Route Backup line

Hi how are you Dear Friends

I have 2 link from different internet provider that hast 2 range ip

for example link a : 208.122.20.0

link b :98.25.20.0

i want Config ip route if once of link is down The valid ip this link can route from other link

if link 98.25.20.0 is down these ip can route and work from link 208.122.20.0

Thanks a lot

so simply addone more default gateway with greater distance and set ‘check-gateway’ option on both routes