[Click] BandwidthShaper element not functioning as it should be

[Peter Dedecker]

Peter Dedecker wrote:
> Peter Dedecker wrote:
>> When I check on Mozart all incoming and outgoing packets with tcpdump, 
>> the packets arriving from Kodaly correctly are correct: 3062 packets at 
>> +/- 4.5 Mbps constantly.  However, a tcpdump on the outgoing interface 
>> tells me 1872 packets are sent out:
>> - from 0 to 0.6 s at +/- 4.5 Mbps
>> - from 0.6 s to 3.3 s at +/- 2 Mbps
> 
> FWIW: the same occurs when I use an altered click configuration which 
> sends all outgoing traffic to a dumpfile instead of a ToDevice and I 
> manually insert an entry in the ARP-table of the sending host.

I'm sorry for this other update, but it seems the problem might be 
somewhere else.  I used this config to test:

FromDevice(eth2, PROMISC 1) -> T1 :: Tee;
T1[0] -> C1 :: Counter -> Q1 :: Queue(10) -> BandwidthShaper(250000 Bps) 
-> ToDevice(eth1);
T1[1] -> ToDump(eth2in.pcap)
FromDevice(eth1, PROMISC 1) -> T2 :: Tee;
T2[0] -> C2 :: Counter -> Q2 :: Queue(10) -> BandwidthShaper(250000 Bps) 
-> ToDump(eth2);
T2[1] -> ToDump(eth1in.pcap)

It seems that the strange behaviour (the described flow pattern with 0.6 
s @ 4.5 Mbps and the rest of the time at 2 Mbps) can allready be found 
in the dumpfile at the incoming side.  However, a tcpdump at the 
incoming interface shows a correct flow pattern at a constant rate of 
4.5 Mbps the whole time.  Does anyone have an idea why incoming traffic 
in click is something else than incoming traffic on the interface?  Is 
this some "feature" about how the kernel delivers packets to the click 
router?  Thanks a lot!

Peter


-- 
ir. Peter Dedecker
IBCN Research Group
Department of Information Technology (INTEC)
Ghent University - IBBT
Gaston Crommenlaan 8 bus 201, B-9050 Gent
Tel: +32(0)9 3314977, Fax: +32(0)9 2649969
Peter.Dedecker at intec.UGent.be