Session 3232 CANLAB: A Multi-Purpose Computer Architecture and Networking LAB Jiying Zhao y, Richard Paweska z, Yanni Giftakis z, Mila Kwiatkowska z, and Bernie Kirkey z y School of Information Technology and Engineering, University of Ottawa, 150 Louis Pasteur, Ottawa Ontario, K1N 6N5, Canada z Department of Computing Science, University College of Cariboo, 900 McGill Road, Kamloops, BC, V2C 5N3, Canada ABSTRACT We introduce CANLAB (Computer Architecture and Networking LAB), which facilitates the lectures and labs of courses such as computer architecture, computer networks, internet/intranet, advanced computer networks, advanced database system, e-commerce, etc. The lab provides students a place to practice what they have learned from class and gain practical experience outside of lecture. It provides teachers a place to present their lectures and labs. This paper will introduce the necessity and importance of the dedicated lab, lab equipment allocation and structure, lab implementation and use, and future development of the lab. Keywords: CANLAB, dedicated lab, computer networks, computer architecture, e-commerce 1. INTRODUCTION The Department of Computing Science at University College of the Cariboo (UCC 1 ) offers two degree-programs -Bachelor of Technology in Applied Computing Science and Bachelor of Science (Major in Computing Science), and one diploma program - Computer Systems (Operations and Management). Those three programs are respectively abbreviated as BTACS, Major in Computing, and CSOM. BTACS is designed for those wishing to enter a career using modern information technologies to design, implement, maintain and upgrade information technology systems. The program combines theory, technical and hands-on skills, communication skills and business skills. Major in Computing at UCC is a 4-year degree program that provides students with a rigorous training in science (concentrated in the first two years), and then a thorough training in Computing Science (concentrated in the last two years). Graduates will then be well qualified for a wide range of employment opportunities, for further study in advanced degrees and for research positions. This degree provides a more rigorous scientific training than the more applied BTACS degree. CSOM is designed to produce graduates who will immediately become productive employees, and who will have the breadth of background necessary for advancement as their career progresses. Career opportunities may include computer programming, E-commerce programming, website developer, network administrator, software development, computer operations, systems design or systems management. Table 1 gives the courses that need dedicated lab or are accommodated in CANLAB. The five columns in the table respectively represent course number, course title, course vector, program(s) the course is oriented to, and course credits. The course vector indicates the weekly hours of instruction for the course. The first digit inside the bracket indicates the number of lecture hours per week, the second digit indicates seminar hours per week, and the third digit indicates laboratory hours per week. The listed courses are critical to those three programs, and students need both theoretical and hands-on knowledge on those topics. All diplomas and degrees have Proceedings of the 2002 American Society for Engineering Education Annual Conference &Exposition Copyright cfl2002, American Society for Engineering Education Page 7.277.1
Table 1: Courses accommodated in CANLAB Number Title Vector Program(s) Credits COMP 253 Small Computer Systems: (3,0,2) CSOM 3 Organization and Architecture COMP 262 E-Commerce Systems Development (3,1,0) CSOM 3 COMP 263 Small Computer Systems: (3,1,0) CSOM 3 Communication and Networks COMP 323 Computer Networks Principles (2,0,0) BTACS 2 COMP 324 Computer Networks Implementation (1,0,1) BTACS 1 COMP 327 Computer Networks (3,0,1) Major 3 COMP 423 Advanced Computer Networks (3,1,0) Major, BTACS 3 COMP 424 Internet/Intranet (3,1,0) BTACS, Major 3 COMP 448 Directed Studies in Computer Science Major, BTACS 3 COMP 461 Advanced Database Systems (3,1,0) BTACS, Major 3 COMP 462 E-Commerce Systems Development (3,1,0) BTACS, Major 3 core courses in both architecture and networking. Along with academic lecture material, students have labs, workshops, and projects involving the physical installation and configuration of systems. For all university students (computing science and otherwise) a number of computer labs are available on campus, containing generally the same software set and being completely open, requiring personal username/passwords for access only to specialized software. The systems in these labs have strong virus-detection and error-correction schemes. By locking the configurations, these methods ensure stability, but limit how many options are available to students - essentially, students are only able to use pre-installed applications and not make changes to the system. Three dedicated programming labs are set aside for students in the computing science programs. Even though these labs have a more focused selection of software, they are also closed in terms of allowing software installation and reconfiguration although not as locked as general labs. Unix and Novell NetWare 2 are two majornetworking operating systems. Exposure to those OS's is a must for the students in those programs. There is only one Unix machine running on the UCC campus. Students cannot practice installation, configuration, and administration of NetWare or Unix, in any existing labs. In support of the courses that need specialized, dedicated, and open equipment available to students, the Computing Architecture and Networking LAB (CANLAB) was established. Initially, the lab was utilized by only two courses, but has expanded its use to many courses. At the writing of this document, a second lab is under consideration to help focus the CANLAB's resources directly to its many courses. Although limited in physical resources for its varied and concurrent uses, the lab supports multiple student projects and configurations by using hard drive/partition imaging technology - in essence, giving a system multiple personalities. 2. ARCHITECTURE OF CANLAB In the CANLAB, instructors can present lectures and labs, demonstrate the computer hardware architecture, operating system installation and administration, computer networks concepts and hardware, network installation and configuration, and web and database server administration for both advanced database systems and Page 7.277.2
Internet Hub Campus Router Labs for BTACS, Major in Computing, and CSOM KIDNEY LIVER MEDULLA GURU Switch Hub Hub Hub Hub Hub Hub Access Point S1 C1 S2 C2 S3 C3 S4 C4 S5 C5 S6 C61 C62 Figure 1: The network topology of CANLAB Table 2: Computers and functions Name OS Functions NIC LIVER Linux router, proxy server, firewall, DNS server, NFS server, 2 NIS server, web server, telnet server, ftp server KIDNEY NetWare file and print server 1 MEDULLA NT Server web and application server 2 GURU NT Workstation download server, backup of images, 2 printer server, multimedia station S i Linux, NT Server, cluster server 1 NT Workstation, Windows 98 C i NT Workstation, Windows 98 cluster client 1 e-commerce. Students can learn to build computers, computer networks, web servers, and can test their assignment and projects within CANLAB or from their classroom or their home. Instructors can help students and evaluate students' work in CANLAB or from their office or home. Various labs can be accommodated in CANLAB. The essential components of the CANLAB are the six network clusters and the three main servers. In general, the lab is a multi-protocol/multi-operating system local-area network, connecting all clusters together Page 7.277.3
in a tier through a central switch. In detail, each cluster consists of three components: a server system, a workstation system, and a 10/100 Mbps hub. The server is multi-booted with Linux, Microsoft 3 Windows 98, NT Workstation, and NT Server. The workstation is dual-booted with Windows 98 and NT Workstation. The network hub links both systems together in a small Intranet, as well as connecting the cluster to the central switch. Each system (server and workstation) contains multiple partitions on the single drive to support the various operating systems and an area for image backup. Table 2 gives the operating systems and functions of each main server and cluster computers. The lab accommodates Linux, Novell NetWare, Microsoft Windows 98, Windows NT Server, and Windows NT Station. NetWare (on KIDNEY) is used as backup server, disk server, and printer server. The Linux server (LIVER) serves as a router, proxy server, DNS server, and web server. NFS and NIS are configured on those Linux servers to offer uniform account access. Wireless LAN in CANLAB makes the lab use more flexible. Figure 1 shows the architecture of CANLAB. Due to the IP address limitation, only three computers in CANLAB - LIVER, MEDULLA, and GURU - have public IP address in addition to an internal IP address (refer to Figure 1). All other computers have only an internal IP address from block 192.168.100.0/24. LIVER, MEDULLA, and GURU have 2 Network Interface Cards (NIC) inserted, so that they connect to outside of CANLAB as well as inside. Computers in CANLAB are configured to use LIVER as proxy server, so all the computers can access the Internet without having to have a public IP address. Access to CANLAB from Internet is also enabled by using the proxy server. Operating system images are saved and a fresh restoration to the computers is possible whenever needed, so that one lab session will not affect the next. Important data are backed up automatically on daily basis by the primary Linux server to NetWare server. 3. IMPLEMENTATION OF CANLAB This section will describe how CANLAB is implemented, by giving important technical guidance and not going into too much detail. 3.1. Router LIVER is configured as the router for CANLAB, in which two Network Interface Cards (NICs) are inserted. One of those two NICs is for connecting to the Internet, while another to the CANLAB network. LIVER is naturally configured to server as a proxy server, firewall, DNS server, NFS server, NIS server, Linux account server, telnet, ftp, and web server. 3.2. Proxy and Firewall DeleGate 4 is a multi-purpose application level gateway, or a proxy server which runs on multiple platforms (Unix, Windows and OS/2). DeleGate mediates communication of various protocols (HTTP, FTP, NNTP, POP, Telnet, etc.), applying cache and conversion for mediated data, controlling access from clients and routing toward servers. It translates protocols between clients and servers, merging several servers into a single server view with aliasing and filtering. Besides proxy, DeleGate can be used as a simple origin server for some protocols (HTTP, FTP and NNTP). CANLAB uses DeleGate a proxy for http, telnet, and ftp. The following proxy services are used to enable access to http, telnet and ftp service from inside to outside of, and from outside of to inside CANLAB, which are automatically started by putting the following lines into file =etc=rc:d=rc6:d=k99local: /usr/local/src/delegate7.3.0/src/delegated -P8023 SERVER=telnet /usr/local/src/delegate7.3.0/src/delegated -P8021 SERVER=ftp /usr/local/src/delegate7.3.0/src/delegated -P8080 SERVER=http By configuring a browser on client computers to use LIVER as its proxy server, web pages and telnet and ftp services on the Internet can be accessed from inside CANLAB. Telnet and ftp service can also be accessed by respectively issuing the following commands: Page 7.277.4
telnet liver 8023 telnet liver 8021 By changing options of delegated command, proxy server can be configured to allow or disallow a certain group of computers or networks from using the proxy services. It is the proxy server that makes access between inside and outside of CANLAB possible without using public IP address. 3.3. DNS The domain name system (DNS) is the waythatinternet domain names are located and translated into Internet Protocol addresses. CANLAB has an internal DNS server implemented on LIVER, which provides the mapping between internal domain name and internal IP address. Also it provides a demonstrative configuration for students who are required by project to implement theirown DNS server. The configuration files for DNS consist of named:conf, named:ca, named:local, named:hosts,andnamed:rev. The default configuration file named:conf provdes the location of other configuration files. File named:ca provides a list of root DNS servers. File named:hosts provides the maping from domain names to IP addresses. File named:rev provides the mapping from IP addresses to domain names. DNS server for subdomain in CANLAB can be configured to form hierarchy of DNS servers. Students can configure their own caching-only DNS server, IP-forwarder, or a primary DNS server, which uses LIVER as their parent DNS server. 3.4. NFS and NIS The Network Information Service (NIS) is an administrative database that provides central control and automatic dissemination of important administrative files. The advantage of using NIS is that these important administrative files can be maintained on a central server, and yet completely accessible to every workstation on the network. All of the maps are stored on NIS server LIVER. The maps are queried remotely by client systems. By using command ypinit, NIS converts the following standard UNIX files into databases (NIS maps) that can be queried over the network: /etc/passwd /etc/group /etc/hosts /etc/networks /etc/services /etc/protocols /etc/netgroup /etc/rpc Command ypserv is automatically issued on LIVER to initialize NIS service, and ypbind must run on every NIS client machine that uses the NIS service. The Network File System (NFS) is a client/server application that lets a computer user view and optionally store and update files on a remote computer as though they were on the user's own computer. LIVER in CANLAB is configured as a NFS server providing centralized directories. NIS and NFS together enable users access their UNIX account from any computers. To do this, we configured all the Linux servers to belong to the same NIS domain, create user accounts under LIVER : =home2 directory, and let all other servers share the databases on LIVER. LIVER exports its directory =home2 to all Linux servers, and all other servers mount LIVER : =home2 to its own files system. By putting it into configuration file =etc=exports on LIVER, and directory =home2 can be exported to other Linux machines. By putting the following entry to file =etc=fstab on each NFS client machine, the directory =home2 of LIVER can be mounted to each NFS client machine: Page 7.277.5
192.168.100.254:/home2 /home2 nfs where 192:168:100:254 is the IP address of LIVER. 3.5. NetWare Novell NetWare is one of the most widely-installed network server operating systems. Having a NetWare server installed provides file and printer services, and serves as a demonstration to students how NetWare is installed, configured, administrated, and used. KIDNEY in CANLAB serves as NetWare server, which is equipped with 512 MB RAM and 8 GB hard disk. Both Linux machines and Windows machines can access the file and printer servers provided by Netware server. The router LIVER is so configured that the NetWare server cannot be seen from outside CANLAB. The following is included in LIVER's file =etc=rc:d=rc6:d=k99local. /sbin/ipx_configure -ipx_interface=off -ipx_primary=off /sbin/ipx_interface delall /sbin/ipx_interface add -p eth0 802.2 /sbin/ipx_interface add eth0 802.3 /usr/bin/ncpmount -S KIDNEY -U username -P password /mnt/netware where username and password are respectively the username and password of a NetWare user. To automate the mount process, the following two lines are inserted into file =etc=rc:d=rc:local: /etc/rc.d/rc6.d/k20nfs start /etc/rc.d/rc6.d/k99local The file and printer services of KIDNEY also can be accessed using Novel Client for Windows on machines that run Microsoft Windows. 3.6. Automatic Backup Cron is a daemon to execute scheduled commands on Unix. LIVER is configured to automatically backup user home directory =home2, to NetWare server KIDNEY, on daily-basis, by putting the following into =etc=cron:daily=local:cron - the daily configuration file of cron utility. /bin/tar czfv /mnt/netware/sys/home/liver/backup/home2/home2.tar.gz /home2 /bin/tar czfv /backup/home2.tar.gz /home2 In case system problems happen, the file =home2:tar:gz on KIDNEY or under directory =backup can be restored to alleviate damage. 3.7. Multi-boot configuration The cluster servers and clients can boot to different operating systems depending on needs, therefore the hard disks are configured into multiple partitions. The cluster servers have seven partitions configured, shown as in Table 3: Cluster workstations have three partitions respectively for Windows 98, NT Workstation, and a partition reserved for Ghost imaging. Page 7.277.6
Table 3: Partitions of cluster servers No. Partition type Partition File System Mount point Use 1 Primary Linux ext2fs /boot Linux 2 Primary Windows FAT16 Windows 98 3 Logical Windows FAT 32 Ghost partition imaging 4 Logical NT Server NTFS NT Server 5 Logical NT Station NTFS NT Station 6 Logical Linux swap /swap Linux 7 Logical Linux ext2fs /root Linux 3.8. Image Switching One of the most important aspects of the CANLAB's set up is the use of imaging software - Norton Ghost. On its backup partition, each server and workstation holds a compressed image file of each operating system. These images can be used to restore an installation that has been damaged by use or student configuration. For security, and allowing an entire system to be rebuilt easily, all images are also kept on a lab file server (GURU). The secondary use of the imaging software is to permit clusters to maintain multiple configurations of student projects. With the limited number of clusters, and great number of courses and students, imaging permits a student group to save its current configuration, restoring it when necessary and continuing work. Projects on the same machine do not interfere with each other, and it is easy to step back after creating a faulty configuration. 3.9. Wireless LAN An Access Point is needed for connecting the wireless LAN with the existing CANLAB network. Each wireless node needs a wireless NIC inserted. The wireless solution facilitates the convenient access to CANLAB network. 4. USE OF CANLAB The CANLAB is used by a number of courses from the Department of Computing Science, each course using the same equipment but in a different aspect. The courses range from fundamental introductions to computer architectures (hardware) and networking, to advanced discussions involving communication systems, network protocol development, and interconnectivity of services (web, database, e-commerce servers). The task of supporting each course independently is daunting enough, but in the case of the CANLAB these courses share the same equipment over different labs, projects, and configurations. Although not requiring exact choreography, instructors discuss upcoming student work to ensure a minimal possibility of one group creating an unexpected (and irreversible) configuration for another group. And although the CANLAB contains a whiteboard and wall space for projections of lecture materials, it is primarily a hands-on working environment. Unless otherwise denoted, all resources are available to students during their tutorial, assignment, or project work. Of special note is the CANLAB's configuration and maintenance. Since students are required to perform most (if not all) of the hands-on activities, guided only by the instructor, UCC's Computer Services support department is not involved, aside from initial purchases or linkages from the CANLAB to the campus network. Students and instructors perform all assembly, configuration, repair, and troubleshooting of CANLAB equipment, from the student clusters to main lab servers. This provides students with the necessary skills of finding the final solution, as well as having the instructors work with the same equipment and problems faced by students. Page 7.277.7
In subsections 4.1, 4.2, and 4.3, we list a few of the use cases for courses related to computer networking, computer architecture, and e-commerce. 4.1. Computer Networks The following lists a few networking related experiments that can be accommodated in CANLAB and cannot be done in a general lab: ffl Conceptual knowledge on networking hardware: Students can have conceptual knowledge on basic network hardware such as Network Interfaces Cards, hubs, shielded or unshielded twisted-pair cables, coaxial cables, fiber optics cables, various connectors, terminators, wireless networking devices. Students are also introduced to routers, various networking operating systems, and LAN topology. This lab helps students understand concepts taught in class. ffl TCP/IP configuration: Students physically connect the computers in their cluster to the rest of LAN, and configure TCP/IP on Windows and Linux to enable communications. ffl DNS: Students configure their own DNS server (forwarder, caching only, primary) to serve their own subnetwork (intranet), by using LIVER as their parent DNS server. ffl Router and routing protocol: Students insert two Network Interface Cards into their server computer, cable correctly, and configure router and routing protocol such as RIP. ffl Firewall: Students configure firewall by using DeleGate software, and simple firewall function such as packet filter by using Microsoft's RAS (Remote Access Service). ffl Web server: Students configure their own web server, supporting static, dynamic, and active documents. ffl SNMP: Students use SNMP utilities in the lab to help them better understand the protocol. For example, the wireless LAN access point can be configured by using SNMP. ffl DHCP and Dial-in: Students configure RAS to enable dial-in service and DHCP. ffl Proxy server: Students configure proxy server by using software such as DeleGate and Squid. ffl NetWare: Students install, configure, administrate NetWare server, to better understand the popular networking operating system. ffl Linux: UNIX and Linux are very important operating systems, and exposure to those OS's are indispensable. Students install, configure, and administrate Linux in CANLAB. ffl Network troubleshooting: Students use their knowledge to trouble-shoot various problems generated in CANLAB. 4.2. Computer Architecture COMP253 (Small Computer Systems: Organization and Architecture) is a first-semester (of first-year) course in the CSOM diploma program. The course covers a wide range of lecture and practical topics. The practical topics are presented in form of weekly workshops, covering: introduction to DOS, overview of the PC, internal PC configuration, operating system install, components (internal & peripheral) and conflict resolution, introduction to Unix/Linux, basic networking (hardware & software), and complete system assembly and a special project. Each workshop uses the CANLAB in a particular way, requiring different combinations of equipment and software, both preinstalled and installed by students. Page 7.277.8
4.3. E-Commerce It is instructor's discretion to decide how server MEDULLA is used to support and prepare e-commerce course. The CANLAB has been used for COMP262 and COMP462 (E-Commerce Systems Development). MEDULLA was connected with the BTACS lab and used as an IIS 4 web server for web applications with Access97. Students could upload their work to MEDULLA from their lab or home. This year MEDULLA is used as a very special server that has Windows 2000, Oracle 8i database server, two web servers (Apache and IIS 5), TomCat, and XML native database Tamino from Software AG. Oracle 8i server with XML extension and OLAP is used for COMP461 (Advanced Database Systems), and Tamino with Oracle 8i for COMP448 (Directed Studies course) which is on XML and distributed databases. MEDULLA is used as an experimental server for installing new software and configuration. After about 2 semesters, most of the software and setup will be moved to other servers. 5. CONSIDERATION FOR FUTURE LAB DEVELOPMENT The establishment and use of CANLAB is a success. As the university's programs advance, along with technology and demand, demands for educational environments such as the CANLAB will also increase. Of course, since students have complete control over the configuration and use of the hardware and software, care must taken for access security and equipment loss. Along with increasing the performance and storage of all systems, future plans include adding a set of powerful Linux servers to handle local, remote, and cross-server traffic, along with supporting experimental multi-processor configurations. The purpose of such is to support advanced research in networks, and permit testing of distributed systems in a more open environment than is seen in the dedicated programming labs. The lab's current imaging software does not support backup/restore over the LAN. This is a consideration as a future upgrade when the CANLAB will also support remote booting. The School of Information Technology and Engineering (SITE) at University ofottawa 5 offers the following undergraduate programs: B.A.Sc. in Computer Engineering (Honours), B.Sc. in Computer Science (Honours, concentration), B.Sc. in Computer Science, Information Management Systems (Honours, concentration), B.Sc. in Computer Science (Honours) with concentration in Mathematics-Science, B.A.Sc. in Electrical Engineering (Honours), B.A.Sc. in Software Engineering (Honours). Due to market demands, computer networking related courses are well received by students. Anumber of computer networks related courses need a `dedicated' lab, so students can implement their ideas, and practice what they have learned in class. A common lab can be used as a lab for special experiments or projects. In doing so, several images need be prepared. Out of 3-hour block, half an hour can be used for preparation, half an hour for cleaning-up, and two hours for the assigned experiment or project. If a project or assignment cannot be finished in one session, the intermediate image can be saved for the next lab session. In this way, quite a few networking-related experiments, such as DNS, TCP/IP configuration, router and routing, proxy server, can be accommodated with little extra software and hardware. 1. http://www.cariboo.bc.ca. 2. http://www.novell.com. 3. http://www.microsoft.com. 4. http://www.delegate.org. 5. http://www.site.uottawa.ca. REFERENCES Page 7.277.9