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15 or 20 mbps up is about the theoretical maximum on cable because of how the spectrum is allocated by cable companies. Cable TVs didn't need much upload compar
by snazz 6y ago
15 or 20 mbps up is about the theoretical maximum on cable because of how the spectrum is allocated by cable companies. Cable TVs didn't need much upload compared to download.
- kortilla 6y agoNo, that’s just cable companies allocating significantly more to download spectrum than upload. There isn’t anything fundamental in docsis preventing you from giving more spectrum to upload to have way less contention on the upload slots.
- jcrawfordor 6y agoWhile no DOCSIS revision has symmetric theoretical caps, DOCSIS 3.1 which is currently in use is capable of up to 2Gbps upstream, while the upcoming (for the most part) DOCSIS 4.0 standard is capable of up to 6Gbps upstream, and was developed largely to response to increasing demands for upstream bandwidth. While these are obviously best-case speeds, gigabit symmetric is quite achievable with DOCSIS3.1 and available in some markets. However, it is unfortunately true that many cable carriers are constrained in their channel planning by legacy devices with fixed channel requirements. For example, Comcast has at least historically struggled with planning DOCSIS channels around legacy Motorola STBs that require their on-screen guide information on a specific channel. Essentially, in order for Comcast to switch to full DOCSIS3.1 upstream channel allocations they will need to first get every customer with a legacy STB to swap it out for a new one. This is a formidable task and not one they have so far completed, so in my area upstream remains limited to 35Mbps even with 1Gbps downstream.
- lorenzhs 6y agoNah, there are cable companies that offer 50 mbps upstream, and the DOCSIS 3.1 standard that's currently in use supports much more. They're just stingy.