over IP?

Finally a clean desk

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Internet and more

• After all, digitised voice is data!– Not really understood in society, parliament, legislation

• GWDG is experimenting with Voice over IP– Solution by Siemens: Software running on a PC– VoIP-Gateway to our PABX already installed– Real telephone calls from your PC….

• Including real blue screens

• Build your own mobile phone with this?? No, after all:– www.spectralink.com (VoIP-mobile based on 802.11b)

• New questions– why DECT????

• If we can scrap the DECT project of the university PABX, we have more money for WaveLAN

– why UMTS????• Compared to the € 50 billion licence fees in Germany, WaveLAN is really cheap• http//www.tagesschau.de/archiv/2001/03/21/sendungen/tt-2230/videos/cebit.ram

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Data and “voice” over one wireless network

WAN

PSTN

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Voice is no longer an expensive special case

Connection to the old world

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Summary:wireless vs traditional LAN

• Wireless is easy to install– Especially when it comes to respect conservation laws

• Wireless is „shared“ media– 802.11b gives at most 11 Mbit/s for all participants in one cell

– „good old“ Ethernet in a new box• With all its disadvantages

• In Göttingen the wireless LAN is an additional offer for the „roaming user“– Cabling infrastructure is expanded constantly

– Connect remaining sites to GöNET fast

– Instant cover of large rooms• library, Café,

– No replacement for cabling infrastructurew.r.t. multimedia

Library in the Paulinerkirche

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Future conferences?

Only portable – no – wearable!

900g on belt or arm, 233 MHz, 128 MB RAM, 4,3 GB HDD, 2x PCMCIA, Audio I/O, USB, ext. scanner, ext. keyboard, ext. mini camera