From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stef Coene Date: Fri, 17 May 2002 07:58:15 +0000 Subject: Re: [LARTC] bandwidth limit Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: lartc@vger.kernel.org On Friday 17 May 2002 08:06, Rendel, Thorsten wrote: > Hi, > i am using the CBQ Qdisc as a shaper for my 100Mbit/s Ethernet LAN. > I want to limit a bounded, isolated CBQ Class to 10 Mbit/s. > # TC class add dev $DEVICE handle X:0 classid X:Y cbq bandwidth 100Mbit/s > rate 10 Mbit/s prio bounded isolated avpkt 1000 allot 1514 weight 1 > maxburst 15 In my testbed i use a SmartBit Hardware traffic generator to > generate traffic streams, with different protcols and different paket > length. I send a UDP traffic stream with 20 Mbit/s. The results of my > measurementes are that for a paket length of 1518 Bytes the shaping works > fine, but for a length of 64 Byte the shapings works very bad. I got at t= he > outgoing interface a bandwidth of 4 Mbit/s. I changed the avpkt, maxburst > and allot parameter, but the results didn=B4t become better. What is the > reson for this behavior? CBQ implementation. =20 It uses the packet size as an internal parameter to calculate the idle time= =20 of the link. With the avpkt you set the average packet size, so if you lea= ve=20 it on 1000, the shaping is fine for packets of 1528 bytes. If you use=20 smaller packets, you should adjust avpkt (packet size of 64byte : avpkt 64 = or=20 even smaller). After that, you should be able to shape the small packets=20 like you want. But I never tested it for such small packets. Anyway, for normal traffic, avpkt =3D 1000 is a good choice. Stef --=20 stef.coene@docum.org "Using Linux as bandwidth manager" http://www.docum.org/ #lartc @ irc.openprojects.net _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/