[c-nsp] Two routers with Single ISP Scenario

[shadow floating]

HI all,
I've one of my customers who wants to stick to single ISP but wants to
implement the full redundancy (no single point of failure) network
scenario, is there a way to connect to 2 routers internet facing with
in an active/standby fashion to a single ISP with a single IP range?
thanks a lot all
I really appreciate your great advice

regards,
nad