QoS capping question

Discussion in 'Tomato Firmware' started by rs232, Aug 27, 2011.

  1. rs232

    rs232 Network Guru Member

    Let's say I have 10Mb of bandwidth and I set the QoS inbound bandwidth to 5Mb.
    If I define 3 classes and limit each class to 50% (inbound), how much bandwidth can be used in the worst scenario (all three classes maxed out)?

    5Mb or 7.5Mb?

    I guess what I'm asking is:

    Is the Q0S inbound bandwidth a limit itself or just a reference for the classes where the limit if instead applied?

    Thanks :)
  2. ntest7

    ntest7 Network Guru Member

    Total input will not exceed the defined limit -- in this case 5Mb.
  3. Toastman

    Toastman Super Moderator Staff Member Member

    There is no overall incoming limit on Tomato - the "Max Bandwidth" setting is just a figure used to calculate the limits for the individual classes below. If you use one of my builds I clearly marked it as such, because most people (including myself) originally incorrectly assumed it was indeed a limit. However, it turns out that Tomato's QOS system could be improved - one could say that it's half finished.

    With the setting you suggest it is even possible to exceed your maximum available bandwidth.

    You should take a look at these posts/threads which will explain why:


    There's a small cheat you can use with one of my builds, where the Bandwidth Limiter system uses IMQ and therefore can work at the same time as QOS. Just use it to apply the missing maximum limit. It's only a partial solution, because it has no priorities, but may work to prevent congestion. Or you can turn off QOS and use it as a "bandwidth limiting QOS system" with priorities in its own right. Try it and see if it can do anything for you!

    [EDIT -No longer true - Better Ingress System added early 2012]....
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