Packet shaping. Should I get an ADSL PCI card?

[stelardactek]

I've been considering setting up packet shaping/QoS on my Gentoo box. It does a lot of network stuff already: DNS, DHCP, web/ftp serving, so having to have it on to access the internet would be no big deal. The issue is that, according to the information I've found, getting it to work relies on getting the ethernet port connected to the ADSL router to limit uploads to just slightly less than the line will handle. This doesn't sound ideal to me, especially when I'm not sure exactly how fast my line is. I have an 8Mbps plan ADSL1, but live a fair distance from the exchange.
I'd think an ADSL PCI card would solve this issue. Only problem is I've only seen ADSL1 cards available, and I'm hoping my area will have ADSL2+ before too long. That and I don't know if it would be worth it in the long run. Does anyone know?

[alex.blackbit]

i do not understand what difference having a pci card instead of a ethernet connected blackbox makes.
if you want to test the speed of your connection you have many options. a good one for the download speed is just using wget to download anything, like emerge does it. or enter "dsl speed test" on a internet search engine. you will get shiny websites.

[stelardactek]

I may be wrong, but I'd think the difference would be that the PCI card wouldn't have its own packet queue. That would mean I wouldn't have to throttle an interface and would thus always be getting the most out of my connection, yet would still be able to handle the packet queue.

[alex.blackbit]

to my understanding that makes no difference.

[stelardactek]

Maybe I misunderstand, but the idea of packet shaping is to control the packet queue. If the packet queue is on my ADSL device, I can't control it. So a PCI card would be advantageous if it has no packet queue, as then the packet queue would be handled by GNU/Linux and thus under my control.

[Hu]

The instructions assume you are dealing with a blackbox which has its own queue, which is why they want you to set the limit to be slightly less than line speed. If the line can send 100kb/sec, and Linux never sends more than 96kb/sec, then no traffic will back up in the modem and Linux has complete control over it. If Linux sent at or above 100kb/sec, then the blackbox might start queuing traffic and Linux would be less effective in scheduling the traffic.

[stelardactek]

[nobspangle]

I don't think it makes any difference. The thing about ADSL is that the line speed is not the same as the maximum speed.
Your ADSL connection is 8MBps, let's say your sync speed is 7MBps your maximum ADSL speed is probably around 6MBps. Even with a PCI card the line speed of your connection will still be 7MBps.

The other thing to bare in mind is that you can only really shape upstream traffic.

I used to use a PCI ADSL card and it worked great until my connection was upgraded to 8MBps at which point the card became unstable so I switched to an external ADSL router.

[stelardactek]