Level 3 Communications has blamed Verizon, not Netflix, for the low-quality network access for streaming videos.
The telecommunications firm, which carries Netflix traffic to Verizon's network, said the congestion is the result of Verizon refusing to increase the capacity on the interconnect points.
Last week, Verizon had argued that it was Netflix's mismanagement of its video streaming traffic that had led to slower speeds for users.
At the time, Verizon's VP of regulatory affairs, David Young, wrote: "Netflix chose to attempt to deliver that traffic to Verizon through a few third-party transit providers with limited capacity over connections specifically to be used only for balanced traffic flows. Netflix knew better.
However, in a blog post yesterday, Mark Taylor, VP of content and media with Level 3, said Verizon had refused to allow access to faster links that would relieve the slow speed Verizon customers experience when using the on-demand video service.
"We could fix this congestion in about five minutes simply by connecting up more 10Gbps ports on those routers," he wrote.
"Simple. [It'something] we've been asking Verizon to do for many, many months, and something other providers regularly do in similar circumstances. But Verizon has refused. So Verizon, not Level 3 or Netflix, causes the congestion."
He added: "Maybe they can't afford a new port card because they've run out - even though these cards are very cheap, just a few thousand dollars for each 10 Gbps card which could support 5,000 streams or more. If that's the case, we'll buy one for them. Maybe they can't afford the small piece of cable between our two ports. If that's the case, we'll provide it. Heck, we'll even install it."