BGP Lab 12

Topology used is over here:

BGP Lab 12:

  • AS7, AS9 and AS11 are all customers of ISP1
  • AS7 has it’s own address space – advertised via a loopback
  • ISP1 owns the address space
  • AS9 has been assigned from ISP1 – insert via loopback
  • AS11 has been assigned from ISP1 – insert via loopback
  • Ensure that AS7’s address space is advertised to AS9 and AS11
  • ISP1 needs to advertise the entire range and not the more specific routes. Ensure AS7 sees only 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 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

Published by


Network Architect. Dual CCIE and JNCIE-SP.

Leave a Reply