show ip eigrp topology

indicates:

Successor

Feasible Successor

Possible Successor?

 

 

I thought the last successor is handled by:

show ip eigrp topology all-links

 

 

 

The source:

 

EIGRP Troubleshooting

BRKRST-3330

 

http://andrei.clubcisco.ro/cursuri/4prc/troubleshooting/BRKRST-3330.pdf

 

Page 60:

 

Contrary to popular belief, the topology table also contains routes which

are not feasible; these are called possible successors and may be

promoted to feasible successors, or even successors if the topology of the

network were to change

 

 

 

Comments

  • Not sure what it is you are asking but the command " show ip eigrp topology all-links" will show all eigrp advertisments learnt. This includes advertisments that have failed eigrp's loop prevention (if AD is greater than FD of successor).

    The show ip eigrp top will only show Successors and Feasible Successors but NOT advertisments that have a greater AD than the FD of the successor.

  • JoeMJoeM ✭✭✭

    Hi Sakamoto,

    I am not sure what your quesion is. 

    If a route is not a successor or feasible successor, it is because of the following.

    1. It is not a best route (even with added Variance)
    2. It did not pass the Feasibility Condition

     

    All routes are still in the topology table. However, although the name does make sense, I must admit that I did not know they were called a possible successor(s).

  • Hi Sakamoto,

    The feasible successor routes are back up routes that have possibility of being the successor route in the case of failure of primary route. So, you can say it possible successor route as well.  The "all-link" option shows the feasible successor routes including active or passive state in the EIGRP topology table.

    HTH

  •  

    Thanks, guys.

     

    Contrary to popular belief, the topology table also contains routes which

    are not feasible; these are called possible successors and may be

    promoted to feasible successors, or even successors if the topology of the

    network were to change

     

    I presume the above indicates:

    there are three successors.

     

    Successor

    Feasible successor

    Possible successor

     

    The first and the second,

    we can watch them by

    show ip eigrp topology.

     

    The last one by all links.

     

     

    I have second thought the above Contrary to popular belief,

    but my understanding might not be mistaken.

     

  • JoeMJoeM ✭✭✭

    The so-called possible successors will NOT be promoted to feasible successors -- until a query process is done.

    The difference is the ability to immediately use the routes....

    FEASIBLE Successors will automatically replace the SUCCESSOR routes if needed.  Otherwise a QUERY is needed.

     

    The "possible successor" could be a possible loop -- because it did not pass the "feasibilty condition".

     

  •  

    JoeM,

     

    Thanks.

    I began to realize the meaning of Enhanced.

     

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