said by anon202 :TWC modes are fiber fed I'm pretty sure in the 1-2Gig per node
That's not how cable works. Cable is restricted by the bandwidth on the coax side of the node. It depends on how many individual QAM256 channels they dedicate to DOCSIS. Each one represents ~30mbit shared. That's why channel bonding, even if you don't have a high throughput package, is important. You get to "share" a bigger pipe, even if you're on a 15mbit package.