Traffic shaping and causing bandwidth loss?



  • I'm attempting to shape traffic in my lan/wan and ensure latency remains smooth etc.  Generally I can get hfsc queues to do what I want them to using the wizard and then tweaking, as well as following some guides on this forum.

    However, one thing I have noticed is that with traffic shaping enabled at all, I find huuuuge bandwidth drops unless I inflate the queue's bandwidth #.

    For example I need to limit both upstream and downstream. So I have rules on my wan link for upstream and rules saying traffic out of LAN bridge must be traffic shaped as well as long as its from the internet.

    Recently my provider just upped my download speed immensely.  So.. I throw some queues in for the new speeds (300 down, 20 up) and find that … I only get 160-170ish down and like 16 up.  i was able to get the queues to behave as expected and offer relatively close speeds by drastically changing them.  For example, the upstream thinks it's 23 Mb/s. And the downstream a whopping 475Mb/s.  With those values, linksharing is honored correctly and everything is fine...

    The question I have is why do I need to artificially experiment with the values to gear near my speeds?  Shouldn't 300 Mb/s equal 300Mb/s?

    Operating without traffic shaping rules and things just work normal speed.  However, any download or upload saturates my pipe and causes latency in other applications (which is the main reason I am trying to shape).

    Thanks for the assistance if anyone can tell me I'm crazy and it's a pebkac, I'm all for hearing it. :P



  • Strangely I tried this on another piece of hardware at my office it SEEMS to work as expected (15 meg there = 15 meg).

    Currently tested my home setup again and set it to 300/20.  Speedtest reports 128 down and 17 up.  Remove the traffic shaper and get 300 down.

    I'm using a bridged lan interface. Could this have something to do with it? I'm setting all of my rules on the bridge.


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