An earlier exchange about someone seeing the rate larger than the
ceiling is posted below. Andy explained the reason for the "above
ceiling" rate in Daniel's output . . . but I just saw an example that
doesn't fit.
>> tc output >>
class htb 1:14 parent 1:1 leaf 14: prio 1 quantum 3072 rate 256000bit
ceil 282000bit burst 1820b/8 mpu 0b overhead 0b cburst 1851b/8 mpu 0b
overhead 0b level 0
Sent 2639448 bytes 1128 pkt (dropped 0, overlimits 0 requeues 0)
rate 325360bit 17pps backlog 0b 25p requeues 0
lended: 981 borrowed: 122 giants: 1155
tokens: -48548 ctokens: -56127
<< tc outpu <<
I see a 43360 difference, where the rate is more than the
ceiling . . . of which only 952bits are accounted for in the
following exchange. I have actually seen the rate be as much as
80408bits off . . . at only 19pps.
Is there something else I am missing?
Stone
Daniel Harold L. wrote On Tuesday 03 July 2007 22:50:
>> Dear all,
>>
>> First, sorry for my bad English ..
>>
>> To night one of my client is the victim of UDP attack from
internet. It's tons
>> of UDP packets from internet with destination to port 80. But
when I look at
>> class of that victim client, the actual class rate is over than
configured
>> rate class.
>>
>> Below is my screen capture. You can see at class 1:913 which have
actual rate
>> 105136bit while configured with ceil at 96000bit. Also it's
parent class
>> (1:91) which have actual rate 107680bit while configured with
ceil at
>> 96000bit.
>>
>> Is this normal? Or I have miss something in my script. Sometimes
ago I found
>> this situation but I forgot to capture the screen and the traffic
is UDP too
>> (maybe from torrent-like client)
>
>Yes it is normal!
>
>The rate tables that tc use normally have an 8 byte steps, so it is
>possible for up to a 56bit/s error per packet and you have 300 pps.
>
>There was a small patch submitted for tc to make the error fall on the
>underrate rather than overrate side, but I think it got lost in the
>middle of the long ATM overhead patch thread on netdev.
>
>Andy.
_______________________________________________
LARTC mailing list
LARTC@xxxxxxxxxxxxxxx
http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
