2. Network Infrastructure
During 2000-1 the National Academic Network introduced the latest phase of its development, known as SuperJANET 4. As part of this, in March 2001, the University's connection to Janet was upgraded from a (nominal) speed of 34 Mbit/second incoming and 12 Mbit/second outgoing to 622Mbit/second in each direction. This upgrade came at a time when traffic was previously reaching maximum throughput during peak times. As the graphs in figures Figure 1, Janet Monthly Inwards Traffic, MBytes/Day and Figure 2, Janet Monthly Outwards Traffic, MBytes/Day show, the upgrade has allowed the rise in traffic volume to continue unabated. The theoretical daily maximum traffic rate, ie the upper boundary on these graphs, is now about 5 Terabyte/day (5000,000 MB/day).
During the previous period the decision was taken to upgrade the University backbone network from a 100 Mbit/second FDDI ring to a Gigabit Ethernet switched system. An EU procurement exercise was conducted by OUCS, overseen by a University group, and a system based on Cisco equipment was selected. A double-star configuration was planned, giving dual connections from the two central level-two switches to the ten outlying level-three switches. A small amount of extra fibre installation was required to accommodate this, but most used the existing fibres. The Gigabit network was brought into operation during the summer and autumn of 2000, with minimal disruption or downtime to the departmental networks. One of the design aims was to preserve the address structure for all connected networks.
Another development was the introduction of a second fibre link to Headington, going via Cowley Road and Morrell Avenue to the Churchill site [figure Figure 4, ].
This completes a loop with the first link via Marston to the John Radcliffe site, and so provides resilience for the connection to the University departments in Headington, and also for the Oxford Brookes University link to the Janet connection point at OUCS. This was completed in May 2001.
A schematic of the data network connections is shown in figure Figure 4, and figure Figure 5, Gigabit Ethernet Daily Traffic (GBytes/day) shows the Gigabyte Ethernet daily traffic levels.
The dial-up service continues to be popular and heavily used [figure Figure 6, Dial-up Calls (weekly figures)], although the year-on-year growth has levelled off, and there are now signs of a slight drop. This may be because of the increased availability and falling costs of other forms of home connection, such as NTLWorld. The future of this service will be kept under review.