Case Study: Porttracker earns networking honours at University of Hertfordshire

UoH's network has more than 600 switches

When the University of Hertfordshire (UoH) needed to provide new students with a switch port, IP address and domain name services (DNS) at the start of the academic year, its network management team was under pressure from day one.

UoH has more than 24,000 students and 2,500 staff spread across three main sites in Hatfield. The university prides itself in its high-tech approach to education, according to network manager Alan Dickson. “This is a technology-based university, content is delivered not just by lectures, but also by our StudyNet managed learning environment, and students and staff have to be familiar with this, so everybody has to have online access,” he says.

Dickson has to manage about 600 switches, giving over 20,000 switch ports. “A network of this size needs a number of tools to manage it – and it’s not a heterogeneous one, it’s a completely homogeneous Cisco-architected network,” he says. “We have a gigabit Cisco core, Cisco distribution and mainly 10/100Mbit/s Cisco edge switches for access.”

UoH has around 2,500 students in halls of residence, which are split over two main sites separated by the A1(M) motorway. “We have optical fibre going underneath the motorway connecting the two,” says Dickson.

The problem for the network team was that switch ports were needed for new students, teachers and other users, as well as existing students. Additionally, the team needed to identify switches and switch ports that had been made redundant as a result of changes in where and how the network was being used, and reallocate them. The university’s expansion plans for new buildings and facilities also added to the demand for ports.

In the past, the process of correlating available switch port capacity with user demand was a very laborious process. UoH needed a system that would allow the network team to easily identify switch ports in use and those available for redeployment. The team also needed an automated way to identify the users of active switch ports.

Dickson went in search of a system that would enable his team to able to better manage the network and negate the need for additional switches. After assessing a number of candidates, Dickson picked a system called Porttracker. “We evaluated the package for a month and then decided to buy it,” he says.

Porttracker comes as a 1U, 64bit plug-and-play appliance, or as a downloadable VMware virtual machine. The system uses distributed pollers that collect SNMP information, allowing reports to be produced using filters employing Boolean operators that can be used to mine specific information from the Porttracker appliance database.

Porttracker can track and report exactly what is connected to the network, automatically identifying reusable switch ports, and monitoring switch and port use through last-seen and last-changed times and dates. This allowed easy reassignment of switch ports and monitoring of network capacity and usage.

Dickson says that by using Porttracker, the network team can pick up users’ systems in seconds rather than in minutes, which was the case with the Cisco Works package they used before. “That’s quite a time saving,” says Dickson. “It’s also dependent on the time of year. Only for a month or two after registration in September, when the new students arrive along with their virus-loaded systems, is there a lot of troubleshooting.”

Dickson says the system has also helped his team to allocate bandwidth. “Students are prone to download and share files extensively, and they can use a fair amount of bandwidth doing this, but we can knock them off the network if they have too many connections open to the Joint Academic Network [Janet],” he says.

Dickson points out that Janet could threaten to take UoH off the network if it doesn’t play by the rules. “Our philosophy is to give students what they have at home, nominally 1Mbit/s access, but we have to be able to trace where people are misbehaving and deal with them,” he says.

Dickson says Porttracker has enabled his team to spend more time on other priority network management tasks. “One of our network managers left recently, reducing the team to four. One of the benefits of Porttracker is that it had a big influence on our decision whether or not we actually needed to replace him,” says Dickson.