Boys' High IT manager Steve Merritt said the upgrade saw the installation of a "fibre optic backbone" with copper branches throughout the school.
"All at a higher speed than we had before and it goes further across the school."
Mr Merritt said the infrastructure provided the school with more computer access points. "We've got greater access in classrooms - where we only had one or two [access] points before, now we've got a minimum of eight ... and computer labs can have about 40."
"We're not restricted by location. We can teach a class in multiple areas rather than build a building, like we used to, which is specifically designed for one curriculum. It's all interchangable."
"[SNUP] gives us the ability to have faster connections for students to the outside world. It also gives us the ability to do video conferencing sessions, distance learning and provide the students with courses and classwork that we otherwise couldn't provide."
"The possibilities are endless."
The SNUP project is one of several Ministry of Education initiatives aimed at allowing schools to take full advantage of ultra-fast broadband.
Others are the establishment of a dedicated online network for use by schools, teaching teachers how to use information technology to enhance student learning, and a project to provide laptops for principals and teachers.