Upload congestion?

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« A word on QOS and prioritization

dadkins
Can you do Blu?
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join:2003-09-26
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Hmmm... Comcast CRAN - redundant 10G to the headend.
Pretty sure that is a symmetrical 10G... both of them.
So, I can have 16+mbps down and 2mbps up - where is the rest of all the upload getting chewed up at?

The problem lies with the technology(so I'm told) - not the capacity.
So stop with the horseshit, Quitcha Bitchin!
Simple math indicates that I should be able to light up my upstream with TONS of headend room to spare.

NOTE: Currently, I can, and do, get all of my connections provisioned speeds - all times of the day.
If that offends anyone - sorry!

--
Think outside the Fox... Opera

permalink · 2008-07-15 12:20:13 · Print ·

espaeth
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Re: Upload congestion?

said by dadkins

:

Hmmm... Comcast CRAN - redundant 10G to the headend.
Pretty sure that is a symmetrical 10G... both of them.
So, I can have 16+mbps down and 2mbps up - where is the rest of all the upload getting chewed up at?

It's getting chewed up by RF interference and the need to control upstream broadcast transmit intervals.

On the downstream it's one transmitter, multi-receiver. The CMTS transmits downstream constantly with no need to pause, the cable modems grab whatever frames are theirs off the wire and life is happy. The CMTS can only listen to one modem at a time, however, so that's where mechanisms like TDMA divide out bandwidth timeslots that each modem can request to transmit up. Multi-speaker / single-listener is a more complicated problem to solve, and one of the principle reasons that upstream capacity is limited.

permalink · 2008-07-15 14:38:55 · Print ·

Dogfather
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Laguna Hills, CA

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Comcast's upload crunch (and certainly not all markets are seeing it) is only between the node and headend and is caused by channel saturation. As they continue to deploy SDV, work on ditching analog and other ideas that save significant bandwidth, they can dedicate more channels to HSI and with DOCSIS 3 bond those channels for speeds to the end user far exceeding what customers are willing to buy (as evidenced by Verizon selling mainly low tier FiOS).

The bandwidth crush is a myth. Some use it to try and sell hardware while others use it as justification for draconian network management with the real goal being to squash emerging video competitors.

permalink · 2008-07-15 14:41:05 · Print ·

20217732 join:2008-07-16	Hi everyone, Bandwidth is infinite so is natural resource
	permalink · 2008-07-16 12:00:14 ·

RogerADSL join:2004-12-10 Lawrenceville, GA ·Comcast ·AT&T Southeast	Re: Upload congestion? said by 20217732 : Hi everyone, Bandwidth is infinite so is natural resource Step away from the bong please....you have had enough!
	permalink · 2008-07-17 16:44:18 ·

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