shutdown BGP neighbor

[Aoi]

Hi
I have a very simple network topology with BGP configured on three routers.
What i am trying to do and need help is how i can shutdown BGP neighbors when a specific route is unreachable.

Basically I am trying to ping R1 from R2 and if it fails, R3 will be removed from the BGP peer.
IP SLA was an idea but not sure how to accomplish this.

R1-----R2-----R3

Thanks

[Flavio Miranda]

Hi @Aoi 

 shutdown a neighbor because one route is unreachable  seems to be too much.  If you have alternative path for that route what you can do is create a static route with higher Administrative distance and change the AD using the IPSLA as trigger.

[MHM Cisco World]

R1-ebgp-R2-ebgp-R3 <<- this your network ?

[Aoi]

@MHM Cisco World 
Thank you. Yes that is how it's set up.

[MHM Cisco World]

ebgp have direct link check, what that meaning, when the link between R1 and R3 is down R3 automatic will remove since it eBGP
NOW there is some limitation in this check which is if there is SW between R1 and R3 then the link not down but the reachable loss.
solve this there is 
1- track IP SLA with EEM 
even track status down EEM cli no neighbor R3
2-using multihop BFD or single hop BFD