dual routing

hi. i am running a mikrotik 750 with pppoe to a adsl modem of my isp to provide internet access to my LAN.
there is also a second router that i would like to add it on the mikrotik just in case the first one fails to have internet access.
the second router works with NAT now, but it can act as modem only and get the pppoe in mikrotik as well.
both services are from different providers.

You need VRRP

hi. thanks a lot for the reply. may i have some honts where to look at or how to implement it, please?