Cable internet

[HCHTech]

In our area Comcast is the main provider of cable internet, but we also have a couple of other cable systems in parts of our service area. All of these cable internet options provide asynchronous service, which is the main disadvantage when you compare it to Verizon FIOS in areas where both are available.

This came up in conversation today, and I didn't know the answer, so....Is cable internet asynchronous because it has to be - due to some technological limitation? Or is it purely a business decision for the providers to divvy up their pipe to favor downloads over uploads? DOCSIS 3.1 clearly supports multi-gigabit traffic both ways as far as I can tell, but I couldn't find anything really answering the question pointedly. If it IS purely a business decision, I guess I understand why they would do that, but their lack of options in the face of the competition from FIOS makes me think it's more than just business. Does anyone know for sure?

 

[mikeroq]

I think you mean asymmetric? As in why is the upload so small compared to download?

It's mainly due to cable systems historically used for television service. Most of the signaling was reserved for downstream vs upstream. They didn't need much for upstream to handle set top boxes/descramblers and transactions like pay per view.

This is also due to the cable system being shared, as in a line goes to a neighborhood and it is split and amplified to service many homes.

Since a customer (at least residential) will substantially download more than upload, that is how they designed the system and operate it.

Sure full duplex DOCSIS 3.1 can do 10 Gbps. But that is going to take money and infrastructure changes. Cable providers are already using fiber, and that fiber will inch closer and closer to the consumer. I suspect eventually it will be FTTN (fiber to the node/neighborhood) and then from there go over existing coax to the customer. Then maybe one day it will all be straight fiber and coax will be no more. Will we still call them the cable company?

But yes it's mostly a business decision. It costs money to upgrade your network and add capacity. They will of course want to get by with cramming as much as possible with that they got.

 

[thatdude]

It's always fun trying to explain to a layman the difference between upload speed, download speed, and latency.

Layman: "I don't understand why my computer is so slow when I'm uploading all these pictures. I thought I had the fastest cable Internet speed."
Me: "Well that's your download speed that's fast. Your upload speed is only 8Mbps"
Layman: "Wait, what?"