BGP Conditional Advertising / Advertise MAP

Hello Rene
Please update the lesson on BGP Conditional Advertising / Advertise MAP.
If already in the lesson list, Please share the URL/Link.


Hello Raj

As far as I know, there is no material yet on BGP conditional advertising. If you would like to suggest a lesson idea, feel free to go to the following link and post your idea. Others on the forum may have also suggested a similar lesson, and you can vote on the lessons you would like to see on the site in the near future.

In the meantime, take a look at these two Cisco documentations that may help you in looking at this particular feature.

As well as some case studies that may help…

I hope this has been helpful!


Hi raj,
the whole idea of Conditional advertising you could easly find the materials online.

it is used to play a role in multihomed architecture where you will only advertise routes to 1 ISP, if the link faills then the router sees the link down and immediately change to advertise the routes to the 2nd ISP.

you achieve this behavior using route-map and you inherit the route-map into the advertise-map in the bgp command options

for example:

access-list 1 permit host
access-list 2 permit any    -    this command is only an example 

route-map NEIGHBOR1 permit 10
  match ip address 1

route-map MYROUTES permit 10
  match ip address 2

router bgp 1
  neighbor advertise-map MYROUTES non-exist-map NEIGHBOR1 

in the above configuration, the router will check it’s RIB (routing table) and search the host route of as included in the NEIGHBOR1 route-map.

the “non-exist-map” feature will make that process and if the route doesnt exist, the router would advertise neighbor the “MYROUTES” routes included in that route-map.

you could specify any network you want to advertise or in this case I want to advertise everything to neighbor

if the non-exist-map find the route for host then the router wouldn’t advertise anything that included in the “MYROUTES” route-map to neighbor

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