Linux shaping packet loss

Bazy bazy84 at
Wed Dec 9 00:02:12 CST 2009

On Tue, Dec 8, 2009 at 5:14 PM, Chris <chris at> wrote:
> Thanks, Steiner and everyone for the input. It's good to see the list is
> still as friendly as ever.
> There are two paths I'm trying to get my head round after someone offlist
> helpfully suggested putting cburst and burst on all classes.
> My thoughts are that any dropped packets on the parent class is a bad thing:
> qdisc htb 1: root r2q 10 default 265 direct_packets_stat 448 ver 3.17
>  Sent 4652558768 bytes 5125175 pkt (dropped 819, overlimits 10048800
> requeues 0)
>  rate 0bit 0pps backlog 0b 28p requeues 0
> Until now I've had Rate and Ceil at the same values on all the classes but I
> take the point about cburst and burst allowing greater levels of borrowing
> so I've halved the Rate for all classes and left the Ceil the same.
> I've gone done this route mainly because I really can't risk breaking things
> with incorrect cburst and burst values (if anyone can please tell me on an
> i686 box at, say, 10Mbps the ideal values I can translate them into higher
> classes, TC seems to work them out as 1600b/8 mpu by default and the timing
> resolution confuses me.)
> Thanks again,
> Chris
> 2009/12/8 <sthaug at>
>> > Won't say I'm an expert with TC, but anytime I see packet loss on an
>> > interface I always check the interface itself...10% packet loss is
>> > pretty much what you would get if there was a duplex problem. I always
>> > try to hard set my interfaces on both the Linux machines and Switches.
>> Used to set everything hard five years ago. Nowadays auto works just
>> fine most of the time.
>> Steinar Haug, Nethelp consulting, sthaug at

Hi Chris,

Try setting txqueuelen to 1000 on the interfaces and see if you still
get a lot of packet loss.


More information about the NANOG mailing list