Use of WaveLAN 2Mbps CDMA for Metropolitan Area Networking (MAN).
As part of our effort to do high speed networking at low cost, we purchase some of the WaveLAN produced by Lucent Technologies (check out - Lucent Technologies, “WaveLAN ISA Card User’s Guide” Lucent Technologies Bell Labs innovations). In the figure, we show the typical WaveLAN equipment. Some of WaveLAN manufacturer are:
Solectek Corporation "http://www.solectek.com/"
It is basically a Code Division Multiple Access (CDMA) board running at 2Mbps in 915 MHz ISM-band.
In our homebrew WaveLAN experiment, the ISA WaveLAN Card is put into a 486 motherboard, an additional Ethernet card is used on the board to set the board as a router in the network. A homebrew loop yagi antenna at 915 Mhz is connected directly to the output of the WaveLAN card. We managed to link sites at approx. 15 km apart using the plain WaveLAN card at 250 mW @ 915 Mhz. Those who wish to connect longer distances could add a power amplifier to it.
A Metropolitan Area Network (MAN) 2Mbps has been established at our city using this technology. Both UNIX (Linux & FreeBSD) as well as KA9Q NOS variant has been used as the software to drive the router. We found UNIX will perform better in most cases, however, it requires more computing resources, e.g., memory & disk, than NOS.
Some of the consequences of having CDMA 2Mbps Metropolitan Area Network (MAN) within our cities observed in the last couple of month are we promote an alternative to build high speed MAN within Indonesian cities needed to inject the necessary traffic into our Internet gateway. Our Telco company in Indonesia is currently having a limited number of N-ISDN lines throughout Indonesia (in the range of 300 lines). Thus, a wireless high speed MAN would be an attractive solution to the need of deployment of high speed MAN.
Wireless Data Network in Indonesia
The need of mobile computing is quite high for some business community in Indonesia. An alternative for wireless data network would be of interest to enable these people in getting the necessary connection for delivering their messages. To achieve this PT. Elektrindo Nusantara (http://www.en.co.id) has been in collaboration with Institute of Technology Bandung (ITB) in getting such technology to work in Indonesia. The technology would enable the users to have:
Interface to FAX.
Interface to Pagers.
Interface to Short Message Services (SMS)
No commercial operation of such network is performed. The test bed of feasibility of the network has only been performed by PT. Elektrindo Nusantara. Typical specification of the current network is based on:
Native Control Language 2.1 (NCL) & RIM's Radio Access Protocol (RAP).
Power management protocol:
Dual RF Air Protocol (MDC 4800 & RD LAP 19.2), including nationwide fully automatic roaming.
GMSK 64Kbps packet radio systems.
To support our aim to develop low cost computer networking infrastructure, especially in rural area, we are currently developing a very low cost medium speed networking packet radio system. This system is basically the same as G3RUH 9.6 Kbps packet radio. However, instead of creating modulator & demodulator from scratch, we use a single chip modem GMSK MX 589 from MX-COM (http://www.mxcom.com) and put our effort in developing a simple & low cost , wideband FM radio. This project is spearheaded by Adnan Basalamah (email@example.com)
This Wideband FM radio consist of Four part: Reactance modulator FM Transmitter, Single chip Power Amplifier, a Quadrature FM Demodulator & Signal Source to drive the first down converter/mixer of this Demodulator.
Not like other Radio Modem which use TNC or Serial Communication Controller card for interfacing with PC, our modem used LPT port for Interfacing. The Device Driver for this modem is a modified Boycott Device driver, which can be found at many Linux operating system Kernel. AX.25 link layer protocol will be used in this project while TCP/IP will run on top of it.
Fast Ethernet Test Bed
Our old 10 Mbps LAN has been overloaded by MPEG-3 traffic. Thus, there is a strong need to have a faster LAN environment to support such traffic. Intel has been interested in supporting us in building a test bed for high speed 100Mbps Fast Ethernet LAN.
Low Cost Internet Access for Schools
Low cost access for schools to Internet would be of interest to open the information access for Indonesian future generation. A conventional Telco leased lines would be out of questions for most of Indonesian schools as it would cost a fortune for most of them.
We are currently building a model for low cost Internet access for Indonesian schools. The typical setup of such system is shown in the above figure. Some of the main features of the model can be described as follows:
Low speed (1200bps) & low cost packet access (can be less then US$300 / gateway) is used for transmitting the Internet E-mail. Most of the software required for it can be obtained from Internet, such as, ftp://ftp.ucsd.edu/ or http://www.lp.itb.ac.id/yc1dav/. Having a 24 hours packet radio access enable us to off load the need of costly leased line into the schools.
Proxy & dial-on-demand router is used to accommodate the need for browsing the Internet if needed & if local phone lines dial up access are available. Proxy server software can be downloaded from Internet.
For those who wish to build their own 1200bps modem, it will cost approx. US$10 / modem. The circuit diagram of the modem is shown in the figure below.
The major component used in the 1200bps packet radio modem are
One chip modem Texas Instrument TCM3105, CMOS Inverter 4049, x'tal 4.4336MHz (PAL color burst).
Comparison between VSAT TDMA vs. SCPC
We have been using VSAT TDMA 128Kbps outbound / 64Kbps inbound shared for linking several Indonesian universities to Internet. We found TDMA 30% link efficiency is very limited for Web access from various universities. We have tried to tune inbound packet length from 256byte to 40byte doesn’t help in increasing the throughput of our satellite link for Web traffic.
We are now migrating our setup from VSAT TDMA to VSAT SCPC starting from 19.2Kbps to higher speed, such as, 64Kbps.
Research Results in Network Layer
Major portion of research results on network management was performed by firstname.lastname@example.org and can be seen on http://netmon.itb.ac.id/ which consists of:
Sample of traffic by protocol, port, etc.
Graph of Total Traffic
We use Scotty http://wwwsnmp.cs.utwente.nl/schoenw/scotty/, which uses high level and string-based API based on Tool Command Language http://www.sunlabs.com:80/research/tcl/. Scotty consists of two major component, namely,
Tnm Tcl Extension to access network information.
Tkined - frame work for network management.
Most of the needed information can be downloaded from:
http://wwwsnmp.cs.utwente.nl/software/, list of software on network management
http://wwwsnmp.cs.utwente.nl/schoenw/scotty/, main page of Scotty.
Shown in the figure above is the map in X-Windows of major Indonesian education network connected to AI3 gateway. The same map can be seen on the Web at http://netmon.itb.ac.id/map.html. Thus all network operator can easily access & seen the network condition.
Based on tcpdump software available in Internet we have developed an simple processing software to see the dominant traffic on our network. It appears that web cache is the dominant traffic within the Indonesian AI3 network.
Logging our traffic weekly shows that Wednesday is the highest traffic, while for E-mail the peak traffic occurs normally in the morning and in the afternoon after 4 o’clock & Web peak occurs around lunch time.
Multi RouterTrafficGrapher (MRTG) is a program for Internet traffic visualization writen by Tobias Oetiker . It log the Internet traffic and converted into HTML format. Shown above is the traffic on one of our router, our MRTG Web is located at:
http://nic.itb.ac.id/ To do this, we need to get some of the software from:
PERL version 5.002 or above, check http://www.perl.com/perl/info/software.html.
Some UNIX version such as FreeBSD has included Perl in their distribution.
MRTG 2.0 can be downloaded from http://www.ee.ethz.ch/oetiker/webtools/mrtg.
GD1.2 the graphics library to convert MRTG into GIF can be downloaded from http://www.boutell.com/gd/ Research Results in Application Layer
Some of the activities in the application layer can be listed as follows:
Homepage for network beginners.
cache & cache monitoring.
MPEG-3 test bed.
Java test bed.
Java Test Bed
Several parties seem to be trying to make Java a favourite programming language for various Web application. Sun microsystem & Intel are trying to dominate the Java development in the market as both has contacted us to disseminate the tools among our students. Some of the public domain tools & documentation have been provided. No machine is dedicated as yet to be used. It is our aim in Indonesia to make these tools available for AI3 users.
To support technical / engineering information on Internet technology, we have developed a preliminary resource homepage on Internet technology at:
http://www.lp.itb.ac.id/yc1dav/beginner/ Materials deposited on this homepage are mainly on:
Packet Radio Technology.
Tools to integrate Novell to Internet.
We have also deposited some materials on our majordomo server so that users with no full internet access can download the information via E-mail.
We cache most of our Web traffic to Internet. Several parents are being used, such as, cache in Nara, cache in nlanr. Squid is used as our cache software and can be downloaded from:
or latest version. ITB has set up several parents, namely,
The person in charge on our cache is email@example.com or firstname.lastname@example.org. most of our cache consists of:
Pentium 133 (or better)
RAM 32Mbyte (or higher)
SCSI disk 1.7Gbyte (cache needs lot of disk space).
Collaboration with local Indonesian ISP is currently being pursued to set a sibling to their cache server.
In the next figures, we show the result of our monitoring of the cache system. It can be seen at:
http://www.lp.itb.ac.id/cachers/ Shown in the figure, the total request on one of our main cache is approx. 60.000 hit / day. Most of the hit occurs during mid day.
Summary of method usage can be seen in the figure above. As shown ICP_QUERY is dominating the request via UDP. TCP GET is dominating the traffic through our cache server.
The summary of protocol usage through our cache server is shown in the above figure.It shows clearly that http is the major protocol used through the cache. Altough, FTP generate siginificantly less count - it generates more Mbyte / count as compared to other method.
Summary of server usage can also be seen at http://www.lp.itb.ac.id/cachers/. It shows the dominant Web server access by the users. A social scientist would be of interest to see the user characteristics.