Les et al, Thank you for getting back to me. The core concept I understand, but what was confusing me was defining Tc through the adjustment of Bc (Bucket Size). After some further reading my understanding is that 1. IOS has the defaults as I've previoiusly stated but 2. dependent on the traffic type it may be beneficial to adjust the Tc i.e. lower Tc for voip type traffic and 2. higher Tc for burstier traffic types e.g. TCP streams.
Thoughts? Point being there is no right and wrong answer, the Tc merely governs how often your sampling end result is you always hit your shaping rate within the second, but your bucket size means more tokens which means for packets in any one hit. Thanks B On Thu, Apr 12, 2012 at 10:57 PM, Les Waller <[email protected]> wrote: > Let me respond within your email... > > On Thu, Apr 12, 2012 at 10:53 AM, Bal Birdy <[email protected]>wrote: > >> Hello Experts, >> >> Need some guidance please on QoS with respect to shaping and Tc/Bc/Be >> values. I just need to confirm what i'm reading and the way im >> interpreting >> it. >> >> 1. CIR <= 320 Kbps: >> >> If I'm shaping below 320 Kbps my Bc/Be values will always be 8000 bits, >> with the Tc calculated using Tc=Bc/CIR >> > > Your Tc will be determined by your value of the Bc. > > The CIR is the total data to pass in one second. The Bc is the data that > will pass in one slice of time for x number of times per second. > > Let's say you have a pizza that is 16 inches in circumference. If the Bc > is 2 inches then it will take 8 pieces of pizza to make a whole. If the Bc > is 8 inches, then it will only take 2 pieces to make a whole. > > Put another way, it takes an hour to eat a pizza. You won't eat the whole > thing at one gulp, so you break it into pieces (bursts). So the pieces are > 2 inches in size then you can eat eight pieces each 7.5 minutes apart or > you can eat two 8 inch pieces 30 minutes apart. > >> >> 2. CIR >= 320 Kbps >> >> If I'm shaping above 320 Kbps, my Tc is always 25ms, my Bc = shaping rate >> * >> Tc and my Be = Bc >> >> Thanks >> Bal >> _______________________________________________ >> For more information regarding industry leading CCIE Lab training, please >> visit www.ipexpert.com >> >> Are you a CCNP or CCIE and looking for a job? Check out >> www.PlatinumPlacement.com <http://www.platinumplacement.com/> >> >> http://onlinestudylist.com/mailman/listinfo/ccie_rs >> > > > > -- > Les Waller, Network Engineer > > Home Page: www.leswaller.com > > MBA, CISSP, CCNP > > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
