DLink DSL-2750u simultaneous upload and download

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floomby

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I have an online backup server and spend quite a lot of time uploading stuff.

I had an old Billion router before and everything worked fine. Then I got a DSL-2750u for the WiFi and everything is great except that now when I upload stuff my download speed drops to about 5kb/s which makes browsing painful.

According to the internet this is caused by the TCP ACKs being queued causing downstream to be throttled. This makes sense...

Does anyone know how to prioritize ACKs on the DLink DSL-2750u (not Telkom branded) or to get it working like my old, cheap Billion router? I had a look at the QOS settings but couldn't see anything useful there (and certainly nothing useful in the manual!).

Thanks
 
I'd also like to know.
 
If you're going to upload at your ADSL line's max speed, then you're not going to have bandwidth left for TCP Acknowledge packets like you said.
Just dial your upload speed a bit down to leave room.

You cannot really/effectively prioritize incoming traffic, because for that you need to do it from the sending side - or at least at the place where you have more bandwidth.
So ideally you'd want your ISP to do this prioritization for you.
 
Be very aware of those DLink 2750U modems.
About 3 months ago my good ol Billion got smacked by lightning and did all crazy things so I went out and bought a 'brand new' DLink 2750U.
First I found the password was telkomnet after trying to change the DNS, which made me suspicious about this 'new' modem.
Within about a month my downloads slowed down to a snails pace and my pings started going up to around 200.
This happened randomly, maybe 2 or 3 times a day.
If I reset the modem it was ok for an hour or so and it started it's nonsense again.
Then I found what the problem was, the modem was seeing an attenuation on my line of over 100 dB with a SNR of -6 dB, and it's CPU would try and disconnect the modem because of this 'bad line'.
I temporary put back my old Billion which connects but thats about all and it saw my attenuation as 3.5 dB and SNR as 26 dB which is what it really is.
I took the modem back and they gave me a Netgear in it's place and now all is well.
 
Pada said:
If you're going to upload at your ADSL line's max speed, then you're not going to have bandwidth left for TCP Acknowledge packets like you said.
Just dial your upload speed a bit down to leave room.

You cannot really/effectively prioritize incoming traffic, because for that you need to do it from the sending side - or at least at the place where you have more bandwidth.
So ideally you'd want your ISP to do this prioritization for you.
Click to expand...

Why can't the router prioritize sending ACKs over sending other traffic? E.g. like http://www.benzedrine.cx/ackpri.html

I just want to know if I can do it with my new router?


@ProAsm I got one of the normal ones, not the Telkom one.
 
floomby said:
I have an online backup server and spend quite a lot of time uploading stuff.

I had an old Billion router before and everything worked fine. Then I got a DSL-2750u for the WiFi and everything is great except that now when I upload stuff my download speed drops to about 5kb/s which makes browsing painful.

According to the internet this is caused by the TCP ACKs being queued causing downstream to be throttled. This makes sense...

Does anyone know how to prioritize ACKs on the DLink DSL-2750u (not Telkom branded) or to get it working like my old, cheap Billion router? I had a look at the QOS settings but couldn't see anything useful there (and certainly nothing useful in the manual!).

Thanks
Click to expand...

Ive always had this issue on all routers :/ Unfortunately - QOS is very difficult to setup on the 2750u :/
 
on adsl, how it SHOULD work, is that your maximum total throughput is your connection/account/port speed, like 4mbps or what ever you have.

so if you upload at a certain speed, you can download at the difference, for example. 4096kbps total. 512kbps up. then 3584kbps down should be available. at the same time. (subtract IP overhead, usually like 7%-10%. unless the ISP carries it.)

with sdsl, you can upload and download at the same time at your maximum speed. 4096kbps up and 4096 down, at the same time.

using maximum upstream should not kill the downstream, in my experience anyway. unless some equipment is faulty, or just very poor/unskilled configuration from the provider...




just to give a simple everyday example. downloading and uploading torrents at the same time. remove all limits and check the counters..
 
I have this modem and just sending email totally constipates it. Any ideas how to fix it?
 
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