I am getting full internet route from ISP-1 and getting just a default route from ISP-2. ( Both ISP connection is terminated on the one central site router.) What i am trying to do , to make an ISP-2 connection is completly backup for inbound traffic. To achieve that ,i am trying to use BGP conditional advertisemet configuration. I have got a problem with NON-EXIST route map's access-list. In the NON-EXIST router map i am using the commands which is written below ;
ip as-path access-list 1 permit ^200 !!! (ISP-1 AS number) !!!
access-list 65 permit any !!! (permit any packet from ISP-2) !!!
route-map NON-EXIST permit 10 !!! (this matches any route from AS200) !!!
match ip address 65
match as-path 1
router bgp 10 !!! (My AS number) !!!
neighbor X.Y.Z.W (ISP-2 ip address) advertise-map ADVERTISE non-exist-map NON-EXIST !!! (What is says. This router will only advertise "networks defined in the route-map named ADVERTISE" if and only if "routes that are defined in the route-map named NON-EXISTS" do not appear in the BGP routing table.) !!!
with this configuration when the ISP-1 connection is up , my router still adversite my subnet to the ISP-2. What should i write in the access-list 65 to not advertise my subnet to the ISP-2 until the failure of ISP-1 connection ? ( As i said , i am getting the full internet table from ISP-1.)