# EIGRP metric calculation

The 5 Day Bootcamp workbook v4.2 task 3.16 states "Configure the EIGRP domain so that only delay is used for composite metric calculations" the solution guide shows this as

"metric weigths 0 0 0 1 0 0"

My understanding of the values are:

K1 = Bandwidth (default 1)

K2 = Delay (default 0)

K3 = Delay Reliability (default 1)

K4 = Load (default 0)

K5 = mtu (default 0)

metric weights takes 6 arguments total (tos, k1, k2, k3, k4, k5). So to calculate on delay wouldn't we need to use only the K2 value "metric weight 0 0 1 0 0 0" to calculate on delay vice delay reliability?

Thanks,

Pete

## Comments

Pete,

The metric names aren't what they seem. You would expect the k values to translate to bandwidth, delay, reliability, load, and MTU but they actually do not follow this same sequence. I've looked online and found the actual representation of the k values:

ToS is the first 0 as you know:

k1=bandwidth

k2=load

k3=delay

k4=reliability

k5=MTU

The answer, according to the workbook, is correct. I struggled with this a bit myself then just realized the k values don't line up to what you memorize about the order of EIGRP metrics.

I'm not so sure about the MTU there. From the Command Ref....

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)]

MTU.

"default-metric" command, or "metric" on a redistribution command line puts

CHARACTERISTICS in place which include a place for MTU, but it's not exactly

like that when calculating the MTU.

itself. The configuration guide for EIGRP should have the whole algorithm

used for EIGRP metric calculations, this may be good to look

at!

Scott Morris,

CCIE4#4713, JNCIE-M #153, JNCIS-ER, CISSP, et al.

CCSI/JNCI-M/JNCI-ER

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From:[email protected] [mailto:[email protected]]On Behalf OfpesawyerSent:Tuesday, December 30, 2008 3:03AM

To:[email protected]Subject:[CCIER&S] EIGRP metric calculation

The 5 Day Bootcamp workbook v4.2 tas 3.16 states "Configure the EIGRP domain

so that only delay is used for composite metric calculations" the solution guide

shows this as

"metric weigths 0 0 0 1 0 0"

My understanding of the values are:

K1 = Bandwidth (default 1)

K2 = Delay (default 0)

K3 = Delay Reliability (default 1)

K4 = Load (default 0)

K5 = mtu (default 0)

metric weights takes 6 arguments total (tos, k1, k2, k3, k4, k5). So to

calculate on delay wouldn't we need to use only the K2 value "metric weight 0 0

1 0 0 0" to calculate on delay vice delay reliability?

Thanks,

Pete

Internetwork

Expert - The Industry Leader in CCIE

Preparation

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I took Mock Lab 5 on Saturday. One of the tasks asked for a certain combination of metrics to be considered throughout the EIGRP domain. By looking at the formula in the Configuration Guide I was able to correctly identify the k-values to enable the required metrics.

This is one time where using the documentation is better than relying on memory.

EIGRP Metric = 256*((K1*Bw) + (K2*Bw)/(256-Load) + (K3*Delay)*(K5/(Reliability + K4)))metric weightstos k1 k2 k3 k4 k5Ok, thanks. It's a little more clear to me now.

I think in this case, the Command Ref is a better source than the Config Guide. The Command Ref lays the formula out nicely and the variables are explained clearly....

http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_eig2.html#wp1011716

> The 5 Day Bootcamp workbook v4.2 tas 3.16 states "Configure the

> EIGRP domain so that only delay is used for composite metric

> calculations" the solution guide shows this as

>

> "metric weigths 0 0 0 1 0 0"

>

> My understanding of the values are:

>

> K1 = Bandwidth (default 1)

>

> K2 = Delay (default 0)

>

> K3 = Delay Reliability (default 1)

>

> K4 = Load (default 0)

>

> K5 = mtu (default 0)

>

> metric weights takes 6 arguments total (tos, k1, k2, k3, k4, k5). So

> to calculate on delay wouldn't we need to use only the K2 value

> "metric weight 0 0 1 0 0 0" to calculate on delay vice delay

> reliability?

>

Hi Peter,

K1 and K2 are for Bandwidth. K3 is for Delay. Just check the formula

to get a better understanding.

Thx

David Sudjiman

www.davidsudjiman.info

"redistribute" command with the K values. They are different.

If you look at the algorithm used for metrics, you'll find that:

K1 - bandwidth

K2 - load

K3 - delay

K4 - reliability

K5 - just a modifier

Tos is always 0 in the "metric weights" command.

HTH,

Scott

----- Original Message -----

From: "David Sudjiman"

Sent: Sun, February 22, 2009 21:43

Subject:Re: [CCIE R&S] EIGRP metric calculation

On 30/12/2008, at 7:03 PM, pesawyer wrote: > The 5 Day Bootcamp workbook

v4.2 tas

3.16 states "Configure the > EIGRP domain so that only delay is used for

composite

metric > calculations" the solution guide shows this as > > "metric

weigths 0 0 0 1

0 0" > > My understanding of the values are: > > K1 = Bandwidth (default

1) > > K2 =

Delay (default 0) > > K3 = Delay Reliability (default 1) > > K4 = Load

(default 0) >

> K5 = mtu (default 0) > > metric weights takes 6 arguments total (tos,

k1, k2, k3,

k4, k5). So > to calculate on delay wouldn't we need to use only the K2

value >

"metric weight 0 0 1 0 0 0" to calculate on delay vice delay >

reliability? > Hi

Peter, K1 and K2 are for Bandwidth. K3 is for Delay. Just check the

formula to get a

better understanding. Thx David Sudjiman www.davidsudjiman.info

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