Arch Linux

tpolich

Member

Registered: 2009-08-07

Posts: 44

traffic shaping downlink, QoS

I am moving into an apartment later this summer. It is going to be 4 college students so I have been doing a lot of research into QoS. I have found some really nice detailed guides on how to manage uplink but almost nothing relating to downlink.

The only real content I have found about downlink has been the suggestion to drop traffic that starts coming in too fast with a tc rule. Is that all I can do to manage downlink? Is it a smart things to do? If it isn't to much trouble could you explain why it's a smart thing to do?

I am exceited about moving in but worried about our connection with 4 people who I know all use P2P. I would really appreciate any help.

Tpolich

brebs

Member

Registered: 2007-04-03

Posts: 3,742

Re: traffic shaping downlink, QoS

First of all: Disclaimer: I am by no means an expert in this. However, I expect the beings who thoroughly understand such matters, are too busy shadow-controlling the universe, to respond to a puny single human's problems.

Dropping incoming traffic is stupid, because computers can just *process* the incoming traffic, far faster than the traffic can, er, come in.

tc can prioritize upload traffic based on port numbers, which is what you want. The whole point of this, is that the CPU can reorganize packets, a heck of a lot faster than the packets can be *sent*.

If someone blatantly abuses your setup (e.g. by trying p2p over port 80, if that's even possible), then the threat of a baseball bat to the knees from the local jocks (or whatever you American kids call paid bullies), or blacklisting entirely, should do the trick. This is why ISPs have "terms of service" - and it sounds like you will be the service provider.

Sin.citadel

Member

Registered: 2008-01-22

Posts: 267

Re: traffic shaping downlink, QoS

tc can be used to prioritize traffic based on port numbers or iptables firewall MARKs. to do downlink traffic control, upload becomes your internal network and downlink becomes your external traffic.

goto http://bbs.archlinux.org/viewtopic.php?id=92852 i have uploaded a tc script file, combine that with iptables firewall's mark rules. as for p2p, because it uses many random ports, you cant shape its traffic using normal rules, either use an iptables addon to get MARK capability for p2p traffic, or simply, give p2p traffic a lower priority.