bridging

hi, i have routerboard 2011, i have 2 adsl lines connected to 2 tplink adsl routers one for each line, how can I connect (and merge/or bridge) those 2 Ethernet (coming from tplink routers) (routerboard input), and give one ethernet interface (line1 speed+line2 speed) as output.
thanks

This is not a job for a bridge. As I understand it you want Dual WAN :

http://aacable.wordpress.com/2011/07/27/mikrotik-dual-wan-load-balancing-using-pcc-method-complete-script-by-zaib/

@Cybertod good and working load balancing.
+1