I'm trying to prioritize null acks on OpenBSD 3.5 with a simple setup like http://www.openbsd.org/faq/pf/queueing.html#example1. I use ADSL and the userland PPP, so I'm queuing on tun0.
My problem is that although the suggested altq rules allow simultaneous full speed downloads and uploads, latency increases from tens or hundreds of milliseconds to between two and four seconds. Strangely, both TCP and ICMP seem to be affected. So the atlq rules make it possible to download something large like an ISO, but browsing and online gaming are still nearly impossible while uploading at full speed. Is this latency problem inherent to pf and altq, or might I have done something wrong?
