RFC 7868, "Cisco's Enhanced Interior Gateway Routing Protocol (EIGRP)", May 2016

Errata ID: 6084
Status: Reported
Type: Technical
Publication Format(s) : TEXT
Reported By: Rafał Cygnarowski
Date Reported: 2020-04-10

Section 5.6.2.3. says:

   The formula for the conversion for Max-Throughput value directly from
   the interface without consideration of congestion-based effects is as
   follows:

                                  (EIGRP_BANDWIDTH * EIGRP_WIDE_SCALE)
        Max-Throughput = K1 *     ------------------------------------
                                       Interface Bandwidth (kbps)


   If K2 is used, the effect of congestion as a measure of load reported
   by the interface will be used to simulate the "available Throughput"
   by adjusting the maximum Throughput according to the formula:

                                           K2 * Max-Throughput
        Net-Throughput = Max-Throughput + ---------------------
                                              256 - Load

It should say:

   The formula for the conversion for Max-Throughput value directly from
   the interface without consideration of congestion-based effects is as
   follows:

                           EIGRP_BANDWIDTH * EIGRP_WIDE_SCALE
        Max-Throughput =  ------------------------------------
                               Interface Bandwidth (kbps)


   If K2 is used, the effect of congestion as a measure of load reported
   by the interface will be used to simulate the "available Throughput"
   by adjusting the maximum Throughput according to the formula:

                                                K2 * Max-Throughput
        Net-Throughput = K1 * Max-Throughput + ---------------------
                                                     256 - Load

Notes:

K1 can't be a part of Max-Throughput as it affects Net-Throughput twice. Moreover: in case of K1=0, K2 become ignored as it will be multiplied by 0.

Together with errata ID: 5242 which fixes metric formula {metric =[Net-Throughput+Latency+(K6*ExtAttr)] * K5/(K4+Rel) }, results become correct and are same as on live equipment.

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