Does anyone have some idea on how to make sure the outbound/inbound route along the same path when connecting to 2 different ISPs?
Thanks and Regards,
Be aware that ISP provisions asymmetric traffic flows (when outbound traffic goes out one link and returns via a different link). This is the internet norm.
In your local router connected to your upstream ISP, you can turn on CEF and apply "ip verify unicast reverse-path" in the incoming interface. Take note that this will or may drop packets that the best return path is not the inbound path.