NUSNET-III Facts and Figures

NUSNET-III is a campus-wide network which inter-connects 104 departments in 90 buildings and  covers a campus area of 150 hectares. It serves a population of 24,000 students, and 2,700  academic, research and administrative staff members. A comprehensive fibre cable plant was  built in 1990 with many add-ons recently due to renovation and commissioning of new buildings.  Three main stretches of 20-core 62.5/125 micron multimode fibre intersects at Computer Centre  forming the first level fibre plant. Secon d level cabling involves either 4 cores, 8 cores or 12  cores of multimode fibres which completes the inter-building connectivity with a total of 200 km  fibre run. For intrabuilding cabling, UTP Category 5 is widely deployed for desktop connections.  NUSNET-III has entered the third phase of development in seven years' time. It is not an  evolution phase but has taken a revolutionary approach completely by adopting the latest multi- mega bits cell switching ATM technology as the core backbone and 10Base-T switching for  desktop connectivity. The topology is hierarchically divided into three tiers. First tier comprises of  four (4) main core switches with an aggregate transmission bandwidth of 310 Mbits/s. It is highly  fault tolerance with redundant switching engine, power supply and fibre links. The versatile  configuration of the core switches allow a combination of NNI, UNI, Fast-Ethernet and 10Base-T  connections. The second tier switches are placed in strategic locations to either act as edge dev  ices for desktop connections or to provide connections for edge devices in the third tier in order to  reach every desktop at the far end.

Multiple faculty-based VLANs are constructed based on port numbers and are mapped over ATM  ELANs across multiple ATM switches for logical grouping of users for security and minimizing the  size of the broadcast and multicast domains. NUSNET-III supports r outing protocols of TCP/IP  for Internet and Intranet services, IPX and AppleTalk for file and print services. Lan Emulation  services (LECS, BUS and LES) residing in the switches provide a transparent way of connecting  to legacy systems. Two one-arm route rs are employed for routing between VLANs in order to  access centralized services. Much of the file and print traffic are localized to the faculty-based  VLANs as faculties sharing the same file server are grouped into the same VLAN.  As of today, NUSNET-III provides over 12,000 network points for data and video transmission  serving 6,000 network nodes and 4,500 SPnP (Secure Plug-and-Play) points.  Network services  and accesses include a Cray supercomputer, UNIX-based servers and workstations, database  servers, Web servers, Netnews servers, FTP servers, course online servers, file and print  servers, Internet Firewalls, messaging servers, personal computers running Windows 95,  Windows 98, Windows NT, OS/2 or linux and Macintoshes, etc.  NUSNET-III provides a wealth of network services with gateways to Internet, e-journal, Dow  Jones and Government Intranet, newsfeed of Carinet, CDROM databases, board-room video- conferencing, desktop video-conferencing, PPP remote access and Video-on-Demand (VoD).  VoD allows users to select and view an archive of video clips at their own leisure. The VoD offers  a high quality playback of 30 frames per second. Users can play, rewind or forward with a  customized front-end GUI menu developed in-house.

Windows Shopping

A new concept of Windows Shopping has been introduced as the standard NUSNET-II interface for Windows users. It is further enhanced as a 32-bit application in NUSNET-III. Windows Shopping is developed in-house using Visual Basic allowing user to customi ze their own Windows desktops to their needs. It allows users to pick and choose from a complete listing of services and applications offered in NUSNET-III. The objective of Windows Shopping is two-fold. One is to simplify the desktop as previously users had difficulty in locating an ICON in a cluttered desktop. Users may like to keep their most frequently accessed ICONs only. Also, with a simplified desktop, time taken from logon to a complete display of Windows desktop is minimized because of less grou p files to open.

Installation of Windows applications often requires updates to users' own system and registry files such as the user.dat, system.dat, system.ini, win.ini and progman.ini, etc. The procedures can be very tedious especially since various Dynamic Link Librar ies (DLLs) have to be updated. As a second objective, Windows Shopping provides an efficient way for users to access a common pool of Windows applications and all other related application DLLs and drivers in the server. Windows Shopping updates users' ow n system files and any other initialization files required by the Windows applications transparently for users if they "shop" for it, thus providing instant access to network-based applications with minimum overheads in disk storage.

File and Print Services

Novell NetWare 4 is the key network operating system used to provide the crucial file and print services to over 24,000 users in NUSNET-III. There are 32 units of Pentium-based and 486-based file servers running Novell NetWare 4.10 with over 10,000-user licenses and 34,000 objects on a single NDS tree. The University is the largest site having the most number of NDS objects in a single tree in this region. Most of the file servers are configured with 128 to 192 MB RAM, 16 Gigabytes RAID 5 disk storage and ECC memory. RAID 5 allows multiple R&Ws for enhanced disk I/O. The in-build fault tolerance of RAID 5 provides data integrity should any one of the hard disk fails. The hot-swappable hard disk allows it to be replaced without closing down the syste m in order to minimize service interruption. Novell NDS provides a single fast login with a slim client interface. All sign-on sessions are protected using RSA encryption with public and private key. With automatic replication of the NDS partitions, in the event that any server is shutdown, users can still login and use the file server resources. Updates to the NDS are constantly synchronised and all changes take immediate effect.

File server provides a central repository for PC and Macintosh application software in the areas of:

Print Services

Network printing facilitates sharing of high quality laser and postscript printers. There are about 120 print servers, which are 386 or 486-based or dedicated print spool devices located at users' departments for the convenient collection of printouts. Pr int queues are defined in the Pentium-based file servers with high performance SCSI-II disk sub-systems leading to minimum delay in print spooling.

Access to INtv

INtv is Singapore's teletext service provided by TCS (Television Corporation Singapore). The two channels (Channel 5 and 8) contain a wide spectrum of information resources including up-to-the minute global and local news, sport news, currency rates, sto ck and share prices, classifieds, TV and radio programs, flight schedules and horse racing results, etc. The INtv pages are received off the antenna by two 486/33-based INtv receivers with one dedicated for each channel. The receivers are equipped with specific TV tuner for receiving the pages broadcasted by TCS. These receivers are running a Windows-based program in capturing the pages with a network drive mapped to an INtv server over a private 10Base-T subnet in order to minimize collision which wou ld potentially affect the timely updates. Users do not contact these receivers to retrieve the pages since it would take up too many CPU cycles for the receivers to provide the file service. Experiment shows that if the CPU is overloaded, it may render loosing pages completely, corrupted pages or incomplete pages received. Pages received are then formatted properly and written to the network drive of the INtv server which will, in turn, serve the users directly. The INtv server is a high-end 486/66 ma chine equipped with a fast-wide SCSI hard disk as fast disk I/O is the key success factor for this whole system. This is also a NetWare 4.1 server providing file service to campus users for the pages retrieval.

Campus Messaging System - Microsoft Exchange

Exchange is the campus-wide messaging system serving a population of 26,000 users, including students, academic and administrative staff members. It provides an integrated platform for E-mail exchange, sharing information through public folders, workflow applications, reading and posting of Internet newsgroups and exchange of Internet mail. Features being exploited heavily include:

1. Rich-text Formatting

This allows specific fonts, paragraph formats and colours to be chosen for the message text and thus, making it simple and easy for general users to format a message text nicely.

2. Inbox-Assistant

Specific rules can be set up by users to manage their Inboxes effectively. For example, mail addressing to the address "xyz@nus.edu.sg" can be either copied, forwarded, moved to another folder, deleted or replied with custom template automatically.

3. Out-of-Office-Assistant

This is for users to reply automatically to mail addressed to them while they are away from offices.

4. Share Information Through Public Folder

Public folders provide an easy and effective way to share information with others on your team or across your entire organisation. The information in a public folder can be in any format: messages, forms, documents, spreadsheets and URL links, etc.

5. Internet Mail

Sending and receiving Internet mail is made easy with the native support by Exchange. Users can send Internet mail by just specifying the Internet E-mail address of the recipient at the appropriate input fields without special formats. Internet mail are received and deposited directly to the users' Exchange Inboxes.

6. FAX Support

A FAX gateway is provided for Exchange users to send local FAX at their fingertips. You can address to a FAX recipient by specifying "[FAX:name@fax_number]" at the appropriate input field. Please ignore the double quotes but the square brackets are nece ssary.

7. Using Web Browser to Access Personal Inbox

Web browser has proven to be a convenient and efficient tool for Web surfing. Exchange allows browser users to manipulate their Inboxes through browser clients like Netscape or Internet Explorer. Using the browser clients, users can read and send person al Email, read and post articles to public folders and Internet newsgroups and thus making it convenient for users who travel often to stay tune of the office correspondence.

8. Hot-link to Web Sites

All URL links specified in Exchange mail can be activated by a single point and click thus making it convenient for users to exchange favourite Web sites and make reference to it in Email.

Implementation Details

Planning for the upgrade of MS Mail to Exchange started in March, 1996. A working group was formed with members in different functional groups appointed by the Director, Computer Centre for the design, procurement, implementation, migration and training . The working group comprises of engineers from Academic Computing Group, Administrative Office Information System Group, Internet Technology and Services Group and Network Group. Microsoft consultancy was sought in helping the group for the design.

Exchange services are provided by ten (10) Compaq 5000 Pentium-Pro 200 servers with five (5) each for staff users and students respectively. Each server has two Pentium-Pro 200 MHz CPUs, 256 MB ECC memory, 512 K secondary cache, 2 x 2 GB SCSI hard disk , 3 x 9 GB RAID 5 disk subsystem, 3 PCI slots, 3 EISA slots, external DLT tape drive and FDDI network adapter. The first 2 GB hard disk is formatted in NTFS for enhanced file system security while the second 2 GB hard disk is formatted in FAT and is dedi cated for the transaction log of the Exchange database. The effective 18 GB of the RAID 5 disk storage is provided for users' mail messages and attachments. Initially, staff user is allocated 4 MB each for the mail storage in the server while student i s given 3 MB.
 
Exchange is riding on top of NT server and authentication is done through the NT domain controller. NT domains are created hierarchically with two top level domains - NUSSTF and NUSSTU for staff and students respectively. The top level domains establish a two-way trust relationship. Though this is not absolutely necessary as there are no shared resources amongst staff and student users at this moment, it is done for the sake of server administration. There are at least one Primary Domain Controller (P DC) and one Backup Domain Controller (BDC) in each domain. The PDCs and BDCs are Pentium-166 computers with 48 MB RAM. The Exchange servers reside in its own resource domain NUSEXS. It has one-way trust to the two top-level domains where all users shal l be logging onto it. The load of sign-on is distributed to the PDCs and BDCs in the top-level domains and never be exerted to the Exchange servers unnecessarily.