dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
21
share rss forum feed

technocar2

join:2009-05-29
Brampton, ON
kudos:2

1 edit
reply to elitefx

Re: [Extreme Plus] New Speeds Effective December 1st

Basically there are two kinds of congestion on docsis.

One is the usual type, where there is 304mbps on the node and too many people are online and everyone gets slow speed.

The second kind of congestion is temporal. Meaning your modem is not online all the time. Its only online for a fraction of a second per second. And its in this fraction of a second that a modem can upload stuff. The more modems there are the smaller this fraction of second becomes; this is know as the time slot. This is what makes the upload to max of 10mbps because it takes a fraction of a second to upload 10mb vs 108mb will take 1 whole second with 4 channels. 10mb with 4 channel takes only a fraction of a second.

How it works is a node can only receive data from one modem at a time. Therefore the node listens to each modem for only a fraction of second and in that fraction of a second the modem can upload whatever it wants but since its only a fraction of a second its limited to 10mbps or whatever the time slot duration is based on the # of modems.

If the node only listened to just one modem then the modem can upload stuff for the full 1 second (so 108mbps) but since there a more than one modem, none of the modems gets 1 full second, they each get a fraction of a second to upload and this is repeated every second. This is pretty much a modem congestion, the more modems there are the smaller the time slot is for each modem and thus a lower upload speed per modem.

Think of it this way, you can only upload as much as the node is willing to listen to you. If the node wants to listen to you for 1 full second then its 108mbps. If the node wants to listen to your modem for 5/54 of a second then its 10mbps and the rest of the remaining bit of that second the node will listen to other modems.

clementlo

join:2005-06-11
Scarborough, ON

1 edit
I am on Extreme... my upload speed still 1 MB and hasn't upgrade yet... I guess I have to wait till December 1 before I can call and ask?

I am in Scarborough, near McCowan and Steeles area.