Hello Jaime,
you can:
use L3 load balancing features having the two links as equal cost paths in the routing protocol in use or using static routes.
But this cannot guarantee a fair load sharing on the links
there are bundling options :
PPP multilink
FR multilink FRF.16.1
I would suggest PPP multilink
Unfortunately I cannot search in CCO it is not working
Hope to help
Giuseppe
