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Forum Replies

  1. Rene,

    You explain everything so clearly and everything look so simple.

    Thank you so much.

  2. Thank you so much for this clear explanation

  3. Hi Francesco,

    EIGRP will store all the possible paths in its topology table, between the brackets it stores the FD (feasible distance) and AD (advertised distance). For example:


    156160 = feasible distance
    128256 = advertised distance

    Sometimes they use “computed distance” to refer to feasible distance and “reported” distance to refer to the advertised distance.

    In the topology table you will find at least 1 successor and possible some feasible successors. To become a feasible successor, its AD has to be lower than the FD of the successor.

    Hope this helps!


  4. Hi Rene,

    How does EIGRP come up with the local metric for the interface it’s using to reach the destination network? And where can we see it. Thank you

  5. Hi Victor,

    EIGRP uses this formula to calculate the metric:

    Here is an example of a directly connected gigabit interface with a network that is advertised in EIGRP:

    R1#show ip eigrp topology
    EIGRP-IPv4 Topology Entry for AS(1)/ID( for
      State is Passive, Query origin flag is 1, 1 Successor(s), FD is 2816
      Descriptor Blocks: (GigabitEthernet0/1), from Connected, Send flag is 0x0
          Composite metric is (2816/0), route is Internal
          Vector metric:
            Minimum bandwidth is 1000000 Kbit
            Total delay is 10 microseconds
            Reliability is 255/255
            Load is 1/255
            Minimum MTU is 1500
            Hop count is 0
            Originating router is

    You can see the metrics that are used for the formula (bandwidth and delay by default) and the FD which is 2816.


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