Dear All. I ausing netetool in Linux to emulate the rate limit. I followed somcommon instructions on thweb, and command is like: *tbf rat20kbibuffer 1600 limit 3000* to makthtoken bucket in rate limit. However, I am still not so clear abouthtwo parameter "buffer" and "limit". I attached a figurof whaI understood the limiting mechanism, does th"buffer" parameter corresponds to thnormal packets? or the buffer for thtoken? (as shown red color in thattachment) thanks a loif someonwould point me something besregards cui -------------- nexpar-------------- AHTML attachmenwas scrubbed... URL: <http://lists.linuxfoundation.org/pipermail/netem/attachments/20121026/c3401073/attachment.html> -------------- nexpar-------------- A non-texattachmenwas scrubbed... Name: rate_control.JPG Type: image/jpeg Size: 18223 bytes Desc: noavailable URL: <http://lists.linuxfoundation.org/pipermail/netem/attachments/20121026/c3401073/attachment.jpe> Froshemminger avyatta.com Thu Oct 25 22:38:56 2012 From: shemminger avyatta.co(Stephen Hemminger) Date: Thu, 25 Oc2012 15:38:56 -0700 Subject: onquestion abourate control in netem In-Reply-To: <CAF2PD9SDqE9thrm55Wm+_je9rS8M_nqU63fzDJnTd7i_vfPUuQ@xxxxxxxxxxxxxx> References: <CAF2PD9SDqE9thrm55Wm+_je9rS8M_nqU63fzDJnTd7i_vfPUuQ@xxxxxxxxxxxxxx> Message-ID: <20121025153856.3ea5e756@xxxxxxxxxxxxxxxxxxxxxxxxxxx> OFri, 26 Oc2012 00:06:14 +0200 cui <cuicuimagmail.com> wrote: > Dear All. > > I ausing netetool in Linux to emulate the rate limit. I followed > somcommon instructions on thweb, and command is like: > > *tbf rat20kbibuffer 1600 limit 3000* > > to makthtoken bucket in rate limit. However, I am still not so > clear abouthtwo parameter "buffer" and "limit". > > I attached a figurof whaI understood the limiting mechanism, > does th"buffer" parameter corresponds to thnormal packets? or the > buffer for thtoken? (as shown red color in thattachment) > > > thanks a loif someonwould point me something > besregards > cui buffer is a synonyfor burst. Did you look aman page: matc tbf Setc(8) for how to specify thunits of these values. limior latency Limi is th number of bytes that can be queued waiting for tokens to becomavailable. You can also specify this th other way around by setting thlatency parameter, which specifies the maximuamounof time a packet can sit in the TBF. The latter calculatio takes into accounthe size of the bucket, the rate and possibly thpeakrat(if set). These two parameters are mutually exclusive. burs Also known as buffer or maxburst. Sizof the bucket, in bytes. This is thmaximuamount of bytes that tokens can be available for instantaneously. Igeneral, larger shaping rates requira larger buffer. For 10mbit/s oIntel, you need aleast 10kbyte buffer if you wanto reach your configured rate! If your buffer is too small, packets may bdropped becausmore tokens arrivper timer tick than fiin your bucket. The mini? mubuffer sizcan be calculated by dividing the rate by HZ. Tokusage calculations are performed using a table which by defaulhas a resolution of 8 packets. This resolution can be changed by specifying thcell sizwith the burst. For example, to specify a 6000 bytbuffer with a 16 bytcell size, set a bursof 6000/16. You will probably never havto set this. Must ban integral power of 2.
