FD Calculation

Have a question or want to start a discussion? Post it! No Registration Necessary.  Now with pictures!

Threaded View
Many thanks to all those who respond.

OK here is the scenario; focus on network

router#sh ip eigrp top
IP-EIGRP Topology Table for AS(1)/ID(

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

P, 1 successors, FD is 1761792
         via Connected, Serial0/1
P, 1 successors, FD is 2169856
         via Connected, Serial0/0
P, 1 successors, FD is 2169856
         via Summary (2169856/0), Null0
P, 1 successors, FD is 1761792
         via (1761792/28160), Serial0/1


Router#sh ip eigrp top
IP-EIGRP topology entry for
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is
  Routing Descriptor Blocks: (Serial0/1), from, Send flag is 0x0
      Composite metric is (1761792/28160), Route is Internal
      Vector metric:
        Minimum bandwidth is 2048 Kbit
        Total delay is 20000 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1

The FD is 1761792 the AD is a direct link into that network so this is
just one link!

BW + Delay does NOT = the FD

10,000,000 / 2048 *256 = BW part of the metric

20000 * 256 = delay part of metric

add the two and you should have your metric, do i then add the AD as
 I've tried a few combinations but no luck reaching that figure.


Re: FD Calculation
stropiter wrote:
Quoted text here. Click to load it

Almost. remember where the metrics come from. They are eigrp metrics, scaled by
256. I am not 100% certain if the individual parts of the metric are scaled, or
if the final is scaled.

try again, using:

INT(10,000,000 / 2048) *256 = BW part of the metric

Item    Value    igrp    eigrp
Band    2048    4882    1249792
Delay    20000    2000    512000
Total        6882    1761792
Paul Matthews                          

Site Timeline