Hi,

My goal: have full bandwidth of my 4Mbit ADSL line available for newsgroup downloading (NNTP traffic on port 119), but give all other traffic priority (so HTTP download, videostreaming etc).

So when I do nothing but NNTP traffic, I want 475KB/s downloadspeed, but when I do a download via HTTP, I want 25% for NNTP and 75% for HTTP or other traffic.

So I thought this was a job for Quality-Of-Service in my 2820Vn.
But: as soon as I enable QoS for all inbound traffic, my download speed decreases to about 370KB/s. Without specifying any rules, just the default but with inbound QoS enabled.

Is there an explanation for this? Or does QoS impact the router performance in such a way that bandwidth is decreased this much?

OK, I hope I followed what you said...
In that case, what I would do :

Check your Bandwidth management. You' ve got 3 classes...
If HTTP has a higher priority, you can use the class 2 for HTTP download.
( HTTP Download priority > NNTP download priority )

1) Don't forget to select : "Outbound TCP ACK Prioritize" into
Broadband management -> Quality of service
then WAN1 Enable -> setup

2) if you want to allocate the rest of the unused bandwidth,
into : Bandwidth Management -> Bandwidth limit , also tick : Allow auto adjustment to make the best utilization of available bandwidth.

That should do the job

I didn't want to hijack your thread so I've posted a new thread:
http://www.forum.draytek.co.uk/viewtopic.php?t=14746

I could be talking complete nonsense of course..!