Task 2.6

Can anyone explaain why we need the next-hop self command on R1 , since R1, R2,R3 all on EIGRP then the next hope will be reachble to R2 and no need to put the command on R1 , what I am missing ?

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  • Can anyone explaain why we need the next-hop self command on R1 , since R1, R2,R3 all on EIGRP then the next hope will be reachble to R2 and no need to put the command on R1 , what I am missing ?

    Hi hamood

     

    Is necessary as in task 2.2 you had to configure variance on EIGRP right... so you can balance traffic with diferent metrics and the result is next hop 164.1.13.3 advertised by R1 is reachable via both frame relay links:

     

    Rack1R2#sh ip ro 164.1.13.3

    Routing entry for 164.1.13.0/24

      Known via "eigrp 100", distance 90, metric 6023936, type internal

      Redistributing via eigrp 100

      Last update from 164.1.12.1 on Serial1/0.12, 03:37:54 ago

      Routing Descriptor Blocks:

      * 164.1.23.3, from 164.1.23.3, 03:37:54 ago, via Serial1/0.23

          Route metric is 6023936, traffic share count is 80

          Total delay is 40000 microseconds, minimum bandwidth is 512 Kbit

          Reliability 255/255, minimum MTU 1500 bytes

          Loading 1/255, Hops 1

        164.1.12.1, from 164.1.12.1, 03:37:54 ago, via Serial1/0.12

          Route metric is 21024000, traffic share count is 23

          Total delay is 40000 microseconds, minimum bandwidth is 128 Kbit

          Reliability 255/255, minimum MTU 1500 bytes

          Loading 1/255, Hops 1

     

    So you need to force the next hop to R2 address (self address that is directly connected to R2) ....more outputs

     

    before:

    Rack1R2#traceroute 116.0.0.1

     

    Type escape sequence to abort.

    Tracing the route to 116.0.0.1

     

      1 164.1.12.1 76 msec

        164.1.23.3 148 msec

        164.1.12.1 224 msec

      2 164.1.0.4 100 msec 4 msec 280 msec

      3 204.12.1.254 224 msec 172 msec 140 msec

      4 172.16.4.1 256 msec *  180 msec

    Rack1R2#

     

    after next-hop-self to R2 in R1:

     

    Rack1R2#sh ip bgp

    BGP table version is 35, local router ID is 150.1.2.2

    Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

                  r RIB-failure, S Stale

    Origin codes: i - IGP, e - EGP, ? - incomplete

     

       Network          Next Hop            Metric LocPrf Weight Path

    *>i28.119.16.0/24   164.1.12.1               0    150      0 100 54 i

    *                   164.1.23.3                             0 100 54 i

    *>i28.119.17.0/24   164.1.12.1               0    150      0 100 54 i

    *                   164.1.23.3                             0 100 54 i

    * i112.0.0.0        164.1.12.1               0    100      0 100 54 50 60 i

    *>                  164.1.23.3                             0 100 54 50 60 i

    * i113.0.0.0        164.1.12.1               0    100      0 100 54 50 60 i

    *>                  164.1.23.3                             0 100 54 50 60 i

    *>i114.0.0.0        164.1.12.1               0    150      0 100 54 i

    *                   164.1.23.3                             0 100 54 i

    *>i115.0.0.0        164.1.12.1               0    150      0 100 54 i

    *                   164.1.23.3                             0 100 54 i

    *>i116.0.0.0        164.1.12.1               0    150      0 100 54 i

    *                   164.1.23.3                             0 100 54 i

    *>i117.0.0.0        164.1.12.1               0    150      0 100 54 i

    *                   164.1.23.3                             0 100 54 i

    *>i118.0.0.0        164.1.12.1               0    150      0 100 54 i

     

    Rack1R2#tra

    Rack1R2#traceroute 116.0.0.1

     

    Type escape sequence to abort.

    Tracing the route to 116.0.0.1

     

      1 164.1.12.1 132 msec 56 msec 104 msec

      2 164.1.13.3 184 msec 160 msec 72 msec

      3 164.1.0.4 260 msec 276 msec 140 msec

      4 204.12.1.254 196 msec 264 msec 308 msec

      5 172.16.4.1 224 msec * 

    Rack1R2#


    Gonzalo
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