Journal reference: Computer Networks and ISDN Systems, Volume 28, issues 7–11, p. 1187.
Manfred Bogen
Michael Lenz
Susanne Zier
GMD - German National Research Center for Information Technology
D-53754 Germany
Founded in 1953, the Deutsche Welle, Germany's international broadcasting service with radio and television programs, is on the Internet since the end of 1994, with a program in the World Wide Web (WWW). The management of Deutsche Welle had decided to enter the game as fast as possible as other broadcasting companies like 'BBC' and 'Voice of America' with a similar mission as Deutsche Welle had already started on the Internet as information and program providers. As World Wide Web is by far the most popular and most frequently used information service on the Internet today and as it starts to become a synonym for the Internet, this was felt an ideal starter application. The solution wanted should meet strict security requirements and different quality characteristics like scalability, extendibility and migration possibilities and the financial risks for the company should be minimised.
This paper gives an overview on the activities of German broadcasting companies on the Web and describes GMD's experiences in bringing the Deutsche Welle (DW) to the Internet. DW's decision to rely on two external co-operation partners speeded up the process and minimised the risks and costs for the Deutsche Welle. It became obvious that WWW is not enough for an international broadcaster and that an integration of different value-added services like electronic mail (email), FTP and WAIS is urgently needed to fulfil the needs of a broadcaster and its audience. A guaranteed quality of service level and a secure access to Internet was as crucial since the service start as statistics.
In the first chapter after the introduction we present German broadcasters in the Web and the rationale behind it. The next two chapters describe the procedure which led to an Internet-based program of Deutsche Welle, how our first plan was overridden by the Internet reality only three weeks after the service start and how a more general plan has been set-up among the co-operation partners. The last chapter heading the conclusion shows our experiences made in terms of statistics and quality characteristics. The conclusion sums up our lessons learnt and predicts our next steps to reach the final goal to move the services to the Deutsche Welle responsibility and to introduce Internet applications in the Deutsche Welle organisation itself.
A special service offered by two radio stations is radio on demand:
Using a WWW form any user can request to save parts of the ordinary radio
program to a file. After successful recording they are notified by email and
can then retrieve the personal audio clip via FTP. Beside video tape and audio
tape recorders this is a third possibility to record the favourite progam and
to reproduce it whenever suitable on a PC.
What went wrong?
It is rather easy, a few hours students work, to start a Web-based information
service. The software is freely available and running on any platform, HTML is
not that complicated, there are also many converters from any data format to
HTML in the net, if needed and people are in general very enthusiastic when
they start. Many radio and tv stations went on-line very fast with impressive
results, at a first glance.
To keep a certain quality level related to the information provided and to the availability of the service is much more difficult and sometimes tedious. The trap is: once you have started, you have to continue especially if your service is of public interest. So many broadcasters' pages are under construction, today and tomorrow.
Most Web sites consist of static HTML documents. This makes it hard to keep them up to date because the generally electronically available raw material has to be converted first. In contrast, within database based Web sites new documents are available as soon as they are put into the database. However, the powerful database software needed is not public domain, not cheap and resource consuming.
When the broadcasting people meet the Web people, each of them being an artist in their discipline, there is sometimes an explosive mixture of cultures and an amount of enthusiasm which makes almost everything look possible and feasible. So nice pictures and animation are integrated into the Web. The most recent and tricky, unfortunately not standardised features of a new browser's version are used and everything looks really nice, if you are on the Web server itself and have the most newest version of the browser.
Network aspects as a fast Internet connectivity for the broadcaster itself are neglected and nobody is thinking about the poor end user sitting behind a slow modem trying to load the megabytes of data.
The result of this euphoria are pages which can not be loaded, sessions which can not be established, long waiting periods and at last frustration and lost of the intended audience. Two very popular German tv stations went off-line with their Web server recently. As with other Internet applications, a careful planning and in most cases external help is urgently needed.
Deutsche Welle radio (DW-radio) in Cologne transmits programs in German and 39 other languages to every part of the world via short-wave, satellite and rebroadcasting facilities. Total broadcasting time per day: 91 hours including approximately 130 news bulletins. Total broadcasting time per week: over 640 hours.
The heart of DW-radio is the German program. The current affairs program is transmitted world-wide in an eight-hour format with a full news bulletin on the hour, a shorter bulletin every half hour and a current affairs magazine every two hours. The German program can be received in stereo around the clock via the satellite ASTRA 1A, transponder 2. Deutsche Welle also transmits radio programs in European foreign languages via EUTELSAT II-F1 and ASTRA 1A satellite, transponder 2.
Operating from Berlin since April 1992, Deutsche Welle tv (DW-tv) transmits a current affairs program in three languages (German, English, Spanish) covering 14 hours daily (16.00 to 06.00 UTC)
Setting up Internet services require networking and system administration knowledge as well as skill in organising and preparing the data [LPJB94]. Therefore two external partners were sought to co-operate with the DW-Internet task force being responsible for the program itself and the raw material:
Figure 1: http://www-dw.gmd.de/
GMD is the German National Research Center for Information Technology [GMD96]. In its research department for network engineering it was responsible for the establishment of national and international wide-area networks in a multiprotocol environment and it performed the development of communication software and the engineering of value-added services like email, file transfer, and directory services for different national and international customers.
High-speed networking with ATM and multimedia applications are the main work items here, especially WWW-based developments, the interface design, and works related to Secure Internet. GMD qualified to be the co-operation partner of Deutsche Welle for the service operation.
gekko is a small, spin-off company of GMD located in the GMD premises
called "GMD Technopark". As a combination of a traditional consulting and
advertising agency with a general purpose technical service provider gekko
specialises in the provision of access methods as well as the development of
ways of representation and turn-key information and advertising systems for
companies wishing to establish their presence on the Internet [gekko96]. The
main objective in this context is research of new methods of communication.
gekko qualified to be the co-operation partner of Deutsche Welle for the
information design and layout.
A plan to attack
In order to give DW's Internet start a sound basis careful planning was
absolutely necessary. In a couple of initial meetings we identified some basic
guidelines, the service level, the realisation steps as well as the
responsibilities and the distribution of work. In our first plan, an
introduction phase of one year for setting up the Web contents, introducing the
services and merchandising was scheduled. Afterwards, depending on the results
of this phase it should be decided whether and how to continue.
We agreed upon the major goals:
By October 1, 1994 DW was on the Web! The service was announced on different national and international mailing lists as well as the central Web page of all German Web sites. In addition DW started advertisement in their radio and tv programs.
To cope with scalability as one of our major goals we defined a Domain Name System (DNS) alias for each service offered (i.e. 'www-dw.gmd.de' for WWW). We also used generic email addresses ('username@dw.gmd.de') since the beginning. This enables us to migrate to multiple server machines if it becomes necessary. Using the second-level domain name 'gmd.de' for DW's Internet service names was a fast and less-expensive solution for an early start of the service.
But already three weeks after going on-line all planning was passed by reality. DW's on-line information at the evening of the '94 election of the German parliament (Bundestagswahl 1994) was an overwhelming success: 35,000 accesses at that day and another 30,000 during the next week exceeded the most audacious expectations by far. The service machine owned by GMD already reached its limits. So following our contract we had to talk to each other again.
People at DW were very impressed and motivated by the results of the early
phase, especially by the events around the Bundestagswahl. DW decided to
finish the introduction phase immediately and to continue with a regular
production phase. It was our task now to map their additional requirements to
feasibility with respect to hard- and software as well as bandwidth
limitations.
Quality of Service
For the production phase effective quality of service guarantees were clearly
needed related to:
Our solution now relies on email and mailing lists. Different roles like e.g. ftpmaster or webmaster are defined. Each role is related to a mailing list where respective failures can be announced. These messages are forwarded to multiple people. Internally we clearly defined the responsibilities of the involved system administrators (machine, network, services) for reactions upon announcements.
In addition, in order to guarantee the quality and to talk about all existing
or arising problems we (GMD, DW and gekko) meet on a regular basis
[BHW94] [BHW95]. In the
beginning of the co-operation we meet more frequently to fix all the details
and to train our co-operation partner, lateron the intervals between the
meetings became longer.
Security
According to its mission DW contributes to the view of Germany in foreign
countries. The content of the services therefore has a somewhat official image
so that its integrity has to be ensured. On the other hand the Internet isn't
secure today and DW has a very exposed position due to its international
activities and presence. Thus, considerable security efforts had to be
undertaken.
First of all the service machine should be placed on a separate network which is protected by a firewall system against the Internet. Accordingly, GMD's and DW's internal networks are secured by similar mechanisms. All attempts to attack one of these networks had to be detected and defeated.
Placing DW's server machine on a separated network protected by a firewall system [Ches94] [ChZw95] (see figure 2) allows us to use IP filtering [Chap92] and access lists to enhance security. To improve the security of our services even more we used some host and network security scanners [SATA95]. We also permanently monitor the activities on the machines in order to detect any unusual behaviour which might be a clue to hacker activities. And even if an intruder manages to break into the service machine he will not get direct access to GMD's or DW's local networks as they are separated by additional router.
For the ISDN connection between DW and GMD additional filtering for protocols,
ISDN numbers of the sending and receiving sites etc. are activated. GMD's
internal networks are also secured by additional security mechanisms. Thus DW's
net is secured against attacks from the Internet and the server machine as vice
versa GMD against attacks from the server machine and over the ISDN connection.
The Production Phase
The production phase started January 1, 1995. After the Bundestagswahl
event it was immediately clear that we needed a much more powerful machine
to run all services on for administration and cost optimisation. We used a SUN
Sparc 20/621 with 64 MB RAM and 9 GB on harddisk operating under Solaris 2.4
which was sponsored by GMD again. The service net is linked via a firewall to
GMD's IP backbone which in turn is connected to the WIN (figure 2). As a member
of GMD's Technopark gekko is also connected to the central backbone.
Figure 2: System structure
DW is connected by ISDN to the Firewall system. One interface is reserved for DW only to transfer raw text material from DW to gekko for conversion into HTML as well as to give some selected employees of DW full Internet access via GMD.
We used standard software (ftpd from the Washington University in St. Louis, freeWAIS and sendmail [LPJB94, CoAR93]) for realising the additional services too due to their rich functionality and widely usage within the Internet community.
The migration to our new server machine at the beginning of the production phase was smoothly and nearly transparent to the users. One service after the other was transferred by changing its DNS entry after preparing the service on the new machine. In the beginning, some users and programs (especially Web crawler for indexing entire Web sites) continued to use the old IP address. Thus, for a transitional period we kept the old servers running but pointing any users to the new machine.
As quality assurance and assessment measure we included the affected hardware (the service machine as well as the router) into our internal SNMP-based network management system [EiHo93, RFC1157]. Using these mechanisms we were also able to detect any violations of agreed resource limits (like e.g. Internet bandwidth) and to obviate them if necessary. In the beginning we also managed DW's ISDN router for their connection to GMD. We keep access data for all services as well as the router utilisation in order to produce our monthly usage statistics. Backups of the data areas are made automatically over night.
The following figure shows the usage of the Web server, the FTP server and email since the beginning.
Figure 3: service usage
The most important service for Deutsche Welle is the Web server. During the first months the number of requests increased slowly. Since October 95 parts of the program of the Süddeutsche Zeitung, one of the most popular newspaper of Germany, are hosted on the Deutsche Welle server too. As a result the number of requests grows by nearly 300%. In November 1995 there were 1,091,775 requests in total with a maximum of 17 requests per second. In December there was a slightly decline at and after Christmas but the numbers in January so far promise a new maximum.
FTP and email services were installed at the begin of 1995. Compared with the Web server the utilisation of the FTP and the email services is small. Despite the low traffic volume email is important for Deutsche Welle to get fast feedback from their Web readers and their radio and television audience [2]. It is also important for GMD to get error messages from the users. The messages are delivered within 5 minutes from all corners of the world on average. Two staff members of DW's Internet task force are engaged full-time in handling and answering all the emails from the audience.
The DW program is bilingual in principle (English and German), but for special reports like on the occasion of the Febral '95 exposition in Sao Paulo, Brazil, a hundred new Portuguese pages were introduced.
Figure 4: http://www-dw.gmd.de/febral/index.html
The most frequently requested Web pages are the actual news, DW's so called
monitor service providing some background information to recent topics, DW's
actual tv and radio program schedules and a database of the top 500 German
enterprises. In December 1995 DW's WWW pages were accessed by people from more
then 75 countries in all continents.
Quality Characteristics
In the contract with Deutsche Welle we defined the quality characteristics CPU
utilisation, storage capacity and network bandwidth (see: chapter Quality of Service) for our
service machine.
The average CPU utilisation is around 30%. This is a high value for a Web server with this number of requests. It is caused by the dynamic creation of HTML documents. Most of HTML pages are individually constructed on request from a database. The advantage is the high flexibility in serving different user interests and it is easier to manage the Web content [BBKL94]. The disadvantage is a higher CPU utilisation compared with Web servers with static HTML pages. Further more malfunctioning software caused operational problems at the beginning.
The disk utilisation is smaller than expected but constantly growing. At the
moment the Web server offers mostly text documents and, with the exception of
the Süddeutsche Zeitung, maintains no archive of older documents.
In addition, Deutsche Welle will soon offer audio and video files and these
files need a lot of storage capacity. The used bandwidth increased steadily
according to the numbers of requests.
Consulting
In addition to setting up the server machine and to maintaining the services we
had to support the external users as well as the DW employees.
Quite often Web users send error messages for problems that are caused by configuration or usage errors of their local Web clients. If possible we offer help for solving these problems. If there are questions about the contents and representation of the pages or problems with cgi-script our partner gekko will solve it.
To prepare the server migration to Deutsche Welle, we have to train their employees. Later on they will manage the hardware and software by their own. Important in this context is knowledge about the Internet. Further more they had to know hardware requirements for the different services. The result of this training will be expertise in the Deutsche Welle.
In addition to train administrators we have to support the normal employees of DW - especially their editors. Normally they have no experiences with the Internet and its applications (like FTP and email). They need advisory how to configure and use the services. Further more they need support about security, personal email accounts, and passwords.
In spite of the pressure from the market and the competition it is very important not to start in a hurry but to do a careful planning of the activities and the service to be offered. Once you have started a Web-based service you have to continue it in a professional manner which is much more work-intensive and difficult than just coming up with a Web server.
Our advice to newcomers in the Internet business is: if you feel uncertain in any aspect, rely on external, experienced support.
Our next steps to reach the final goal to move the services to the Deutsche Welle responsibility and to introduce Internet applications in the Deutsche Welle organisation itself are
[1] Unfortunately cache servers hide the real access numbers.
[2] Only 3 minutes after the closure of the polling stations during the Bundestagswahl '94, the first graphic related to the election was on the Web and the first audience reactions dropped in.
Manfred Bogen has
been active in the area of group communication, X.400
development, and X.400 standardisation as expert of the German PTT since 1983.
In 1987 he became head of the VaS group being responsible for the provision of
value-added services. He studied computer science at the University of Bonn and
is co-author of two books about X.400 and distributed group communication. At
present, he is the convenor of the TERENA working group on quality management
for networking (WG-QMN) and a member of the TERENA Technical Committee and the
Internet Society.
Michael Lenz received
his masters degree in informatics (computer science) from
the university of Bonn. He is working at GMD in the Department for Network
Engineering since 1993. His major topics are value-added services, security and
information systems. Since late 1993 he has been involved with establishing and
maintaining the Web server at GMD and for a German broadcasting company with
international program.
http://www.gmd.de/People/Michael.Lenz/
Susanne Zier was a
trainee and became a mathematic-technical assistant (MTA) at
GMD from 1988 to 1991. Afterwards she worked for 2 years in a German hardware
manufacturer company. She joined GMD in July 1992 again. At present, she is
responsible for the quality management and assurance of the communication
servers and Internet applications in different projects with German
broadcasters and public administration.
http://www.gmd.de/People/Susanne.Zier/