Re: NMC #2 -> BGP advertise-map

From: Bob Sinclair (bsin@cox.net)
Date: Sat Apr 23 2005 - 22:10:22 GMT-3


Hi Dennis,

You are entirely correct in your understanding of how the BGP advertise-map
operates. The first route-map matches on the prefix(s) to advertise,
conditional on the existence of routes matching the second route-map. In the
update to V6 we changed the target network from 7.7.7.0 to 6.6.6.0 (to match
the originating router number), and this is reflected in the SHOWiT
configuration and tables. However, the task and AK still need to be updated.
Will do asap! Thanks for pointing this out. Sorry if any misunderstanding.

Bob Sinclair
CCIE #10427, CCSI 30427, CISSP
www.netmasterclass.net

  ----- Original Message -----
  From: Dennis J. Hartmann
  To: ccielab@groupstudy.com
  Sent: Friday, April 22, 2005 6:11 PM
  Subject: NMC #2 -> BGP advertise-map

      I'm going through the NMC scenario #2. The scenario is like this....
we
  only want to advertise the 7.7.7.0 network from an external AS to another
  external AS if the router of 5.5.5.0 is lost.

      I'm 99% sure that the configuration below is a mistake because the
  network that we'll advertise is 6.6.6.0, not the 7.7.7.0 the scenario calls
  for. Please let me know if I'm missing something here.

  router bgp 100
   no synchronization
   bgp log-neighbor-changes
   neighbor 172.16.34.4 remote-as 400
   neighbor 172.16.34.4 advertise-map Advertise-if non-exist-map
  If-not-present

  access-list 17 remark ------ If-not-present ---------------------
  access-list 17 permit 5.5.5.0 0.0.0.255
  access-list 18 remark ------ Advertise-if -----------------------
  access-list 18 permit 6.6.6.0 0.0.0.255
  access-list 18 remark -------------------------------------------

  route-map If-not-present permit 10
   match ip address 17

  route-map Advertise-if permit 10
   match ip address 18

  Sincerely,

  Dennis J. Hartmann

  White Pine Communications

  dh8@pobox.com

  CCSI#23402/CCIP/CCNP/CCDP/CCNA/CCDA

  Cisco IP Voice Support & Design Specialist

  Cisco Optical, VPN & IDS Specialist

  MCSE

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