Quote:
Originally Posted by roughbeast
LOL.  Not even I, am that nerdy. |
The obsessive speedtester need not necessarily be you - remember, all capacity is shared. Some other person obsessively speedtesting (and using up over 50% of the network capacity at such a time) could well be the cause.
---------- Post added at 17:35 ---------- Previous post was at 17:34 ----------
Quote:
Originally Posted by Kushan
It's funny how the worse the service gets, the prettier the graph is...
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Derp:
---------- Post added at 17:37 ---------- Previous post was at 17:35 ----------
Quote:
Originally Posted by craigj2k12
So on a channels with (in best case) 18Mbit useable bandwidth, on 8 downstreams, 8.8Mbit could be used just on acknowledgements, then there are users expecting to get 10 or 12Mbit upload speeds  |
Best-case involves ACK suppression (VM don't bother with this) SACK's, zero packet loss and large RWINs that reduce ACK overhead to well under 1%.
The 1.5% - 3.0% overhead I quote is for typical real-world scenarios.
[Edit]
Never mind, you meant at best 18Mbps useable upload bandwidth, yes, right.
That said I'm only speculating on the number of upstream channels. Some people supposedly report their area only has one, but in the past common practice was to have at least two (at that time they were half the capacity per channel though)
---------- Post added at 17:40 ---------- Previous post was at 17:37 ----------
Quote:
Originally Posted by Kushan
It's never ONE guy. One person does not have the ability to congest the entire network.
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Yes they do.
A "one guy" with 10Mbps upload speed on a 20Mbps channel can easily cause congestion - congestion can become visible at as low as 60-70% utilization on the upstream. All other users need only be using 30% of available capacity between them before one 100/10 user can "congest the entire network"
---------- Post added at 17:41 ---------- Previous post was at 17:40 ----------
Quote:
Originally Posted by craigj2k12
I bet the techs have projectors flicking through slides of pretty graphs at hubsites.
Heres what the Bristol hubsite, looks like
From the outside, it is merely a standard looking hubsite...
...but inside...... |
Way to advertise... "Press here to cripple our network".
---------- Post added at 17:42 ---------- Previous post was at 17:41 ----------
Quote:
Originally Posted by Kushan
So it's because Virgin uses QAM16, then? Today I learned.
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Up until a few months ago some areas still used BPSK. The BPSK => 16QAM upgrade only started in 2011.
That said till recently the Superhub also clearly displayed 20Mbps next to the upstream channels on its normal status pages.