BGP Lab 12

Topology used is over here: http://mellowd.co.uk/ccie/?p=243

BGP Lab 12:

  • AS7, AS9 and AS11 are all customers of ISP1
  • AS7 has it’s own address space – 77.48.16.0/24 advertised via a loopback
  • ISP1 owns the address space 180.16.0.0/16
  • AS9 has been assigned 180.16.9.0/24 from ISP1 – insert via loopback
  • AS11 has been assigned 180.16.11.0/24 from ISP1 – insert via loopback
  • Ensure that AS7′s address space is advertised to AS9 and AS11
  • ISP1 needs to advertise the entire 180.16.0.0/16 range and not the more specific routes. Ensure AS7 sees only 180.16.0.0/16 HOWEVER it must still know that some routes have come from AS9 and AS11
  • On AS9, configure an attribute so that ISP1 does not advertise the more specific 180.16.9.0/24 address to anyone.
  • You should notice that ISP1 is now not advertising the aggregate because it has inherited the no-export community from above
  • Now on ISP1, ensure that the community is changed so that the aggregate can be advertised again

Click on the thumbnail for the full size topology:

BGP 12 150x150 BGP Lab 12

Leave a Reply