I have configured DSL PPPoE with WAN IP 18.104.22.168/32 and routed a subnet
22.214.171.124/24 (on my BRAS router). Same Pool has been routed towards ISDN as
backup (on my DIST router). The problem occurs when PPPoE goes down, routing
entry dose not take backup ISDN path. The reason behind is that my BRAS gets
next hop WAN pool 126.96.36.199/24 from Core router i.e. towards Null0 for BGP advertisment
Kindly suggest me the changes to overcome this problem. Also see attached
Diagram for better understanding.