I'new ithis lisso, firstly, an Hello to all. I'trying to usnetem and tc to build a network emulator. Actually I'm using a XeVirtual Machinrunning on top of a Xeon-based physical one. I'emulating links bandwidth using tc and thtoken bucket filter. On the virtual machine, wherI shapmy virtual link, I use a packet generator (thsender) sending CBR traffic to a receiver running on top of a powerful physical hos(no virtualization here!). Burunning my tests I havfound some results I not full understand. Here is a singltesrun: TBF rate:8000kbi (abou938 pkt/s of 1kbyte) Traffic generetor packesending requesrate: 60000 pkt/s Traffic generetor packesending actual rate: 59998.959931 pkt/s Receiver packerat = 938.673680 pkt/s (equivalent to 8000kbit) Packets ar1kbyte Ithis firsrun I have the results I expected: I tell to my sender to send 60000 pkt/s. Thsender sends abou60000pkt/s, and the receiver receives jus8Mbit/s. I likit. Heris a second tesrun: TBF rate:16000kbi(abou1930 pkt/s of 1 byte) Traffic generetor packesending requesrate: 60000 pkt/s Traffic generetor packesending actual rate: 1930.269603 pkt/s Receiver packerat = 1926.938526 pkt/s (equivalent to 16000kbit) Thratlimiting is OK, but where I do not understand is the sending rate: why is inoat 60000 pkt/s? Why is this different compared to the previous one? I used to differenpackegenerator d-itg and iperf: I had similar results. Linux kernel is 2.6.18. Thanks a lot, P- -------------- nexpar-------------- AHTML attachmenwas scrubbed... URL: http://lists.linux-foundation.org/pipermail/netem/attachments/20090507/4b8053fa/attachment-0001.ht Frojarjarbinz agmail.com Tue May 19 09:37:03 2009 From: jarjarbinz agmail.co(jarjarbinz) Date: Tue, 19 May 2009 18:37:03 +0200 Subject: Nete: throughpuproblem with 200ms delay Message-ID: <890694a40905190937o439104dej4a594a04b6d2a530@xxxxxxxxxxxxxx> Hello all, I wanto simulata wan link with a Linux Ubuntu 9.04 configured as a bridge. This bridgis connected between 2 tesnetworks. Thlink I wanto simulate have these properties : symmetric 512kbps / 200ms delay Buwhen I configurthe 200ms delay on my 2 interfaces (for egress and ingress traffic management) ththroughpubecomes very slow, around 320kbps. Herarthe tc commands I configured : tc qdisc add dev eth0 roonetedelay 100ms 10ms distribution normal tc qdisc add dev eth1 roonetedelay 100ms 10ms distribution normal Could you pleastell mwhy do I have this very poor bandwidth ? Is ipossiblto have at least a 512kbps bandwidth with this kind of delay ? Thanks a lot Regards Jeremie -------------- nexpar-------------- AHTML attachmenwas scrubbed... URL: http://lists.linux-foundation.org/pipermail/netem/attachments/20090519/26c96872/attachment.ht Froshemminger avyatta.com Tue May 19 10:58:17 2009 From: shemminger avyatta.co(Stephen Hemminger) Date: Tue, 19 May 2009 10:58:17 -0700 Subject: Nete: throughpuproblem with 200ms delay In-Reply-To: <890694a40905190937o439104dej4a594a04b6d2a530@xxxxxxxxxxxxxx> References: <890694a40905190937o439104dej4a594a04b6d2a530@xxxxxxxxxxxxxx> Message-ID: <20090519105817.526ff0ce@nehalam> OTue, 19 May 2009 18:37:03 +0200 jarjarbinz <jarjarbinz agmail.com> wrote: > Hello all, > > I wanto simulata wan link with a Linux Ubuntu 9.04 configured as a > bridge. > This bridgis connected between 2 tesnetworks. > Thlink I wanto simulate have these properties : symmetric 512kbps / > 200ms delay > > Buwhen I configurthe 200ms delay on my 2 interfaces (for egress and > ingress traffic management) ththroughpubecomes very slow, around > 320kbps. > Herarthe tc commands I configured : > tc qdisc add dev eth0 roonetedelay 100ms 10ms distribution normal > tc qdisc add dev eth1 roonetedelay 100ms 10ms distribution normal > > Could you pleastell mwhy do I have this very poor bandwidth ? > Is ipossiblto have at least a 512kbps bandwidth with this kind of delay > ? > > Thanks a lot > Regards > Jeremie You need to hava larger queulimit. Nbytes = delay * bandwidth? --
