CTShaper 1.1.1

CTShaper is a shell-script that helps setting up a traffic shaper, using Linuxs built-in network QoS (Quality of Service) infrastructure.

Have you ever noticed how your SSH/gaming sessions become sluggish when you start downloading something, or how your downloads slow down when you start uploading?

Have you ever been annoyed by other peoples downloads forcing you to wait ages while an email is being sent? Or making your web navigation painfully slow?

Well, if your outgoing link is managed by a Linux router/gateway, then you could benefit from using CTShaper.

CTShaper reduces link latency by preventing packet queues from getting too long on your side (your ADSL or Cable modem) and on your ISPs side (their routers). Long packet queues is what makes your uploads interfere with your downloads, and your downloads interfere with your SSH or gaming sessions.

Additionally, CTShaper sets up four traffic queues with different priorities and configurable flow rates (to have minimum bandwidth guarantees for each class). By default, only traffic with ToS (Type of Service) information gets prioritized (which could be enough, if lots of software had support for it, which they dont), but you can use your firewall (iptables, or an iptables frontend like FireHOL) to "mark" traffic.

The traffic shaper will then prioritize (outgoing) traffic based on those "marks". You can, for instance, give priority to SMTP and HTTP traffic. This will only affect outgoing HTTP and SMTP traffic, but thats enough to make your emails go out faster, and your web navigation more responsive.