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My 'Slow Broadband' - what should I expect?

 
 
canon paora
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      09-25-2006
It's 256/128 which gives me a speed of 30kB/s up and 15kB/s down. The
question is should I be able to have maximum up speed and down speed
simultaneously or will a maximum up speed at 15kB/s affect my down
speed?

 
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~misfit~
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      09-25-2006
canon paora wrote:
> It's 256/128 which gives me a speed of 30kB/s up and 15kB/s down. The
> question is should I be able to have maximum up speed and down speed
> simultaneously or will a maximum up speed at 15kB/s affect my down
> speed?


If you're downloading from multiple sources such as bittorrent then full
upload will most certainly cripple your download as the ack packets won't
get through. I'd suggest setting a max of 6kB/s up for your connection when
downloading a torrent, unthrottled when just uploading.

Ignore that it it doesn't apply.
--
Shaun.


 
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Lawrence D'Oliveiro
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      09-25-2006
In message <(E-Mail Removed). com>, canon
paora wrote:

> It's 256/128 which gives me a speed of 30kB/s up and 15kB/s down. The
> question is should I be able to have maximum up speed and down speed
> simultaneously or will a maximum up speed at 15kB/s affect my down
> speed?


I believe ADSL is a full-duplex channel, which means in principle you should
be able to hit both limits simultaneously. Depending on what bottlenecks
you may hit elsewhere, of course.
 
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juicyjuice
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      09-25-2006
wouldn't that be nice, but no. They didn't stick the A in front of DSL for
nothing.

"Lawrence D'Oliveiro" <(E-Mail Removed)_zealand> wrote in message
news:ef8d8h$fui$(E-Mail Removed)...
> In message <(E-Mail Removed). com>, canon
> paora wrote:
>
>> It's 256/128 which gives me a speed of 30kB/s up and 15kB/s down. The
>> question is should I be able to have maximum up speed and down speed
>> simultaneously or will a maximum up speed at 15kB/s affect my down
>> speed?

>
> I believe ADSL is a full-duplex channel, which means in principle you
> should
> be able to hit both limits simultaneously. Depending on what bottlenecks
> you may hit elsewhere, of course.



 
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Chris Wilkinson
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      09-25-2006
Hi there,

canon paora wrote:
> It's 256/128 which gives me a speed of 30kB/s up and 15kB/s down. The
> question is should I be able to have maximum up speed and down speed
> simultaneously or will a maximum up speed at 15kB/s affect my down
> speed?


As Lawrence D says it is able to do both simultaneously. In
practice you lose a bit of performance either way while doing
both, due to checksumming etc...

I tested this with a simultaneous 100MB download and 15MB
upload to/from local servers that I can max out my ADSL2+
on. I got just over 1.2 MB/sec download on a 12600 kbps
downstream link and just over 100 kByte/sec on the 1020 kbps
upstream link, at the same time. In both cases thats quite
close to my theoretical maximum down and up speeds. If I
paused one transfer the other did speed up, but only a little.

So yes you will get very close to maximum up and down at the
same time...

~misfits~ advice re torrents is very good, but also limit the
number of simultaneous peers to connect to, because some ADSL
modems are limited in the number they can reliably handle (my
old D-Link DSL-502T used to sometimes bomb starting download
of torrents with many seeds, or running Limewire).

--
Kind regards,

Chris Wilkinson, Brisbane, Australia.
Anyone wishing to email me directly can remove the obvious
spamblocker, and replace it with t p g <dot> c o m <dot> a u


 
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David
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      09-25-2006
juicyjuice wrote:
> wouldn't that be nice, but no. They didn't stick the A in front of DSL for
> nothing.
>
> "Lawrence D'Oliveiro" <(E-Mail Removed)_zealand> wrote in message
> news:ef8d8h$fui$(E-Mail Removed)...
>> In message <(E-Mail Removed). com>, canon
>> paora wrote:
>>
>>> It's 256/128 which gives me a speed of 30kB/s up and 15kB/s down. The
>>> question is should I be able to have maximum up speed and down speed
>>> simultaneously or will a maximum up speed at 15kB/s affect my down
>>> speed?

>> I believe ADSL is a full-duplex channel, which means in principle you
>> should
>> be able to hit both limits simultaneously. Depending on what bottlenecks
>> you may hit elsewhere, of course.

>
> wouldn't that be nice, but no. They didn't stick the A in front of DSL for
> nothing.
>

No, they didn't, they stuck it there to signify the fact that the
downstream rate is much higher than upstream.

http://en.wikipedia.org/wiki/ADSL

"The distinguishing characteristic of ADSL over other forms of DSL is
that the volume of data flow is greater in one direction than the other,
i.e. it is asymmetric."


 
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Mark C
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      09-26-2006
"canon paora" <(E-Mail Removed)> wrote in
news:(E-Mail Removed) ups.com:

> It's 256/128 which gives me a speed of 30kB/s up and 15kB/s
> down. The question is should I be able to have maximum up speed
> and down speed simultaneously or will a maximum up speed at
> 15kB/s affect my down speed?


Yes, using the maximum up speed of ~16kB/s will affect your down
speed.

When downloading stuff you are receiving packets. Every packet
received (or every second packet...) must be acknowledged in a timely
manner, or else the sending host will stop sending (until an
acknowledgement is received).
The acknowledgements are sent as packets back to the host you are
downloading from.

If you are uploading at the same time as downloading, your upload can
cause the outgoing acknowledgments to get delayed or wait in a queue
(for a short while), and this delay can cause your downloads to stall
or slow.

If you can limit your upload speed to a few kB/s less than max, this
will leave some upload room for the acknowledgements to be sent
without delays, and your download will not be affected.
(I suggest limiting upload to ~13kB/s)

You can use bandwidth software such as Netlimiter (I use) or CFos to
limit upload and/or download speeds.

Many bittorrent programs also have bandwidth limiting features, but I
have found that uTorrent (for example) does not do as good a job at
limiting bandwidth as Netlimiter does.

HTH
Mark

(BTW, 256kbps = ~32kB/s, 12kbps =~16kB/s)
 
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Lawrence D'Oliveiro
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      09-26-2006
In message <45188d03$0$16398$(E-Mail Removed)>, Mark C wrote:

> When downloading stuff you are receiving packets. Every packet
> received (or every second packet...) must be acknowledged in a timely
> manner, or else the sending host will stop sending (until an
> acknowledgement is received).
> The acknowledgements are sent as packets back to the host you are
> downloading from.


TCP does in fact allow acknowledgements to be "piggybacked" on packets
carrying outgoing data.

 
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David Empson
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      09-27-2006
Lawrence D'Oliveiro <(E-Mail Removed)_zealand> wrote:

> In message <45188d03$0$16398$(E-Mail Removed)>, Mark C wrote:
>
> > When downloading stuff you are receiving packets. Every packet
> > received (or every second packet...) must be acknowledged in a timely
> > manner, or else the sending host will stop sending (until an
> > acknowledgement is received).
> > The acknowledgements are sent as packets back to the host you are
> > downloading from.

>
> TCP does in fact allow acknowledgements to be "piggybacked" on packets
> carrying outgoing data.


Yes, but only if you are sending and receiving data on the same TCP
connection. I believe the assumption here is that you are doing
independent uploads and downloads at the same time.

--
David Empson
http://www.velocityreviews.com/forums/(E-Mail Removed)
 
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