Hi, On Tue, Aug 11, 2009 at 6:47 PM, Jowi Nkwe (JM)<[email protected]> wrote: > > Please clarify this, what is the correct EIGRP K values > representation. That is K1, K2, K3, K4, K5, I know they represent > bandwith, dealy, load, mtu, reliability... But please confirm the > following > K1 = ...... > K2 = ...... > K3 = ...... > K4 = ...... > K5 = ...... > > I've searched the doccd, but this is not explicitly indicated as such. > Metric weight command under EIGRP process does not offer much help.
>From the DocCD (command reference for 'metric weights (EIGRP)'): "If k5 equals 0, the composite EIGRP metric is computed according to the following formula: metric = [k1 * bandwidth + (k2 * bandwidth)/(256 - load) + k3 * delay] "If k5 does not equal zero, an additional operation is performed: metric = metric * [k5/(reliability + k4)] So the weights don't strictly map one-to-one with the 5 elements mentioned -- bandwidth, delay, load, reliability and MTU. In fact, MTU values, while tracked along a path, are not actually used in the composite metric calculation at all -- k5 might seem to map to MTU because that's what the context-sensitive CLI help indicates, but you can see that the actual MTU value is not used in the above calculation. Using the default weights, the formula is effectively simplified to: 256 * (10,000,000 / BANDWIDTH_IN_KBPS(min)) + 256 * (DELAY_IN_uSEC(sum) / 10) e.g. if the minimum end-to-end bandwidth is 100Kbps and the total end-to-end delay (in microseconds) is 124000, the composite metric is: 256 * (10,000,000 / 100) = 25600000 + 256 * (124000 / 10) = 3174400 = 28774400 The first 'metric weights' parameter -- ToS -- is always zero. An original design goal was for EIGRP to be able to do Type of Service routing, but this was never implemented. cheers, Dale _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
