How can I prioritise network bandwidth on a per application basis?

Question

Is there a way in Linux to give a specific application more/less priority for network bandwidth? Something like how nice does for CPU priority.

Context: I'm currently on a very low bandwidth connection (3G dongle). While I'm performing a quite large upgrade using aptitude, it becomes virtually impossible to browse the web since the upgrade download is hogging my Internet connection.

So what I would like to do is somehow decrease the network bandwidth priority of the aptitude process (and all its children) so that it won't use too much bandwidth while another process is using it.

Answer 1

You can use force_bind to set a priority for all sockets of an application, and then, using Linux QoS (tc command), you can assign applications to a priority band. Check the README file for an example.

http://kernel.embedromix.ro/us/

Disclaimer: I am the author.

Example:

14: Force priority (between 0 and 6 for non-root users). You can
        use 'tc' command from iproute to set-up 'prio' qdisc and to
        assign prio to queues:
        # 0. setup
        export FORCE_NET_VERBOSE=1
        export LD_PRELOAD=${LD_PRELOAD}:/usr/lib/force_bind.so
        # 1. Make sure you have a 'prio' qdisc attached to eth0, for example:
        tc qdisc add ev eth0 root handle 1: prio
        # 2. Assign applications to classed (bands):
        export FORCE_NET_PRIO=6 # interactive, band 0
        your_voip_program_here
        export FORCE_NET_PRIO=0 # best effort, band 1
        your_mail_program_here
        export FORCE_NET_PRIO=2 # bulk, band 2
        your_remote_backup_program_here
        # 3. Run tc statistics so you can see the classification:
        tc -s class show dev eth0

Of course, you may use htb or any other qdisc.