Business relationships between major broadband providers and Internet backbone providers appear to be the cause of major drags on performance from early 2013 to early this year, according to a new study from a think tank advocating for strong net neutrality rules. Five major U.S. broadband providers, including Comcast, AT&T and Verizon Communications, saw major performance degradation during those months, according to the study published Tuesday by the New America Foundation's Measurement Lab Consortium [M-Lab].