[LARTC] Ethernet bridge overflow ?

[Sébastien CRAMATTE]

Hello,

I've setuped  an ethernet bridge on a debian sarge 3.1 with  l7-filter +
ipp2 shapper rules
The server is a supermicro p4sci + celeron pentium 4 base 3ghz  + 512Mb
+ 2 ethernet e1000

One interface is connected to a cisco catalyst switch
The other interface is connected directly to a CMTS (a sort of router
for cable modem) configured as bridge too.

More than 20Mbps of bandwith cross this bridge. Most of this traffic is
p2p (~80%)
When traffic goes over 14Mbps the  bridge seems to saturate (overflow ?
) and start to make colision and loose packets

I've take a look to this  paper
http://facweb.cti.depaul.edu/jyu/Publications/Yu-Linux-TSM2004.pdf

And with a duron 1,3Ghz+512 mbps he obtain these values

Input Rate   28,444,444
(bps)
Latency    29
(us)
Throughput 28,000,000
(bps)
Linux CPU 77%
Occupancy

A duron 1,3 is less powered than a celeron p4 3 ...  So I don't
understand why I've got this problem :(


When I make a  "top" or "uptime" all seems that works well ...
I've got rrdtool graphs that check cpu and load and seems normal too ...

Does someone  have got somes ideas ?
Any clue or tips to isolate/resolve the problem are welcome


Regards