2. Infrastructure Group

2.1. University Backbone Network

During the summer of 2004 a major exercise was conducted to upgrade the backbone network from 1Gbs to 10Gbs, and allow individual unit connections at 1 Gbs. This was successfully completed with minimal disruption to service. The basic configuration of the backbone network, a double star network consisting of two central switches and 10 edge switches, connecting to about 190 departmental and college subnetworks, remains unchanged.

Network Map
Figure 1. Network Map
Network Schematic
Figure 2. Network Schematic

The purpose of the upgrade is to meet the steady growth in demand (as illustrated in figures 3 and 4), and to be prepared for the inevitable increase in demand which will be brought about by new applications, in particular new Grid-related projects. The number of nodes connected via the subnetworks continues to rise, with an 8.5% increase over the year resulting in 55,186 nodes at 31 July 2004.

Backbone traffic
Figure 3. Backbone traffic
JANET traffic
Figure 4. JANET traffic

2.2. Central Web Servers

The central web servers hold the University's top-level pages, the OUCS web pages, many departmental and college pages, and those for many individual users. In all they support about 170 domain hierarchies and pages for about 5,000 individuals. In total that amounts to about 700,000 files, occupying some 35 GB. The number of web accesses now exceeds 1.5 million per day. Response time remains excellent.

2.3. Email Relay

The email relay service (http://oucs.ox.ac.uk/network/smtp/ - out of date) handles the vast majority of the University's incoming and outgoing email, and inter-system email within the University. It directs email to the appropriate email server, performs address checks and rewrites addresses to the standard form (where requested by the relevant department to do so), handles distribution of multiple-recipient email, spools email intended for non-responding recipient systems, etc. The number of messages handled during the year averaged more than 615,000/day, with the volume of traffic amounting to over 12.6 GB/day on average. Each of these figures is more than double that of the previous year. Regrettably, unsolicited email, or ‘spam’, contributes a large part.

 Number of messages delivered weekly
Figure 5. Number of messages delivered weekly

At the beginning of August 2003, new methods of scanning email to determine whether it was likely to be spam were introduced on the central mailers. The method adopted assigns a score to each incoming message, which is contained in an extra header added to the message. The central Herald mail store gives users the ability to sort or discard mail based on these scores, as do other email client systems that may be used by people whose mail does not pass through Herald. These scanning techniques take into account both the content of the message and its original sender; these factors in combination give a good rate of accurate spam detection. In many cases, as much as 90% of spam is automatically detected and flagged.

Since August 2003 the mailers have also scanned mail for known viruses; over the past year an average of about 18,000 infected messages have been detected and rejected every day. This figure is however very variable, with huge peaks when major international outbreaks occur.

2.4. External Access Services

Many people need to work from locations not directly connected to the Oxford network, but still have use of facilities available within the network, and OUCS supports two such remote access methods. Registration for use of these services is through a common route, and nearly 7,000 people have obtained remote access accounts. Some use them frequently, but the majority make only occasional use.

The Virtual Private Network (VPN) Service (http://www.oucs.ox.ac.uk/network/vpn/) provides a way of giving computers that are connected to the Internet but not to the Oxford network a "virtual" connection to the University network, so that they can be used to access restricted web pages and services. These restricted services include many of the library electronic resources, such as OxLIP and WebSPIRS, together with OXAM (Oxford Examination Papers Online), and various departmental and college pages.

This service is becoming increasingly popular as more people get internet access from home, and regularly achieves a concurrency of 70-80 users. It is planned to enhance this service to meet the increasing demand.

The dial-up service (http://www.oucs.ox.ac.uk/network/dialup/) provides a direct link over the telephone lines, so can be used by anyone working from home without the need for broadband access. Although it continues to be popular, the fall in usage noted last year has continued this year as shown in the figure below, presumably because of the increased broadband coverage available from commercial providers. The service will be kept under review, and line capacity reduced if appropriate.

Dialup traffic
Figure 6. Dialup traffic

2.5. Herald Email Server

Alan Gay cuts Webmail
The central email server, Herald, offers a mail-store facility for all University members. The mail can be accessed by desktop mail clients using IMAP or POP, or by a dedicated web interface. A major new release of this interface known as Webmail was introduced in March 2004. The Webmail service offers: improved appearance and ease of use; powerful junk mail filtering; flexible sorting and searching of messages; better handling of attachments; improved address book facilities. It has proved a popular enhancement to an already widely-used facility. There are now about 32,000 registered users of the Herald service, and although the number of users is now growing only slowly (as most potential users already have accounts) the demands on the service increase inexorably, with the increasing volume of email traffic. The servers have been regularly upgraded and expanded to meet demand. The discrete model chosen has been proved to be as scalable as planned, and regularly supports a concurrency of over 5,000 users.

2.6. Alumni Email Forwarding Service

The University decided that it would provide an email forwarding service for University Alumni (http://www.oxon.org) and OUCS was asked to develop a suitable service. The specification and implementation was carried out between the Infrastructure Group and the NSMS section of the Technical Support Services Group. In June 2004 the service was made available to all leaving undergraduates and in September leaving postgraduates were invited to join.

2.7. Hierarchical File Server (HFS)

The HFS service (http://www.oucs.ox.ac.uk/hfs/) provides large scale central filestore services to the University community. The HFS runs IBM software named the Tivoli Storage Manager (TSM) which supports both a backup service for desktops or Departmental and College servers and a long term data repository service for the university's digital assets.

Since the original procurement of the HFS systems in 1995, a rolling programme of upgrades to the principal hardware components has kept system capacity in pace with demand. During 2003, significant funding was made available from the HEFCE Capital programme (supplemented by University funding) which enabled the first major upgrade to be made to the server, storage and network infrastructure of the system. The upgrade to the systems was planned in four main stages to take place throughout 2003, the first three of which were completed and reported on in the last Annual Report. The final stage, in 2004, was the installation of twelve IBM 3592 tape drives, which followed participation in an early-release programme.

The 3592s are the follow-on technology to the 3590s (installed first in 1995, subsequently upgraded to the current third generation with a capacity of approximately 100GB per tape). The 3592s can be used in the IBM 3494 tape library along-side the 3590s. The roadmap for the 3592 subsequent improvements foresees an uncompressed tape capacity of a terabyte (TB) on a tape by the end of the decade. The current first generation technology will write tapes of up to 300GB (uncompressed) capacity, up to 500GB compressed, typically. The capacity of the tape library, were it to be populated with 3592 tapes, would be approximately 1.5 petabytes (PB).

During the extensive hardware upgrades over the last year, the user service was maintained with only brief interruptions, and the growth in demand has continued unabated. During the summer of 2004 an additional TSM server for the Departmental/College Server backup service was introduced, taking over the backups for the very largest and most demanding of the servers.

Figure 7shows almost 60% growth in the desktop backup service over the year, measured in TB of data held on the server, and broken down by division. Figure 8 shows nearly 50% growth for server backup data, and is similarly broken down by division.

Desktop Backup Service
Figure 7. Desktop Backup Service
Server Backup Service
Figure 8. Server Backup Service

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