Customer Services & Capped Upload Speeds (NTL Reading)

[tdw]

NTL, Reading area, 2mb cable connection.

My Ambit cable modem is capped upstream at 200000 bps giving me about 192k upload speeds. When I max out the upload, it kills my download bandwidth - which is to be expected, but annoying because it stops my email and browsing.

I thought the upload speed should be a maximum of 384k variable, rather than my 192k fixed.

I've talked to various parts of Virgin support over the last few days, and once I've got over the initial requirement to explain to them the difference between upload and download - and run the *download* speed tests they still insist on - and get to the real issue, they have all initially said that upload should be faster. "Broadband Support" reckon I should be getting 1/6th of my download speed, so 333k-ish, however when I re-explain that I can't ever get that speed because of the cap, and email them the screen shot of the modem's config they back down and tell me that 192k is the correct speed for me.

Am I wrong and is 192k correct?

What speeds do others get? Or has anyone had a similar experience?

TIA

Tim

[quadplay]

Hi, and to CF!

The 2Mb service has a 200k upstream speed. 192k is about as high as it'll go after overheads.

I forget the 4Mb upstream, but the 10Mb upstream is 512k. If you really want a higher upstream speed, you'll have to upgrade to a higher tier.

[tdw]

Thanks for the welcome

Fair-enough, so all is working as it should, oh well

Thanks for the quick response too.

Tim

[djb61]

The reason the download suffers when you max out your upstream is all to do with ACK packets. The way TCP/IP works is that when you receive download packets you send an ACK packet (very small as it contains no data) back to the host you are downloading from to confirm you received the data.
When you max out your upstream these ACK packets take longer to get sent back as they wait in the queue with all other outgoing data, this causes the remote host to either throttle or worse case resend data thinking you haven't received it, resulting in a slowing down of download speed either way.

The solution is either to simply throttle your uploading application below your upstream limit to leave room for ACKs to be sent or to use some kind of traffic shaping/QoS software to give ACKs higher priority so they don't have to wait in the queue. I do the latter on the FreeBSD machine my cable modem is connected to and it works well, I can max out upstream with marginal affect to my downstream. I'm guessing however that you are using Windows and I can't suggest any software to do the same there, but undoubtably there is some, maybe someone else has some suggestions.

[grubbymitts]

Presuming you are using bit torrent, set your upload to 80% this way you should be able to get those packets through. If you have full upload, not only will it knacker your surfing and downloading from BT, but it has the high possibility of adding to any congestion on the network and causing problems for everybody else attached to your ubr.

[Richy99]

upload speed is what it shold be, where did you read/think it was higher?

2mb = 200
4mb = 384/400
10mb = 512

[popper]

yes as Richy99 points out for NTL the 2Mb is 200k up and the 4Mb is 400k up so you would expect the 10Mb to be 1000k up but its NOT its almost half that as 512k ,likewise following the patton of the first two new 20Mb would give 20000k up but they are it seems going to fix it at a paltry 768k up today that doesnt seem like a wise PR move .

it will just give the other ISP's and users a chance to ignore the 20Mbit down and talk down the lowest upload rate ratio in the uk.

[Richy99]

lowest upload rate in the uk? 768 is more than you get on 8meg adsl packages which is 448

dont forget cable is primarily made for downstream not upstream which si why there is a difference in ratio's

[popper]

Originally Posted by Richy99

lowest upload rate in the uk? 768 is more than you get on 8meg adsl packages which is 448

dont forget cable is primarily made for downstream not upstream which si why there is a difference in ratio's

yes lowest ratio as in 20Mbit down 768k up.

as for your below average adsl example, its simlar to the 10Mbit down 512k up ratio of VM at 20/1.

the VM 20Mbit at VM will be way werse than that ratio YES?.
it would stay at 20/1 if they gave us 20Mbit down 1Mbit up.

NO i dont forget anything, the ratio in the speeds we are talking here are way easy to put into even the oldest Euro DOCSIS1.1 spec kit that VM are currently useing in the headends.

go look up the official specs and speeds for Euro Docsis 1.1 (and 2.0 and 3 if you like)and paste them here for everyone to read.

[Richy99]

whats going to be looked at more by people wanting intertnet speeds the upload speed or the upload/download ratio?