Dedicated Internet Access means that the specified amount of bandwidth sold has been carved out and dedicated for your Company’s use. DIA service performs consistently and has guaranteed minimums and uptime.

This is different than what most residential clients use which is “best effort” internet. “Best effort” means that there is shared data lines among many customers. You share the same uplink as your neighbors, so your upstream link fluctuates with the traffic your neighbors push over that same stream.
Dedicated internet access is like having your own personal lane on the Information Superhighway as opposed to sharing the same traffic lanes as everyone else. 

This is symetrical fiber based and 99.9% SLA backed internet service.