From: John Matijevic (matijevi@bellsouth.net)
Date: Fri Jun 13 2003 - 13:06:19 GMT-3
OK I got it, first I understood the 1 and 0 which means weather to use the
value or not, next if you enter a value higher than one than it will
multiply the k value by the number you specify. Now on to my dialer watch
issue.
Thanks for everybody help on this.
Sincerely,
Matijevic
----- Original Message -----
From: "Brent D. Stewart" <brent@stewart.hickory.nc.us>
To: "John Matijevic" <matijevi@bellsouth.net>; "Biondino, Joseph"
<joseph.biondino@au.unisys.com>; <ccielab@groupstudy.com>
Sent: Friday, June 13, 2003 9:55 AM
Subject: RE: eigrp and metric
I'm paraphrasing a post I made a few weeks ago here:
****
For an excellent discussion of this, refer to Alvaro Retana's book
"EIGRP for IP".
EIGRP builds a metric using the equation:
Metric= (k1*bw + k2*bw/(256-load) + k3*delay) (k5/(reliability+k4)
By default, k1=1, k2=0, k3=1, k4=0, k5=0 and k2, k4, and k5 really
shouldn't ever be changed. K1 and k3 are very seldom changed. If k5=0,
the last part is ignored, so this reduces to:
Metric= bw + delay
Each of these deserves a discussion.
"bw" is actually 10^7/min(bw). In other words, the bw part uses the
slowest link along the path and is inversely proportional to 1 million.
"delay" is an accumulation of all interface delays along the path.
Load and reliability should not be included in the calculation (by
changing k values) because EIGRP does not send out updates if they
change. MTU isn't even an option, but the idea was that it might be
used for minimum MTU discovery along a path. As far as I know, this was
never implemented.
EIGRP actually also tracks hops. The default max is 100. EIGRP doesn't
use this in the metric, it's there as a loop-detection mechanism.
****
Your other question was - "what does it mean that the k values convert
the EIGRP vector into a scalar quantity?" A vector is a variable
composing multiple values - for instance, a car travels along a vector
because it has a "northerly" speed component and an "easterly" speed
component. What we call "speed" is a scalar, a single quantity (in this
case equal to the hypotenuse of the NS and EW values).
-----Original Message-----
From: John Matijevic [mailto:matijevi@bellsouth.net]
Sent: Thursday, June 12, 2003 10:04 PM
To: Biondino, Joseph; ccielab@groupstudy.com
Subject: Re: eigrp and metric
Joseph,
So if you change the value other than one on K1 for example, then how
does
that fit in to the equation? How does eigrp come up with the new metric,
does it multiply the factor lets say bandwidth 2000 and you specify 5=k,
does it mulitply, divide, etc.?
because you can set up to 0-4294967295.
Sincerely,
Matijevic
----- Original Message -----
From: "Biondino, Joseph" <joseph.biondino@au.unisys.com>
To: "John Matijevic" <matijevi@bellsouth.net>; <ccielab@groupstudy.com>
Sent: Thursday, June 12, 2003 9:31 PM
Subject: RE: eigrp and metric
> John;
>
> My understanding is that K1 - K5 actually stanges for each of the
possible
> Metrics used by EIGRP.
> Only K1 and K3 equal 1 the others equal zero. This is why Bandwidth
and
> Delay are the only metrics used by EIGRP by default. If you change the
other
> K values for 0 to 1 the other variables Load, rely and MTU come into
play.
>
> Kind regards,
>
> Joseph Biondino
> Network Specialist
> UNISYS
> Network Command Centre
>
> 115 - 117 Wicks Rd
> North Ryde NSW 2113
> Phone: 02 9857 3149
> Group: 02 9390 1107
> Fax: 02 9857 3122
>
> -----Original Message-----
> From: John Matijevic [mailto:matijevi@bellsouth.net]
> Sent: Friday, 13 June 2003 9:56 AM
> To: ccielab@groupstudy.com
> Subject: eigrp and metric
>
> Hello Team,
> I am currently studying the commands in the ios guide. And I have come
> across
> the following:
> metric weights tos k1 k2 k3 k4 k5, tos
> Type of service. Currently, it must always be zero.
>
> k1-k5
> Constants that convert an IGRP or enhanced IGRP metric vector into a
scalar
> quantity
>
> basically this command is to tune the metric calculation for eigrp.
Question
> what is meant by convert an eigrp metric vector into a scalar
quantity?
> Maybe
> this should be a question for the eigrp developer, but I just want to
> understand why you would want to change the eigrp metric formula? I
know
> that
> the offset command can increase the metric after calculation. It seems
that
> this is another way to change the metrics? Any insight greatly
appreciated.
> Sincerely,
> Matijevic
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