Re: EIGRP K values

The formula from the link that you provided is not the same as the
formula from the DOC CD available during lab.

#1 : Formula from your link:
metric = [K1 * bandwidth + (K2 * bandwidth) / (256 - load) + K3 *
delay] * [K5 / (reliability + K4)]

#2 : Formula from DOC CD, IOS 12.4 Configuration guide
metric = 256*((K1*Bw) + (K2*Bw)/(256-Load) + (K3*Delay)*(K5/(Reliability + K4)))

The differences are:
a. Compare how K values are grouped with brackets in both formulas. If
K5=1 then calculation is different in formula #1 and #2
b. In #2 there is multiplication by 256, not in #1

One of them (or both) must be wrong. Which one ?

I am referring to this DOC CD article:
http://www.cisco.com/en/US/docs/ios/iproute_eigrp/configuration/guide/ire_cfg_eigrp_ps6350_TSD_Products_Configuration_Guide_Chapter.html

On Thu, Oct 7, 2010 at 4:44 AM, Narbik Kocharians <narbikk_at_gmail.com> wrote:
> If K5 is set to it's default value (Which is zero), the last portion of the
> formula (K5/K4+rel) will not come into play:
>
> http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094cb7.shtml
>
>
>
> On Thu, Oct 7, 2010 at 1:09 AM, Elias Chari <elias.chari_at_gmail.com> wrote:
>
>> Yes, the maths do not work out when you look at it that way. May be
>> another
>> way to represent the formula, which may make it easier to interpret would
>> be:
>>
>> (a) For K5>0, the formula applied by the router is:
>>
>> EIGRP Metric = 256*((K1*Bw) + (K2*Bw)/(256-Load) +
>> (K3*Delay)*(K5/(Reliability + K4)))
>>
>> (b) For K5=0, the formula applied by the router is:
>>
>> EIGRP Metric = 256*((K1*Bw) + (K2*Bw)/(256-Load) + (K3*Delay))
>>
>>
>> On 7 October 2010 07:53, Narbik Kocharians <narbikk_at_gmail.com> wrote:
>>
>> > If K5 is set to zero (Which is the default), then, the last section of
>> the
>> > formula (K5/(Reliability + K4) will not come into play.
>> >
>> > On Wed, Oct 6, 2010 at 9:18 PM, Piotr Malarski
>> > <piotr.malarski.99_at_gmail.com>wrote:
>> >
>> > > Hello,
>> > >
>> > > What should be K values so only delay is used to calculate the metric ?
>> > > OK, I know that the answer is 0 0 1 0 0 (K1,K2,K3,K4,K5) but this does
>> > > not fit the Doc CD formula:
>> > >
>> > > EIGRP Metric = 256*((K1*Bw) + (K2*Bw)/(256-Load) +
>> > > (K3*Delay)*(K5/(Reliability + K4)))
>> > >
>> > > If K3=1 and K4=K5=0 then the last section of the above formula equals
>> > > 0 and Delay will not be considered at all:
>> > >
>> > > (1*Delay)*(0/(Reliability + 0)) = (1*Delay)*0 = 0
>> > >
>> > > Actually, if K values are 00100 then the whole metric equals zero. I
>> > > thinks that my math is correct. Can someone please clarify ?
>> > >
>> > >
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>> > >
>> > >
>> > >
>> > >
>> >
>> >
>> > --
>> > Narbik Kocharians
>> > CCSI#30832, CCIE# 12410 (R&S, SP, Security)
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>
>
> --
> Narbik Kocharians
> CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> www.MicronicsTraining.com
> Sr. Technical Instructor
> YES! We take Cisco Learning Credits!
> Training And Remote Racks available
>
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Received on Thu Oct 07 2010 - 09:12:20 ART