9.24 Summary of BGP

Can anyone explain to me why a /60 will not work? although they do match up.

 


  16  +   3 2   + 48   
+ 12 = 60

2003 : 0001 : 0000 : 00000000 0000 1011= 11 /61

  16    +  
32 +  48   + 12 = 60

2003 : 0001 : 0000 : 00000000 0000 0001= 1 /64

 

 

Thanks

Comments

  • got it.... forgot abut hex and decimal... argg..

  • I'm feeling stupid but I don't get why in the wb they use /59 and not /60
    00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    16 32 48 64 80 96 112 128

    00000000 00000001
    00000000 00001011
    00000000 0000---- -> /60
    tasks say I need to summarize this:

     

      network 2003:1:0:1::/64
      network 2003:1:0:10::/61

     

    thanks

     

  • uhhh.. I got it..

    (and there's the explanation in the wb)..

    11 it's in HEX and therefore it's 17 in decimal and 10001 in binary..

    therefore I need a /59 for summarizing.

     

  • When it comes to 9.24 I have one question regarding solution :

     

    On R1 we set loopbacks 101 and 102

    ipv6 add 2003:1:0:1::1/64

    ipv6 add 2003:1:0:11::11/61           <----- is this correct ?

     

    Now in router bgp 100 we advertise them :

    address-family ipv6 unicast

    network ipv6 add 2003:1:0:1::/64

    network ipv6 add 2003:1:0:10::/61      <--- is this typo or I'm missing here something ?

     

  • ipv6 add 2003:1:0:11::11/61           <----- is this correct ?

    Yes. It required by the task.

     

    network ipv6 add 2003:1:0:10::/61      <--- is this typo or I'm missing here something ?

    The ipv6 add 2003:1:0:11::11/61 command results in network address of 2003:1:0:10::11/61. The mask is 61, so the first 60 bits matched are 2003:0001:0000:001. The remaining bit matches the first bit in the hex 1 of the 11 (0001). So the result is 2003:1:0:10::11/61 which is a supernet of networks 2003:1:0:10::/64 through 2003:1:0:17::/64 . An anlogy of this in IPv4 is ip address 192.1.2.1 255.255.252.0  resulting in network address of 192.168.0.0/22 which includes 192.168.2.0/24.

     

    HTH,

    Bassam

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