I was meaning that perhaps he uses Kbps instead of bps for the CIR or milliseconds instead of seconds for the interval. According to his formula, Bc=CIR(Tc/1000). Let's use a 256k circuit with 10ms as an example:
Bc=256000(.010/1000) = 2.56 That doesn't quite work out. As you can see, Tc in the Cisco documentation is in seconds, not milliseconds, so that formula doesn't work. In Cisco-land it would be Bc=256000(.010)=2560. That's what I was getting at. Sorry for the confusion. John >>> "Steven A. Ridder" 12/19/01 5:59:56 AM >>> No we all use ms, including Wendel Odom. ""John Neiberger"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Actually, that web page is correct. Tc = Bc/CIR, and the > answer is in seconds. If you get an answer such as .125, that > is 1/8th of a second, or 125ms. > > At work we use a Bc of 5120 on 512k links. 5120/512000 = .010, > or 10ms, which is the recommended interval. It all depends on > what units you're using, as well. Perhaps he is using > different units of measurement. > > Regards, > John > > > ________________________________________________ > Get your own "800" number > Voicemail, fax, email, and a lot more > http://www.ureach.com/reg/tag > > > ---- On Tue, 18 Dec 2001, Steven A. Ridder ([EMAIL PROTECTED]) > wrote: > > > I believe the true calculation for the interval (Tc) is Bc=CIR > (Tc/1000). > > This web page over-simplifies it. I have read in varoius > sources > > (Intergrating Voice and Data Network, and from Wendel Odom > himself, that > > it's actually the above calculation. I have other problem > wih CCO web > > pages > > also, especially Dialer Watch, CBAC, etc. I think Cisco is > too big to > > manage :) > > > > > > ""John Neiberger"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > I only see two examples on that page that are different. > The first is > > > on a 56k link, Bc=1000 and CIR=56000. Bc/CIR = .0178, or > basically > > > 18ms. I know that's higher than the recommended 10ms, but > perhaps > > there > > > are drawbacks to lowering the Bc below 1000 that I'm not > aware of. > > > > > > The other example is on a 256k link. Bc = 1000, CIR = > 256000, so > > > Bc/CIR = .004, or 4ms. This will set your Tc to the > minimum of 10ms, > > > IIRC. > > > > > > Regards, > > > John > > > > > > >>> "Steven A. Ridder" 12/18/01 5:22:56 PM >>> > > > The bc info for the Frame-Relay traffic shaping info on > that page is > > > wrong. > > > One should always target Bc to get a Tc of 10ms, but the > config > > > examples are > > > more like a Bc of 36.4. So you have the serialization > delay time at > > > 36.4, > > > but optimally you want 10ms. The packets will be going out > at 10ms > > (or > > > less > > > cause fragmentation ias correct) but the time interval the > router uses > > > is at > > > 36.4ms. > > > ""John Neiberger"" wrote in message > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > Here is another link that deals with WAN QoS, including > some items > > > that > > > > might not occur to you such as sizing the interface > transmit ring. > > > > > > > > > > > > > > http://www.cisco.com/univercd/cc/td/doc/product/voice/ip_tele/av > vidqos/qoswa > > > > > > n.htm > > > > > > > > > > > > HTH, > > > > John > [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=29642&t=29559 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
