From: Chris Larson (clarson52@comcast.net)
Date: Mon Dec 01 2003 - 22:56:24 GMT-3
Sorry, I thought you just wanted to know about modifying the metric
weights.... which is done by changing the k values. I did not realize you
needed to know how the metric is actually calculated. Which despite all the
fancy formula really only uses bandwidth and delay.
In lab scenarios, you probably won't need any of that. You will probably
just need to know how to modify the K values and which K does what.
----- Original Message -----
From: "Stuart Reabow" <stuartbr@hotmail.com>
To: "'Chris'" <clarson52@comcast.net>; <ccielab@groupstudy.com>
Sent: Monday, December 01, 2003 4:51 PM
Subject: RE: EIGRP Weights
Thanks,
I've just managed to find the details below :
If k5 equals 0, the composite IGRP or Enhanced IGRP 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 done:
metric = metric * [k5 / (reliability + k4)]
Bandwidth is inverse minimum bandwidth of the path in bits per second scaled
by a factor of 2.56 % 1012. The range is from a 1200-bps line to 10 terabits
per second.
Delay is in units of 10 microseconds. This gives a range of 10 microseconds
to 168 seconds. A delay of all ones indicates that the network is
unreachable.
The delay parameter is stored in a 32-bit field, in increments of 39.1
nanoseconds. This gives a range of 1 (39.1 nanoseconds) to hexadecimal
FFFFFFFF (decimal 4,294,967,040 nanoseconds). A delay of all ones (that is,
a delay of hexadecimal FFFFFFFF) indicates that the network is unreachable.
Table 30 lists the default values used for several common media.
Table 30 Bandwidth Values by Media Type
Media Type Delay Bandwidth
Satellite 5120 (2 seconds) 5120 (500 Mbits)
Ethernet 25600 (1 milliseconds [ms]) 256000 (10 Mbits)
1.544 Mbps 512000 (20,000 ms) 1,657,856 bits
64 kbps 512000 (20,000 ms) 40,000,000 bits
56 kbps 512000 (20,000 ms) 45,714,176 bits
10 kbps 512000 (20,000 ms) 256,000,000 bits
1 kbps 512000 (20,000 ms) 2,560,000,000 bits
Reliability is given as a fraction of 255. That is, 255 is 100 percent
reliability or a perfectly stable link.
Load is given as a fraction of 255. A load of 255 indicates a completely
saturated link.
-----Original Message-----
From: Chris [mailto:clarson52@comcast.net]
Sent: 01 December 2003 20:52
To: Stuart Reabow; ccielab@groupstudy.com
Subject: Re: EIGRP Weights
Under eigrp you issue the metric weights command. TOS will be 0 and then it
will be in order k1 k2 k3 k4 k5 values. The default is K1 = 1 and K3 = 1
I remeber them using bldg and rm as in building # room #
k1, k2, k3, k4, k5
B andwidth, L oad, D elay, R eliability, Mtu
BLDg RM
----- Original Message -----
From: "Stuart Reabow" <stuartbr@hotmail.com>
To: <ccielab@groupstudy.com>
Sent: Monday, December 01, 2003 3:15 PM
Subject: EIGRP Weights
> Hi,
>
> Does anyone have any docs on modifying the EIGRP metric weights? I can't
> find any details on the Cisco site.
>
> Thanks
>
> Stuart
>
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