Cable Bandwidth & 4K Content
In regards to bandwidth, there are two types of HDMI cable: Standard HDMI Cable and High Speed HDMI Cable. Standard cables only have enough bandwidth to push through 720p and 1080i video signals. Note that's 1080i, not 1080p. In order to get access to 1080p and 4K content, you'll need a High Speed HDMI cable. Manufacturers are required to specify whether their cables are Standard or High Speed, the difference being the amount of bandwidth each cable can handle. Any High Speed HDMI cable can transmit 4K content from your source to your TV.
Broadband Cable Internet access is provided via the same coaxial cable system that's used to receive cable television programming. Generally if your local area offers cable TV service, then high speed cable Internet service is also most likely available.
Most cable Internet providers offer a discounted when you combine two or more of their services. You can get High Speed Cable Internet access bundled with their digital cable television and/or digital phone services and save a "bundle". This is usually the cheapest Internet option, so always check with your cable provider to see if they offer any current Cable Internet Deals.
Who provides the service, EarthLink or my cable TV provider?
Both. Your cable provider provides a portion of the network that EarthLink High Speed Cable uses to deliver broadband Internet access to your home. EarthLink provides the other portion of the network and all the services. EarthLink has been a leading cable Internet provider (ISP) since 1997.