On Sat, Nov 19, 2011 at 08:58:46PM -0500, quartz wrote: > is there a way to set up altq+priq on an internet connection with highly > variable/unknown bandwidth? > > I'd like to create a simple one layer queue system that prioritizes empty > ACKs over anything else (always, all the time, no matter the load or > congestion). it looks like priq is the way to do this, but all the > documentation I can find seems to say you have to type in a hard number, > which won't work for my case. This is usually impossible. The packets get re-queued in the modem or whatever device is next to the choke point, and any prioritization you configure becomes useless. Typically the only way around it is to send at a rate slightly lower than the choke point bandwidth, so the buffer of the modem never starts to get utilized. If the bandwidth is variable, you're screwed.
You can try if your modem or other device supports DiffServ or 802.1q priority tags. Some DSL modems do, which helps - DSL has an extra perk of the extra headers causing more overhead for small packets, so you need a shaper that can account for that, or you need to configure the max rate lower than what the line is capable of with large packets.
