Quick K Value Order Question

Dieg0MDieg0M Member Posts: 861
in CCNP
Hello,
Quick question, why is it that the EIGRP metric weight K value order is different then the redistribution K value order?
metric weight = TOS Bandwidth Load Delay Reliability MTU
redistribution = Bandwidth Delay Reliability Load MTU

Thanks.
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Comments

  • networker050184networker050184 Mod Posts: 11,962 Mod
    It really doesn't matter what order they are listed in as the equation is the same regardless.

    whitepaper_C11-720525-23.jpg

    As for why IOS is that way, I suppose you'd have to ask the developers!
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  • Dieg0MDieg0M Member Posts: 861
    Yea I was referring to why the IOS is that way, it seems counter intuitive to have to memorize 2 different orders...
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  • powmiapowmia Users Awaiting Email Confirmation Posts: 322
    When you modify the metric weights, you are modifying K values, so they go in order K1 -> K5

    When you redistribute, you are changing metrics, not K values. Those go in order of most relevant to least relevant. It's intuitive, just not intuitively intuitive.
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  • Dieg0MDieg0M Member Posts: 861
    Thanks alot didnt think of it that way
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  • iamme4evaiamme4eva Member Posts: 272
    Dieg0M wrote: »
    Hello,
    Quick question, why is it that the EIGRP metric weight K value order is different then the redistribution K value order?
    metric weight = TOS Bandwidth Load Delay Reliability MTU
    redistribution = Bandwidth Delay Reliability Load MTU

    Thanks.

    To be picky, the command is:

    metric weight tos k1 k2 k3 k4 k5

    You are not setting bandwidth, delay, reliability or load directly, you are setting a value between 0 and 255 to plug in to the equation at the relevant bits.

    However, when you redistribute or set the default redistribution metric, then you are actually setting those values.

    MTU is not actually used in the calculation of the EIGRP metric. If you look at the formula which networker posted, you can see that MTU is never referenced. K5 actually effectively turns on or off the final fraction in the equation - if K5 is 0, then K4 is irrelevant, as 0 / anything = 0.
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  • MrXpertMrXpert Member Posts: 586 ■■■□□□□□□□
    When EIGRP was introduced into the IOS, two different engineers worked on development. And this is why the order of K values between metric weights and redistribution is a bit different in terms of order. Bob Ikid and Pasqual Derriere were the guys who did it.
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  • powmiapowmia Users Awaiting Email Confirmation Posts: 322
    MrXpert wrote: »
    When EIGRP was introduced into the IOS, two different engineers worked on development. And this is why the order of K values between metric weights and redistribution is a bit different in terms of order. Bob Ikid and Pasqual Derriere were the guys who did it.

    Did you pull that one out of your Derriere?
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  • MrXpertMrXpert Member Posts: 586 ■■■□□□□□□□
    powmia wrote: »
    Did you pull that one out of your Derriere?

    :) No harm in a nice little story to explain things.
    I'm an Xpert at nothing apart from remembering useless information that nobody else cares about.
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