Looza wrote: > > Hi, > > I'm trying to simulate a LFN(Long Fat Network) to test various TCP versions. > I am using iperf on the end PCs. I'm trying to use FreeBSD's ipfw to > simulate a LFN. > ex. throughput=1 Gbit/s and delay=100ms, trhoughput=100 Mbit/s and delay=1s > > This is how my hardware is connected. > > |Linux PC|--Gigabit--| FreeBSD box |--Gigabit--|Linux PC| > > > With this configuration: > > >ipfw 500 add allow ip from any to any > > I get speeds of about 200 to 300 Mbit/s and the CPU usage goes up > to 99%. I've googled this problem and it seems that some good > quality NIC do most of the processing so that the CPU doesn't have > to. Unfortunately I have bad quality NICs so the CPU does all the > processing, stoping the throughput at these speeds.
Try sysctl net.inet.ip.fastforwarding=1 . With this set I can formard and filter in excess of 500kpps using less than 5% CPU on a Xeon. I highly recomend the Intel 82546GB chip based adaptors (em driver). Ian -- Ian Freislich _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-ipfw To unsubscribe, send any mail to "[EMAIL PROTECTED]"
