A Unique Laboratory for Teaching Administrative Aspects of Computer Networking

Session T2C

A UNIQUE LABORATORY FOR TEACHING ADMINISTRATIVE ASPECTS OF COMPUTER NETWORKING

Masahiro Ukigai1, Syunichi Kawamura 2 and Yoshiro Miida3

Abstract  Explosive growth of the Internet has brought approach to offer a practical course about computer forth a shortage of skilled engineers to design, construct and networking. For effective learning, it may require a number maintain an appropriate LAN environment in the majority of of workstations, PCs, HUBs, routers and so on in addition to the organizations connecting to the Internet. However, it is the Cisco basic learning kit. Furthermore, due to the generally difficult to construct a practical learning difference of requirements, there is less standard LAN environment where learners are able to experiment with configuration suitable for every organizational situation, or administrative tasks without any risks. This paper proposes practical learning experience that is desired. In this paper, a unique laboratory approach for teaching administrative we will focus on how to teach administrative skills of aspects of computer networking. For our purpose, sixteen computer networking practically and effectively. SPARCstation 5/85 are currently employed, which were During the last summer vacation, the computing center originally intended to be replaced. Each workstation has a of our institution replaced a workstation-based educational SCSI hard disk, which is easily installable with a convenient system with a PC-based one. About eighty SPARCstation attachment. Considering this mechanism results in a unique 5/85, with 32MB of main memory and 1GB of HDD, had laboratory for teaching administrative aspects of computer been operating for six years at the time under the Solaris 2.3 networking. The idea is to prepare pre-installed hard disks operating system. This version of the operating system could with functionality such as a DNS server, that can be used as not be upgraded due to a CAD application software. It was a building block to construct experimental LAN only capable of running under the Solaris 2.3 operating configurations easily. Necessary server functionalities have system. Many of these workstations were offered to our staff been identified considering typical learning patterns based free of charge to our staff members whom expressed interest on our administrative experiences, and on the evaluation of in the system. However, many workstations were left for the laboratory currently in use. discard. As a result, we considered an alternative usage of the unwanted workstations. Since, they were obviously Index Terms  Computer Networking Laboratory, LAN, powerless for computing or software development, we Network Administrator Education thought they might be usable for a laboratory, such that teaching administrative aspects of computer networking INTRODUCTION would be possible. Fortunately, all workstations had been maintained by a contract, and we could legally install newer The study of computer networks is very important version of the Solaris operating system without any considering the rapid progress of the Internet. It has caused a additional cost. The majority of the 21-inch CRT displays shortage of skilled engineers to design, construct and were fully usable for our laboratory plan. maintain a LAN environment in universities, companies and We have carefully reconfigured 16 workstations by so forth. Concerning the teaching of theoretical aspects of selecting the best components among the old units while computer networking, studies such as a web-based tutoring considering the possible room space. Thus, each workstation and testing[1] has been studied. A simulation-based has been reconfigured with 64MB of memory, 1GB HDD, a approach using COMNET is also reported[2] in teaching 21-inch CRT display and a Type 5 keyboard with a mouse. construct, tuning and analysis of network performance. Initially, we tried to install Red Hat Linux 6.2 for SPARC Although practical learning for computer networking is systems considering the hardware specifications. However, essential, it is very difficult to offer learners an appropriate we could not manage its installation on our SPARCstation learning environment. It is almost impossible to allow 5/85 against the Red Hat Linux Hardware Compatibility learners to use an existing network environment for study. List. On the other hand, we could manage installation of Red For example, reconfiguring the existing network and/or Hat Linux 5.2 for SPARC systems. However, its server settings of a Domain Name System (DNS) could environment was not so attractive for our purpose. Finally, possibly cause fatal damage to the system. However, it is Solaris 2.6 was selected, which had no problem for also very difficult to learn such administrative skills by installation. Although the Solaris 2.6 CDE (Common lectures or simulations. Cisco Networking Academy Desktop Environment) window system starts quite slow, it Program[3] is an alternative, but a very cost-consuming

1 Masahiro Ukigai, Chiba Institute of Technology, Faculty of Information Science, 2-17-1 Tsudanuma, Narashino, 275 Japan, [email protected] 2 Syunichi Kawamura, Chiba Institute of Technology, Faculty of Information Science, [email protected] 3 Yoshiro Miida, Chiba Institute of Technology, Faculty of Information Science, [email protected] 0-7803-6669-7/01/$10.00 © 2001 IEEE October 10 - 13, 2001 Reno, NV 31st ASEE/IEEE Frontiers in Education Conference T2C-17 Session T2C showed better response for command operation within the students, who intended to learn how to set up a DNS server, window environment. Mail server, NIS server, etc. From observations of their A CD-ROM drive was only installed in two experiences, it was concluded that they could easily set up workstations, we removed the top panel of all workstations server functionalities on PCs by themselves by referring to for considering Solaris 2.6 installation. As each workstation technical books and/or computer magazines. However, they has two SCSI connectors in it, we decided to make clone experienced difficulty constructing their necessary network disks from an installed disk instead of considering a remote structure for learning a sub-network delegation, using BIND installation procedure. During the installation procedures, for example. It was difficult and very time consuming to we directed our attention to the mechanism of the disk configure such learning environment by themselves. From attachment for its installation. As a fact, this installation the experiences in our research laboratory, we had been approach brought us an idea to design a unique laboratory to considering how to support in teaching administrative support students' practical learning pertaining to computer aspects of computer networking effectively. networking. The SPARCstation 5 family employed a very By employing 16 workstations with 31 pluggable disks, convenient attachment to install a disk drive to secure the we have designed and developed a unique laboratory. SCSI connection to the corresponding unit. Just placing a Currently, only 10 inexpensive switching HUBs, 20 RJ- disk drive into the drive bay through a guide lane, then 45LC extension connectors and UTP cables have been simply closing the handle of its attachment will complete the purchased additionally. Four Ethernet adopters for process. The idea is named as a pluggable approach, which SPARCstation 5, which were not in use, were also collected will be described in detail in the latter section. in our department to construct router functionality using two Then, we considered the possibility of preparing pre- SPARCstation 5/85. UTP cables connected to each installed disks as a building block to configure a wide workstation are concentrated into two groups, which are variety of LAN structures for learning. They were intended connected to a handmaid patch panel, respectively. UTP to resemble a pre-configured DNS server disk, Mail server cables of 1M length have been prepared for use as a patch disk, FTP server disk and so on. In our research laboratory, cable. This has eased the configuration of experimental we previously offered several old PCs and HUBs for networks considerably, because the cabling can be managed

site router main network

WWW DNS&Mail Proxy server router server server

sub network

DNS&Mail Proxy router server server client WWW server research lab

DNS&Mail server

client client WWW server printer

FIGURE. 1 TYPICAL NETWORK STRUCTURE OF A CAMPUS LAN

0-7803-6669-7/01/$10.00 © 2001 IEEE October 10 - 13, 2001 Reno, NV 31st ASEE/IEEE Frontiers in Education Conference T2C-18 Session T2C from one place. The Solaris 2.6 operating system has been The idea is named as a pluggable hard disk approach, installed on all pluggable disks. A DNS software and a Mail which is conceptually similar to a building block to Transport Agent software have been pre-installed on several configure a network structure. As shown in FIGURE 2, the disks with pre-determined IP addresses, which can be used SPARCstation 5 product family employed a convenient to ease construction of a typical hierarchical network disk attachment to install a disk drive to secure the SCSI structure. With this laboratory equipment, typical learning connection to the corresponding unit. As shown in the patterns have been studied by some students. In the sequence from (A) to (C) in FIGURE 2, placing a disk drive following section, the design concept of the laboratory employing pluggable hard disks is described. guide CONCEPT OF THE PLUGGABLE APPROACH SCSI connector It is generally difficult for students to experience administrative operations in a real computer network environment which is connected to the Internet. Therefore, they could hardly have a chance to learn how to set up a Domain Name System, Mail Transport Agent and so forth. In our research laboratory, we could offer a few old PCs for such a learning purpose; however, they could only learn such administrative skills in a closed, small, and very restricted LAN. Although it is rather easy to learn such administrative aspects on PCs with no risks, it is difficult to construct a domain hierarchy within a real computer (A) DISK DRIVE BAY AND SCSI CONNECTORS network environment. From such experiences in our research laboratory, it seemed that students often felt difficulty in constructing a necessary networking structure to meet their learning demands. For example, if they intended to learn how to delegate a sub-domain administration using BIND e.g., they had to construct and set up at least two individual LAN for learning. FIGURE 1 shows a typical network structure in organizations which will be desirable to experience administrative aspects of computer networking practically. Initially, we had planned to offer sixteen SPARCstation 5/85 with additional HUBs and UTP cables in a laboratory room for students who are interested in studying any administrative skills of computer networking. Due to old workstations, students are able to learn practically without (B) SLIDE THE DRIVE INTO THE DRIVE BAY the fear of damaging any hardware. Although a CD-ROM drive is only installed in two workstations, we had to manage installation of the Solaris 2.6 operating system on all workstations. If all of them pre-installed a CD-ROM drive, we might have planned concurrent installation procedure by purchasing additional Solaris 2.6 media. Students could then have had a chance to experience the Solaris installation by themselves. It is also important to know how to install operating systems; however, we could not purchase any CD-ROM drive installable to old workstations. Instead, as each workstation has two SCSI connectors in it, we have decided to copy the whole contents of installed disks after the completion of some Solaris installation instead of a remote installation procedure. We removed the top panel of all workstations (C) SECURE THE SCSI CONNECTION for Solaris 2.6 installations. As a result, this approach FIGURE.2 brought us an idea to design a unique laboratory to support OVERVIEW OF THE PLUGGABLE HARD DISK INSTALLATION students' practical learning.

TABLE I NETWORK ADDRESSES AND HOST NAMES PRE-DEFINED FOR EACH NETWORK DOMAIN cit.jp 192.168.16.0/24 ns.cit.jp 192.168.20.0/27 cs.cit.jp 192.168.25.0/28 xx.ns.cit.jp 192.168.20.32/27 ns1 192.168.16.1 x ns1 192.168.20.1 x ns1 192.168.25.1 x ns1 192.168.20.33 x ns2 192.168.16.2 ns2 192.168.20.2 ns2 192.168.25.2 ns2 192.168.20.34 www 192.168.16.3 www 192.168.20.3 www 192.168.25.3 www 192.168.20.35 proxy 192.168.16.4 proxy 192.168.20.4 proxy 192.168.25.4 proxy 192.168.20.36 ftp 192.168.16.5 ftp 192.168.20.5 ftp 192.168.25.5 ftp 192.168.20.37 wtm 192.168.16.11 ns-ws1 192.168.20.11 x cs-ws1 192.168.25.11 x xx-ws1 192.168.20.51 x nlp 192.168.16.12 ns-ws2 192.168.20.12 x cs-ws2 192.168.25.12 x xx-ws2 192.168.20.52 x s-gate 192.168.16.33 r ss-gate 192.168.20.29 r cs-def 192.168.25.14 r xx-def 192.168.20.62 r cit-ws1 192.168.16.101 x ns-def 192.168.20.30 r cit-ws2 192.168.16.102 x x: pluggable disk exists dhcp addr.192.168.16.240-9 r: default route

into the drive bay through a guide lane, then simply following software has installed considering benefit for closeing the handle of its attachment will complete the possible learning situations. process. As long as the top panels of all workstations have • bind-8.2.3 (not configured) been kept removed, the installation procedure of a hard disk • sendmail-8.9.3 (not configured) is quite easy even for unskilled students. Following these • CF-3.7Wpl2 considerations, we have concentrated on the laboratory CF-3.7Wpl2 is a sendmail.cf generation tool generally development as described in the next section. used in our country. Thus, only 90MB of free disk space has been left for learners. We have also kept and named this LABORATORY DEVELOPMENT hard disk as the ADVANCED system disk to produce the At first, we had to manage how to identify the pre- other clone disks. Although it was a very time consuming installable server functionalities required to configure a job to produce these master disks, the producing procedure typical network structure. As the number of hard disks is of clone disks of them is quite easy by using the UNIX "dd" currently limited to about thirty, we had to carefully select command. important functionalities for networking from a DNS On the other hand, although routers are requisite to server, Mail server, NIS server, WWW server, Proxy configure a hierarchical network structure, it is rather server, FTP server and so forth. Since the storage capacity expensive and complicated to set up properly for students. of each hard disk is also limited to 1GB, we could not Instead, we have planned to configure a SPARCstation 5 as install the entire Solaris software group in order to keep a router installing additional Ethernet adapters, which are sufficient free space for learning. The developer Solaris currently unused in our department. We collected four software group installation requires about 642MB disk unused adopters, then two workstations were configured as space, excluding the swap space of 128MB. Considering routers, where each workstation had three network the requirements for free software installation like a Web interfaces. However, considering the router configuration server, and necessary software environment for learning, we and preparation of plugguble disks, it seemed better to pre- have prepared additional software to the Solaris operating determine network addresses and typical hostnames along system as follows. with pre-determined network domains. TABLE I shows the pre-determined information; however, it will not restrict • 2.6_Recommended patch learning variations. It is only pre-determined to ease typical • Netscape communicator 4.7 network configurations. Therefore, learners are able to • traceroute-3.5 configure any network addresses, hostnames and domain • perl-5.005_03 names as they like using the other pluggable disks by • gzip-1.2.4, tar-1.12 themselves. It may take much time to configure a desired • patch-2.5, make-3.77 network structure; however, they will learn much more • gcc-2.7.2.3, bison-1.27, flex-2.5.4 practically during the process comparing to use pre- After the installation of all of the above software, we installed building blocks. could keep about 145MB of free disk space. We have kept To ease cabling during the configuration of a network the master hard disk and named it as the BASE system disk structure, UTP cables connected to each workstation are to produce clone disks for laboratory workstations. In carefully concentrated at one place, where stacked addition to the contents of the BASE system disk, the switching HUBs and a handmaid patch panel are placed. The patch panel was created using RJ-45LC extension 0-7803-6669-7/01/$10.00 © 2001 IEEE October 10 - 13, 2001 Reno, NV 31st ASEE/IEEE Frontiers in Education Conference T2C-20 Session T2C connectors. FIGURE 3 shows stacked switching HUBs and • 5 disk drive with attachment (2GB SCSI) a patch panel on the desk, where cabling can be managed • 10 switching hub (purchased) using UTP cables of 1M length. There is another set in the • 2 SS5/85 (2 additional Ethernet adapter each) laboratory room for concurrent learning in the laboratory. • 1 color display (13-inch) • 1 color display (17-inch) • 1 network printer • UTP cables (purchased) • 20 RJ-45LC connector (purchased)

FIGURE. 3 STACKED SWITCHING HUBS AND A HANDMAID PATCH PANEL FIGURE. 4 OVERVIEW OF THE LABORATORY WORKSTATIONS Moreover, archive files as shown in the following are stored on a workstation in the laboratory for further learning We hope that the current laboratory equipment can be related to networking. enhanced when the proposed laboratory works effectively • apache-1.3.14 for teaching administrative aspects of computer networking. • bind-8.2.3, bind-9.1.0 FIGURE 4 shows an overview of the laboratory • majordomo-1.94.4 workstations whose top panels have been kept removed for • php-3.0.16 disk installation. • postgresql-6.5.3 • qmail-1.03 ASSESSMENT • qpopper-2.53 Currently, the proposed laboratory is not included in the • sendmail-8.9.3, sendmail-8.11.2 curriculum of our undergraduate course. We are planning to • squid-2.3 offer it for undergraduates and graduates who are interested • tcp_wrappers-7.6 in learning administrative aspects of computer networking. • wu-ftpd-2.6.1 In our department, about 10 research laboratories have been By downloading these files to any workstation in the maintaining delegated sub-network domains, respectively. laboratory LAN, students are able to experience installation Each year, around 10 bachelor candidates are allocated to and necessary configuration procedures practically within each research laboratory, and the proposed laboratory can the laboratory environment. For example, in case of be opened for them to enhance administrative skills learning how to develop a Web-DB application software required to maintain their research laboratory’s network. which should be inaccessible from the other network Up to the date from the planning stage of the unique domain, pluggable disks can be useful to support quick networking laboratory, some students in our research configuration of the required network structure. laboratory have been studied using the laboratory equipment. They were interested in learning administrative aspects of computer networking practically, and LABORATORY EQUIPMENT experienced somewhat using PCs as described in the former section. The laboratory proposed in this paper consists of the As a case study, a student who learned to set up a DNS following equipment, where the majority of them are server (BIND) and MTA (sendmail) on a PC tried to obtained free of charge. configure a hierarchical network structure as shown in 14 SPARCstation 5/85 (64MB memory) • FIGURE 5. The site router is not available now due to • 14 color display (21-inch) security aspects. It can be possible to configure the network • 31 disk drive with attachment (1GB SCSI)

site router cit.jp 192.168.16.0-192.168.31.255

s-gate s-gate

router ns1 wtm nlp router 192.168.16.1 192.168.16.11 192.168.16.12 cs-def ns-def

ns.cit.jp 192.168.20.0/27 cs.cit.jp 192.168.25.0/28 ss-gate ss-gate

ns1 ns-w s1 router router 192.168.20.1 192.168.20.11 ns1 cs-w s2 xx-def 192.168.25.1 192.168.25.12 zz-def xx.ns.cit.jp 192.168.20.32/27 zz.ns.cit.jp 192.168.20.64/27

xx-w s1 ns1 192.168.20.51 192.168.20.33

FIGURE. 5 NETWORK CONFIGURATION AVAILABLE USING PRE-DETERMINED NETWORK ADDRESSES AND HOST NAMES using pre-installed pluggable disks as shown in TABLE I. Although not many students have participated in the study, The student started to set up the virtual top domain (cit.jp: the reaction from students who managed a DNS and Mail 192.168.16.0/24) first using a clone disk of the server configuration is very favorable. As the number of ADVANCED system, where he could make it easily. Then, pluggable hard disks is limited now, we are considering using another clone disk, he tried to set up a sub-network how to increase the learning variation with pre-installed domain (ns.cit.jp: 192.168.20.0/27). However, since he had disks. They will include a Web server, Proxy server, FTP no experience to set up within such a situation, he wasted server, Database software and PHP software, which can be much time by trial and error. It seems difficult to complete effective to create a typical network environment. the task by analogy from the former experiences. Using our Introducing a site router is a bit expensive, but it is support, he finally managed operating both DNS servers necessary to connect the laboratory LAN to the Internet. properly. There were no appropriate technical books or However, a misconfiguration of the laboratory LAN or the computer magazines which describes in detail on such site router itself may cause fatal damage to our configurations. Furthermore, it was difficult for him to set departmental LAN, campus LAN, and so forth. The up the network domain named xx.ns.cit.jp, because it alternative is a Linux PC with two NICs, which is running required knowledge to construct a classless domain IP Masquerade software. The proposed laboratory can be configuration. expandable to include security aspects and statistical From the consideration on the case study, we felt the aspects of networking using the current equipment. A PC- necessity to offer a Web-based teaching material where based laboratory could possibly be developed if a pluggable students are able to consult anytime. A FAQ server can also disk mechanism could be resolved. be quite effective to accumulate the knowledge of typical trouble shootings which can happen during learning in the REFERENCES laboratory. As the BASE system has a Web browser, [1] Ayman Kayssi, Ali El-Haji, Mahmoud El Assir, Ramzi development of them is continueing in order to support Sayyid,"Web-Based Tutoring and Testing in a Computer Networks learners in the laboratory. Course", Computer Applications in Engineering Education, Vol.7, No.1, 1999, pp.1-7. SUMMARY [2] Nizar Al-Holou, Knicolas K. Booth, Ece Yaprak,"Using computer network simulation tools as supplements to computer network A unique laboratory approach employing pluggable hard curriculum", 30th ASEE/IEEE Frontiers in Education Conference, disks is proposed for practically teaching administrative 2000, pp.S2C-13-16. aspects of computer networking. Evaluation and [3] http://www.cisco.com/ (Cisco Networking Academy Program) enhancement of the laboratory is continueing with the development of Web-based teaching material and laboratory support systems, including a FAQ server. 0-7803-6669-7/01/$10.00 © 2001 IEEE October 10 - 13, 2001 Reno, NV 31st ASEE/IEEE Frontiers in Education Conference T2C-22