Carphone Warehouse is building its own optical fibre network to serve its broadband customers, as opposed to relying wholly on BT's network.
The firm is using Infinera to supply a national backbone network across the UK.
Carphone Warehouse, which is the UK's third-largest internet service provider, with 2.5 million customers, decided last year to build its own nationwide backbone network to carry data and voice traffic for its growing customer base.
Neil McArthur, chief executive of Carphone Warehouse Networks, said, "We chose Infinera for our national backbone because it allows us to achieve far better economies of scale. More importantly, it gives us control of our own destiny when it comes to rolling out high-capacity, high-quality services when and where our customers need them."