Volumn II Lab 9 task 2.5

In the solution guide, under SW1's RIP process, it has "distance 171 0.0.0.0 255.255.255.255 RIP_AD" statement.  I don't have that confiigure but still have full reachability.  So I don't understand the purpose of that statement other than forcing SW1 to reach those subnet in the RIP_AD access-list using R5 via EIGRP instead of via SW4 via RIP.  Please explain.  Thank you very much.

Comments

  • JoeMJoeM ✭✭✭

    Hi HeavyD,

    This was a tricky redistribution, because there is an overlapping routing domain (RIP existing with EIGRP).  The AD change is a partial solution to complete the last two bullet-points.

     

    Here are a couple of really good threads about this in the sub-forum for Lab 9.   

    Forum >>  Workbook-2 version 5 >>  Lab 9   >>  Task 2.5 IGP Redistribution



    Forum >>  Workbook-2 version 5 >>  Lab 9   >>   re: 2.5 IGP Redistribution

     

     

    Here is a good summary from BenGood24 in the first thread:

    "Without modifying the AD to 171 to make the routes preferred via EIGRP,
    they will get advertised to BB3 with whatever RIP metric they learned
    from SW4. This in conjuction with the metric 15 redistribution from
    EIGRP fulfills the last bullet point."

  • Oh OK I got it now...tricky tricky.  So the metric 15 statements only affect whatever in the EIGRP routing table.  And the EIGRP routing table do not have the routes indicated in the access-list due to them being AD 170 and the ones from SW4 are AD 120.  So the AD 171 statement is to cancel out the routes from SW4 thus allow them to be in EIGRP in SW1.

  • JoeMJoeM ✭✭✭

    Yes, it allows the routes to be in EIGRP.  So then, we can redistribute them back into RIP with the metric.  This is all because we are not allowed to use  offset-list.

    router rip
          redistribute eigrp 100 metric 15

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